NBME CBSE flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Major depressive disorder criteria

At least five of nine symptoms lasting two weeks or more, and one of them must be depressed mood or anhedonia.

Alcohol withdrawal treatment

Benzodiazepines are first line, dosed using a withdrawal scale such as the CIWA-Ar; thiamine is given to prevent Wernicke encephalopathy.

Serotonin syndrome features

Clonus, hyperreflexia, hyperthermia, agitation and diarrhea after serotonergic drugs; stop the offending agent and give cyproheptadine if severe.

Sensitivity and specificity

Sensitivity is TP/(TP+FN), the fraction of diseased patients who test positive; specificity is TN/(TN+FP), the fraction of healthy patients who test negative.

Positive predictive value

PPV is TP/(TP+FP), the probability that a positive test indicates disease; unlike sensitivity and specificity, it rises as prevalence rises.

Relative risk

Incidence in the exposed group divided by incidence in the unexposed group, calculated in cohort studies; a value of 1.0 means no association.

Iron deficiency anemia labs

Microcytic anemia with low ferritin, high TIBC, low transferrin saturation and elevated RDW; serum ferritin is the most specific test.

B12 versus folate deficiency

Both cause macrocytic anemia with hypersegmented neutrophils, but only B12 deficiency raises methylmalonic acid and produces neurologic deficits.

TTP versus HUS

Both show microangiopathic hemolytic anemia with schistocytes and thrombocytopenia; TTP reflects ADAMTS13 deficiency and is treated with plasma exchange, while HUS follows diarrheal illness.

Aortic stenosis murmur

Crescendo-decrescendo systolic ejection murmur at the right upper sternal border radiating to the carotids, accompanied by a delayed, low-amplitude carotid upstroke.

Mitral regurgitation murmur

Holosystolic blowing murmur heard best at the apex and radiating to the axilla; it becomes louder when afterload rises, such as with handgrip.

Tetralogy of Fallot

Four defects: right ventricular outflow obstruction, ventricular septal defect, overriding aorta and right ventricular hypertrophy; cyanotic spells worsen with crying and improve with squatting.

Diabetic ketoacidosis

Anion-gap metabolic acidosis with ketones and hyperglycemia; total body potassium is depleted, so potassium is replaced once serum potassium is not elevated.

Primary hyperparathyroidism

Elevated calcium with low phosphate and inappropriately elevated PTH, most often from a single parathyroid adenoma, causing stones, bones and abdominal groans.

SIADH

Euvolemic hypotonic hyponatremia with high urine osmolality and high urine sodium; treatment is fluid restriction plus correction of the underlying cause.

Celiac disease serology

IgA anti-tissue transglutaminase is the screening test; biopsy shows villous atrophy with crypt hyperplasia, and HLA-DQ2 or DQ8 is required for disease.

Crohn disease versus ulcerative colitis

Crohn disease is transmural with skip lesions and granulomas anywhere in the GI tract; ulcerative colitis is continuous mucosal disease beginning in the rectum.

Glycolysis rate-limiting enzyme

Phosphofructokinase-1 catalyzes the committed step of glycolysis; it is activated by AMP and fructose-2,6-bisphosphate and inhibited by ATP and citrate.

Collagen type locations

Type I is in bone, skin and tendon; type II in cartilage; type III in blood vessels and early granulation tissue; type IV in basement membrane.

Hardy-Weinberg carrier frequency

For a recessive allele with frequency q, heterozygous carriers occur at frequency 2pq, and the genotype frequencies p-squared, 2pq and q-squared sum to 1.

Gout crystals

Needle-shaped, negatively birefringent monosodium urate crystals in joint fluid; pseudogout instead shows rhomboid, positively birefringent calcium pyrophosphate crystals.

Pemphigus versus pemphigoid

Pemphigus vulgaris causes intraepidermal flaccid bullae with anti-desmoglein antibodies and a positive Nikolsky sign; bullous pemphigoid causes subepidermal tense bullae with linear IgG.

Melanoma prognosis

Breslow thickness, the depth of invasion measured in millimeters, is the strongest prognostic factor and guides wide excision and sentinel lymph node biopsy.

Upper motor neuron signs

Spasticity, hyperreflexia, an extensor plantar Babinski response and minimal atrophy, caused by lesions above the anterior horn cell.

Epidural hematoma

Lens-shaped blood collection from a torn middle meningeal artery, often with a lucid interval after head trauma, requiring urgent surgical evacuation.

Multiple sclerosis

Demyelinating plaques in periventricular white matter with oligoclonal bands in the CSF; symptoms transiently worsen with heat, known as Uhthoff phenomenon.

Prerenal versus intrinsic AKI

Prerenal azotemia shows a BUN/creatinine ratio above 20 and fractional excretion of sodium below 1%; intrinsic injury such as acute tubular necrosis shows muddy brown casts and FENa above 2%.

Nephrotic syndrome

Proteinuria above 3.5 g per day with hypoalbuminemia, edema and hyperlipidemia; minimal change disease is the most common cause in children.

LH surge

A sharp midcycle rise in LH triggers ovulation about 34 to 36 hours later; it follows the estradiol positive-feedback peak and leads to corpus luteum formation.

Preeclampsia management

Hypertension after 20 weeks with proteinuria or end-organ dysfunction; magnesium sulfate prevents and treats seizures, and delivery is the definitive treatment.

Obstructive versus restrictive spirometry

Obstruction lowers the FEV1/FVC ratio below 0.70 with air trapping; restriction lowers both FVC and TLC while the FEV1/FVC ratio stays normal or high.

Sarcoidosis

Noncaseating granulomas with bilateral hilar lymphadenopathy, elevated serum ACE, and hypercalcemia from granulocyte-mediated vitamin D activation.