Abstract
Hookworms are recognised as a cause of iron-deficiency anaemia in endemic areas. They are, however, often not considered in the differential diagnosis of overt gastrointestinal bleeding. We report the endoscopic diagnosis of hookworms as the cause of gastrointestinal bleeding in three patients, two of whom had frank haemorrhage with one presenting in hypovolemic shock. Hookworm infestation is an important treatable cause of gastrointestinal bleeding in tropical countries.
Introduction
Hookworm infestation is common in tropical countries and is predominantly due to the two nematodes: Ancylostoma duodenale and Necator americanus. The infestation is related to poor hygienic practice and is transmitted by cutaneous exposure to the soil contaminated with infected human faeces containing the larvae of the organisms, or by their ingestion in the case of A. duodenale. Although infestation may remain clinically silent in a large proportion of patients, dominant clinical manifestations include pulmonary eosinophilia, iron-deficiency anaemia and, occasionally, cutaneous larva migrans. 1 Although hookworm is well-recognised as a cause of occult and slow gastrointestinal blood loss, overt bleeding is uncommon. 2 We report three such cases diagnosed by endoscopy.
Case 1
A 25-year-old man was evaluated for mild epigastric discomfort and melaena over a period of 6 weeks. He had no history of haematemesis or haematochezia. He denied intake of non-steroidal anti-inflammatory medication or any history suggestive of chronic liver disease. At presentation his haemoglobin concentration was 7.7 g/dL with the microcyte volume (MCV) of 68 fL with microcytosis and hypochromatosis on a peripheral smear, with a total white blood count (WBC) 11,800/µL and platelet count 459,000/µL. He had received 12 units of packed red cells elsewhere. His blood urea level was 4.65 mmol/L and serum creatinine 61.88 µmol/L with urea/creatinine ratio of 40. An upper gastrointestinal endoscopy and colonoscopy were reported as normal and he was referred for capsule endoscopy. Prior to embarking on this, an endoscopy was repeated which revealed that the duodenum was loaded with multiple hookworms and many worms showed evidence of blood in their lumina (Figure 1). The patient was treated with albendazole and improved. He was discharged on iron supplements.
Duodenum stuffed with hookworms. Note the red streak inside the lumen of the hookworms.
Case 2
A 19-year-old man, who was symptomatic for 1 month with generalised fatigue and weakness, presented with increased symptoms one week prior to an episode of melaena. At presentation he was hypotensive at 70 mmHg systolic and tachycardic at 128 beats/minute. The haemoglobin concentration was 5 g/dL and MCV 72 fL, with a WBC of 7800/µL and platelet count of 55,000/µL. His blood urea level at presentation was 6.972 mmol/L and creatinine 35.36 µmol/L, and the urea/creatinine ratio was raised at 105. He was transfused with two units of packed red cell transfusion. Contrast-enhanced computed tomography (CT) of the abdomen was normal. The patient underwent gastroduodenoscopy once haemodynamically stabilised. The duodenum was teaming with hookworms and active oozing blood was noted (Figure 2). The patient was treated with albendazole and started on iron supplementation. At the 2-month follow-up he remains well with a haemoglobin level of 13 g/dL.
Multiple hookworms in the second part of the duodenum and an active ooze of blood visible.
Case 3
A 62-year-old woman was evaluated for generalised weakness of 6 months’ duration and increasing pallor. Her haemoglobin concentration was 6 g/dL and MCV 70fL. The peripheral smear showed microcytosis and hypochromasia. Her iron profile revealed a transferrin saturation of 10% and ferritin levels of 4 ng/mL. A gastroduodenoscopy revealed multiple hookworms in the first and second part of duodenum (Figure 3a and b). She also improved with oral albendazole and iron supplements.
(a) Hookworm with bleeding in the first part of the duodenum. (b) Multiple hookworms in the second part.
Discussion
Hookworm infection is a well-recognised cause of iron-deficiency anaemia in endemic regions. Indeed, blind deworming with albendazole for patients with iron-deficiency anaemia is a routine practice. 3 The mechanism of gastrointestinal bleeding due to hookworm is possibly related to mechanical injury, ingestion of blood by the worms and the release of serine proteases which inhibit clotting factors Xa and VIIa, TF inhibitors and hookworm platelet inhibitor protein.1,4
Hookworm infestation is a less well-recognised cause of massive gastrointestinal bleeding.2,5 Indeed, Western guidelines for obscure gastrointestinal bleeding do not even mention worms as an important cause, while several reports from India report that hookworms continue to be an important cause of gastrointestinal blood loss in the country.2,5–7 In one report of 15 patients with obscure gastrointestinal bleeding, two were diagnosed to have hookworms on endoscopy. 2 In another report, based on capsule endoscopic evaluation of 163 patients with obscure gastrointestinal bleeding, 21 (13%) had hookworms. Of these, 16 had overt bleeding. 5
While some authors have questioned the reality of hookworms causing overt bleeding, our cases clearly demonstrate that hookworms can indeed cause massive haemorrhage. 8 Furthermore, dramatic response to albendazole therapy and lack of recurrence on follow-up clearly demonstrate causality. Therefore, clinicians in regions endemic with hookworm infestation should consider hookworm in their list of differentials for patients with gastrointestinal bleeding, whether occult or overt.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support with respect to the research, authorship, and/or publication of this article.