This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
In which of the following condition is spastic ileus seen? 
Select and explain. 
A. Porphyria, B. Retroperitoneal abscess, C. Hypokalemia, D. MI
A: Porphyria
Answer: A: Porphyria 
Explanation: Spastic, or dynamic ileus is rare and results from extreme and prolonged contraction of intestine. It is seen in: Heavy metal poisoning Uremia Porphyria Extensive intestinal ulceration Ref: Harrison 17/e, Page 1912.