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The Medical student Review

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    The Medical student Review (OP)


    I don't know how many med students there are on board, or how useful this review will be for you.. I am a firm believer in slow and consistent than an intellectual enema two days before the exam where once released never again to be regained.. So what I plan to do here, is share some things I feel are important..

    In my pre-clinical years, I was president of the pharmacology club, and I enjoyed teaching it and exchanging ideas with others.. so if you have your own forte, quirks mnemonics that you'd like to share we can make a useful compendium..

    I am only going to focus here on pharmacology and diagnostic testings.. so every day I'll give you five of each..

    I am not going to start in any particular order but once in a section, I plan to complete it.. this will be just the high yield..


    __________________________________________________ ___________

    Oncology diagnostic testing
    _____________
    AFP (what disease is associated with it, and when do you answer this for a question?)
    AFP is associated with the development of
    1-hepatocellular ca.
    2-ovarian cancer
    3-non-seminomatous germ cell tumors
    Answer AFP when you see a patient with alcoholic cirrhosis or chronic hepatitis B or V. AFP together with radiological imaging is used to screen for hepatocellular ca

    ____________________________________________
    CEA
    1-A protein elevated in a variety of cancers including colorectal cancer
    2-serum CEA have a prognostic value in pts with newely diagnosed CRC. Those with higher levels have worse prognosis.
    3-CEA level to monitor in colon cancer in pts after a surgical resection, it determines the presence of persistent, recurrent or metastatic disease

    __________________________________________________ ___________
    Colposcopy
    Colposcopy is the direct visualization of the cervix, by use of a magnifying scope with a lamp
    2-The transition zone must be visualized to ensure an adequate colposcopy. The border between squamous and columnar epithelium
    3-a colposcopy is the answer for a pt with an abnromal pap
    Atypical squams can't exclude high grade lesion ASC-II
    low grade squamous intraepithelial lesions LSIL
    high grade intraepithelial lesions HSIL
    Atypical sqams of undetermined significance ASCUS if HPV DNA testing is positive
    __________________________________________________ ___________
    Estrogen and progesterone receptors
    Should be done on all pts with breast cancer, in order to determine who should receive hormone therapy
    2-Therapy with either tamoxifen or raloxifene should be added to any pt. with positive receptors. This is either for estrogen or progesterone positivity alone or in combination. The response to tamoxifen is better if both receptors are positive
    __________________________________________________ ____
    Mammogram
    screening should begin at age 40 and should be performed every 1~2 years, screening at age 50 should be yearly
    2-when mammogram shows abnormalities, a core biopsy including sentinel lymph node biopsy is the next best step. carcinomas of the breast are associated with clustered polymorphic microcalcifications.
    3-screening lowers mortality most after age 50 and the dec is greater than that of a colonscopy or a pap smear
    __________________________________________________ ________________

    Now pharm
    _____________

    will start with infectious disease because it is the longest chunk
    Acyclovir/valcyclovir/famiciclovir

    all the above are the correct answer for
    Herpes simplex including, genital, cutaneous, orolabial
    for Herpes Encephalitis (acyclovir) IV form only in a hospital setting
    Varicella zoster
    shingles: Herpes zoster or reactivation
    Bell's palsy

    the above meds work by inhibition of thymidine kinase
    -most common adverse effects are nephrotoxicity presumably from precipitation of the meds in the kidney tubule, sx of neurological toxicity in the kidney tubule, sx of neurological tox, such as confusion, tremors and hallucination occur rarely
    __________________________________________________ __
    Rifaximin
    used to treat travelers' diarrhea such as that from E.coli, it isn't used for invasive diarrhea. an associated fever and bloody diarrhea indicate and invasive pathogen, such as campylobacter. When fever and bloody diarrhea are described, ciprofloxacin is the best answer.

    rifa is a nonabsorbed version of the rifamycin antibiotic, it inhibits ribosomal RNA production of essential proteins
    There are no major side effects since it isn't absorbed from the GI tract. it doesn't cause C.Diff, and may in fact treat it.
    _________________________________________________
    Daptomycin and Linezolid

    they are both used for gram +ve organisms such as MRSA, streptococci and vanc resistant enterococci. Linezolid is the only oral antibiotic for MRSA. They can both be used for Vanc resistant organisms .

    Liezolid is an oxazolidinone and inhibits protein synthesis at the ribosome. Daptomycin is a cyclic lipopeptide and disrupts cell membrane they are both unique classes of drugs

    Linezolid commonly causes thrombocytopenia, and is a MAO inhibitor, avoid tyramine foods. Dapto caused CPK on liver functiion tests to be elevated!!
    __________________________________________________ _____________
    Tigecycline
    an extremely broad spectrum anti-biotic that covrers MRSA, staph aureus, and well as gram negative bacilli. Tigecycline is the answer for complicated hospital of ICU acquired infections, tigecycline alone is equivalent to vanc and aztreonam in combination, it is also active against resistant enterococci and PCN resistant penumococcus

    tigecycline is a glyclycyline antibiotic that binds to the ribosome and inhibits protein synthesis, it is unique that it covers staph, strep, gram negatives, anerobes and organisms resistant to vanc
    tigecycline is hepatotoxic , caused nausea and diarrhea
    __________________________________________________ ________

    Polymyxin B (PMB) and colistin
    useful for conjunctivitis, infections of the skin, and otitis externa, also correct for multi drug resistant gram negative bacilli, that cause ventilator associated pneumonia and sepsis from pseudomonas or acinetobacter.

    works by disrupting phospholipids in the cell wall membrane
    Polymyxin B (PMB) and colistin are very toxic to the kidney and nerves and is limited to topical applications of the skin and ear, they are also used for multi drug resistant gram negative bacilli when there are no other therapeutic options..

    __________________________________________________ ______
    That is it for today..
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

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    format_quote Originally Posted by Light of Heaven View Post


    Sis I'm taking Organic Chemistry and Genetics, would that be a smart move to do at the same time? And will these notes help me in them?

    sister

    with all honesty organic chemistry was my downfall in undergrad, not even calculus I, and II were as bad as ochem -- sob7an Allah those who got it got it, but I wasn't one of them.. I had to drop it first time I took it and when I finally passed it, it was barely by the skin of my teeth, I was just so glad to have it behind me considering there were two courses of O.chem, and my happiness was short lived with one, on how I was to get by in the other..

    my advise is to get a tutor early on, the first couple of chapters are deceptively simple but you can fall behind fast.. nothing on this thread pertains at all to O.chem.. maybe a few things on genetics, but undergrad is about understanding how things work together, graduate school is about their relevance to the real world, you can't get to one level without having completed the other as your knowledge base to build upon..

    Now your experience might be completely different than mine -- I think if anything you should get out of this thread is to do at least just a little bit every day and not let it build up...genetics was fairly easy, it takes dedication so it is up to you.. the problem isn't with genetics it is with O.chem.. can you manage your time wisely or should you dedicate yourself to the difficult course get it behind you and take genetics later? only you are the best judge of your time and your ability..

    and Allah swt knows best

    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review



    Wow that sounds tough. JazakAllah Khair sis. InshaAllah I'll try my best.
    The Medical student Review

    *Without Allah, without Islam, life would be meaningless. If I've ever learned patience, it's because of this. Alhamdulillah...*

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    Re: The Medical student Review

    a few skin conditions and later will go over dermatological pathology in common diseases of infants...

    erythrasma 39806 lg - The Medical student Review


    Erythrasma is a long-term bacterial infection that usually appears in the area between overlapping skin (skin folds).
    Caused by a bacteria Corynebacterium minutissimum.
    Erythrasma is more common in warm climates. in diabetics
    appears link a ring worm infection but it isn't examine under woodslamp.. coral red because of coroporyphyrin III in the stratum corneum


    fot3 peq - The Medical student Review


    inverse Psoriasis--Inverse psoriasis is an unusual type of psoriasis that occurs in skin folds. These patches look different than other types of psoriasis. They are usually smooth, deep red, and glistening without any scale

    1intertrigo3 - The Medical student Review

    intertrigo refers to an inflammation of the body folds. This is usually located in the inner thighs, armpits, and underside of the breasts or belly. It is a form of contact dermatitis.


    22320084 1 - The Medical student Review

    Seborrheic dermatitis is a papulosquamous disorder patterned on the sebum-rich areas of the scalp, face, and trunk. In addition to sebum, this dermatitis is linked to Malassezia, immunologic abnormalities.. when resistant to treatment think pt with undiagnosed HIV.
    Last edited by جوري; 07-03-2009 at 03:46 AM.
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    corresponding coronary arteries that supply regions of the heart
    1- inferior wall st segment elevation in leads II, III, and AVF= right coronary artery
    2- posterior wall (tall broad R waves in V1, V2, ST depression; and tall, upright T waves in V1, V2, V3) =posterior descending artery
    3-Anteroseptal wall ( ST elevation from V1-V3) left anterior descending artery
    4- Anterior wall (ST elevation V2-V4)= left anterior descending artery
    5-Lateral wall ST elevation in I, AVL, V4, V6) circumflex artery

    em 0028 - The Medical student Review
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    a Hodge bodge of review notes I know, but many are either high yields or areas that have caused me personal difficulty so for the sake of the greater good ...

    a young woman presenting with nausea, diarrhea, abdominal cramps, vomiting for at least two weeks, her other hx is noncontributory, she does drink 'socially' has mild lower abdominal tenderness and these are her lab results

    sodium 136/meq
    potassium 3.0/meq
    chloride 116/meq
    bicarbonate 10/meq
    BUN 16
    cr 0.9m/dl
    glucose 90
    urinary sodium 12
    urinary potassium 10
    urinary chloride 110

    the cause of her metabolic acidosis is?
    diarrhea

    because:

    the patient has a non anionic gap metabolic acidosis
    you calculate the anion gap as such :

    (Na+ + K+) - (cl- +HCO3-) in this case gives us = 13 the normal value is (10-12)
    anyhow,
    the two most important factors of non-anionic gap metabolic acidosis are diarrhea where there is loss of bicarbonate in the stool and renal tubular acidosis (there are four) in which there is an inability to excrete sufficient amounts of hydrogen in the urine . the best way to differentiate between the two is to calculate the hydrogen ion excretion in the urine .. one expects hydrogen ion excretion in the urine to be high in diarrhea because the kidney attempts to get rid of excessive acid load -- and it will be low in RTA.
    urinary hydrogen concentration is calculated as such: H+ = Cl- (K+ + Na+)
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    covering the topic of nephrology today:



    figure out what kidney is failing?
    ______________

    your approach:

    renal failure has three main causes
    pre-renal azotemia .. kidney not to function not because the problem is in the kidney rather in the circulation.

    the second is intra-renal azotemia, or intrinsic renal disease--
    and the third is post renal azotemia

    problem with inflow to the kidney, or the outflow being blocked or can have disease within the kidney.

    Now we start with pre-renal azotemia:
    pre-renal many think of as dehydration, it is true in part, but it is a problem that is caused by poor perfusion, cause occur from dehydration and volume depeltion, or lost fluid from burn, third spacing during pancreatitis, or bad burn, kidneys aren't getting enough blood flow in, can have also cardiovascular disease, hypotensive because of poor cardiac output, not enough circulation to the kidney will be read as poor blood volume. inadequate blood to the kidney.

    the same thing can happen if you have a situation of low albumin level leading to decreased oncotic pressure, like in nephrotic syndrome or cirrhosis, dec. intravscular volume because they run a low vascular volume. Kidney thinks it isn't getting enough blood.

    the final main cause, is overt circulatory problem, like narrowing of renal artery, stenosis. Or medication induced vasconstriction, NSAIDS for instance, some of the blood flow is prostogandin dependent. cause the kidneys not to function and cr. goes up.

    these are the causes of pre-renal. Not enough blood flow and not just because of dehydration.

    why is pre-renal azotemia important. Important, conceived of as ischemic situation, if stays untreated, it will progress to where the kidneys necrose.

    what you'll need to do is tell pre-renal from intra-renal because treatments are completely different.

    ________________

    Next post renal, outflow problem

    1- outflow of bladder can be obstructed, tumor in pelvis, scarring, strictures, BPH, back pressure goes back to kidney, causing obstruction of outflow..

    or at level of ureters, stones, tumors, papillary necrosis, also putting back pressure unto the kidneys.
    significance is back pressure on kidneys and damage

    _______________

    intra renal failure.. problem with the integrity of kidney, the most complicated of the three kinds..

    intrinsicrenal, often acute tubular necrosis are many names due to kidneys not working.
    how do you distinguish:
    specify tests or lab data to interpret:

    tests for post renal azotemia
    first prostate exam, obstructed urethral outflow.
    the best test however, check for residual urine in the bladder, have them urinate put catheter or scan with bladder scan to see how much urine is left after they urinate, typically they should only have 50cc or less

    the best of all is an ultrasound, that looks at ureters, bladder.. which will detect hydronephrosis

    now pre-renal azotemia

    bunch of tests, the most widely used, is the ratio of BUN/CR
    Cr level of 1
    BUN 10
    BUN more than 10 more than 30 it is a good indication of pre-renal
    so that is a key labtest

    the other more accurate
    is measurement of urine sodium or fractional excretion of sodium

    if kidneys are in a pre-renal situation , the kidneys say I am not getting enough blood, they think you're bleeding to death, so when they think that will, start retaining sodium to keep vascular volume, so urine sodium will be very low. short term treatment is fluids

    urine sodium less than 10 is low

    other things, same principal.. kidneys will also concentrate urine, high specific gravity and high urine osmolalaity, they are corroboratory findings.

    typical case.
    62 yr old for nausea and vomiting
    his crt is 3.6 was normal 3 months ago, he also has orthostatic hypotension
    BUN 82
    urine sodium 6
    specific gravity 1.028
    BUN is more than 20:1
    kidneys trying to replete vascular volume.. faced with this, this is pre-renal azotemia.
    rx: fluids

    _______________

    intra-renal will see the opposite
    BUN/CR is normal not elevated 10:1 or even less
    will see instead of low urine sodium it will be high, because the kidneys are failing, they start leaking, so high levels of urine sodium
    only place that falls down is pt who is on diuretic, so the test then loses value.
    look for low BUN/CR
    look for sodium spillage in urine
    urine specific gravity and osmolality is low

    you might also see red blood cell casts or granular casts, the kidney is falling apart and pieces of it coming apart, released into urine.

    algorithm: approach to Azotemia

    1- faced with high creatine level first thing you want to do is to exclude pre-renal azotemia :
    a- what is the BUN/CR if >20:1
    b-Urine Sodium <10
    c-FeNA <1
    d-OSM >300
    f-specifc gravity > specific gravity rising by.001 for every 35 to 40 mosmol/kg increase in osmolality. Thus, a urine osmolality of 280 mosmol/kg (which is isosmotic to plasma) is usually associated with a specific gravity of 1.008 or 1.009. so higher than those values and now you know how to calculate 'normal'

    sounds like pre-renal

    if pre-renal is the case, then treat the cause, whether volume depletion, renal artery stenosis or heart failure..

    also need to exclude post renal, using sonogram and post void residual urine, if see hydronephrosis then treat obstruction with stent etc
    if no evidence or pre or post renal, then the problem is intra renal

    BUN/CR not high
    urine sodium that is high more than 20 or more than 30, FeNA that is greater than 1 and osm less than 300 and urine specific gravity is low since urine can't concentrate since kidneys aren't working properly.. that will tell you intrarenal ..

    intrarenal failure there are many causes:
    but they will either occur in the tubules and interstitum and the other occur in glomeruli which is glomerulonephritis ...

    main categories:

    first category and most important is ATN
    acute tubular necrosis ..
    occurs in different settings.. the tubules start falling apart, for instance in prolonged ischemia (shock kidney) hypotensive, labs look pre-renal but then kidney falls apart.. prolonged above conditions, clots of A fib, occluding renal artery...
    2nd which are also common are toxins like
    radiological contrast, drugs like amonoglycosides and amphotercin B, pigments like myoglobin from muscle breakdown

    ATN occurs in phases, prodromal period of time
    from beginning of insult to effect on kidney..
    then when you have outright ATN, stop making urine, drop to nothing or 2cc an hr (oliguric) then there will be a diuretic phase of ATN
    metformin with contrast are at a great risk..

    another category is acute allergic interstitial nephritis, an allergy to a drug.. common drugs cephalosporins, beta lactams, methcillin hence we don't use it, sulfas, allopurinol
    acute allergic nephritis, takes offending drugs, they'll get fever, rash, high eosinophil count, especially in the urine.
    rx steroids short term
    other tubulointersistial disorders
    deposition disease, any number of chemicals can get into kidney, like hemoglobin is hemolyzed and out in circulation can deposit, myoglobin from rhabdomylisis, rx with high flow fluid to keep from crystalizing.
    pts with Multiple myeloma crystalize Bence John's proteins
    or crystalization of crystals, like oxalate, ethylene glycol antifreeze, part of mechanism of toxicity, is oxalate crystals depositing in kidney, also vitamin C in very big doses, can cause stones and crystalization.
    crystalization of uric acid, for any disorder, like someone with lymphoma and it breaks off giving out uric acid, also in gout as well.
    hypercalcemia, hyperparathyroid and crystallize calcium in the interstitum etc etc.
    other causes of tubular interstitial disorders, infections like pyelonephritis, develop intrarenal, with white cell casts in urinary sediment.
    others drugs and toxins, various analgesics NSAIDs, antibiotics.. outdated tetracycline.
    variety of cancer deugs, cisplatin, mitomycin, methotrexate etc.
    radiation nephritis, heavy metal poisoning...

    glomeruldisorders

    vasculitis type disorders (not very common) like wegner's granulamtosis
    disorder with granulomatous dz in lung, paransal sinuses who also get lesions in the kidneys, intrarenal failure, high sodium in urine, cr high, problems with chronic sinusists and nasal congestion, maybe lesion in the lung as well.. test here is ANCA

    Henoch shcnolen purpura, thrombotic thrombocytopenic purpura, htn etc.

    other glomerular disorders, glomuerlonephritis, post streptococal glomerulonephritis.. get hypertensive and edema
    do ASO titer to prove that the glomerulonephritis in someone who had a sore throat== post streptococoal glomerluonphritis

    IGA nephrpathy, deposition of IgA following a viral illness...

    chronic, like with collagen vascular dz. like SLE, also goodpasture syndrome
    antibodies against basement membrane and lungs, will show up with intrarenal failure, and they will have lesions in lung and cough blood. order antibasement membrane antibodies

    another Alport renal failure with hearing failure.
    __________________________________________________ _


    Now, how will we decide who has what...

    glomerulonephritis

    high urine sodium >20
    High fractional excretion of sodium >1
    BUN/CR suggesting not pre-renal
    urinalysis will be key
    hematurea and RBC casts = glomerulonephritis
    most definitive tests to prove Glomerulonephritis is a kidney biopsy

    things that go along with glomerulonephritis is nephrotic syndrome, also occurs in vascuilitis..
    1- massive proteinurea massive 3.5 g 4+ dipstick positive and more
    they lose intervascular oncotic pressure and develope edema, will run albumin down and hyperlipdemia

    best test for nephrotic syndrome is a 24hr urine protein
    best test to determine the type of glomerulonphritis causing this nephrotic syndrome is a biopsy.

    some nephrotic syndrome are treated with prednisone

    best first test (initial test) in a pt. with high urine sodium and indicators of intra renal failure.. is urinalysis!!!


    infection, drug hypersensitivity, glomerulopnephritis, nephrotic syndrom, meyloma, uric acid (gout) and myoglobinurea.

    what do we see in each of these?

    infection= WBC and bacteria
    pyelonphritis WBC casts
    Drugs/ eosinophillia
    glomuerlonephritis = RBC casts
    Nephrotic syndrome = Hyperlipedmia, heavy protenurea
    Multiple myeloma _ proteinurea
    uric acid = uric acid crystals
    Myoglobinurea = High CK levels and dipstick positive test for blood but no blood cells.


    a different way
    pyuria = infection
    RBC casts = glomerulonephritis test with kidney biopsy
    blood urine dipstick but not micro = myoglobinurea
    crystals in uine = gout
    eosinophils = allergic drug reactions
    massive proteinurea = nephrotic syndrome
    __________________________________________

    cases:

    62 yr old nausea vomiting, creatinine is 3.6 was normal 2 months ago, takes no meds
    has large prostate, pulse is high, BUN is 72, urine specific gravity is 1.023
    urine sodium = 9
    all else is WNL

    best initial rx..
    likely cause.. he has a large prostate gland, potential outflow obstruction
    tempted to get sono to measure post void.
    his other things.. BUN 72 and cr 3.2 ratio of 20
    concentrated urine
    urine sodium of 9
    all point to pre-renal azotemia
    best initial rx is fluids
    _____________________

    case II
    62 yr old nausea vomiting. CR 3.6, taking NSAIDS
    labs
    urine specific gravity 1.004 dilute
    BUN 41/ 3.6 almost 12:1 ratio
    urine sodium = 42

    renal problem spilling sodium, can't dilute urine even though dehydrated, he has renal disease, with many dx to consider..

    what is next? do sonogram to exclude post renal azotemia, then go back and say renal dz and work it up.

    ________________________

    boy with high BP, edema, urinalysis, proteinurea and RBC casts..
    young boy with glomerulonephritis.. blood test to do is ASO titer.

    __________________________________

    ESRD

    end stage renal disease
    renal failure that is incompatible with survival..
    need dialysis or kidney transplant

    how does it show up?

    chronic findings and acute findings
    important points, need for dialysis isn't determined by creatinine

    hypocalcemia
    kidneys are supposed to make 1.25 hydroxy vitmin D, because they are not working, you don't have this chemical so don't absorb calcium in GI tract, thus your body makes more PTH to absorb calcium from bone, causing bones to become osteopenic. renal failure need their calcium and Vit D supplementation

    people get hypermagnesemia because they can't secrete it.

    also have accelerated HTN through renin angiotensin system, very difficult to control, combo of accelerated HTN and high lipids, causes death.

    always anemia, since kidneys make erythropoeitin, pts on dialysis, will usually receive erythropoietin but anemia is concomitant to ESRD

    impaired immune functions, as well presumably because of toxins not excreted get pruritic.

    all of these things are common, become osteopenic and break hip, acceprated lipids and HTN and get MI.

    Hyperkalemia, potassium high enough you'll die
    potassium is too high from changes it makes on EKG, focus on T waves..
    T waves are so sharp and pointed, you don't want to sit on them:

    MMPE 12END 156 02 eps - The Medical student Review




    hyperkalemia, that is an acute manifestation that potentially needs dialysis..

    metabolic acidosis, in non working kidneys, is severe enough fatal needs dialysis..

    fluid overload to the point of pulmonary edema, if kidney can't urinate then dialysis

    pericarditis, build up in pericardial sac needs dialysis

    pts with high BUN, obtunded, encephalopathic, comtaosed needs dialysis.

    renal dialysis, in blood, or direct connection in the blood, venous shunt, or pertoneal, fluid swish around and come back through cath.

    ________________________

    62 yr old pt on dialysis, returns from 4 days trip, feels very poorly (pts need dialysis every two days) he has nausea, vomiting and SOB, he has tall peaked T waves. Cr. 5.2
    Hco3- is 16
    metabolic acidosis
    best rx is dialysis immediately..

    __________________

    quick recap with key words:
    Eosinophils in urine = drug reaction
    RBC casts= glomerulonephritis
    Heavy proteinurea= nephrotic syndrome
    high triglycerides= nephrotic syndrome
    Radiological contrast = ATN
    Urine sodium < 10 pre-renal (kidney trying to retin its plasma volume)
    BUN/CR > 20 = pre-renal
    Last edited by جوري; 07-06-2009 at 11:58 PM.
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    Part II nephro.

    Now with electrolyte disorders.. very important...
    follow this recipe and you can't lose :X



    let's start with hyponatremia which is the most common:

    SX that folks have, when it is mild and gradual, pts are asymptomatic, sodium falls slowly, with severe, they gets headaches and confusion, and abnormal mental status changes, and at an extreme that is rapid, they can develop CNS coma and seizures ..

    causes of hyponatremia, or pseudo hyponatremia
    in couple of situations, sodium is low when the blood is hyper-osmolar, what is ahppening the patient is hyperglycemic, sugar is high and as an artifacts of balancing fluids, the sodium falls... the relationship for every 100 mg glucose goes up the sodium falls 1.6mg

    pseudo hyponatremia with normal osmolality, artifcat with high triglycerides or hyper-proteinemia like with multiple myeloma

    and there is real hyponatremia

    so another way to look at it, is you can have hypeonatremia with high osmolality which is seen in hyperglycemia
    you can have hyponatremia with normal osmolality which can be seen with lipids or proteins .
    or you can have hyponatremia with low osmolality and that can be seen with multiple causes..

    ____________________________________

    high and normal is a pseudo..

    so first step to determine hyponatremia is to look at the osmolality

    going to continue this review tomorrow insha'Allah since I am falling asleep...

    __________________________________________________ __________

    picking up from where we left off:

    low osmolality multiple causes real hyponatremia..
    first step is to determine the osmolality to see if psuedo or real..
    send blood plasma but sometimes you have to figure out by calculating
    formula: 2xserum sodium + glucose/18 + bun/2.8 = osmolality
    or better easier, 2 x sodium + 10 is glucose is normal
    normal osmolality is between 280~300

    _____________________

    hyponatremia with high osmolality.. there is a new solute in high concentration usually glucose, causes fluid shift.
    1.6mg% for every 100% rise in glucose
    ex. if glucose is 342 and sodium is 126, glucose account for 3.2 sodium drop..
    how much higher than normal is glucose of 342? that is 200 units higher than it should be, so for every 100 unit, the sodium drops 1.6
    200 points higher, 200x1.6 =
    adjusted sodium is 129 so doesn't account for all the drop in sodium thought..

    another example
    glucose 342
    sodium 131

    does the glucose explain hypontremia?
    400-100 = 300 units higher
    300x1.6= 4.8
    4.8 + 131 = normal sodium

    ____________________

    now hyponatremia with normal osmolality
    coming from proteins and lipids..

    certain amount of blood is made of protein and lipid..
    conc. of sodium
    in abnormal situation, the protein and lipid is higher leaving less space for water and sodium
    the amount of sodium is normal but less of it per liter of blood.

    patient presents with weakness.
    sodium 128
    glucose 142
    serum osmolality 282
    total protein 7.2

    what test will show cause of hyponatremia? lipids
    normal osmolality hyponatremia..

    ____________________________

    real hyponatremia, measure extra-cellular fluid volume
    divide into multiple causes of low osmolality

    determine volume status
    if have high volume status, then edematous condition

    ecf is low
    fluid loss, from diuretics, kidney, sweat, burns, etc.

    if ecf is normal euvolemic..
    multiple causes like
    SIADH (ecf normal category)
    if high hypervolemic
    if low hypovolemic
    if euvolemic there aremultiple causes.

    low osmolality with hypovolemia, volume depeltion either renal or extra-renal, going to tell by urine sodium.
    burn patients or marathoon runners.
    or get volue depletion from losing fluid from kidneys

    hypoaldosteronism, glucocorticoids deficiency

    the most important of the three conditions, the one that does it with a normal volume..

    common cause is SIADH
    other causes are pathological water intoxication, psychogenic polydipsia, low osmolality hyponatremia but will retain normal volume
    hypothyroidism

    the most important thought is SIADH
    the urine osmolality is abnromally high in face of hyponatremia and low serum osmolality-- if blood is hyponatremic diluted, appear to have extra water in the blood, the kidneys ought to protect me, pee out water so that the sodium level can come back up? expect to have dilute urine to get rid of dilute water in blood.. but here the antidiuretic hormone is abnrmal, actually excretes very concentrated urine high urine osmolality in urine with low osmolality in blood, which should be fixed.. but it is because I have an inappropriate ADH causing me to retain fluid and get rid of sodium ..
    high urine osmolaity when serum osmolality is low.. need to also look for renal or thyroid function or drug problem too.

    SIADH causes are lung disease, can cause brain to secrete inappoporiate amounts of ADH, concentrate urine and dilute the blood. any brain disease, tumor, subarachnoid hemorrhage, small cell lung cancer, or drugs, like TCA, MAOi, fluxoteine, carbamezapine, narcotics, phenothiazines, clofibrate, vincrsine, cyclophosaphamide, vinblastine.

    drugs that increase ADH from brain or on kidney, oxytocin in labor acts like ADH.

    SIADH dx. serum hyponatremic, low osmolality, and urine ought to have low osmolality but instead inappropriately high.

    rx: either reverse the cause, but you can't always do that,if you can't reverse the cause, restrict fluid, or give furosamide with normal saline..

    or two drugs that decrease the action of SIADH on the kidney
    demclocycline and lithium
    emerency rx for serious hyponatremia as convulsion and seziures is normal saline.

    someone comes in with hyponatremia
    measure serum osmolality and see if high low or normal.

    figure out volume status.
    if high, edematous conditions, heart, liver failure
    if ecf is low, they are fluid depelted, measure urine sodium, if low they are losing from skin or GI
    if high then probably losing it from the kidneys

    if fluid volume is normal,
    then SIADH or previousely discusses..

    cases:

    82 yer old vomitting and confusions, takes thyroxine, fluoxetine, glucose 342, has pneumonia

    he is vomitting can cause dehydration
    low ecf volume hyponatremia
    taking thyroid med can cause SIADH like syndrome
    as well fluoxetine and chlorpropmide
    glucose is high running glucose level down
    how to determine?

    need osmolality and volume status as well urine sodium to figure out
    if efc is normal then check urine sodium
    _________________________________________

    again

    approach to hyponatremia



    key points..
    Determine serum osmolality high and normal are artifacts of glucose lipids and proteins
    with low osmolality determine the ECF volume
    High ECF edematous state
    low, renal or extra renal depending on whether the sodium is greater than 10 or less than 10
    normal ECF then SIADH, drugs, thyroid, cancer etc

    _______________________________________________

    Next topic is hypernatremia which is the least common of these metabolic disorders:

    cause of hypernatremia
    people typically dehydtrated, losing fluid more than sodium, thus sodium level rises, occurs through insensible water loss, people with bad burns, also common from GI tract in diarrhea, and become hypernatremic that drive to drink more when you go alot..

    another cause is diabetes insipidus, no ADH action, ADH either not made or can't work on kidney, so either a tumor in pituitary or such or nephrogenic, ADH is made but doesn't work on kidney, due to lithium or kidney failure, spill water in urine like crazy..
    lethargy, sezures and coma like hyponatremia

    rx is fluids, treat the dehydration, think of diabetes inspidus like you'd think of diarrhea..
    correct the problem slowly, as to not cause serious central myelnosis

    if can't correct this problem right away think diabetes inspidus..
    do water restriction test

    with passage of time measure urine volume and urine concetration as we restrict their fluid intake..
    in a normal person. the urine volume will be less with restriction and the urine comes out should be yellower and more concetrated.
    if you have diabetes insipdus, you don't have any ADH, you'll mak urine at same volume, if give antidiuretic at that stage and are unable to respond because of kidneys it will keep right on then you can make dx of nephrogenic diabetes inspidus.. on the other hand if given antiiduretic hormone and it become normal then you've responded to it, you had a CNS lesion that prevented you from making ADH.

    rx correct the underlying problem, if tumor or lithium, or replace antidiuretic by given internasal DDAVP
    if nephrogenic because of kidney defect, you can give thiazide diuretic causing sodium depeltion helping keep water or NSAIDS impair ability of concentrating ability, neither of those methods are really all that great.

    __________________________

    now low potassium problm hypokalemia

    common causes, GI loss, diarrhea.. various tube drainages in the bowel, medications, diuretics, people on lasix and furosamide, beta agonists like albuterol cause calcium to enter into cells, decreasing k+ in circulation.
    Insulin, and drive sugar from circulation into cells potassium goes with it.
    then there are rare causes

    hypoaldosteronism (conn's syndrome) primary hypoaldosertonism, cushing's syndrome, bartter's syndrome, can't absorb sodium chloride, lose potassium along the way.

    liquiorice, not common but has mieralcorticoid effect. Glyceric acid.. chemical in liquiorice with mineralcorticoid effect.


    Hypokalemia

    73 with COPD and CHF, has diarrhea for three days, he is on lasix, furosamide, and multiple albuterol rx in the ER

    multiple causes of hypokelamia

    diarrhea in stool
    lasix in urine
    multiple albuterol (potassium to go into cells

    mild is specific t wave changes, severe can cause cardiac toxicity as well potentiate digoxin effects, because of hypokalemia

    rx replace the potassium, orally, best if possible..
    but in hospital pts at times given IV 10meq/hr

    too much potassium can cause cardiac conduction defects, this is how you execute people in prison, you cause heart block and asystole
    ____________________________________

    hyperkalemia
    increased intake of potassium, error in hospital, or meds that causes hyperkelamia, like potassium sparing diuretic, ace inhibitor, potassium artificat from venipuncture...
    the tourniquet and blood sample hemolyzed and caused potassium to go extracellularly..

    also in situations where potassium moves from cells into blood, like familial periodic parlaysis, myoglobuniurea, renal failure, drugs. hypoaldosteronemia

    adrenal inssufiency ..

    tall pointed peaked t waves..
    pt on ace inhibitor or on NSAIDS or spirnolactone or others and potassium is high, specify treatment

    67 y/s with DM on glyburide, and ace inhibitr
    cr 4
    and potassium 6.6
    number of reasons
    ace inhibitor
    because cr is rising renal failure can't excrete potassium
    how will you fix it?

    in stages:

    first stage if you get an EKG changes protect the heart stabilize cardiac membrance
    so give calcium chloride or gluconate infusion.

    next lower the potassium level by driving potassium out of circulation by giving glucose and insulin 50% dextrose and insulin or give doses sodium bicarbonate create a situation of alkalosis, potassium will go into cells
    or get rid of potassium from body keyexylate
    or if in renal failure then dialyze them

    number one with EKG changes protect the heart give calcium
    number two lower serum potassium
    if no EKG changes then lower potassium and get it out of the body

    __________________________________________________ _______

    Now for acid base disorders (RTA's) acidosis and alkalosis.
    have a systematic approach to it all...interpret blood gases...

    alkalosis= PH is high
    acidosis = PH is low

    first step is to determine acidosis or alkalosis..
    7.4 is normal
    less than 7.37 acidosis if more than 7.4 alkalosis
    first level decision

    now decide whether respiratory or metabolic acidosis or alkalosis..

    arterial blood gases..
    get PH, will get PCO2 normal is 35-45 and dependent on breathing rate, the faster the lower the PCO2, the slower the Higher

    bicarbonate normal is (20-28)

    normal mid twenties.. bicarbonate is a metabolic buffer
    and changes develop slowely..
    if bicarb is trying to fix acidosis, it will happen over days as opposed to PCo2 in a matter of minutes

    O2 and PO2 level which varies by altitutde, and saturation which should be over 90

    let's start with respiratory alkalosis

    caused by a bunch of things
    hyperventillation, rapid acute fast breathing..
    respiratory alkalosis will drive PCO2 now, various causes, can be caused by anxiety, acute pain, panic attack, and if this happens, PCO2 will go down but there is no other problem

    other acute prbs, like Pulmonary embolism and pneumonia, also early asa toxicity, breathe fast, breathe down their PCO2..

    no time for metabolic compensation... will see high PH, and PCO2 that is low because of fast breathing, and HCO3 didn't have time to change so it will be normal..

    24 year old female, feeling suffocating and tighteness in chest, RR 36
    get blood gases, find out PH 7.52 alkalotic
    O2 is 99%
    PCO2 is low and HCO3-

    thus respiratory lkalosis

    __________________

    another 24 year old everything the same
    PH 7.52
    however her PCO2 25 and her O2 sat is 76% which is low
    HCO3- 27

    there is a respiratory problem

    ON BCP and had a PE
    she is hypoxemic

    ___________________

    metabolic alkalosis
    the problem is you are gaining an alkali bicrbonate or you are losing an acid
    how does it happen?
    lose acid with prolonged vomiting or other GI loss, like NG tube, or diuretics or rather than losing acid, gain HCO3- people who use sodium bicarbonate pills (antacids) calcium bicarbonate for antiacids build up of bicarb, or H2 blockers or proton pump inhibitors..
    it is a slow chronic process, losing acid, or gaining bicarb gradually.. as you start to become alakaline, the body will breathe slower so that PH falls from alkaline level to closer to normal..

    increasing PH almost back to normal..

    typical case..
    67 yr with HTN on HCTZ complains of fatigue, her exam shows dehydration with orthostatic, hypokalmic, hypnatremic, hypchloremic... PH 7.42 (a little alkalotic)
    PCO2 is high and bicarbonate is high

    alkaline, because she has high base in her blood, metabolic alkalosis. body compensating by breathing slow.

    ________________________

    respiratory acidosis, hypoventillation.. could be acute or chronic.. an inability to blow of PCO2
    COPD, can't exhale all the air, will build up PCO2 in blood..
    breathing poorly become acidotic.. kidneys retain alakli (hco3)
    acute respiratry acidosis .. inability to breathe at normal level, taking narcotics that lower respiratory rate, or ashtma..
    on chronic basis.. chronically elevated PCo2 from Obesity, or COPD

    ABG
    dec PH
    high PCO2
    if acute the bicarbonate won't have time to rise..

    typical case
    27 yr unconscious
    rr is 7
    pupils is pinpoint
    ph 7.28
    O2 is low
    PCO2 is high (not breathing)
    no time for bicarb compensation thus it is normal

    72 yr with COPD getting worst, getting more SOB
    ABG
    PH 7.37
    O2 sat 90%
    PCO2 is very high
    HCO3- is also high

    acidotic because she is breathing ineffectively, in attempt to crrect HCO3 tries to correct it

    ________________________________

    question on the same ABG
    Ph. 7.37
    O2 sat 90%
    pCO2 56 (high)
    HCO3- (34) high
    metabolic alkalosis (HCO3-) high with high PCO2 as compensation?

    how do you know that the alkali isn't the primary thing?
    because PH is not alkalotic it is acidotic.. without over comepnsating

    ______________________________

    metabolic acidosis the most complicated...

    causes a relative increase in the quantity of acid, due to any of the following, addition of acid, inability to excrete acid, loss of base HCO3-
    mechanism in blood gases
    low PH decreases b/c acidosis
    bicarbonate dec because less base
    respiratory rate will increase to blow of PCO2 to increase PH back to normal..
    sudden acidosis, the respiratory rate will kick in right away

    17 yr old with DM and not taking his insulin presents with altered mental status.. PCO2 is low and Bicarb is low, metabolic acidosis because the bicarb is low, and as comp. body has been breathing fast to blow off PCO2

    first step in sprting metabolic acidosis is it?
    metabolic with high anion gap, or normal anion gap, called non anion gap..


    what is an anion gap?
    it involves
    adding the postive cations and subtracting from them the two negative anions as such

    [NA+ +K+] - [cl- + HCO3-]

    normal anion gap is 11+/- 3 i.e between 8-14

    high anion gap acidosis higher than above number means another organic acid has been added to the body.. normal anion gap acidosis, either excess HCL- or loss of bicarbonate...

    high anion gap acidosis a few causes
    over production or under secretion of acid, chloride levels unaffected

    four causes
    1- ketoacidosis ( alcoholic ketoacidosis, diabetic ketoacidosis, starvation
    lactic acidosis
    renal failure
    or intoxication with any number of different intoxicants
    ethylene glycol, methanol, salicilates

    la mud pie
    l lactic acidosis
    a aspirin
    m methanol
    u uremia
    D DKA
    P propylene glycol
    I isopropyl alchol
    e ethlyene glycol

    normal anion gap acidosis

    they are either losing HCO3- or can't excrete acid..
    common causes of these are diarrhea, loss of bicarbonate, or RTA inability to excrete acid in the urine___________________

    normal anion gap (RTA)

    they all have one thing in common, inability to acidify the urine..
    renal tubular acidosis kidneys can't do that.. less acidic urine or overtly alkaline which is wrong...

    type I RTA occurs in distal tubule of the kidney, you can't acidify urine, your urine PH will be high 5.6 or higher
    seen in kidney stones, amphotercin B toxicity, lithium tox, sickle cell disease. give acid challenge test.. expect that acid spills in kidney and they should acidify urine, but they can't.. the rx is to neutralize the urine by giving bicarbonate.

    _____________

    RTA type II which occurs in proximal renal tubules and the problem here is inability to absorob HCO3- until the levels becomes very low, eventually in the distal tubule some bicarbonate will be salavged..so again inability to acidify the urine
    occurs, in myeloma, fanconi syndrome, wilson's disease
    RTA II inability to absorb bicarbonate..
    bicarbonate is lost in urine even in face acidic blood, and the treatment here is volume restriction , the kidneys will absorb a little more

    Type IV hypoaldosteronism, adrenal defienciy, some diabetes..
    the presentation is key, presents with hyperkalemia..
    restict salt, and even in restricing salt, the sodium is lost, it is treated with fludrocortisone.

    _______________________

    so let's do chart

    RTA type I

    defect: Distal tubule cannot excrete acid.
    Results: urine is alkaline even when blood is acidic
    K+: is low
    test is acid load test -- urine remains alkaline
    RX: oral bicarbonate
    ________________________
    RTA type II
    defect: proximal tubule can't absorb bicarbonate at normal urine volumes
    Results: urine remains alkaline except at very low urine flow volume
    K+= low
    Test: do a bicarbonate load test renal tubules don't absorb alkali and the urine remians alkaline
    RX: volume restriction
    _________________________
    RTA IV
    defect: renal or aldosterone deficiency
    Results: in high urine sodium -- aldosterone usually causes you to retain sodium and lose potassium, and when you have an aldosterone defcicney you'll lose sodium and retain potassium. increase in sodium excretion in the kidney exchanges with potassium and hydrogen -- thus you build up high hydrogen ion -- that is how you get acid in RTA type IV
    K+: high
    Test: salt restriction test.. the urine sodium remains high, spilling sodium in urine
    RX: replace mineralcorticoid with fludrocortisone..

    ___________________________________________















    Last edited by جوري; 07-07-2009 at 11:01 PM.
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    An interesting case of a 28 yr old woman who presents for eval of oligmenorrhea and infertility. P.E reveals acne, hirsuitim, and mild clitromegaly. Lab tests reveals mild hyponatremia, and normal levels of 17-ketosteroids and plasma dehydropiandrosterone levels and no change in aldosterone levels. The Pt is diagnosed with a defect in CYP21A2.. What best explains the late onset of her disease?

    and the answer is an incomplete 21 hydroxylase defect.
    The Patient described has disease resulting from partial dysfunction of CYP21A2 (21-hyroxylase P450C21). defects in CYP21A2 are the most common cause of CAH. There are two copies of each gene in the human genome, one derived from the mother and the other from the father. A complete deficiency of a gene product therefore, requires inactivating mutations in both copies of the gene in question. CAH evident in infancy thus requires that both genes for an enzyme required for adrenal steroid hormone synthesis be inactivated- Adult-onset CAH, however is most commonly the result of an inactivating mutation in one copy of a steroid synthesis gene. The remaining copy is able to code for sufficient enzyme to prevent catastrophic infantile presentation of CAH. In the case described, the patient's single remaining copy of CYP21A2 was able to synthesize sufficient aldosterone precursors to prevent extreme salt wasting and was able to prevent and extreme accumulation of steroid precursors, thereby preventing virilization in infancy. She does however, overproduce androgenic adrenal hormones on ACTH stimulation, and this is likely the cause of her oligmenorrhea, infertility, hisruitism and acne.


    Now to look at other similar defects in the same pathway. A complete 3-hydroxysteroid dehydrogenase defect, would cause defects in aldosterone and cortisol and overproduction of adrenal androgens. Clinically male pts. would present with ambiguous genitalia and female pts with virilized genitalia. Hypertension isn't a feature of this disease..

    11-hydroxylase (CYP11B1) deficneyc causes hypertension through accumulation of mineralcorticoid 11-deoxycorticosterone.
    The Medical student Review

    Text without context is pretext
    If your opponent is of choleric temperament, seek to irritate him 44845203 1 - The Medical student Review


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    Re: The Medical student Review

    70 year old woman with a long history of DM brought to the ER with a sudden onset of weakness on the right side of the body. She has a 20 pack year hx of smoking and is currently taking metformin and hormone replacement therapy. She is oriented to time and place and person, and seems to answer all questions appropriately. She was able to dress herself before showing up to the ER. Her vitals are BP of 140/90 mmHg and PR of 85/min. P.E confirms loss of strength in the right upper body and lower extremeties. There is a right sided facial weakness as well. The visual field is intact. A CT scan of the head is ordered. Occlusion of which vessel is the most likely cause of her SX?

    and the answer is penetrating arterioles of the posterior limb of the internal capsule. Lacunar infarcts are small (<0.5cm) focal areas of parenchymal loss found in the basal ganglia, anterior and posterior limb of the internal capsule, pone and occasionally cerberal white matter. The five classic syndromes include pure motor hemiparesis, pure sensory stroke, ataxic hemiparesis, and clumsy hand dysarthria. They are presumed to be ischemic in origin and due to occlusion of the pentrating arterioles aforementioned structures. Lacunar infarcs are particularly frequent in persons suffering from hypertension or DM. The most common type is a pure motor lacunar infarct most often occur in the genu or posterior limb of the internal capsule (Aphasia, Agnosia, Hemianopsia, neglect etc) pure motor infarcts most often occur in the genu of posterior limb of the internal capsule where the descending corticospial and corticobulbar tracts are located. Infarction of the anterior limb of the internal capsule, most often results in ataxic hemiparesis where both the pyramidal (weakness) and frontocebellar (ataxia) are located.

    Now the other major arteries like Anterior cerberal artery occlusion presents with contralteral weakness and cortical sensoty loss in the contralteral leg without weakness in the arm. Urinary incontenance, confusion and behavioral distrubances are likely.

    The Middle cereberal artery occlusion presents with contralteral hemiplegia, hemisensory loss, aphasias and homonymous hemianopia. our pt here has intact visual fields and not suffering aphasia.
    Posterior cerberal artery occlusion presents with contralteral homonymous hemianopia visual hallucination and agnosias.

    vertebral artery occlusion may not cause clinically noticeable sx because of good collateral circulation when sx occur they are similar to basialar artery occlusion.

    490b6c1148232Territorybasalekernen 1 - The Medical student Review


    thmb 48e6c40d05324VD20thal infarct - The Medical student Review

    Lacunar infarcts

    CerArtDistBlum1 1 - The Medical student Review

    self explanatory...
    The Medical student Review

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    Re: The Medical student Review

    I'll be writing the step up to USMLE step 3 on here.. will save most of you a good $40 insha'Allah..

    we'll start with cardio ..

    little factoids first..

    the left anterior descending is the most common site of coronary artery occlusion cor art - The Medical student Review

    coronary arteries fill during diastole. while systemic arteries fill during systole. conditions or drugs that reduce diastolic filling decrease coronary perfusion during a given period of time.

    As heart rate increases, the time available for diastolic filling decreases.
    During exercise, cardiac output initially increases due to increased stroke volume and then due to increased heart rate.


    • cardiac output is dependent on the rate of contraction. I.E heart rate, and the volume of blood forced out of the left ventricle per contraction. i.e stroke volume.
    • heart rate is the number of contraction per unit time and is expressed as beats per minute.
    • stroke volume is the change in volume from immediately before a contraction to the completion of a contraction. SV = (end diastolic volume) - (end systolic volume)
    • dependent on contractility i.e force of heart's contraction, preload i.e the amount of stretching force on cardiac muscle fibers at the end of diastole, and after load, i.e the vascular resistance which ventricles must overcome to produce outflow.
    • increases with catecholamine release e.g epinephrine, increased intracellular calcium, decreased intravscular sodium, digoxin use, and stressful events. e.g anxiety, exercise

    decreases with beta blockers, heart failure, hypoxia with acidosis.
    ___________________________________

    Vascular pressures
    _______________________________

    • systolic blood pressure is the maximum vascular pressure expereinced during heart contraction, diastolic blood pressure. DBP is the baseline vascular pressure between contractions.
    • pulse pressure is the increase in blood pressure attributed to cardiac outflow during contraction
    • pulse pressure = (SBP)-(DBP)
    • mean arterial pressure (MAP) is the average BP considering the unequal amounts of time spent in systole and siastole
    • MAP = (DBP) + (1/3 X SBP)

    _________________________________________
    heartantmajorvessels - The Medical student Review

    Aorta gives rise to the left and right coronary artery.

    Aorta >>>>>>left coronary artery>>>>>>>left anterior descending branch >>>>>septal branch supplies anterior wall of left ventricle, the septal branch supplies anterior 2/3 of intraventricular septum.
    Also from the left coronary we get the circumflex branch which supplies the left atrium lateral wall of left ventricle, posterior wall of left ventricle.

    now from the AORTA TO THE right coronary we get three branches off the right coronary artery (the posterior descending branch which supplies the inferior wall of left ventricle, and posterior 1/3 of intraventrciular septum, the marginal branch supplies the right atrium, right ventricle, and the SA, AV node branches.. very important to pay attention to that infarction to the right coronary will spell disaster to the SA and AV nodes.

    now the physiology of heart contraction.
    Key principles


    • increasing the end diastolic ventricular volume causes an increaased stretch on cardiac muscle fibers, this leads to an increase in the force of contraction i.e the frank starling relationships
    • the end systolic volume and pressure generated by the ventricles are dependent on afterload

    increased contractility i.e force of contraction independent of preload and afterload leads to increased muscle fiber tension during isometric contraction
    _____________________________
    The Medical student Review

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    Re: The Medical student Review

    49680550x0475 1 - The Medical student Review

    EKG
    P wave, normal atrial depolarization
    PR interval: conduction through the arterioventricular node (<0.2 sec)
    QRS interval: ventricular depolarization (<).12 sec)
    ST interval: isoelectric ventricular contraction
    T wave: ventricular repolarization
    U wave: relative hypokalemia

    40221 1 - The Medical student Review
    ___________________

    Normal cholesterol function
    Cholesterols and triglycerides are carried by lipoproteins
    increased low density lipoprotein (LDL) levels lead to an increased coronary artery disease (CAD) risk
    increased HDL is protective
    Increased LDL and decreased HDL result from a diet high in fatty foods, tobacco and obesity, alcohol use, DM, and certain meds like OCP and diuretics.

    Pre-operative cardiac risk assessment:
    for surgical pt estimating the liklihood of an undesired cardiac event occuring as a result of surgery and anesthesia

    • considers measurable cardiac function, pre-existing cardiac dz, age and important co-morbidities
    • young healthy pts. maybe cleared for surgery with a normal EKG
    • older pts with existing co-morbidities require and extensive workup by a cardiologis
    • factors suggesting and increased risk of an adverse cardiac event
    • age >70
    • pulmonary function, forced expiratory volume in 1 sec/functional vital capacity (FEV1/FVC) <70% of expected. Partial pressure of carbon dioxide (pCO2) >45 mmHG, pulmonary edema.
    • cardiac dz: MI within the last 30 days, poorly controlled nonsinus arrhythmia, pathologic Q waves on the preoperative ECG, severe valvular dz., decompensated heart failure with poor ejection fraction.
    • Renal insufficiency: creatinine (CR) > 2.0 or a 50% increase from baseline
    • surgery type: cardiac/vascular surgery or anticipated high blood loss
    • higher risk pts should have their cardiac function optimized prior to elective surgery and should be made aware of the risks is the surgery is emergent
    • perioperative B blockers and postoperative noninvasive cardiac monitoring are recommended for pts determined to be at an increased cardiac risk.
    • ______________________

    Invasive cardiac monitoring

    • Arterial line: constant access to artery, e.g radial, femoral, axillary, brachial, dorsalis pedis) that allows accurate measurement of arterial BP and allows easy access to arterial blood for blood gas measurments
    • pulmonary artery cath I.E swan-Ganz Cath: inserted through the left subclavian or right internal jugula veins that run through the heart to the pulmonary artery; a transducer in the cath. allows the measurement of cardiac output, mixed oxygen (O2) saturation, systemic vascular resistance, and pressures in the right atrium and pulmonary artery; a baloon maybe inflated at the cath tip to fill the pulmonary artery lumen and to measure the wedge pressure equivalent to the left atrium pressure.
    • ______________________

    fetal circulation.
    fetalcirculation3 1 - The Medical student Review


    • Gas exchange occurs in the uteroplacental circulation
    • fetal HG has a greater )2 affinity than adult HGb and oulls O2 from maternal blood
    • umblical arteries carry deoxygenated blood to placenta, umblical veing carry oxygenated from placenta to the portal system
    • changes following birth
    • lung expansion causes an increased pulmonary blood flow leading to an increase in relative blood oxygenation
    • a decreasing serum level of prostoglandin E results in ductus arteriosus closure; umblical cord clamping results in the end of placental circulation and increase in systemic vascular resistance
    • this increased vascular resistance, in trn induces the ductus venosus closure and umblical artery and vein constriction
    • left atrial pressure increases due to increased pulmonary blood flow, and umbilical circulation decreases, causing a decrease in inferior vena cava pressure.
    • decrease in inferior vena cava pressures leads to foramen ovale closure.
    The Medical student Review

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    Re: The Medical student Review

    cardiac transplantation

    1. indicated for end stage cardiac disease (e.g. CAD, congenital DZ. cardiomyopathy with an estimated survival of <2 yrs
    2. contraindicated in pts. with pulmonary HTN. and Renal insufficiency. COPD, or other terminal diseases, smokers and pts > 70 yrs old are also excluded
    3. acute rejection is common
    4. most death occur in the initial 6 m after transplant, 5-yr survival is 70%

    __________

    case 1-
    25 yr old man presents to PCP for a wellness checkup, he has been in good health. His only complain is recurrent Achilles tendon and hamstring pain that occurs following significant exertion. He has noticed some small bumps in the back of his heels and knees in the past yr in the regions of the pain. He denies medical conditions but states that his father died last year at a young age from a heart attack. He denies substance abuse, review of system and the remainder of his family is unremarkable. P.E is normal, but he has multiple small hard nodules behind his knees and heels.

    Differential:
    Chronic tendonitis, crystal arthropathy, hypercholesterolemia

    labs unremarkable
    ECG normal sinus
    biopsy of the lesion shows a large collection of cholesterol laden material

    DX. Familial hypercholesterolemia (hetrozygote)
    RX

    1. the pt was placed on a regular exercise regimen and a low fat low cholesterol diet
    2. the pt was prescribed a regimen of simvastatin and ezetimibe

    a repeat lipid analysis in 1 month found the LDL to be 155mg/dl
    the tendon xanthomas gradually regressed
    the pt was followed regularly to confirm an adequate reduction of lipid levels and cardiac screening.

    The majority of cases of hypercholesterolemia are acquired

    1. steps to DX
    2. congenital hypercholesterolemia
    3. inherited form of hypercholesterolemia in which a genetic defect causes abnormally high levels of total cholesterol, LDL and/or triglycerides

    common types:

    1. familial hypercholesterolemia autosomal dominant defect in LDL receptors with an associated increased total cholesterol and LDL : the dz is much more severe in homozygotes than hetrozygotes
    2. hypercholesterolemia and hypertriglycerdemia associated with an increased hepatic production of apolipoprotein B-100 protein
    3. Familial defective apolipoprotein B-100 similar to FH except that the defect is in the LDL particle and not LDL receptor
    4. history: tendonitis around xanthomas, xanthlesmas, cholesterol emboli are seen in the retina on fundoscopic exam
    5. total cholesterol and LDL >250 mg/dl in hetrozygotes and >600mg/dl in homozygotes
    6. triglycerides are elevate >200 in familial combined hyperlipidemia and a biopsy of xathomas will detect collections of cholesterol; genetic testing is available but typically uneeded for dx
    7. RX:
    8. healthy diet, exercise
    9. pt education
    10. lipid lowering agents , consisting of one statin and at least one other cholesterol lowering drug to achieve LDL levels <160 mg/dl or lower depending on cardiac risk factors
    11. trig drugs maybe added if required

    Blood serum cholesterol levels should be collected from a fasting pt (12-14 hrs) to minimize post prandial influence.
    The Medical student Review

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    Re: The Medical student Review

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    The Medical student Review

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    Re: The Medical student Review

    can't go wrong with a couple of aunty ji's teaching you about the EKG? ..
    The Medical student Review

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    The Medical student Review

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    Re: The Medical student Review

    Wow G.S. you seem to have put a lot of effort into these notes mashaAllah. I will inshaAllah take my time to go through these...it'll be good revision for me. (I'm a fresh graduate from med school)
    JazakAllahu khairan!

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    Re: The Medical student Review

    I'm impressed you took the time to actually do this.

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    Re: The Medical student Review

    Interesting...I hope to become a med student one day

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    Re: The Medical student Review

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    JV catheter

    indications:
    Major surgery
    drug admin- vasoactive drip meds.
    hyperalimentation ( TPN)
    chemo
    prolonged abx therapy
    CVP pressure monitoring
    pulmonary artery cath.
    transverse cardiac pacing
    temporary hemodylaysis
    Aspiration of air emboli

    relative contraindications
    previous carotid surgery
    documented carotid disease
    superior vena cava obstruction
    severe trauma of the neck
    coagulopathies




    The Medical student Review

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    Re: The Medical student Review

    Jazakillah Khair sis Skye. Somehow I never noticed this thread until today. I will defo make use of it in the future. It looks really good MashaAllah.

    May Allah reward you abundantly


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