23rd August 2023

A 65-year-old man with chronic constipation presents with crampy abdominal pain and bloating

A 65-year-old man with chronic constipation presents with crampy abdominal pain and bloating. He hasn’t passed flatus or stool for the past two days. On examination, you find abdominal distension. A plain abdominal X-ray shows a ‘bird beak’ sign.

What is the most probable cause of this patient’s symptoms?