Clinical Treatment of Rat Lungworm

What to know

  • Treatment of A. cantonensis is usually supportive with the use of analgesics for pain and corticosteroids to limit the inflammatory reaction.
  • There is no proven treatment for illness caused by A. costaricensis.
  • There is some concern that treatment with anthelminthics for an infection with either species could have adverse side effects, including worsening of symptoms or the disease.

Treatment options

Angiostrongylus cantonensis

Treatment is usually supportive with the use of analgesics for pain and corticosteroids to limit the inflammatory reaction. Careful removal of CSF at frequent intervals can help to relieve headache in patients with elevated intracranial pressure. No anthelminthics drugs have been proven to be effective in treatment, and there is concern that anthelminthics could exacerbate neurological symptoms due to a systemic response to dying worms. The effectiveness of any regimen may vary by endemic region. One randomized, placebo-control study of a 2-week course of prednisolone (60 mg per day in 3 divided doses) found that the corticosteroids reduced the median length of headache from 13 days to 5 days and reduced the need for repeat lumbar puncture. Additionally 9.1% of treatment patients compared to 45.5% of controls still had headache at 2 weeks.

In two small cases series (41 and 26 adults, respectively) adult patients were given prednisolone 60 mg/day and an anthelminthics (mebendazole 10 mg/kg/day or albendazole 15mg/kg/day two weeks, respectively), resulting in resolution of headache in a median of 3 days in the mebendazole case-series and 4 days in the albendazole case-series without serious side effects. As there was no control group, it is difficult to determine if the anthelminthic provided additional benefit. Comparing the results from the placebo-control trial to the 2 case-series, 9.1% of prednisolone monotherapy patients, 9.8% of prednisolone-mebendazole patients, and 11.5% of prednisolone-albendazole patients still had headache after 2 weeks. One small trial that directly compared prednisolone monotherapy to prednisolone-albendazole combined therapy found no benefit of adding albendazole to the regimen.

Additional symptomatic treatment may also be required for nausea, vomiting, and in some cases chronic pain due to nerve damage and muscle atrophy.

Angiostrongylus costaricensis

There is no proven treatment for illness caused by A. costaricensis and there is some concern that treatment with anthelminthics could result in worsening of the disease. Acute episodes may resolve spontaneously or require surgical treatment for intestinal inflammation.

  • Oral mebendazole is available for human use in the United States.
  • Oral albendazole is available for human use in the United States.

Care precautions

Treatment in pregnancy

Mebendazole is a pregnancy category C drug. Data on the use of mebendazole in pregnant women are limited. The available evidence suggests no difference in congenital anomalies in the children of women treated with mebendazole during mass drug administration (MDA) campaigns compared with those who were not. In MDA campaigns in countries where soil-transmitted helminths are common, World Health Organization (WHO) has determined that the benefits of treatment outweigh the risks and WHO allows use of mebendazole in the 2nd and 3rd trimesters of pregnancy. However, in a pregnant woman infected with a soil-transmitted helminth, balance the risks of treatment for the fetus with the risks of disease progression in the woman in the absence of treatment.

Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) plus there are no controlled studies in women, or studies in women and animals are not available. Prescribe mebendazole only if the potential benefits to the woman justify the potential risks to the fetus.

Treatment during lactation

Mebendazole is minimally excreted in breast milk. WHO classifies mebendazole as compatible with breastfeeding and allows its use in lactating women.

Treatment in pediatric patients

The safety of mebendazole in children is unclear. There are limited data in children under 2 years old. The WHO Model List of Essential Medicines for Children lists mebendazole as an intestinal antihelminthic medicine that can be used for children older than 2 years of age.

Treatment during pregnancy

Albendazole is a pregnancy category C drug. There are limited data on the use of albendazole in pregnant women. The available evidence suggests no difference in congenital abnormalities in the children of women accidentally treated with albendazole during mass drug administration (MDA) campaigns compared with those who were not. In MDA campaigns for which the World Health Organization (WHO) has determined that the benefits of treatment outweigh the risks, WHO allows use of albendazole in the 2nd and 3rd trimesters of pregnancy. However, healthcare providers should balance the risks of treatment for the fetus with the risks of disease progression in the woman in the absence of treatment.

Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) plus there are no controlled studies in women, or studies in women and animals are not available. Prescribe albendazole only if the potential benefits to the woman justify the potential risks to the fetus.

Treatment during lactation

Albendazole is minimally excreted in human milk. WHO has concluded that a single oral dose of albendazole can be given to lactating women.

Treatment in pediatric patients

The safety of albendazole in children less than 6 years old is not certain. Studies of the use of albendazole in children as young as one year old suggest that it is safe. According to WHO guidelines for MDA campaigns, children as young as one year of age (able to safely swallow tablets) can take albendazole. These campaigns have treated many children under six years old with albendazole, albeit at a reduced dose.