Complications of Anthelmintics

Intestinal Obstruction

• Few studies highlight that administration of anthelmintic drugs in children with abdominal pain with
• a subacute obstruction may worse the clinical picture  leads to serious complications like intussusceptions, volvulus, hemorrhagic or necrotic bowel; or even perforation.
• complication has particularly been associated with pyrantel pamoate, which causes a spastic (depolarizing) paralysis of the worms, increasing the potential for worm bolus formation
• however, this complication has also been reported in association with piperazine, mebendazole, and albendazole.
• medication during this period leads to complete paralysis of an important number of parasites and accumulate them at level of distal small bowel blocking the lumen.
• History of recent anithelminthic treatment was observed in 59% cases in studies  which may add to an important contributory factor for precipitation of intestinal obstruction

Inflamatory Reactions

• secretions from the worms as well as toxic decomposition products of disintegrating worms are capable of provoking a severe and sometimes necrotizing inflammatory reaction in the bowel or bile ducts systemic and pulmonary hypersensitive reactions
• A host inflammatory reaction to worm-derived haemolysins, endocrinolysins, and anaphylatoxins can be severe enough to obstruct the gut lumen
• Avoidance of anthelmintic agents has been recommended because of their potential for harm from the inflammatory response provoked by antigen release after the death of the parasit

Worm Migration

• Anthelmintics alter the motility of the worms and hamper their clearance
• May stimulate migration of worms (in high worm load cases) to areas with lesser drug penetration such as gall blader and lungs.

Conservative Management

• In general, antihelminthic drugs are not recommended in patients from endemic areas (areas with large worm burdens) who have acute abdominal pain, with or without partial bowel obstruction, because of the risk of precipitating complete obstruction
• Incases with acute abdominal symptoms, conservative treatment is best and the antihelminthic should be administered after symptoms subside
• can be managed with intravenous fluid administration, nasogastric suction, and instillation of oral piperazine, salt, normal saline enema and hypertonic saline enemas
• A recent controlled trial from Pakistan indicated that in patients without peritonitis, hypertonic saline enemas were quicker in relieving obstruction and resulted in shorter hospital stays than intravenous fluids alone
• Malde et al reported that almost all patients responded to hypertonic saline enemas
• hypertonic saline enema causes irritation and promotes disentangling and expulsion of colonic worms, however during its use children should be watched closely for any features of dehydration

References:

1. Conservative Treatment for Round Worm Intestinal Obstruction. Indian Journal of Pediatrics, Volume 74—December, 2007
2. Intestinal obstruction in children due to Ascariasis: A tertiary health centre experience. Afr J Paediatr Surg [serial online] 2008 [cited 2016 Jan 10];5:65-70
3. http://emedicine.medscape.com/article/996482-medication
4. Managing gallbladder ascariasis: To go full throttle or not! Int J Health Allied Sci [serial online] 2013 [cited 2016 Jan 11];2:56-7
5. Senanayake SN, Pryor DS, Walker J, et al; First report of human angiostrongyliasis acquired in Sydney. Med J Aust. 2003 Oct 20;179(8):430-1.