Effects of hypertonic (7%) saline on brain injury in experimental Escherichia coli meningitis

Osmotic therapies added to antibiotics for acute bacterial meningitis

BACKGROUND

Every day children and adults die from acute community-acquired bacterial meningitis, particularly in low-income countries, and survivors risk deafness, epilepsy and neurological disabilities. Osmotic therapies may attract extra-vascular fluid and reduce cerebral oedema, and thus reduce death and improve neurological outcomes.This is an update of a Cochrane Review first published in 2013.

OBJECTIVES

To evaluate the effects of osmotic therapies added to antibiotics for acute bacterial meningitis in children and adults on mortality, deafness and neurological disability.

SEARCH METHODS

We searched CENTRAL (2017, Issue 1), MEDLINE (1950 to 17 February 2017), Embase (1974 to 17 February 2017), CINAHL (1981 to 17 February 2017), LILACS (1982 to 17 February 2017) and registers of ongoing clinical trials (ClinicalTrials.com, WHO ICTRP) (21 February 2017). We also searched conference abstracts and contacted researchers in the field (up to 12 December 2015).

SELECTION CRITERIA

Randomised controlled trials testing any osmotic therapy in adults or children with acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results and selected trials for inclusion. Results are presented using risk ratios (RR) and 95% confidence intervals (CI) and grouped according to whether the participants received steroids or not. We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included five trials with 1451 participants. Four trials evaluated glycerol against placebo, and one evaluated glycerol against 50% dextrose; in addition three trials evaluated dexamethasone and one trial evaluated acetaminophen (paracetamol) in a factorial design. Stratified analysis shows no effect modification with steroids; we present aggregate effect estimates.Compared to placebo, glycerol probably has little or no effect on death in people with bacterial meningitis (RR 1.08, 95% CI 0.90 to 1.30; 5 studies, 1272 participants; moderate-certainty evidence), but may reduce neurological disability (RR 0.73, 95% CI 0.53 to 1.00; 5 studies, 1270 participants; low-certainty evidence).Glycerol may have little or no effect on seizures during treatment for meningitis (RR 1.08, 95% CI 0.90 to 1.30; 4 studies, 1090 participants; low-certainty evidence).Glycerol may reduce the risk of subsequent deafness (RR 0.64, 95% CI 0.44 to 0.93; 5 studies, 922 participants; low to moderate-certainty evidence).Glycerol probably has little or no effect on gastrointestinal bleeding (RR 0.93, 95% CI 0.39 to 2.19; 3 studies, 607 participants; moderate-certainty evidence). The evidence on nausea, vomiting and diarrhoea is uncertain (RR 1.09, 95% CI 0.81 to 1.47; 2 studies, 851 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Glycerol was the only osmotic therapy evaluated, and data from trials to date have not demonstrated an effect on death. Glycerol may reduce neurological deficiency and deafness.

Osmotic therapies added to antibiotics for acute bacterial meningitis

BACKGROUND

Every day children and adults throughout the world die from acute community-acquired bacterial meningitis, particularly in low-income countries. Survivors are at risk of deafness, epilepsy and neurological disabilities. Osmotic therapies have been proposed as an adjunct to improve mortality and morbidity from bacterial meningitis. The theory is that they will attract extra-vascular fluid by osmosis and thus reduce cerebral oedema by moving excess water from the brain into the blood. The intention is to thus reduce death and improve neurological outcomes.

OBJECTIVES

To evaluate the effects on mortality, deafness and neurological disability of osmotic therapies added to antibiotics for acute bacterial meningitis in children and adults.

SEARCH METHODS

We searched CENTRAL 2012, Issue 11, MEDLINE (1950 to November week 3, 2012), EMBASE (1974 to November 2012), CINAHL (1981 to November 2012), LILACS (1982 to November 2012) and registers of ongoing clinical trials (April 2012). We also searched conference abstracts and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials testing any osmotic therapy in adults or children with acute bacterial meningitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results and selected trials for inclusion. We collected data from each study for mortality, deafness, seizures and neurological disabilities. Results are presented using risk ratios (RR) and 95% confidence intervals (CI) and grouped according to whether the participants received steroids or not.

MAIN RESULTS

Four trials were included comprising 1091 participants. All compared glycerol (a water-soluble sugar alcohol) with a control; in three trials this was a placebo, and in one a small amount of 50% dextrose. Three trials included comparators of dexamethasone alone or in combination with glycerol. As dexamethasone appeared to have no modifying effect, we aggregated results across arms where both treatment and control groups received corticosteroids and where both treatment and control groups did not.Compared to placebo, glycerol may have little or no effect on death in people with bacterial meningitis (RR 1.09, 95% confidence interval (CI) 0.89 to 1.33, 1091 participants, four trials, low-quality evidence); or on death and neurological disability combined (RR 1.04, 95% CI 0.86 to 1.25).Glycerol may have little or no effect on seizures during treatment for meningitis (RR 1.08, 95% CI 0.90 to 1.30, 909 participants, three trials, low-quality evidence).Glycerol may reduce the risk of subsequent deafness (RR 0.60, 95% CI 0.38 to 0.93, 741 participants, four trials, low-quality evidence).

AUTHORS' CONCLUSIONS

The only osmotic diuretic to have undergone randomised evaluation is glycerol. Data from trials to date have not demonstrated benefit on death, but it may reduce deafness. Osmotic diuretics, including glycerol, should not be given to adults and children with bacterial meningitis unless as part of carefully conducted randomised controlled trial.

Drug Insight: adjunctive therapies in adults with bacterial meningitis

Despite the availability of effective antibiotics, mortality and morbidity rates associated with bacterial meningitis are high. Studies in animals have shown that bacterial lysis, induced by treatment with antibiotics, leads to inflammation in the subarachnoid space, which might contribute to an unfavorable outcome. The management of adults with bacterial meningitis can be complex, and common complications include meningoencephalitis, systemic compromise, stroke and raised intracranial pressure. Various adjunctive therapies have been described to improve outcome in such patients, including anti-inflammatory agents, anticoagulant therapies, and strategies to reduce intracranial pressure. Although a recent randomized trial provided evidence in favor of dexamethasone treatment, few randomized clinical studies are available for other adjunctive therapies in adults with bacterial meningitis. This review briefly summarizes the pathogenesis and pathophysiology of bacterial meningitis, and focuses on the evidence for and against use of the available adjunctive therapies in clinical practice.