Corticosteroids for the treatment of parasitic eosinophilic meningitis

Review question

Do corticosteroids reduce inflammation in the membrane of the brain caused by parasites?

Background

Eosinophilic meningitis is an inflammation of the membrane covering the brain, the causes of which can be broadly categorised into infectious and non-infectious. Among the infectious aetiologies, Angiostrongylus cantonensis, a rat lung worm, is the major cause of eosinophilic meningitis. It occurs principally in South-East Asia and throughout the Pacific basin. However, this parasite has spread beyond the Pacific basin and is now found in regions of North America due to infected ship rats. Severe headache, which is self limiting, is the main complaint. The headache is probably due to an immune response to the dead parasites. Other signs and symptoms include neck stiffness and pain, visual disturbances, nausea, vomiting, paraesthesia and hyperaesthesia. Corticosteroids are drugs that reduce inflammation, which can occur in eosinophilic meningitis due to dead larvae.

Study characteristics

We conducted a systematic review and meta-analysis of randomised controlled trials of corticosteroids for treating eosinophilic meningitis. The evidence is current to December 2014. We found only one randomised controlled trial that matched our criteria. This trial included 129 patients (63 in the treatment group, prednisolone 60 mg/day, divided into three doses for two weeks and 66 in the control group, placebo). However,19 patients were lost to follow-up.

Key results

The included study showed that the median time to resolution of headaches was lower in the group treated with prednisolone (10.5 days versus 25 days) and the number of patients who still had headaches after 14 days was lower in the prednisolone group compared to the control (9.1% versus 45.5%). There were statistically significant differences, which favoured the treatment group, in other outcomes including the frequency of acetaminophen (paracetamol) use (median of number of times used) amongst those who still had headaches after 14 days of prednisolone treatment and the mean time until complete disappearance of headache. The number of patients who needed repeat lumbar puncture was also smaller in the treatment group. There were no reported adverse effects from prednisolone in the treatment group. Corticosteroids significantly help relieve headache in patients with eosinophilic meningitis, who have a pain score of four or more on a visual analogue scale.

Quality of the evidence

Given the lack of allocation concealment and blinding (especially in a trial with subjective outcomes), and the attrition (loss of participants), we graded our evidence as moderate quality.

Authors' conclusions: 

Corticosteroids significantly help relieve headache in patients with eosinophilic meningitis, who have a pain score of four or more on a visual analogue scale. However, there is only one RCT supporting this benefit and this trial did not clearly mention allocation concealment and stratification. Therefore, we agreed to grade our included study as a moderate quality trial. Future well-designed RCTs are necessary.

Read the full abstract...
Background: 

Angiostrongylus cantonensis (A. cantonensis) is the major cause of infectious eosinophilic meningitis. Dead larvae of this parasite cause inflammation and exacerbate symptoms of meningitis. Corticosteroids are drugs used to reduce the inflammation caused by this parasite.

Objectives: 

To assess the efficacy and safety of corticosteroids for the treatment of eosinophilic meningitis.

Search strategy: 

We searched CENTRAL (2014, Issue 11), MEDLINE (1950 to November Week 3, 2014), EMBASE (1974 to December 2014), Scopus (1960 to December 2014), Web of Science (1955 to December 2014), LILACS (1982 to December 2014) and CINAHL (1981 to December 2014).

Selection criteria: 

Randomised controlled trials (RCTs) of corticosteroids versus placebo for eosinophilic meningitis.

Data collection and analysis: 

Two review authors (SiT, SaT) independently collected and extracted study data. We graded the methodological quality of the RCTs. We identified and analysed outcomes and adverse effects.

Main results: 

We did not identifiy any new trials for inclusion or exclusion in this 2014 update. One study involving 110 participants (55 participants in each group) met our inclusion criteria. The corticosteroid (prednisolone) showed a benefit in shortening the median time to resolution of headaches (five days in the treatment group versus 13 days in the control group, P value < 0.0001). Corticosteroids were also associated with smaller numbers of participants who still had headaches after a two-week course of treatment (9.1% versus 45.5%, P value < 0.0001). The number of patients who needed repeat lumbar puncture was also smaller in the treatment group (12.7% versus 40%, P value = 0.002). There was a reduction in the median time of analgesic use in participants receiving corticosteroids (10.5 versus 25.0, P value = 0.038). There were no reported adverse effects from prednisolone in the treatment group.

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