External radiation therapy commonly causes which symptom that should not be mistaken for a serious complication?

• A. Hair loss
• B. Ulceration of oral mucous membranes
• C. Constipation
• D. Headache

Answer: (C)

Constipation is a common, normally non-emergency side effect of external radiation therapy, especially when the pelvis or abdomen is treated. Radiation can affect bowel motility and stool consistency, so patients may notice changes in bowel habits during treatment. The important point is to recognize it as a routine, manageable symptom rather than a sign of a serious complication like an obstruction or perforation. Management focuses on supportive care—staying well hydrated, incorporating fiber as tolerated, staying physically active as able, and using any laxatives or stool softeners prescribed by a clinician. Other symptoms such as hair loss or mucosal ulcers are tied to the specific treated areas and headaches can relate to treatment in the brain area, but constipation stands out as a common, expected effect that shouldn’t be mistaken for a more serious problem.