Endoscopic diagnosis of hookworm disease of the duodenum: A case report

Hookworm is one of the most common parasites in the world and usually high suspected from eosinophilia on blood examination or diagnosed from characteristic egg shape appearance on microscopic examination of faeces. A 78-year-old man complained of epigastric pain and intermittent black stool passage for 4 months. Laboratory data showed iron-deficiency anemia with microcytic hypochromic erythrocytes. Stool routine examination showed positive occult blood but there was no parasitic egg detected microscopically. Under the impression of peptic ulcer disease with chronic blood loss, upper endoscopy was performed. Many worms were found in the second portion of the duodenum incidentally by endoscopy. Necator americanus was diagnosed and eradicated successfully by mebendazole. It is always crucial to observe the distal duodenum carefully in upper endoscopy although parasite infestation is not suspected clinically, especially when a normal study for esophagus, stomach, and duodenal bulb.