319 Entamoeba histolytica Colitis in a Man With Chronic Silver Ingestion: Case Report With Electron Microscopic (EM) Study. (11th January 2018)

• Record Type: Journal Article
• Authors: Diaz, Daniel; Wieczorek, Rosemary; Lee, Peng; Cassai, Nicholas
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S137
• Page End: S138
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx126.318
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Introduction: Entamoeba histolytica infection is caused by ingestion of eggs of a protozoa. Patients are commonly asymptomatic during infection. Colitis with ulcer formation and liver abscess are the most common manifestations. A compromised immune system can trigger symptom manifestations. We present a case of a man in his eighth decade who had been consuming silver for holistic reasons, and presented with abdominal pain and intractable GI bleeding while traveling in South America. He had a history of taking antibiotics for one month outside of the country. Colonoscopy showed deep undermining ulcers throughout the colon. The patient required two colon resections because of bleeding and perforation. Methods and Results: Gross examination of each colon resection showed multiple deep ulcers with one complete perforation with peritonitis. Microscopically in the ulcer exudate were many PAS+ cells with ingested red cells. CD68 immunostain confirmed some cells as macrophages, but many were negative, raising suspicion for amoeba given the history of travel. A single ulcer bed revealed rare cytomegalovirus (CMV) inclusions (confirmed by immunostain). CBC showed no eosinophilia. HIV testing was negative. Electron microscopy (EM) showed classical Entamoeba, which were themselves infected by a virus (Megavirale family). Rare structures compatible with silver particles were seen inside macrophages. Serology was positive for Entamoeba histolytica . Conclusions: Silver ingestion (heavy metals) led to a compromised immune system in this patient resulting in amebiasis and CMV infection. When patients are infected with the protozoa, they are usually asymptomatic but patients with weakened immune systems may manifest symptoms. Microscopically, these organisms tend to resemble histiocytes in morphology, especially in a background of abscess formation. Eosinophilia is often not seen. Histology including EM and serology are definitive for diagnosis. It is unknown if the virus infection seen in the amoeba made them more infectious.