This patient’s initial diagnosis of G. lamblia infection is likely correct given his history and clinical presentation. Chronic infection with Giardia is uncommon, as metronidazole therapy is usually curative. Lactose intolerance, which can be prolonged, frequently develops following Giardia infection and has very similar symptoms. Ulcerative colitis and Crohn’s disease would likely have a more severe symptom profile and are not associated with Giardia infection.
