NBME Medicine Form 2 - Answers & Explanations

Updated: Nov 16, 2019


1) Enalapril • ACEi are protective against diabetic glomerulonephropathy

2) Idiopathic central diabetes insipidus • 50-100% increase in UOsm w/ DDAVP = Central DI • UOsm > 600 after deprivation = functional ADH (suggests primary polydipsia)

3) Amikacin • Aminoglycosides are nephrotoxic

4) Ambulatory ECG monitoring • Unexplained syncope without prodrome suggests arrhythmia as the cause

5) Bronchitis • Ronchi (low pitch = upper airway) are bronchiole airway sounds

• CAP would have CXR findings of consolidation/infiltrate

• Rales (crackles) + fever → pneumonia

6) Bicuspid aortic valve

• Systolic murmur peaking in late systole = crescendo-decrescendo murmur = Aortic Stenosis (causing slow-rising, sustained carotid pulse)

• Coarctation → brachial/femoral delay

• Rheumatic valve disease = MR w/ holosystolic murmur at apex

• VSD → holosystolic murmur w/ thrill at LSB

7) Measurement of serum creatinine concentration

• This patient already has signs of end-organ damage (HTN retinopathy) → screen other organs as well

• Serum creatinine indicates renal functioning

8) Decreased synaptic activity of cholinesterase

• Organophosphate toxicity

9) Administration of hepatitis B vaccine • IgM anti-HBc may be the sole maker of infection during the window period

10) Chronic myelogenous leukemia (CML) • Basophilia and Metamyelocytes < myelocytes = CML • No basophilia and Metamyelocytes > myelocytes = leukemoid reaction

11) PPD skin test • Patients with HIV should be screened for TB (regardless of CD4 count)

• If screening is positive → CXR to determine if latent or active

12) Duplex ultrasonography of the carotid arteries • U/S is cheaper than arteriography • Arteriography can cause embolization and risk another stroke

• CT with no abnormalities → no need for MRI

13) Decreased sensitivity, Increased specificity • Raising the cutoff point increases false negatives (decreases sensitivity) and decreases false positives (increases specificity)

14) Oxybutynin • Muscarinic antagonist that reduces bladder spasms and urge urinary incontinence (overactive bladder)

15) Abnormality of antiprotenase resulting in destruction of alveolar supporting structures

• Panacinar emphysema (alpha1-antitrypsin deficiency) → lower lobe destruction

• Centracinar emphysema (smoking induced) → upper lobe destruction

16) Increased vascular permeability

• ↑ CO with normal PCWP and LVEDV = distributive shock (most likely septicemia based on vitals and WBC)

• Inflammatory response → vasodilation → vascular content seeps into extravascular space → inability of oxygen to pass through → ↓ PO2

17) Empyema • Light’s criteria - fluid is exudative if ≥ 1 of the following is met:

• Pleural effusion protein/serum protein ratio > 0.5 • Pleural effusion LDH/serum LDH ratio > 0.6 • Pleural effusion LDH > 2/3 the upper limit of normal for serum LDH

• Empyema has pH < 7.2 (uncomplicated parapneumonic effusion has pH > 7.2)

• Not uncomplicated because gram-positive diplococci

18) Felty Syndrome • Rheumatoid arthritis + neutropenia + splenomegaly

19) Renal Failure • ESRD → uremic pruritis → scratching & excoriations • Kidney normally clears leptin; ESRD → ↑ leptin → anorexia

20) Prednisone therapy • Anti-smith antibodies = SLE


21) Adenocarcinoma of the lung • Most common primary lung cancer; more common in women and nonsmokers

• Peripherally located

22) Karyotype analysis • Klinefelter syndrome (XXY) → testicular atrophy, gynecomastia, tall, female hair distribution, developmental delay

23) Variant angina pectoris

• Aka prinzmetal or vasospastic angina → recurrent episodes of angina at rest

24) Abdominal paracentesis • Suspected spontaneous bacterial peritonitis in patients with cirrhosis that develop fever and change in mental status

• Suspected SBP → perform paracentesis → initiate empiric therapy with 3rd generation cephalosporin

25) Zinc

• Deficiency → ↓ alopecia, pustular skin rash, hypogonadism, impaired wound healing, impaired taste, immune dysfunction

26) Packed red blood cells • Hematocrit of 18% ≈ Hemoglobin of 6

• Hemoglobin < 7 → pRBC

27) Intravenous administration of 0.9% saline • Hypercalcemia → confusion; tx with fluids and calcitonin (short term) and bisphosphonates (long term)

• Indication for dialysis - AEIOU

• Acidosis, Electrolyte derangements (hyperkalemia), Intoxication (eg, ethylene glycol), Overload (of volume), Uremia

28) Varicella-zoster virus • Closely groups cluster = dermatomal distribution

29) Decreased myocardial contractility

• Immediately after an MI, the myocardium is stunned and won’t contract

• Stunned myocardium wont push out blood → atria pushing blood into an already filled ventricle → S3


30) Oral administration of an H2-receptor blocking agent

• Upright positioning alleviating symptoms → GERD

• Murmur is benign


31) Reassurance only

• Mid systolic click = MVP

• There is an association between MVP and anxiety (possibly → tachypnea), so all patients should be reassured about the benign nature of the condition

32) Pancreatitis • Presents with fever, tachycardia, hypotension, abdominal tenderness

• Alcoholism → ↑ risk • Saponification → hypocalcemia

• Complications include GI bleeding

33) Intravenous 0.9% saline • Short-term