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
Spastic ileus is seen in - 
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 the intestine.
It is seen in
heavy metal poisoning           
porphyria
uremia                                             
extensive intestinal ulceration.