Corticosteroids and post-herpetic neuralgia

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a common, serious, painful complication of herpes zoster. Corticosteroids have anti-inflammatory properties, and might be beneficial. This is an update of a review first published in 2008, and previously updated in 2013.

OBJECTIVES

To assess the effects (benefits and harms) of corticosteroids in preventing postherpetic neuralgia.

SEARCH METHODS

We updated the searches for randomised controlled trials (RCTs) of corticosteroids for preventing postherpetic neuralgia in the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, two other databases, and two trials registers (June 2022). We also reviewed the bibliographies of identified trials, contacted authors, and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all RCTs involving corticosteroids given by oral, intramuscular, or intravenous routes for people of all ages, with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo, but not with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified potential articles, extracted data, assessed the risk of bias of each trial, and the certainty of the evidence. Disagreement was resolved by discussion among the co-authors. We followed standard Cochrane methodology.

MAIN RESULTS

We identified five trials with a total of 787 participants that met our inclusion criteria. No new studies were identified for this update. All were randomised, double-blind, placebo-controlled parallel-group studies. The evidence is very uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection in preventing postherpetic neuralgia six months after the onset of herpes (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.45 to 1.99; 2 trials, 114 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)). The three other trials that fulfilled our inclusion criteria were not included in the meta-analysis because they did not provide separate information on the number of participants with PHN at six months. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no observed differences in serious (RR 1.65, 95% CI 0.51 to 5.29; 5 trials, 755 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)), or non-serious adverse events (RR 1.30, 95% CI 0.90 to 1.87; 5 trials, 755 participants; low-certainty evidence (downgraded for serious risk of bias and serious imprecision)) between the corticosteroid and placebo groups. One of these trials was at high risk of bias because of incomplete outcome data, two were at unclear risk of bias, and the other was at low risk of bias. The review was first published in 2008; no new RCTs were identified for inclusion in subsequent updates in 2010, 2013, and 2023.

AUTHORS' CONCLUSIONS

Based on the current available evidence, we are uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection on preventing postherpetic neuralgia. Corticosteroids given orally or intramuscularly may result in little to no difference in the risk of adverse events in people with acute herpes zoster. Some researchers have recommended using corticosteroids to relieve the zoster-associated pain in the acute phase of the disease. If further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life, as well as updated measures of pain.

Jaipur block in postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia, a common sequele to herpes zoster infection, is a chronic debilitating problem. The available therapeutic modalities are usually ineffective.

METHODS

A total of 3960 patients (1326 women and 2634 men; age group, 21-84 years), with postherpetic neuralgia as the presenting complaint and with pain lasting from 2 months to 5 years, were treated with Jaipur block, consisting of local subcutaneous infiltration of 2% xylocaine, 0.5% bupivacaine, and 4 mg/mL dexamethasone solution. Patients were followed up at six-weekly intervals with subsequent injections given in non-responders.

RESULTS

Twenty-eight per cent of patients obtained complete relief from pain after a single injection, another 57% after a second injection, and 11% after a third injection; 4% of patients did not respond to treatment. The non-responders were either old (over 60 years) or had pain lasting for more than 2 years. The response to therapy was similar in both sexes. There were 31 left-handed patients in this study. Pain was less severe in left-handed patients and they obtained complete relief after a single injection. Side-effects including giddiness and sweating were seen, occasionally, in a few patients.

CONCLUSIONS

Ninety six per cent of patients obtained complete relief after the block with a follow-up of up to 19 years.

Meta-analyses to evaluate analgesic interventions: a systematic qualitative review of their methodology

A systematic search of the literature was performed to identify the maximum possible number of meta-analyses that evaluated analgesic interventions. Seventy-four reports were identified and retrieved and the scientific quality of 80 separate meta-analyses was assessed under blind conditions by 2 judges using Oxman and Guyatt's index. Most of the meta-analyses evaluated pharmacological interventions for chronic pain conditions and two-thirds were published since 1990. Ninety percent of the meta-analyses had methodological flaws that could limit their validity. The main deficiencies were lack of information on methods to retrieve and to assess the validity of primary studies and lack of data on the design of the primary studies. Meta-analyses of low quality produced significantly more positive conclusions. For several topics, different meta-analyses evaluating the same intervention produced conflicting results. The need to resolve these contradictions is highlighted.