Medical Care
Pulmonary disease
Most cases are asymptomatic.
Most symptomatic cases are mild and self-limited (days) and do not require therapy.
Bronchospasm can be managed with conventional therapy.
Severe cases can be managed with systemic steroids and oxygen supplementation.
Partial small bowel obstruction
In the absence of signs of toxicity (eg, fever, tachycardia, protracted vomiting, peritoneal signs), persisting abdominal pain, or a palpable mass in the same site for more than 24 hours, several conservative management strategies, including supportive care, have proven efficacious. Some of these strategies are as follows:
Intravenous fluids and nasogastric tube with or without an antispasmodic (antimuscarinic)
Intravenous fluids, nasogastric tube, and antibiotics (eg, metronidazole, aminoglycoside, penicillin) with or without an antihelminthic after resolution of symptoms
Saline enema with or without an antispasmodic: Saline enemas are effective in children because 80% have an incompetent ileal-cecal sphincter.
Racine or mineral oil (15-30 mL via nasogastric tube) in conjunction with an antihelminthic: A low dose is used to allow worm death over few days. Several reports note that administration of antihelminthics in patients with partial bowel obstruction can precipitate complete obstruction.
Gastrografin (15-30 mL) via nasogastric tube: The hyperosmolar action results in increased fluid around worms, which favors their separation.
In the presence bowel obstruction, persisting or worsening abdominal pain, or sepsis, surgical intervention is warranted (see Surgical Care).
Hepatobiliary and pancreatic ascariasis
This typically manifests as biliary colic, acalculous cholecystitis, ascending cholangitis, pancreatitis, or hepatic abscess. Ascariasis is a common cause of these conditions in endemic countries.
Aggressive antibiotic therapy for suspected infection and early ERCP to remove the worms are highly efficacious together in the treatment of HPA. During ERCP, worms are sometimes observed to be moving into and out of the duct orifices. Worms are directly removed; when they are out of reach, they can be flushed out with rapid injection of 5-10 mL of diluted dye (eg, 10% Urograffin) into the duct. The entire worm must be removed because fragments lead to infection, granulomas, or stone formation.
After abdominal symptoms improve, antihelminthics can be administered. In one series, the ERCP complication (cholangitis, hypotension) rate was 6%. [13]
Surgical Care
In endemic regions, ascariasis is a major etiology for conditions that require acute surgical intervention, including the following:
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Intestinal obstruction
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Appendicitis
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Volvulus
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Intussusception
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Ischemic bowel
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Hepatobiliary obstruction (if ERCP has failed or is unavailable)
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Failure of conservative management of partial bowel obstruction
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Severe abdominal pain or tenderness with signs of toxicity
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Persisting or worsening abdominal pain
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Severe abdominal pain with a palpable mass in the same site for longer than 24 hours
Surgical procedures used in the management of the bowel obstruction secondary to ascariasis include the following:
Milking the worms through the ileo-cecal valve: This is recommended for a worm bolus in the distal ileum. Milking proximal boluses may cause damage to the bowel. This process has been facilitated by oral administration of mineral oil (15-30 mL).
Enterotomy to remove the bolus if milking is unsuccessful
Segmental resection of damaged bowel with or without temporary ostomy, as needed: Anastomosis should be 2-layers and end-to-end to prevent residual worms from migrating through the anastomosis into the peritoneal cavity, which has been reported.
Consultations
Surgeon
Any patient with acute abdominal pain and tenderness suggestive of an acute surgical process warrants a surgical consultation. If a double-contrast (ie, oral and intravenous dye) CT scan can be performed and the patient is not toxic or septic, the consultation may be deferred until the results of the scan are available. If the patient is toxic or septic, the surgical consultation should take place immediately.
Critical care specialist
Any patient who appears to be septic may qualify for early goal-directed therapy.
GI specialist
Any patient who is diagnosed with HPA or in whom a high index of suspicion for this diagnosis is noted warrants an immediate GI consultation for emergent ERCP. This procedure is often both diagnostic and therapeutic, with removal of the offending worm and relief of the obstruction.
Diet
Advise patients with known ascariasis to avoid peppery and spicy foods because they induce increased worm migration.
Prevention
Prevention consists of improved sanitation and education about the disease. In endemic areas, school screening has demonstrated effectiveness in detection and early treatment of asymptomatic carriers. [26] Benefits in health and educational performance have been reported with large-scale treatment of school-aged children every 6 months in countries where ascariasis is a public health problem.
The WHO ranks STH infections as the prime cause of infectious disease in children aged 5-14 years. Three strategies have been identified to control STH infections: chemotherapy, health education, and sanitation. Sanitation in developed countries is currently too expensive to be provided to the more than 2 billion people who lack safe disposal of their feces. In terms of education, better-educated households have better health. Specifically regarding STH, studies in Sri Lanka demonstrate that the more education mothers receive, the lower the prevalence of STH infection in their children. The challenge is to educate communities without clashing with local customs and cultures.
That leaves chemotherapy as the current mainstay for control of STH infection, although this strategy is limited by the enormous ongoing burden of environmental contamination. The goal is to reduce the intensity of STH infections in the community. Three chemotherapy strategies have been field tested for reducing the intensity of STH infections in the community: universal/mass treatment (all ages, both sexes, no exceptions), [27] targeted treatment (defined age, sex, or other identifier), and selected treatment (current diagnosis of STH infection). Only universal and targeted treatments are effective. Selected treatment does have a role, although it does not reduce community STH infection intensity. Treatment delivered to children through the schools at intervals of a year, 6 months, 4 months, or 3 months has been shown to be effective. When given every 3 months to children in one study, a significant decrease in adult intensity was noted, as well.
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The roundworm Ascaris lumbricoides causes ascariasis. Worms can reach 10-30 cm in length. Clinical disease results from effects of pulmonary larval migration, intestinal obstruction, or migration through the biliary tree.
Tables
Parasite* |
Disease |
Prevalence |
A lumbricoides |
Common roundworm infection, ascariasis |
800 million to 1.4 billion |
T trichiura |
Whipworm infection, trichuriasis |
600 million to 1 billion |
Necator americanus and Ancylostoma duodenale |
580 million to 1.2 billion |
|
Strongyloides stercoralis |
Threadworm infection, strongyloidiasis |
30-300 million |
Enterobius vermicularis |
Pinworm infection |
4-28% of children |
Toxocara canis and Toxocara cati |
Visceral larva migrans and ocular larva migrans |
2-80% of children |
*All major parasites are found in tropical, subtropical, and temperate climates. |
||
Minor Parasite |
Disease |
Distribution |
Ancylostoma braziliense |
Costal regions worldwide |
|
Uncinaria stenocephala |
Cutaneous larva migrans |
Costal regions worldwide |
Ancyclostoma canium |
Eosinophilic enteritis |
Australia |
Ancylostoma ceylanicum |
Hookworm infection |
Asia |
Oesophagostomum bifurcum |
Nodular worm infection |
North America |
Strongyloides fuelleborni |
Swollen belly syndrome |
West Africa |
Ternidens diminutus |
False hookworm infection |
Southern Africa |
