Which condition is least likely to cause chronic constipation?

Hirschsprung disease is a congenital condition characterized by the absence of ganglion cells in part of the intestinal tract, leading to a lack of peristalsis and resulting in severe constipation in infants. While this condition does present with constipation, it typically manifests relatively early in life and is usually diagnosed in infancy or early childhood rather than causing chronic constipation in adults.

In contrast, chronic constipation can be more commonly linked to other conditions such as irritable bowel syndrome, dehydration, and thyroid dysfunction, all of which can develop over time and persist into adulthood. Irritable bowel syndrome often results in a mix of diarrhea and constipation that can be present for years. Dehydration commonly leads to harder stools and can be a frequent cause of constipation. Thyroid dysfunction, particularly hypothyroidism, can slow metabolism and decrease bowel motility, leading to chronic constipation as well.

Therefore, when considering conditions that cause chronic constipation, Hirschsprung disease is the least likely to be involved, as it is primarily a pediatric issue rather than a chronic condition affecting older individuals.