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USMLE Step 1 Questions and Answers
Heterophile ab NEGATIVE Mono-like syndromes Ans: *CMV
HHV-6
HIV
Toxoplasmosis
Wernicke's Aphasia Ans: -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 Ans: -
prevents conversion of propionyl CoA to methylmalonyl CoA
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-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 Ans: 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 Ans: Thiamine def= suppression
of GNG (pyruvate DH) and TCA cyle (alpha-KG DH)
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MCC of Hypoglycemia in advanced renal insuff Ans: impaired
clearance of insulin
Avoid Nitrates in Hypertrophic Cardiomyopathy bc... Ans: 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 Ans: 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
© 2025 All rights reserved
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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 Ans: Commonly presents in young,
asymptomatic patient with soft systolic ejection at right 2nd ICS
-can cause aortic regurg
MCC of Vaginal Candidiasis Ans: 1. Abx use= reduces lactobacilli
pop
2. High estrogen levels- preg
3. System corticosteroid therapy
© 2025 All rights reserved
USMLE Step 1 Questions and Answers
Heterophile ab NEGATIVE Mono-like syndromes Ans: *CMV
HHV-6
HIV
Toxoplasmosis
Wernicke's Aphasia Ans: -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 Ans: -
prevents conversion of propionyl CoA to methylmalonyl CoA
© 2025 All rights reserved
, 2 | Page
-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 Ans: 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 Ans: Thiamine def= suppression
of GNG (pyruvate DH) and TCA cyle (alpha-KG DH)
© 2025 All rights reserved
, 3 | Page
MCC of Hypoglycemia in advanced renal insuff Ans: impaired
clearance of insulin
Avoid Nitrates in Hypertrophic Cardiomyopathy bc... Ans: 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 Ans: 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
© 2025 All rights reserved
, 4 | Page
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 Ans: Commonly presents in young,
asymptomatic patient with soft systolic ejection at right 2nd ICS
-can cause aortic regurg
MCC of Vaginal Candidiasis Ans: 1. Abx use= reduces lactobacilli
pop
2. High estrogen levels- preg
3. System corticosteroid therapy
© 2025 All rights reserved
