NBME Medicine Form 4 - Answers & Explanations

Updated: Aug 28, 2020

1) X-ray of the chest • Clubbing of fingers & toes = hypertrophic osteoarthropathy

2) Hypercarbia • O2 supplementation → ↓ respiratory drive → retained CO2 (hypercarbia)

3) Mycoplasma pneumoniae • young, non-productive cough, low grade fever with patchy or diffuse interstitial infiltrate = atypical mycoplasma pneumonia

• CXR looks worse than the patient feels

4) Legionella pneumophila • Pneumonia + diarrhea = legionnaires disease • Pulse temperature dissociation (fever with relative bradycardia)

5) Renal artery stenosis • Carotid bruit = atherosclerosis of carotid artery; atherosclerosis in one vessel indicates multi vessel disease → RAS secondary to atherosclerosis

6) Erythropoietin • Corrected reticulocyte count is ~1.2%, meaning there is not enough marrow stimulation • Chronic kidney disease → ↓ EPO production

7) Pamidronate • Short term treatment of hypercalcemia is normal saline and calcitonin

• Long term treatment of hypercalcemia is bisphosphonates

8) Drug induced neutropenia • PTU and methimazole → neutropenia

9) Villous atrophy in the small bowel • D-xylose depends only on viable mucosa (not enzymatic breakdown) for absorption in the proximal small bowel • Celias disease → villous blunting → ↓ D-xylose absorption

10) Three-drug antiretroviral therapy only

• Start antiretrovirals straight away regardless of CD4 count

• Need to use three because of increased resistance

• No need for P. jiroveci prophylaxis because CD4 count >200

11) Direct current countershock • Direct current countershock = DC cardioversion • Wide QRS complex = ventricular tachycardia → shock

12) Choledocholithiasis

• This patients high amylase indicates there is a blockage at the pancreatic duct, and the elevated direct bilirubin indicates a blockage of the common bile duct

13) Left medial longitudinal fasciculus • The right PPRF send a signal to the left medial rectus via the left MLF; weakness of left adduction upon right gaze indicates a problem at the left MLF

14) Calcification of a bicuspid aortic valve • Systolic ejection murmur at the young age of 19 indicates a congenital cause

• Aortic stenosis (due to calcified bicuspid aortic valve) → ↑ LV pressure → hypertrophy and stiffening of the LV → S4

15) Supraspinatus tendon • Pain over lateral deltoid, awaking at night (lying on affected shoulder) and pain elicited from abduction against resistance = rotator cuff pathology

16) Acute tubular necrosis

• 3+ blood with no RBC’s → rhabdo → myoglobinuria → ATN

17) Seborrheic dermatitis • Usually appears on hairy areas (eg, scalp behind ears, beard, etc.)

• Greasy looking yellowish scaly rash • Associated with HIV & Parkinson disease

18) Switch from heparin to direct thrombin inhibitor therapy • Heparin-induced thrombocytopenia → stop all heparin products and start a direct thrombin inhibitor or fondaparinux

19) Gout

• Chronic alcohol use with asymmetric arthritis

20) MRI of the lumbosacral spine

• Compression of sacral nerves by tumor → Cauda Equine syndrome (B/L paralysis and numbness of LE, urinary incontinence (overflow), saddle anesthesia, absent DTRs below the knee)

• MRI is the modality of choice to diagnose nerve root compression

21) α1-antitrypsin deficiency

• Increased lucency at lung bases in young patient → panacinar emphysema

22) Hodgkin disease

• Single enlarged LN, pruritis, and absence on pharyngeal erythema make Hodgkin disease more likely than mono

• Pathologic lymphocytes are confined to affected nodes (unless a leukemic transformation occurs) which is why leukocyte count is not elevated

23) Addition of lisinopril to the medication regimen • ACEi → ↓ glomerular hyper-filtration associated with DM

24) Lisinopril therapy

• Hemorrhagic stroke are commonly caused by HTN

• Although weight reduction of 10kg lowers BP by 5-20 mmHg, this patient has already suffered a complication of HTN and must be treated aggressively with BP medication (while he continues to make lifestyle changes)

25) Nonketotic hyperosmolar state

• Glucose > 600 = HHS