Approach

Ascariasis is easily treated with oral anthelmintics. Other treatments, including surgical management, may be required in patients with intestinal obstruction, or hepatobiliary and/or pancreatic involvement. In addition to preventing mechanical and allergic complications of the parasite, treatment of ascariasis in endemic settings may have secondary benefits (e.g., accelerated growth and weight gain), especially in children.

Anthelmintic therapy

Treatment with an anthelmintic is indicated when adult worms are passed, or characteristic eggs are noted in the stool. First-line treatments in the US include albendazole, mebendazole, or ivermectin.[45]​ A chewable tablet formulation of mebendazole is available. One Cochrane review found all three drugs to be effective for the treatment of ascariasis, with no differences detected between them.[46] [ Cochrane Clinical Answers logo ] ​ Pyrantel is considered an acceptable alternative, but is rarely used in the US. Levamisole is also considered an acceptable alternative in some countries (and is on the WHO essential medicines list), but is not available in the US or Europe.[47]​​

The estimated average cure rates vary depending on the drug; 95.7% (albendazole); 96.2% (mebendazole); 97.3% (levamisole); and 92.6% (pyrantel). The estimated egg reduction rate is highest for albendazole (98.5%), followed by mebendazole (98%), levamisole (96.4%), and pyrantel (94.3%).[48]

Although widespread use of benzimidazoles in children has not revealed specific safety issues, there are limited data regarding their use in patients <2 years of age; therefore, risks and benefits should be weighed in this age group.[24]​​[49][50] The World Health Organization (WHO) considers these drugs to be safe in children aged 12 months and older when used at appropriate doses.[51]​ Pyrantel can be used in patients of all ages.[52]

Despite excellent empiric safety profiles, none of the anthelmintics are licensed for use in pregnancy. The risks and benefits of treatment should be weighed carefully before giving these drugs during pregnancy, particularly during the first trimester. If a woman in her first trimester of pregnancy is found to have ascariasis, she must wait until the second trimester to receive treatment. The WHO recommends the use of albendazole or mebendazole in the second and third trimesters of pregnancy.[51]​​

Eosinophilic pneumonitis (Loeffler syndrome)

Treatment is usually supportive, because pneumonitis is self-limiting and often occurs before patients are known to have ascariasis.[23][53]​ Depending on the severity of presenting symptoms, patients may benefit from treatment with bronchodilators and inhaled or systemic corticosteroids. Cough suppressants and antihistamines may also offer some relief from symptoms. Anthelmintic therapy probably does not alter the course of pneumonitis. However, if ascariasis is suspected as the underlying cause, stool may be tested 2 to 3 weeks after the conclusion of respiratory illness, to identify eggs and treat adult intestinal worms.

Intestinal obstruction

In cases of intestinal obstruction without complications (persistent abdominal pain, persistent tender abdominal mass, immobile abdominal mass after 24 hours of medical management, or signs of toxemia), medical management is usually successful.[1][5][27][54]

Although piperazine is the preferred option for these patients, it is not available in the US. Physicians working in countries where it is available should seek to use this drug first. Albendazole, mebendazole, or pyrantel may also be used for intestinal obstruction; however, caution should be exercised when using other anthelmintics, as they may be associated with causing or worsening obstruction.[55][56]

Concurrent treatment with nasogastric suction, nothing by mouth, intravenous hydration, and electrolyte replacement should be instituted.[22][24]​​[25]

Laparotomy for surgical removal of worm boluses should be considered in the following situations:[57]

  • Suspicion of peritonitis

  • Suspicion of bowel strangulation

  • Complete intestinal obstruction

  • Presence of intraperitoneal free air on radiographic exams

  • Lack of improvement after 24 hours of medical management.

During surgery, if the parasitic bundle cannot be manually moved toward the colon and expressed, an enterotomy may be necessary. In cases of gangrene or infarction, resection of affected bowel may be necessary.[52][Figure caption and citation for the preceding image starts]: Laboratory technician holding a mass ofAscaris lumbricoides worms excreted by a child in KenyaPublic Health Image Library, CDC [Citation ends].com.bmj.content.model.Caption@3b06633a

Hepatobiliary and/or pancreatic involvement

Hepatobiliary and/or pancreatic involvement may present as one of the following syndromes:

  • Biliary colic

  • Acalculous cholecystitis

  • Acute cholangitis

  • Acute pancreatitis

  • Hepatic abscess.

In well-resourced settings, obstructing worms can often be removed by endoscopic retrograde cholangiopancreatography (ERCP).[5][27] Piperazine can also be used to paralyze worms, but some experts argue that this treatment impedes back-migration of worms from the biliary tree into the duodenum.[52] If ERCP is not successful or available, surgery is the remaining alternative to relieve obstruction.[24]​​

Patients with pancreatic or biliary colic may be given morphine for analgesia.

Patients with acute cholangitis due to impactedAscaris lumbricoides often have secondary bacterial infection and sepsis, and should be treated with broad-spectrum antibiotics and other supportive measures such as fluid and electrolyte replacement, in addition to the removal of ascarid worms.[52] Local sepsis guidelines should be followed; choice of antibiotics depends on local resistance and susceptibility patterns.

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