NBME Medicine Form 3 - Answers & Explanations
Updated: Feb 25, 2020
1) Vitamin B1 (thiamine) • Wernicke encephalopathy triad: ataxia, ophthalmoplegia, confusion
• Thiamine before glucose
2) Osteosarcoma • Associated with Rb mutation • Periosteal bone reaction - codman triangle
3) Pertussis • Paroxysms of intense cough with posttussive vomiting
4) Enterotoxigenic Escherichia coli
• Travelers diarrhea = ETEC
5) Admit the patient to the hospital
• Stable angina has progressed to unstable angina → admit to hospital (cath lab)
6) Chest tube placement • Complicated parapneumonic effusion ( pH < 7.2, glucose < 60) • Treat with chest tube placement to drain the pus and IV antibiotic
7) Medial degeneration of the aorta • Cystic medial degeneration predisposes to dissection
8) Test for factor VIII inhibitor • During a mixing study, normal plasma is added to plasma from a hemophiliac patient
• Clotting deficiencies should correct (PTT returns to normal)
• Factor inhibitors will not correct (PTT will fail to normalize if factor VIII inhibitor is present)
9) Exercise stress echocardiography • This patient already has an abnormal EKG (LBBB will make EKG difficult to interpret)
• Stress echo should be performed instead (which will likely show areas of hypoperfusion induced by exercise)
10) Bromocriptine therapy • Dopamine agonists inhibit prolactin secretion
11) Impaired DNA synthesis • Megaloblastic anemia (impaired DNA synthesis d/t lack of B9 or B12)
12) Anaphylactic shock • Likely due to a food allergy at the restaurant
• Diffuse bronchospasm, hypotension, tachypnea, tachycardia = shock
13) Pericarditis • Lupus is associated with serositis (eg, pericarditis) • Pain in pericarditis is worsened with inspiration (pleuritic) and relieved by leaning forward
14) Labyrinthitis • Acute onset of vertigo with nausea, vomiting and gait disturbance
• Distortion of light reflex off tympanic membrane due to ear fullness
15) Sclerosing cholangitis • PSC is associated with Ulcerative Colitis
• Direct hyperbilirubinemia
16) Chronic hepatitis C • Blood products weren’t screened for HCV until 1992 • HCV is more likely to become a chronic infection (~75%); HBV rarely develops into a chronic infection (~5%)
17) Lung abscess • Cavitary lesion with air fluid level suggests abscess
• Alcoholics → ↑ risk of aspiration pneumonia
18) Serum insulin-like growth factor 1 • IGF-1 mediates most effects of GH - preferred initial test for Acromegaly
• GH levels have wide fluctuations and are not sensitive
19) Ceftriaxone • Numerous gram-positive diplococci = strep pneumo
• Treat with 3rd generation cephalosporin
20) Infection of the joint secondary to disseminated Neisseria gonorrhoeae
• Purulent mono arthritis and/or triad of polyarthralgias, tenosynovitis, and vesiculopustular skin rash
21) Mild cognitive impairment
• MMSE < 24 is suggestive of dementia or delirium
• This patient is able to live independently (drive alone without getting lost, manage his finance) - this with old age is suggestive of mild cognitive impairment
22) Nephrotic syndrome • Decreased protein and edema are consistent with nephrotic syndrome
• Patient is previously health - unlikely that cirrhosis or malnutrition manifests within a 2 week period
23) Myocardial infarction • EKG is consistent with STEMI • Tamponade EKG shows low-voltage QRS with electrical alternans
24) Type 2 diabetes mellitus • HTN + BMI of 32 → ↑ risk of diabetes
25) Administration of warfarin • DVT prophylaxis with LMWH/Heparin (second line option is warfarin)
26) Primary metabolic acidosis • Cardiogenic shock → hypoperfusion → hypoxemia → ↓ oxidative phosphorylation → lactic acidosis → metabolic acidosis
27) Colonoscopy • Patient FOBT in patients > 50 → colonoscopy; >40 → sigmoidoscopy; <40 → anoscopy
28) Intravenous ceftriaxone • Cant use oral antibiotics since this patient is vomiting (or if patient is elderly or septic)
• IV fluoroquinolone, aminoglycoside, or cephalosporins can be used • Most hospitalized patients can be transitioned to oral antibiotics (eg, TMP-SMX or oral fluoroquinolone) if symptoms are improved at 48hrs
29) High-output heart failure • Blood loss (positive FOBT) and severe anemia (hemoglobin is 5) → high-output heart failure (ejection fraction is 70%)
30) Pulmonary edema • Long standing poorly controlled HTN → LV failure with pulmonary edema
• ↑ LA pressure → cephalization of pulmonary vessels
31) rare WBC, eosinophils • Nafcicillin (penicillin) → tubulointerstitial nephritis
32) Accumulation of β-hydroxybutyric acid
• Anion gap = 22
• DKA has increased AG, HHS has normal AG
• Rapid breathing = Kussmaul breathing
33) Acute urethral obstruction • No urine output = mechanical pathology; decreased urine output = functional renal pathology
34) Synchronized cardioversion • Wide complex tachycardia with hemodynamic instability should be treated with synchronized cardioversion
35) 0.9% Saline • Initial treatment for hypercalcemia is normal saline & calcitonin (short term); Bisphosphonates are used for long term treatment
36) Repeat measurement of serum cholesterol concentration in 5 years • Everyone should be screened with fasting lipid profile every 5 years beginning at 20 years old
37) Rapid infusion of 0.9% isotonic saline
• Fluid resuscitation to treat hemodynamic instability, then emergent EGD
38) Radial nerve injury • Humeral fracture - “ARM”
• Proximal humeral fracture → Axillary nerve injury • Mid shaft humeral fracture → Radial nerve injury → wrist drop
• Distal humeral fracture → Median nerve injury
39) Oral ibuprofen • This questions points to rheumatoid arthritis (RA): pain being worst in the morning, ↑ ESR, symmetric swelling, systemic symptoms (fatigue), subchondral cysts and osteopenia
• First-line therapy for RA is NSAIDs (eg, ibuprofen)
40) Asbestosis • Associated with ship building or shipyard work • Calcified pleural plaques are pathognomonic for asbestosis
• Malignancy effusion → low glucose
41) Activation of mast cells • Asthma exacerbated by smoke • “end expiratory wheeze”, “CXR show no abnormalities” = asthma
42) Surgical excision • New lesion (appeared 6 months ago), irregular borders = melanoma
43) Congenital bicuspid aortic valve
• Slow upstroke, LV hypertrophy are consistent with aortic stenosis
• Most common cause of aortic stenosis in young/middle-aged patients is bicuspid aortic valve
• No change in murmur with Valsalva maneuver rules out HOCM
44) Benign prostatic hyperplasia
• Amitriptyline has anticholinergic properties
45) Gastric bezoar • Mental retardation + area of alopecia + frequent vomiting → gastric bezoar
• A bezoar is a mass trapped in the GI system • This patient is pulling his hair out and ingesting it → gastroparesis
46) Operative repair of the esophageal injury • If the patient is ill or the perforation is large (communication into pleural space) then surgery should be performed
• If perforation is small it can be managed medically (IVF, NPO, H2 blockers)
47) Phlebotomy • Polycythemia vera (myeloproliferative disorder)
• Treat with phlebotomy and hydroxyurea
48) Sexual activity without contraception • Isotretinoin is teratogenic - patients must be on contraception and have a negative pregnancy test prior to beginning therapy
49) Randomized controlled trial of drug X versus standard therapy • Must compare the new treatment to the current standard of care - it is unethical to not treat the patient (placebo)
50) Measurement of serum immunoglobulin concentrations • Common variable immunodeficiency (CVID) → ↑ risk of sinopulmonary infections and bronchiectasis
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