The parasite most notably associated with intussusception, particularly in regions where it is prevalent, is Ascaris lumbricoides.
Understanding Intussusception
Intussusception is a serious medical condition where one segment of the intestine slides into an adjacent part, much like the collapsing sections of a telescope. This telescoping action can lead to:
- Intestinal obstruction
- Compromised blood supply to the affected bowel
- Tissue damage or necrosis
This condition is a medical emergency requiring prompt intervention. While often idiopathic (without a clear cause) in infants, a "lead point" can trigger it in older children and adults.
How Ascaris lumbricoides Contributes to Intussusception
Ascaris lumbricoides, commonly known as the giant human roundworm, is a widespread intestinal nematode. Infections with these parasites, known as ascariasis, can sometimes lead to severe complications. When a significant number of Ascaris worms accumulate in the intestinal lumen, they can form a large, tangled mass or "bolus."
This bolus of worms acts as a mechanical obstruction, particularly at narrow points in the digestive tract such as the ileocecal valve—the junction between the small intestine (ileum) and the large intestine (cecum). If this obstruction persists, the mass of worms can serve as a fixed point around which the intestine telescopes, initiating intussusception. This mechanism disrupts the normal peristaltic movements of the bowel, pulling one segment into another.
Symptoms and Diagnosis
Recognizing the signs of intussusception is crucial for timely treatment. Common symptoms include:
- Sudden, severe, crampy abdominal pain: Often occurs in episodes, with periods of calm in between.
- Vomiting: Initially non-bilious, but can become bilious if obstruction progresses.
- "Currant jelly" stools: Stools mixed with blood and mucus, a classic sign of bowel ischemia.
- Palpable abdominal mass: A sausage-shaped mass may be felt in the abdomen.
- Lethargy or changes in consciousness: Especially in infants.
Diagnosis typically involves a physical examination and imaging studies. An ultrasound of the abdomen is often the primary diagnostic tool, revealing the characteristic "target" or "doughnut" sign. X-rays may also be used to check for signs of obstruction or perforation.
Treatment and Prevention
Treatment for Ascaris-induced intussusception first involves managing the intussusception itself, which may include:
- Non-surgical reduction: In some cases, an air or barium enema can successfully push the telescoped bowel back into place, especially if there are no signs of perforation.
- Surgical intervention: If non-surgical methods fail, or if there are signs of bowel perforation, peritonitis, or necrosis, surgery is required to manually reduce the intussusception and, if necessary, remove damaged sections of the intestine.
Following successful reduction or surgical intervention for the intussusception, deworming medication (e.g., albendazole or mebendazole) is administered to eliminate the Ascaris worms and prevent recurrence.
Preventing ascariasis is key to preventing its complications, including intussusception. Strategies include:
- Improved sanitation: Proper disposal of human feces to prevent soil contamination.
- Hand hygiene: Washing hands thoroughly with soap and water, especially before handling food and after using the toilet.
- Safe food practices: Washing, peeling, or cooking all raw vegetables and fruits grown in soil potentially contaminated with human feces.
Parasites and Intussusception: A Summary
| Parasite Associated with Intussusception | Mechanism of Association | Common Symptoms |
|---|---|---|
| Ascaris lumbricoides | Large bolus of worms acts as a lead point/fixed obstruction, particularly at the ileocecal valve. | Abdominal pain, vomiting, "currant jelly" stools, palpable abdominal mass. |
