Dexamethasone as adjunctive therapy in bacterial meningitis. A meta-analysis of randomized clinical trials since 1988.

OBJECTIVE: To evaluate the effectiveness of dexamethasone in bacterial meningitis in the subcategories of causative organism and timing and nature of antibiotic therapy. DATA SOURCES: MEDLINE, HEALTHLINE, and AIDSLINE were searched with the Medical Subject Headings "dexamethasone" and "meningitis" in any language. Bibliographies, conference abstracts, and the authors of identified studies were consulted. STUDY SELECTION: Randomized, concurrently controlled trials of dexamethasone therapy in childhood bacterial meningitis published from 1988 to November 1996 were selected. Of 16 studies identified, 5 were not eligible. DATA EXTRACTION: Data were extracted by means of standard outcomes in a protocol sent to all principal authors. DATA SYNTHESIS: Random-effects meta-analysis models were used to obtain summary estimates. As the incidence of severe hearing loss differed significantly by organism among control subjects, organism-specific estimates were used. In Haemophilus influenzae type b meningitis, dexamethasone reduced severe hearing loss overall (combined odds ratio [OR], 0.31; 95% confidence interval [CI], 0.14-0.69). Similar ORs were obtained after studies were stratified by the timing of administration of dexamethasone (before or with antibiotics vs later) or by type of antibiotic (cefuroxime vs other). In pneumococcal meningitis, only studies in which dexamethasone was given early suggested protection, which was significant for severe hearing loss (combined OR, 0.09; 95% CI, 0.0-0.71) and approached significance for any neurological or hearing deficit (combined OR, 0.23; 95% CI, 0.04-1.05). For all organisms combined, the pooled OR suggested protection against neurological deficits other than hearing loss but was not significant (OR, 0.59; 95% CI, 0.34-1.02). Outcomes were similar in studies that used 2 vs more than 2 days of dexamethasone therapy. Adverse effects were not significantly increased with dexamethasone except for secondary fever. The incidence of gastrointestinal tract bleeding increased with longer duration of dexamethasone treatment (0.5% in controls, 0.8% with 2 days of treatment, 3.0% with 4 days of treatment). CONCLUSIONS: The available evidence on adjunctive dexamethasone therapy confirms benefit for H influenzae type b meningitis and, if commenced with or before parenteral antibiotics, suggests benefit for pneumococcal meningitis in childhood. Limiting dexamethasone therapy to 2 days may be optimal.

Beneficial effects of dexamethasone in children with pneumococcal meningitis.

Fifty-six children older than 2 years with meningitis caused by Streptococcus pneumoniae were enrolled in a prospective, double blind, placebo-controlled trial to evaluate the efficacy of dexamethasone therapy in addition to antimicrobial therapy. Twenty-nine of 56 received dexamethasone (0.6 mg/kg/day iv, divided into 4 daily doses for 4 days) and the remaining 27 received placebo. At the beginning of therapy the clinical and laboratory characteristics of the patients in the treatment groups were comparable, except for the Glasgow coma score (P = 0.004), which was lower in the dexamethasone group. Patients were examined daily during hospitalization and 6 weeks after discharge from the hospital. Hearing was assessed 6 weeks after discharge by means of pure tone audiometry. Two patients in the dexamethasone group and one patient in the placebo group died. There were no differences between the two groups with regard to the duration of fever, the incidence of secondary fever and electrolyte imbalance, seizure activities occurring during hospitalization and rash. Although the differences were statistically insignificant, moderate or severe unilateral or bilateral sensorineural hearing loss at 6 weeks and the overall neurologic sequelae, including hearing loss, at 1 year were higher in the placebo group, at 23% vs. 7.4% (P = 0.11) and 26.9% vs. 7.4% (P = 0.062), respectively. At 3 months after discharge, because of the improvement in hearing loss in one dexamethasone-treated patient the incidence of hearing impairment was significantly less than that in the placebo group, at 3.7% vs. 23%, respectively (P = 0.044). No improvement in hearing loss was observed after 3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell-mediated immunity in rubella assayed by cytotoxicity of supernatants from rubella virus-stimulated human lymphocyte cultures.

Rubella virus-stimulated lymphocytes from rubella-seropositive donors produced in the culture medium cytotoxic activity with preferential action against rubella-infected over uninfected target cells. The ability of lymphocytes to produce the cytotoxic activity upon stimulation by rubella virus correlated with the humoral rubella-immunity status, i.e. no such cytotoxic activity developed in the supernatants of lymphocyte cultures of rubella-seronegative donors. Stimulation of lymphocytes from seropositive donors by rubella virus was also detected by thymidine incorporation, but the correlation of lymphocyte responsiveness to the humoral rubella antibody status was not so clear as in the cytotoxicity assay. Conversion of lymphocytes from unresponsive to responsive to rubella virus following natural rubella infection and after rubella vaccination was demonstrated using both methods. Following vaccination rubella-specific cell-mediated immunity first became demonstrable at 14 days. The responsiveness of lymphocytes to phytohaemagglutinin (PHA) after rubella vaccination was followed by studying thymidine uptake and the ability of lymphocytes to produce lymphootoxin. By both tests marked suppression of PHA response occurred at days 3 and 7 after vaccination.

Cytotoxic activity against rubella-infected cells in the supernatants of human lymphocyte cultures stimulated by rubella virus.

Supernatant fluids of lymphocyte cultures from rubella-seropositive donors, stimulated with inactivated rubella virus, showed cytotoxic activity against rubella-infected target cells (NYU 32 line of human embryonic fibroblasts) but not against uninfected fibroblasts. The time of appearance of cytotoxic activity in rubella-stimulated lymphocyte cultures correlated with increased rate of DNA synthesis as measured by thymidine uptake. No such cytotoxic activity became detectable in the supernatants of lymphocyte cultures from rubella-seronegative donors cultured in the presence of rubella virus, or in unstimulated lymphocyte cultures from seropositive or seronegative donors. The cytotoxic activity was lost at 60degreesC in 30 min. In contrast to this rubella virus-induced cytotoxic activity, cytotoxin produced in mitogen-stimulated lymphocyte cultures from rubella seropositive and seronegative donors was equally cytocidal against rubella-infected and uninfected human fibroblasts. Although the nature of cytotoxic activity remains to be characterized, it is suggested that it is associated with a lymphokine released immune-specifically from rubella virus-stimulated lymphocytes.