USMLE Step 1 Question of the Week #13

A 26-year-old man presents to ophthalmologist for complain of progressive loss of vision in his right eye for last six months. He has visited multiple doctors till date, but there is no improvement. There is no history of pain or redness in eyes. He often experiences fatigue for last one year. His detailed medical history reveals that he has suffered from fractures of different long bones two times; both the fractures were associated with minor injury. His detailed ophthalmologic evaluation suggests diagnosis of optic atrophy on right side. His recent complete blood counts revealed that his blood hemoglobin level was 9.2 g/dL (5.71 mmol/L). Considering a specific condition as a differential diagnosis, the ophthalmologist orders radiogram of his spine, which confirms the diagnosis. The radiogram is shown below:

Which of the following mechanisms best explains pathophysiology of the condition the man is suffering from?

A. Abnormal accumulation of mucopolysaccharides in chondrocytes

B. Decreased synthetic activity of osteoblasts

C. Primary oversecretion of parathyroid hormone

D. Defective acidification of osteoclast resorption pit

E. Defective assembly of collagen polypeptides.

 

QID #1838

USMLE Step 1 Question of the Week #12

A male newborn, delivered at full term, has abnormal facies and is suspected to have a chromosomal anomaly. Histological examination of his umbilical cord shows following findings:

Which of the following chromosomal anomalies is most commonly associated with above findings in umbilical cord?

 

A. Down syndrome

B. Edward syndrome

C. Klinefelter syndrome

D. Patau syndrome

E. Turner syndrome

QID #1023

USMLE Step 1 Question of the Week #8

A 68-year-old man presents to physician with complain of fever, cough, and difficulty in breathing for last three days. He mentions that his expectorations are rust-colored. He has no known medical disorder and is otherwise a healthy man. On physical examination, his temperature is 103.7ºF (39.8ºC), pulse rate is 92/minute, blood pressure is 128/82 mm Hg, and respirations are 24/minute. Auscultation of his chest reveals decreased intensity of breath sounds and presence of crepitations over right infrascapular region. The physician orders his sputum examination, which shows predominant polymorphonuclear neutrophils and a few epithelial cells. Gram staining of sputum confirms presence of Gram-positive cocci in pairs. Chest radiogram of the man shows lobar consolidation in lower zone of the right lung. Which of the following best describes pathological changes in the affected area of the lung?

A. Neutrophil-rich exudate filling bronchi, bronchioles, and adjacent alveoli

B. Widening of alveolar septa and mononuclear inflammatory infiltrate

C. Fibrin strands in alveolar spaces and extravasation of red blood cells

D. Intra-alveolar fluid and vascular engorgement

E. Fibromyxoid masses rich in fibroblasts and macrophages

QID #2309

USMLE Step 1 – Question of the Week #4

A 40-year-old female patient presents with soft nodules on the volar aspect of her fourth and fifth fingertips. The nodules are painful on flexion and interfere with her day to day work. She recounts being bitten by a stray dog, about one year back, on these same fingertips. At that time, she was treated with painkillers, anti-rabies injection and antibiotics. The wound had healed well and there were no complaints until recently. On examination, there is a soft fleshy mass about 1.0 cm in diameter on the volar aspect of both the fourth and fifth fingertips. The mass was surgically excised and was histologically found to be a neuroma of a peripheral sensory receptor.

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Which of these receptors is most likely involved?

A. Merkel cells

B. Muscle spindles

C. Meissner corpuscles

D. Free nerve endings

E. Pacinian corpuscles