Andrew Moore, MD, Salina Lee, MD, Shriram Jakate, MD, FRCPath
Rush University Medical Center, Chicago, IL
Introduction: Giardia duodenalis is an intestinal flagellated protozoan parasite and is the most common parasitic infection in the GI tract, having been estimated to effect as much as 2-5% of the population in developed countries. Symptoms of giardiasis in children include diarrhea, flatulence, abdominal cramping, nausea, and dehydration; however, in adults the symptoms are often absent or short-lived. Giardiasis is typically diagnosed by identification of cysts or trophozoites with a test for ova and parasites in the stool of infected patients. Here we present a rare care of a patient with chronic abdominal pain who was diagnosed with giardiasis via duodenal biopsy.
Case Description/Methods: A 65 year old male with a past medical history of COPD, HTN, and depression was evaluated for abdominal pain that had been ongoing for the last two years. The pain was primarily epigastric with occasional radiation to the upper quadrants, worse after eating, and often occurred at night, awakening him from sleep. He denied any constipation, diarrhea, hematochezia, melana, or weight loss. He did not take any PPIs or H2 blockers. His last colonoscopy was in 2015 and was notable only for a few polyps. Physical exam was notable for mild tenderness in the upper quadrants and epigastric area. Esophagogastroduodenoscopy (EGD) showed mild dilation in the distal esophagus, nodularity in the gastric corpus, patchy erythema and erosions in the antrum of the stomach. Duodenum was notable for diffuse erythema and friability in the bulb. The second portion of the duodenum appeared normal. Pathology was notable for multiple pieces of the duodenal mucosa showing numerous Giardia parasites and focal acute erosive duodenitis (figure 1). Multiple pieces of gastric mucosa showed chronic gastritis and numerous H. pylori organisms. Moderate esophagitis compatible with reflux was also observed. The patient was prescribed triple therapy with omeprazole 20mg BID, amoxicillin 1g TID, and metronidazole 500mg TID for 10 days to cover both H. pylori and Giardia duodenalis and then was instructed to continue on omeprazole 20mg daily.
Discussion: For patients in whom Giardia or other infectious etiology is suspected, stool O&P are routinely ordered. However, the sensitivity of examining one stool specimen is only 50-70%. This case demonstrates the utility of EGD as a more sensitive diagnostic tool when there is strong clinical suspicion but stool studies fail to reveal a definitive diagnosis.
Citation: Andrew Moore, MD, Salina Lee, MD, Shriram Jakate, MD, FRCPath. P1283 - A RARE CASE OF GIARDIA DUODENALIS ON DUODENAL BIOPSY IN A PATIENT WITH CHRONIC ABDOMINAL PAIN. Program No. P1283. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.