Which finding is most characteristic of peritonitis?

• A. Rigid, tender abdomen
• B. Fever with productive cough
• C. Headache and dizziness
• D. Nasal congestion

Answer: (A)

Peritonitis inflames the lining of the abdominal cavity, and the abdominal muscles reflexively tighten to guard the irritated area. That guarding becomes a rigid or board-like abdomen, which is the most distinctive and characteristic sign of peritonitis. The severe abdominal pain often worsens with movement and can be accompanied by shallow breathing and tachycardia as the body reacts to the inflammation.

Fever with a productive cough suggests a respiratory infection, not peritoneal irritation. Headache and dizziness are nonspecific symptoms that do not localize to the abdomen. Nasal congestion is typical of upper respiratory issues and also not related to peritoneal inflammation.