Diagnosis of pinworm is based on a clear swab to the anus
Diagnosis of pinworm is based on a clear swab to the anus. iStock

During a medical procedure to remove a 16-year-old girl's appendix, doctors discovered that she was suffering from an infestation of pinworms. Enterobius vermicularis (pinworm) causes significant morbidity worldwide and has a high prevalence among children in the UK.

After testing for urinary tract infections, irritable bowel syndrome and ovarian cysts, doctors decided to operate as appendicitis is a common cause of abdominal pain and can be a life-threatening condition.

During the medical procedure, doctors noticed that her appendix was "lily white" instead of pink or red. As the organ was cut at the base, a "multitude of worms", came out which were removed with a suction irrigator, clearing all of the parasites that had escaped into the peritoneum, according to BMJ Case Reports.

A dose of mebendazole and amoxicillin were given and the immediate family was also treated, as pinworms is highly contagious, though not harmful. The girl has made a full recovery.

Pinworm infection is often without symptoms in most of patients. Diagnosis is based on a clear swab to the anus and then examined under a microscope to inspect for eggs.

According to the Global Burden of Disease project, parasitic worms are one of the most common human infections in the world. Estimates of prevalence in children range from 61% in India to 29% in Denmark. While nematode infections are more often seen in hot and humid regions with poor sanitation, the prevalence in UK children infected with E. vermicularis could be around 50%.

Adult female nematodes are 8-13mm in length, while the adult males are 2-5mm. Humans are believed to be the only hosts of E. vermicularis. Female pinworms lay eggs in the folds of skin around the anus and the presence of eggs can cause anal itching and irritation.

Eggs are deposited on perianal folds and self-infection happens by transferring eggs to the mouth with hands that have scratched the perianal area. A small number of eggs can become airborne and inhaled, according to the Centers for Disease Control and Infection. Following ingestion of infective eggs, the larvae then hatch in the small intestine.

If untreated, pinworms can also travel from the anus into the vagina, causing infections of the uterus, fallopian tubes and other pelvic organs.