USMLE Step 1 Questions with Complete Solutions 2023-Graded A+

USMLE Step 1 Questions with Complete Solutions 2023-Graded A+ Heterophile ab NEGATIVE Mono-like syndromes - CORRECT ANSWER *CMV HHV-6 HIV Toxoplasmosis Wernicke's Aphasia - CORRECT 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 - CORRECT 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 - CORRECT ANSWER Neuro: 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 - CORRECT ANSWER Thiamine def= suppression of GNG (pyruvate DH) and TCA cyle (alpha-KG DH) MCC of Hypoglycemia in advanced renal insuff - CORRECT ANSWER impaired clearance of insulin Avoid Nitrates in Hypertrophic Cardiomyopathy bc... - CORRECT ANSWER Nitrates decrease preload, which will increase the LV outflow tract... BUT since the ventricle is abnormally shaped, there is an outflow obstruction Mets through BM - CORRECT ANSWER Clonal 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 - CORRECT ANSWER Commonly presents in young, asymptomatic patient with soft systolic ejection at right 2nd ICS -can cause aortic regurg MCC of Vaginal Candidiasis - CORRECT ANSWER 1. 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 - CORRECT ANSWER -Carbamazepine -Cyclophosphamide -SSRI MC Ankle Sprain due to inversion of plantar-flexed foot - CORRECT ANSWER -Ant Talofibular Lig dmg -ecchymosis at the ant-lat aspect of the ankle Upper Brachial Plexus Injury - CORRECT ANSWER - Musculocutaneous and Suprascapular N. - dystocia mc in neonates; severe trauma mc in adults - should adduction, elbow extension, and forearm pronation