NBME 4 question.1 - francisusmle99mode

[ArchivalUser]

A previously healthy 10-month-old boy is brought to the emergency department by his parents because he has vomited twice during the past 2 hours. During this period, he has had episodes of inconsolable crying and has passed one bloody stool. On arrival, he appears lethargic and is difficult to arouse. His temperature is 38°C (100.4°F), pulse is 110/min, respirations are 24/min, and blood pressure is 90/65 mm Hg. The abdomen is soft with no masses or organomegaly. Rectal examination shows bloody mucus in the rectal vault. Which of the following is the most appropriate next step in diagnosis?

A) test of the stool for Clostridium difficile toxin

B) Contrast enema

C) Upper gastrointestinal series with small bowel follow-through

D) CT scan of the head

E) Colonoscopy

[ArchivalUser]

Contrast Enema

[ArchivalUser]

plz explain B

[ArchivalUser]

this is a scenario of intussusception

Enema is both diagnostic and therapeutic

intussusception is the commonest cause of bowel obstruction in infancy

he's 10 months old

has vomiting,
inconsolable crying ( i.e. abdominal pain ),
passed one bloody stool ( suppose to be red current jelly stool )
no massed on abdominal palpation ( so less likely pyloric stenosis which has olive like mass )
rectal examination has bloddy mucus ( red current jelly stool )