Constipation & ileus in the Kenntnisprüfung

By definition, when do we speak of constipation (Obstipation)?

• With fewer than one bowel movement per day, regardless of consistency and symptoms
• As soon as the stool is hard once or any straining is needed during defecation
• With fewer than 3 bowel movements per week, hard stool and/or heavy straining
• Only when there has been no bowel movement for at least 7 days and the abdomen is distended

Explanation: Constipation: less often than 3× per week, hard stool, heavy straining, often with a feeling of incomplete emptying. “Once a day” is not a requirement — the normal range is from 3× daily to 3× weekly.

Which group of medicines most reliably causes persistent constipation?

• Opioids — the bowel develops no tolerance to them
• Antibiotics — they destroy the gut flora and thereby paralyse peristalsis
• Proton pump inhibitors — they slow down the entire intestinal passage
• ACE inhibitors — they inhibit bowel motility via the renin system

Explanation: Opioids paralyse bowel motility reliably and permanently — unlike with nausea or sedation, the bowel does not get used to it. That is why a prophylactic laxative belongs in the prescription from day 1: an opioid without a laxative is a treatment error (Kunstfehler).