USMLE Step 1

A 32-year-old woman with a history of generalized anxiety disorder develops numbness of her face particularly around her mouth. Physical examination and x-ray show no abnormalities other than markedly increased respiratory rate. Laboratory investigations are as follows: PO2: 100 mmHg PCO2: 30 mmHg Bicarbonate: 18 mEq/L pH of blood: 7.51 Which of these findings shows … Read more

A 37-year-old woman complains of watery diarrhea, abdominal cramps and periodic facial flushing for the last six months. Examination reveals bilateral wheezing and slightly enlarged liver. Urine analysis shows high levels of 5-hydroxyindoleacetic acid (5-HIAA). Multiple tumors are detected by a CT scan. What is the most likely primary site of these tumors? A-Colon B-Esophagus … Read more

A week old female presents for her first checkup. Examination reveals jaundice and splenomegaly. Laboratory investigations show: Total bilirubin level: 27 mg/dL Direct bilirubin: 0.6 mg/dL Hgb: 10.1 g/dL Reticulocytes: 6% A blood smear shows burr cells and spherocytosis. Which of these tests will be positive in this patient? A-Acid hemolysis test B-Coomb’s test C-Osmotic … Read more

A 1-year-old girl is brought to the pediatrician by her parents due to poor growth and skeletal abnormalities. Laboratory investigations show microcytic anemia and higher concentration of hemoglobin A2. Which is the most likely diagnosis? A- Sickle cell anemia B- β-thalassemia C- Lead poisoning D- Iron deficiency Answer β-thalassemia is an inherited blood disorder that … Read more