USMLE Step 1 Study Guide

USMLE Step 1 Study Guide Heterophile ab NEGATIVE Mono-like syndromes - answer*CMV HHV-6 HIV Toxoplasmosis Wernicke's Aphasia - answer-word salad: well-articulated, nonsensical speech paired with lack of lang comprehension -aud association cortex: post part of sup temporal gyrus - supplied by MCA Congenital Deficiency of Propionyl CoA Carboxylase - answer-prevents conversion of propionyl CoA to methylmalonyl CoA -propionyl CoA derived from= val, ile, met, thr, odd # FA, cholesterol side chains -Propionic Acidemia: poor feeding, vomiting, hypotonia, lethargy, dehydration, anion gap acidosis Down Synd Comorbidities - answerNeuro: MR, early onset Alzheimer's Cardio: complete AV septal defect, VSD, ASD GI: duodenal atresia, hirschprung disease Endo: hypothyroid, DM1, obesity Heme: ALL (> 5 yo) and AML (<5 yo) Rheumatology: atlantoaxial stability MCC of Hypoglycemia in EtOH-ics - answerThiamine def= suppression of GNG (pyruvate DH) and TCA cyle (alpha-KG DH) MCC of Hypoglycemia in advanced renal insuff - answerimpaired clearance of insulin Avoid Nitrates in Hypertrophic Cardiomyopathy bc... - answerNitrates decrease preload, which will increase the LV outflow tract... BUT since the ventricle is abnormally shaped, there is an outflow obstruction Mets through BM - answerClonal proliferation of cells can invade/ metastasize* 1. malignant cells to lose their cell-to-cell adhesion molecules (cadherins) 2. cell receptors to attach to laminin (a glycoprotein) in the basement membrane and to release metalloproteinases (e.g., collagenases, stromelysins, gelatinases) to degrade the basement membrane and other enzymes to degrade the interstitial connective tissue- tissue inhibitors of metalloproteinases neutralize these tumor- produced enzymes and limit the degree of invasion 3. cell receptors to attach to bronectin and other proteins in the extracellular matrix (ECM) and to break it down 4. malignant cells to produce cytokines that stimulate locomotion, so that they can move through basement membranes and the intracellular and extracellular matrices Bicuspid Aortic Valve - answerCommonly presents in young, asymptomatic patient with soft systolic ejection at right 2nd ICS -can cause aortic regurg MCC of Vaginal Candidiasis - answer1. Abx use= reduces lactobacilli pop 2. High estrogen levels- preg 3. System corticosteroid therapy 4. Uncontrolled DM 5. Immunosuppression, including HIV Drug causes of SIADH - answer-Carbamazepi