Do intestinal parasites cause gastrointestinal bleeding?

From the Guidelines

Yes, some intestinal parasites, such as those that cause schistosomiasis, can lead to intestinal bleeding, particularly in cases of very heavy infection or chronic colonic ulceration. According to the UK guidelines for the investigation and management of eosinophilia in returning travellers and migrants 1, intestinal schistosomiasis symptoms can include chronic or intermittent abdominal pain, weight loss, and diarrhoea, with very heavy infection manifesting as dysenteric illness or obstruction, and chronic colonic ulceration may cause intestinal bleeding and iron deficiency anemia.

Key points to consider in the management of intestinal parasites that can cause bleeding include:

• The mode of transmission, such as fresh water exposure for schistosomiasis 1
• Clinical presentation, which can range from asymptomatic to severe symptoms like dysenteric illness or obstruction 1
• Investigations, including serology, microscopy of concentrated stool samples, and abdominal ultrasound or upper gastrointestinal endoscopy if necessary 1
• Treatment, which depends on the specific parasite, such as praziquantel for schistosomiasis, with dosages varying based on the species of the parasite 1

It is essential to note that the bleeding caused by these parasites can lead to significant morbidity, including iron deficiency anemia, and thus prompt medical evaluation and treatment are crucial to prevent long-term complications. The treatment approach should be guided by the most recent and highest quality evidence, such as the recommendations provided in the UK guidelines 1.

From the Research

Intestinal Parasites and Bleeding

• Intestinal parasites can cause significant morbidity and mortality, and some species are known to cause bleeding 2.
• Hookworms, such as Ancylostoma duodenale and Necator americanus, can cause blood loss, anemia, and bleeding 2, 3.
• Entamoeba histolytica can cause intestinal ulcerations and bloody diarrhea 2.
• Parasitic colitis can range from mild abdominal discomfort to serious complications, such as perforation or bleeding 4.
• Hookworm infections can cause overt gastrointestinal bleeding, and should be screened in patients with overt obscure gastrointestinal bleeding in endemic areas 3.

Specific Parasites and Bleeding

• Hookworms are a common cause of intestinal bleeding, and can cause chronic intestinal hemorrhage and iron deficiency anemia 3, 5.
• Roundworms can also cause gastrointestinal bleeding, and have been found in patients with obscure gastrointestinal bleeding 5.
• Entamoeba histolytica can cause bloody diarrhea and intestinal ulcerations, which can lead to bleeding 2.

Diagnosis and Treatment

• Diagnosis of intestinal parasites can be made using stool ova and parasite studies, and treatment includes medications such as albendazole and mebendazole 2, 6.
• Hookworm infections can be treated with albendazole, and patients may also require blood transfusions and iron replacement 3.
• Evaluation of the jejunum using an enteroscope can help diagnose worm infestation as a cause of acute gastrointestinal bleeding 5.