microsoft word viewer - internal medicine 1,conrad fisch

Upload: jorgegar58

Post on 10-Apr-2018

221 views

Category:

Documents


0 download

TRANSCRIPT

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    1/35

    USMLE Step 2 Lesson 1: Cardiology: Myocardial Infarction

    Internal Medicine Highlights

    Conrad Fischer, MD

    Maimonides Medical Center

    Residency Director

    Cardiology

    Myocardial Infarction

    Differential of Chest Pain

    A 52-year-old man comes to the ER with 1 hour of severe chest pain on exertion. He

    is nauseated and diaphoretic with slight shortness of breath. The pain does not

    change with respiration or bodily position. Exam shows normal vitals, clear lungs,

    no murmurs, and no tenderness.

    Changes With Respiration

    Pneumonia

    Pneumothorax

    Pulmonary embolus

    Pleuritis

    Pericarditis

    All can give fever - so can MI.

    Changes With Position

    Pericarditis only

    when lying back causes more pain

    Changes With Palpitation

    Costochondritis only

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    2/35

    EKG shows 2 mm of ST segment elevation in V2-V4

    Anything 1 mm in 2 electrically connected leads is sufficient for diagnosing acute MI

    II, III F: Inferior wall

    : Anterior Wall

    I,L, : Lateral wall

    What would you do next?

    Cardiac Enzymes

    Do not answer enzyme testing next:

    Takes too long to obtain results

    Treatment should be initiated first

    Won't be positive yet

    Wont change what to do, regardless of results (positive or negative) at this time

    Cardiac Enzymes

    Begins to

    Elevate Lasts

    CPK-MB 4-6 hr 2 days

    Troponin 4-6 hr 1-2 wk

    Myoglobin 1-4 hr s

    LDH 12-24 hr s

    LDH currently is not useful. Never answer it.

    Best Answers:

    Which has the best sensitivity, but poor specificity?

    Myoglobin

    Which has the best specificity?

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    3/35

    Troponin

    CPK-MB is sensitive and specific, but not as sensitive as myoglobin or as specific as

    troponin.

    Treatment of Acute MI in ALL Patients

    Decrease

    Mortality

    Time

    Dependant

    Aspirin YES (25%) YES

    Nitrates ?? ?

    Morphine (Analgesics) ?? ?

    Thrombolytic YES (25%) YES

    -Blockers YES (10-20%) NO

    Special Circumstances

    Angioplasty

    o Patients with major bleeding or risk of bleeding

    o Patients who cant receive thrombolytics for any reason

    o Patients failing thrombolytics and progressing to hemodynamic instability

    o Equal in efficacy to thrombolytics

    Special Circumstances

    ACE Inhibitor

    o Patients with decreased left ventricle function or CHF

    Lidocaine

    o Neveras prophylaxis

    o All patients who develop major vertricular arrhythmias (ventricular

    tachycardia or fibrillation)

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    4/35

    Pacemakers

    Anything slow or that could become slow

    Third-degree AV block

    Mobitz II second degree block

    Left bundle branch block

    USMLE Step 2 Lesson 2: Cardiology: Congestive Heart

    Failure

    Cardiology

    Congestive Heart Failure

    Congestive Heart Failure/Pulmonary Edema

    A 67-year-old woman comes to the ER with 1-2 hours of severe shortness of breath.

    She has a history of two MIs in the past. She comes with a pizza in one hand and a

    bag of Doritos in the other, and she is chewing a sausage. Her respiration rate is 34;

    BP, 130/82; and PUD, 18. Jugulovenous distention is present. Chest: rales to apices.

    Heart:3/6 systolic murmur at Apex 1. S3 gallop. Abd: Enlarged liver.3+ Edema of

    lower extremities to mid-thigh.

    What would you do next?

    Do Not Answer Lab Tests

    CXR:Congestion of vasculature, enlarged heart, effusion

    Arterial blood gas: Hypoxia, respiratory alkalosis

    EKG: Sinus tachycardia

    Echocardiogram (never used in acute cases): decreased ejection fraction, mitral

    regurgitation, abnormal motion of anterior and, inferior walls

    Radionuclide ventriculogram:(MUGA) never use acute scan, most accurate

    method of assessing ejection fraction

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    5/35

    Treatment of Pulmonary Edema

    Sit the patient upright

    Give Oxygen

    Treatment of Pulmonary Edema

    First Step: Preload reduction

    Diuretics any loop diuretic intravenously Morphine

    Nitrates

    Second Step: Only if preload reduction is ineffective

    Positive inotropes

    Dobutamine

    Amrinone

    Treatment of Pulmonary Edema

    Third Step: Afterload reduction

    Ace inhibitors - IV

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    6/35

    Nitroprusside

    Congestive Heart Failure

    Treatment when the patient has been stabilized

    Ace inhibitors

    Diuretics

    Digoxin

    Blockers (carvedilol or metoprolol)

    Blockers

    Reduce mortality

    Increase ejection fraction

    Improve symptoms

    USMLE Step 2 Lesson 3: Infectious Diseases: Intro. to

    Antibiotics

    Infectious Deseases

    Introduction to Antibiotics

    Introduction to Antibiotics

    The organisms that cause diseases have largely not changed

    The antibiotics that go with the organisms change

    The most important aspect of infectious diseases: ascribe the antibiotics that go

    with each group of organisms

    Think in terms of groups of antibiotics

    Gram-positive Cocci: Staphylococcus and Streptococcus

    Penicillins:

    o Oxacillin

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    7/35

    o Cloxacillin

    o Dicloxacillin

    o Nafcillin

    Gram-positive Cocci: Staphylococcus and Streptococcus

    With mild penicillin allergy

    First-generation cephalosporins:

    o Cefazolin

    o Cephalexin

    o Cephradine

    o Cefadroxil

    Gram-positive Cocci: Staphylococcus and Streptococcus

    With severe penicillin allergy

    Clindamycin

    Macrolides (erythromycin, clarithromycin, azithromycin): Used for minor, non-life-

    threatening infections

    Vancomycin, Synercid, Linezolid: Used for gram-positive infections with life-

    threatening allergy to penicillin and methicillin-resistant Staphylococcus

    Gram-negative Bacilli

    ForE. coli, Proteus, Enterobacter, Klebsiella, Morganella, and Pseudomonas, ALL of

    following provide >90% coverage:

    Aminoglycosides (gentamicin, tobramycin, amikacin)

    Aztreonam

    Quinolones (ciprofloxacin, levofloxacin)

    Gram-negative Bacilli

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    8/35

    ForE. coli, Proteus, Enterobacter, Klebsiella, Morganella, and Pseudomonas, ALL of

    following provide >90% coverage:

    Carbapenems (imipenem, meropenem)

    Extended-spectrum penicillins (piperacillin, ticarcillin, azlocillin, mezlocillin)

    Third-generation cephalosporins (especially ceftazidime)

    Fourth-generation cephalosporins (especially cefepime)

    Second-generation cephalosporins (eg, cefoxitin, cefotetan,

    cefuroxime)

    Good for gram-positive coverage like first-generation cephalosporins

    Good for gram-negative coverage but NOT forPseudomonas

    Cefoxitin and cefotetan are good for anaerobes

    Anaerobes

    Oral anaerobes (anything above the diaphragm)

    Clindamycin

    Penicillin (any penicillin EXCEPT the Ox/Clox/Diclox/Naf group)

    Abdominal anaerobes (below the diaphragm)

    Metronidazole

    Imipenem

    Second-generation cephalosporins

    Beta-lactam/ Beta-lactamase inhibitor combinations

    Antivirals

    Herpes simplex and varicella

    Acyclovir, valacyclovir, famciclovir

    Herpes simplex, and varicella AND Cytomegalovirus

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    9/35

    Ganciclovir, foscarnet, cidofovir

    Antivirals

    Influenza

    Oseltamivir, zanamivir

    Amantadine, rimantadine: Becoming archaeologic

    Hepatitis B

    Lamivudine or interferon

    Hepatitis C

    Interferon and ribavirin in combination

    Antifungals

    Life-threatening infections (eg, endocarditis, meningitis, fungemia)

    Amphotericin

    Candida infections

    Azoles

    Fluconazole, ketoconazole, itraconazole

    Onychomycosis

    Terbinafine, itraconazole

    Griseofulvin is as useful as a rotary telephone

    USMLE Step 2 Lesson 4: Central Nervous System Infections

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    10/35

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    11/35

    Papilledema

    Altered mental status

    If CT is required before lumbar puncture, ALWAYS answer give

    treatment (ceftriaxone) before the lumbar puncture:

    Treatment is more important than the specific diagnosis

    Cell count, chemistry (protein level), gram-stain, and bacterial antigen testing can still

    give the diagnosis if the antibiotics sterilize the culture

    Meningitis

    Diagnostic testing on lumbar puncture: Everything depends on the specific question

    asked!

    MOST SPECIFIC test is CULTURE

    MOST SENSITIVE test is PROTEIN

    NEXT BEST or BEST INITIAL test on CSF is CELL COUNT. (Cell count is not as

    specific as culture or as sensitive as protein level but it is the best combination of

    both.)

    Cultures

    In general, culture is the answer to the

    What is the BEST - Most Accurate - Most Likely to lead to specific diagnosis type

    of question.

    HOWEVER:Dont answer, Wait for the cultures before initiating treatment.

    Meningitis

    A 48-year-old man comes to the ER with 1 day of fever, headache, and nausea. He

    has photophobia and a stiff neck. He has no focal neurological deficits or papilledema

    and is fully oriented and alert. Lumbar puncture shows an elevated protein, cell count

    of3,502, and a negative gram stain. Culture is sent.

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    12/35

    Which type of meningitis is this?

    Cell Count on CSF

    Any type of meningitis can cause an elevated cell count; the differential on the cell count

    gives more specific information.

    Neutrophils Bacterial:

    Streptococcus pneumonia: most common

    Neisseria: look for a rash, particularly a petechial rash in the presentation

    Haemophilus: particularly in children, although greatly diminished because of

    vaccination

    Treatment of Bacterial Menigitis

    Cell Count on CSF

    Lymphocytes (look for these specific features):

    Rocky Mountain spotted fever: rash on wrists/ankles, moving centrally towards the

    body

    Lyme: Facial palsy, target lesion rash (erythema migrans)

    Cryptococcus: HIV+ patients with

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    13/35

    neutrophils.

    What is the best initial therapy?

    Treatment of Bacterial Meningitis

    What is the best intial therapy?

    Ceftriaxone unless T-cell immune deficit present.

    Ceftriaxone AND Ampicillin if there is steroid use, neutropenia, pregnancy lymphoma,

    leukemia, HIV or if the patient is elderly or a neonate. Ampicillin covers Listeria.

    Treatment of Bacterial Meningitis

    A 48-year-old man comes to the ER with 1 day of fever, headache, nausea. He has

    photophobia and a stiff neck. He has no focal neurological deficits or papilledema

    and is fully oriented and alert. Lumbar puncture shows an elevated protein, cell count

    of 3,502, and a negative gram stain. Culture is sent. The differential shows 92%

    neutrophils.

    What is the best initial therapy?

    Treatment of Bacterial Meningitis

    What is the best intial therapy?

    Ceftriaxone unless T-cell immune deficit present.

    Ceftriaxone AND Ampicillin if there is steroid use, neutropenia, pregnancy lymphoma,

    leukemia, HIV or if the patient is elderly or a neonate. Ampicillin covers Listeria.

    USMLE Step 2 Lesson 5: PPD Testing

    Infectious Diseases

    PPD Testing

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    14/35

    PPD Testing

    When to use the PPD? What's it for?

    To screen the asymptomatic: do not use as primary method for diagnosing TB in acutely

    symptomatic patients

    What is considered a positive PPD?

    >10 mm induration, not erythema in most patients; >5 mm in HIV+ patients and close

    contacts

    Always get CXR after a positive PPD

    Treatment for a positive PPD means INH alone

    Treat all PPD+ patients if the risk of developing TB is greater than risk of hepatitis from the

    isoniazid:

    ANY recent (past 2 years) converter

    ANYONE with severe immune deficiency (eg, HIV, steroid use, leukemia, diabetes,

    lymphoma)

    ANYONE

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    15/35

    A 32-year-old, HIV- physician from India who received BCG as a child and has never

    been tested before. She has 12 mm of induration at health screening before starting

    an internship in the US.

    Which of the following patients should receive isoniazid

    prophylactic therapy?

    A 47-year-old HIV+ man who had never been tested before and has 7 mm of

    induration.

    A 95-year-old, HIV-, female nursing home resident who was PPD- last year and has

    11 mm of induration this year.

    Which of the following patients should receive isoniazid

    prophylactic therapy?

    A 3,725-year-old Egyptian mummy who was PPD- last year and is PPD+ this year.

    Which of the following patients should receive isoniazid

    prophylactic therapy?

    The 19-year-old woman: NO

    The 32-year-old physician:YES

    The 47-year-old-HIV+ man:YES

    The 95-year-old nursing home resident:YES

    The 3725-year-old Eqyptian mummy:

    YES, YES, YES!

    USMLE Step 2 Lesson 6: HIV

    Infectious Diseases

    HIV

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    16/35

    HIV

    A 37-year-old man comes to your office after having been recently diagnosed with

    HIV. He has no symptoms. His physical examination is normal. His CD4 count is575, and his viral load is 1,000.

    Which medications are appropriate for this patient?

    None for this patient: CD4>500, viral load 20,000

    Whatto start?

    Any two reverse transcriptase inhibitors AND any protease inhibitor

    A 37-year-old man comes to your office after having been recently diagnosed with

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    17/35

    HIV. He has no symptoms. His physical examination is normal. His CD4 count is

    575, and his viral load is 1,000.

    NONE for this patient: CD4 >500, viral load

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    18/35

    Azithromycin (once a week)

    A 37-year-old man comes to your office after having been recently diagnosed with

    HIV. He has no symptoms. His physical examination is normal. His CD4 count is 5,

    and his viral load is 371,000

    .

    Any two nucleosides AND a protease inhibitor AND

    trimethoprim/sulfamethoxazole AND azithromycin AND

    NOTHING!!

    USMLE Step 2 Lesson 7: Hematology: Microcytic Anemia

    Hematology

    Microcytic Anemia

    Microcytic Anemia

    A 32-year- old woman presents with several weeks of fatigue. She complains of

    nothing else. Initial CBC reveals an hematocrit of28%.

    Symptoms of anemia are largely based on severity not etiology. Iron deficiency

    with hematocrit of 28% will give the same symptoms and the anemia of chronic

    disease, folate deficiency, thalassemia, etc, with hematocrits of 28%.

    A 32-year-old woman presents with several weeks of fatigue. She complains of

    nothing else. Initial CBC reveals hematocrit of 28%. The other portions of the CBC

    are normal, and the MCV is 70 (normal 80-100).

    What is the most likely diagnosis?

    After determining that the patient has anemia, the next most useful step is to

    determine the cell size. This is the next easiest clue as to the etiology of the

    anemia.

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    19/35

    Low MCV

    Iron deficiency

    Anemia of chronic disease (can also be normocytic)

    Sideroblastic

    Thalassemia

    High MCV

    Vitamin B12 deficiency

    Folate deficiency

    Alcohol

    Drug toxicity

    Normal MCV

    Hemolysis

    A 32-year-old woman presents with several weeks of fatigue. She complains of

    nothing else. Initial CBC reveals an hematocrit of28%; other portions of the CBC are

    normal, and MCV is 70 (normal 80-100).

    What is the next best step in the management of this microcytic patient? (ie:

    What is the best initial diagnostic test?)

    What is the next best step in the management of this microcytic

    patient?

    Iron Studies

    Iron deficiency: low ferritin, high iron binding capacity Chronic disease: high ferritin, low iron binding capacity

    Sideroblastic: high serum iron

    Thalassemia: normal iron studies

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    20/35

    After the iron studies, how would you address other questions

    about the specifics of the various low MCV anemias? (What is

    the most accurate diagnostic test?)

    Iron Deficiency

    High red cell distribution of width (RDW)

    What is the most specific test? Bone marrow for stainable iron.

    Sideroblastic anemia

    What is the most specific test? Prussian blue stain for ringed sideroblasts

    Thalassemia

    What is the most specific test? Hemoglobin electrophoresis

    What is the best therapy for this patient?

    Iron Deficiency

    Iron replacement

    Ferrous sulfate tablets

    Chronic Disease

    Correct the underlying disease

    What is the best therapy for this patient?

    Sideroblastic anemia

    Pyridoxine

    Thalassemia trait

    No therapy

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    21/35

    USMLE Step 2 Lesson 8: Hematology: Macrocytic Anemia

    Hematology

    Macrocytic Anemia

    A 32-year-old woman presents with several weeks of fatigue. Initial CBC reveals an

    hematocrit of28%.

    Symptoms of anemia are largely based on the severity not the etiology. Iron

    deficiency with hematocrit of 28% will give the same symptoms and the anemia

    of chronic disease, folate deficiency, thalassemia, etc, with an hematocrit of

    28%.

    A 32-year-old woman comes to the office with several weeks of fatigue. In addition,

    she complains of a sensation of pins and needles in her hands and feet. She drinks

    almost a quart of vodka per day. Initial CBC reveals an hematocrit of 28%. The MCV

    is 120 (normal 80-100).

    What is the next best step in the management of this macrocytic patient?

    Macrocytic anemia is largely due to either vitamin or folate deficiency, although

    several drug toxicities (eg, severe alcoholism, zidovudine or methotrexate use) can

    do it as well. You do NOT need neurological symptoms to have anemia from

    deficiency. However the presence of neurological symptoms means it cannot be

    folate deficiency alone. Alcohol can give neurological symptoms as well.

    Which neurological problems can occur with B12 deficiency?

    Motor, sensory, psychiatric, ataxia, position, vibratory, cognitive, autonomic, sexual

    ANY neurological symptom can occur with deficiency

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    22/35

    Which is the most common neurological symptom with B12 deficiency?

    Peripheral neuropathy

    B12 Deficiency

    What is the best intial test?

    Presence of hypersegmented neutrophils and a low B12 level (NOT a Schilling test).

    Folate Deficiency

    What is the best initial test?

    Presence of hypersegmented neutrophils and a low folate level.

    Alcohol or other drug toxicity

    What is the best initial test?

    Absence of hypersegmented neutrophils and to exclude the B12 and folate deficiency

    and look for the drug in the history.

    What are the specific tests you would do to determine the

    specific etiology of the B12?

    Elevated methylmalonic acid and elevated LDH are characteristic of deficiency.

    Antibodies to intrinsic factor and an elevated gastrin level are characteristic of

    pernicious anemia

    Schillings test is the least often used but most specific way to determine precisely

    how a patient is malabsorbing . Do NOT answer Schillings test if the case gives

    you the elevated LDH, antibodies to intrinsic factor and elevated gastrin level.

    What is the best therapy?

    B12 deficiency: Replace the B12

    Folate deficiency: Replace the folate

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    23/35

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    24/35

    thrombosis such as the portal vein

    Hemolytic uremic syndrome (HUS): Renal failure and thrombocytopenia

    Which clues in the history will tell you which type of hemolytic

    anemia it is?

    Thrombotic thrombocytopenic purpura (TTP): Renal failure and thrombocytopenia

    and neurological symptoms and fever

    Hereditary spherocytosis: Splenomegaly

    Which diagnostic testing is useful to distinguish between

    these?

    All EXCEPT the hereditary spherocytosis can also give:

    low haptoglobin level

    hemoglobinuria

    Hemosiderinuria

    Hereditary spherocytosis will not give these because it is extravascular hemolysis.

    Extravascular means it occurs in the spleen.

    Which of the following tests is the most specific, most

    accurate, and most likely to lead to a definite diagnosis in

    each of these forms of anemia?

    Autoimmune: Coombs test

    G6PD: G6PD level

    PNH: Sugar-water and Hams test

    HUS: Finding renal failure and thrombocytopenia with hemolysis; no specific test

    TTP:Finding renal failure, thrombocytopenia, and neurological symptoms and fever

    with hemolysis; no specific test

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    25/35

    Hereditary spherocytosis:Spherocytes on the smear AND an osmotic fragility test

    Which of the following is the best intitial therapy and mostdefinitive therapy?

    Autoimmune:: Initially, steroids; with life-threatening hemolysis, IV immunoglobulin;

    recurrent, splenectomy

    G6PD:Avoid the oxidant stress

    PNH:Steroids

    HUS:Initially, spontaneous resolution; with life-threatening disease, plasmapheresis

    TTP:Plasmapheresis

    Hereditary spherocytosis:Splenectomy

    USMLE Step 2 Lesson 10: Nephrology: Acute Renal Failure

    Nephrology

    Acute Renal Failure

    An 87-year-old woman with a history of gout and osteoarthritis is found on the floor of

    her apt. by her family. It is not clear how long she has been on the floor. She uses

    NSAIDs for joint pain. In the ER she is found to be confused. Her temperature is 102

    F, pulse is 117, and systolic BP blood is 92; rales are heard on lung examination. She

    has a head CT with contrast to evaluate her confusion and receives penicillin and

    gentamicin for her pneumonia. She has no urine output since admission. On hospital

    day 2 her BUN and creatinine begin to rise.

    How many causes of renal failure can you identify in this

    patient?

    The first step in evaluating a patient with acute renal failure is to determine whether

    there is a problem inside the kidney (tubules, glomeruli, vascular) or with the

    perfusion of the kidney (prerenal) or drainage out of the kidney (postrenal).

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    26/35

    The fever, tachycardia, relatively low BP, and the fact that she was found on the

    floor are all sufficient suggestions of pre-renal azotemia.

    The best initial tests to determine whether it is pre-renalazotemia is as follows:

    Pre-renalAcute Tubular

    Necrosis

    BUN/Creatinine

    Ratio> 20:1 10.1

    Urine Sodium Low < 20 High > 40

    Urine Osmolality High > 500 Low < 350

    To exclude post-renal azotemia (obstruction to drainage OUT of

    the kidney) the following are useful:

    Physical examination to detect enlarged bladder

    Ultrasound to look for bladder size and hydronephrosis

    Urinary catheter placement

    Do NOT assume that the decreased urine output described is from the renal failure. The renal

    failure could simply be from decreased urine output and obstruction.

    Intra-renal Damage (ATN)

    Damage to the kidney could affect tubules, glomeruli, or vasculature. It is NOT very

    useful to think of the diseases as cortical or medullary. Glomerular diseases, eg,

    lupus, Goodpasture, Alport syndrome, Berger disease, or even post-streptococcal

    disease, are unlikely to occur this acutely and without other history of systemic

    disease. The same is true of vascular diseases, eg, polyarteritis nodosa, Wegener

    granulomatosis, TTP, HUS, or Henoch Schonlein purpura.

    Intra-renal Damage (ATN)

    Acute renal failure such as this is most often from tubular diseases, which are most

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    27/35

    often from various toxins combined with possible ischemia from hypoperfusion.

    How many different toxins can you identify in this case?

    An 87-year old woman with a history ofgoutand osteoarthritis is found on the floor

    of her apartment by her family. It is not clear how long she has been on the floor. She

    uses NSAIDs for joint pain. In the ER she is found to be confused. Her temperature

    is 102 F, pulse is 117, and systolic BP blood is 92; rales are seen on lung

    examination. She has a heat CT with contrast to evaluate her confusion and

    receives penicillin and gentamicin for her pheumonia. She has no urine output

    since admission. On hospital day 2 her BUN and creatinine began to rise.

    You could simply say that the tubular diseases are from toxins. However, since

    the answers to questions concerning initial and best tests and treatments are

    different, they must be subdivided so they can be addressed individually.

    Direct Toxins

    Gentamicin acts directly as a toxin to the kidney's tubule. Other drugs include

    amphotericin, cisplatin, NSAIDs, and cyclosporine. Contrast agents also act in the

    same way.

    Best test: Exclude other causes of renal failure. There is no test to determine the

    specific etiology of any toxin-mediated organ toxicity. Biopsy will NOT determine the

    specific agent.

    Direct Toxins:

    Best therapy: Stop the offending agent. There is no specific therapy to reverse ANY

    toxin-mediated organ damage beyond this. Dialysis does NOT reverse the damage; it

    supports the patient while waiting for the kidneys to come back to life on their own.

    Allergic Interstitial Nephritis:

    Penicillin causes damage to the kidney, as it causes an allergic reaction against the

    kidney tubule. Other drugs include sulfa drugs, allopurinol, phenytoin, rifampin and

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    28/35

    NSAIDs.

    Keys to recognizing this as the cause of the renal failure are fever and rash,

    although these do not have to be present.

    Allergic Interstitial Nephritis:

    Best initial test: Measure blood and urinary eosinophils. IgE levels are not

    sufficiently sensitive. Renal biopsy is the most accurate test but should seldom, if

    ever, be used.

    Best initial therapy: Stop the medications. Very severe cases can be treated with

    steroids.

    Crystals:

    Uric acid crystals from the gout as well as from oxalate crystals from ethylene glycol

    ingestion can also damage the tubules. Look for gout or ethylene glycol ingestion in

    the history.

    Best initial test: Urinalysis to look for crystals.

    Therapy: Either allopurinol for gout or ethanol infusion for the ethylene glycolingestion.

    Pigments:

    Myoglobin from rhabdomyolysis and hemoglobin from hemolysis are directly toxic to

    the tubule. The fact that this patient was found lying on the floor of her apartment is

    suggestive of rhabdomyolysis. Clues to pigments as the cause of the renal failure are

    hemolysis or muscle breakdown, as dark urine, on history.

    Pigments:

    Best initial tests: EKG to exclude signs of life-threatening hyperkalemia and

    urinalysis to show dipstick positive for blood with no RBCs on the microscopic

    examination.

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    29/35

    Most accurate and specific tests: Myoglobin in urine and elevated CPK level in

    blood for rhabdomyolysis.

    Best initial therapy: Hydration and alkalinization of the urine with bicarbonate.

    USMLE Step 2 Lesson 11: Nephrology: Hyponatremia

    Nephrology

    Hyponatremia

    A 59-year-old man with a history of lung cancer 1 cm from his carina is admitted to

    the hospital because of mild confusion, which has developed over the past severaldays. His sodium level is 119 (normal 135-145)

    What is the etiology of his hyponatremia?

    The first step in evaluating hyponatremia is to determine the

    volume status of the patient.

    Hypervolemic (presence of rales, edema, jugulovenous distention):

    o Congestive heart failure

    o Nephrotic syndrome

    o Cirrhosis

    The first step in evaluating hyponatremia is to determine the

    volume status of the patient.

    Hypovolemic (orthostasis, dry mucous membranes, decreased skin turgor):

    o GI fluid loss

    o Urinary loss, diuretics

    o Skin losses, sweating, fever, burns

    The above also require replacement with free water to drive sodium down

    The first step in evaluating hyponatremia is to determine the

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    30/35

    volume status of the patient.

    Normal volume:

    Addisons disease does not require free water to drive the sodium down.

    Psychogenic polydipsia

    Pseudohyponatremia

    Syndrome of inappropriate antidiuretic hormone (SIADH)

    Hypothyroidism

    A 59-year-old man with a history of lung cancer 1 cm from his carina is admitted to

    the hospital because of mild confusion, which has developed over the past several

    days. His sodium level is 119 (normal 135-145). Physical examination reveals

    normal skin turgor and no orthostasis, edema, or rales.

    What is the best initial test?

    If a normal persons sodium were suddenly driven below normal, the bodys response

    would be to immediately shut off all ADH secretion, allowing the maximal amount of

    free water to be released. The normal response would be to maximally dilute the

    urine. The normal response to hyponatremia would be to have a urine osmolality at

    the lowest possible amount. The range of urine osmolarity is 50-1200 mOsm/kg. The

    normal response would be urine osmolarity around 50 mOsm/kg and urine osmolality

    less than serum osmolarity. Urine sodium should also be low.

    The best initial test is the

    urine osmolality

    A 59-year-old man with a history of lung cancer 1 cm from his carina is admitted to

    the hospital because of mild confusion, which has developed over the past several

    days. His sodium level is 119 (normal 135-145). Physical examination reveals normal

    skin turgor and no orthostasis, edema, or rales. His serum osmolality is 250

    mOsm/kg (normal 280-300), urine osmolality is 425 mOsm/kg and urine sodium

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    31/35

    is 42 mEq/L.

    What is the best therapy for this patient?

    The urine osmolality in this patient is higher than the serum osmolality. Combined

    with a high urine sodium level this is confirmatory of SIADH. We do not use ADH

    levels.

    Therapy for SIADH is divided as follows:

    Mild, asymptomatic hyponatremia: Fluid restriction to 1/L/day

    Moderate hyponatremia with mild or moderate neurological symptoms: Saline

    infusion and loop diuretic

    Severe hyponatremia with severe symptoms: 3% hypertonic saline sometimes

    combined with diuretic

    What are the complications of changing sodium levels too

    rapidly?

    (>1-2 mEq/L/hr)

    Too rapid a RISE => central pontine myelonolysis

    Too rapid a DROP => cerebral edema

    The patient described above has his sodium corrected by normal saline infusion and

    a diuretic. His neurological symptoms resolve.

    What is the next best step in his management?

    This patients underlying problem probably cant be corrected; lung cancer at the

    carina typically cant be resected. Hence, as soon as the saline and diuretic therapy

    is stopped the hyponatremia will recur. He will probably not be thrilled with

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    32/35

    maintaining lifelong fluid restriction.

    What is the management of chronic SIADH?

    Demeclocycline to block the effect of the ADH at the level of the kidney tubule

    on a chronic basis.

    USMLE Step 2 Lesson 12: Nephrology: Hyperkalemia

    Nephrology

    Hyperkalemia

    A 27-year-old man presents to the ER at your hospital after having just taken the

    physical exam to join the NY City Fire Department. As part of this exam he must do

    50 push-ups followed by suddenly lifting a 175-lb bag of sand. He then has to run up

    and down 3 flights of stairs and across a balance beam followed by 50 more push-

    ups. He comes to see you because of severe muscle pain, muscle tenderness, and

    dark urine developing over the next several hours.

    What is the most important first step in his management?

    The patient seems to have rhabdomyolysis on the basis of severe, sudden exertion.

    Several tests are needed: CPK level, urinalysis looking for blood on dipstick, urine

    microscopic exam, potassium level, and possibly urine myoglobin level. However,

    you must choose the MOST URGENT test. No matter how high the CPK level is,

    hyperkalemia is more immediately life-threatening. Even if the potassium level is

    elevated, it is more important to know whether there are EKG abnormalities from the

    hyperkalemia, which mean he will suddenly die of an arrhythmia.

    The EKG shows peaked T-waves

    What is the NEXT best step in management?

    Calcium chloride or calcium gluconate is given intravenously

    What is the NEXT best step in management?

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    33/35

  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    34/35

    Do NOT answer toxicology screen. This takes too long to come back to be useful

    and it will not change management. No matter what pills she took, the initial answer

    in the first hour of management is to empty the stomach.

    Why NOT the gastric lavage?

    Gastric lavage with an oropharyngeal hose is not very useful, and most awake

    patients do not need this and will not tolerate it. Use gastric lavage in patients with an

    acute overdose who have an altered mental status in the first hour after a pill

    ingestion. You cannot give ipecac to these patients because they will aspirate.

    Perform endotracheal intubation with gastric lavage to protect the airway when

    the patient has altered mental status.

    Do NOT lavage patients with caustic, acid or alkali ingestion.

    After the ipecac, what is the NEXT best step in

    management?

    Activated charcoal

    Charcoal is useful in almost all overdoses and is not dangerous in anybody. In

    addition, charcoal will even remove drug from the body that has already been

    absorbed into the blood stream.

    A 25-year-old medical student gets very depressed while preparing for USMLE Step

    2. After finishing studying at midnight she takes a bottle of pills at 12:15 am in an

    attempt to commit suicide. She removes the label from the bottle so no one can

    determine what she took. At 12:30 am she finds that her last practice test score was

    87% and she will easily pass. She walks across the street to the ER at 1:00 am to

    seek treatment.

    The patient is confused, disoriented, lethargic, sleepy, and

    obtunded and is not thinking so well.

    What is the best initial step in the management of this patient?

    http://www.pdfonline.com/easypdf/?gad=CLjUiqcCEgjbNejkqKEugRjG27j-AyCw_-AP
  • 8/8/2019 Microsoft Word Viewer - Internal Medicine 1,Conrad Fisch

    35/35

    Naloxone

    Thiamine

    Dextrose

    Although you will want to intubate the patient to perform gastric lavage,

    you must FIRST give the naloxone, thiamine, and dextrose. If the

    patient took an opiate or is hypoglycemic she will awaken immediately.

    You will NOT have to do lavage then because the problem will have

    been solved.

    She awakens after being given the naloxone, dextrose and thiamine.

    What is the NEXT best step in management?

    Activated charcoal for the same reasons as described above.

    After this management, then toxicology and specific drug levels are used to

    determine the specific etiology of the overdose.