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.


Which of these receptors is most likely involved?

A. Merkel cells

B. Muscle spindles

C. Meissner corpuscles

D. Free nerve endings

E. Pacinian corpuscles


USMLE Step 1 – Question of the Week #3

A 25-year- old healthy male participated in a running competition. After finishing running, his heart rate was 140/minute, blood pressure was 136/90 mm Hg, and respiratory rate was 20/minute. Also, he had perspired significantly.

Which of the following changes in renal hemodynamics is not expected due to activation of sympathetic nervous system?

A. Decreased renal plasma flow

B. Decreased hydrostatic pressure in glomerular capillaries

C. Decreased glomerular filtration rate

D. Decreased filtration fraction
E. Decreased hydrostatic pressure in peritubular capillaries

USMLE Step 1 – Question of the Week #2

A 38-year-old man presents to physician with complains of excessive thirst and excessive passage of urine for last one week. He also mentions that he has to get up at night for urination, which was not a problem a few days before. He is an otherwise healthy man with no known medical condition. Physical examination of the man is normal. Important findings in laboratory evaluation are as follows:

Urine osmolality          175 mOsmol/kg H2O

Urine specific gravity  1.002

Serum osmolality        290 mOsmol/kg H2O

The man was advised to undergo water deprivation test, which confirmed that urine osmolality remained less than 300 mOsmol/kg H2O and it did not improve after administration of antidiuretic hormone.  After appropriate laboratory evaluation, the physician confirms that the man’s condition is due to an electrolyte abnormality. Which of the following electrolyte abnormalities is known to cause the condition the man is suffering from? Access full Qbank at – 30 day free trial. 

A. Hypokalemia

B. Hypochloremia

C. Hypocalcemia

D. Hypomagnesemia

E. Hyponatremia

USMLE Step 1 – Question of the Week#1

Q1. A 27-year-old man presents to physician with complain of pain in left thigh for last one month. Physical examination shows presence of a painful swelling just above left knee joint. Radiogram of left leg shows a radio-lucent lesion which is located eccentrically near lower end of femur. The lesion is surrounded by a thin rim of bone and soap-bubble appearance is present.


After necessary evaluation, en bloc resection of the lesion is performed and is sent for microscopic examination. Histology of the lesion shows multi-nuclear giant cells in network of sheets of oval mononuclear cells. Necrosis and mitotic activity are present in the lesion and reactive bone is present at the periphery.

Which of the following mechanisms best describe pathogenesis of the bone lesion?

A. Dysregulation of RANKL-RANK signaling cascade

B. Increased production of 2-hydroxyglutarate

C. Defective diffusion of Indian hedgehog factor

D. Inactivating mutation of a tumor suppressor gene

E. Activation of Gs protein and increased production of cyclic adenosine monophosphate (cAMP)