The Effects of Epidural Blockade on the Acute Pain in Herpes Zoster

Abstract

Objective To evaluate the relief of acute pain and possible preventive effects on postherpetic neuralgia through the use of an epidural blockade in the acute stage of herpes zoster.

Design Prospective, nonrandomized, comparative clinical trial.

Setting A dermatologic clinic in a university hospital.

Patients Sixty-five consecutive patients with pain due to acute herpes zoster were treated for a 7-day hospitalization period from July 1, 1996, through June 30, 1997.

Intervention The consecutive patients were divided into 2 groups. Group A consisted of 30 patients who were seen from July 1, 1996, through December 31, 1996, and who were treated with intravenous acyclovir (5 mg/kg) for 7 days. Group B consisted of 35 patients who were seen from January 1, 1997, through June 30, 1997, and who were treated with intravenous acyclovir (5 mg/kg)and an epidural blockade for 7 days. The changes in the intensity of pain and the total duration of pain in both groups were assessed for 12 to 18 months.

Main Outcome Measures The number of days required for relief of pain and the total duration of pain.

Results The mean ± SD number of days required for relief of pain, which was rated on a scale of 100 (worst pain) to 0 (no pain), was significantly fewer in group B than in group A: it took 2.6 ± 1.1 days to go from 100 to 50 on the relief-of-pain scale in group B, but 3.8 ± 1.1 days in group A (P = .03), and 12.5 ± 6.4 days to go from 100 to 10 in group B, but 20.1 ± 14.6 days in group A (P = .04). The duration of late residual pain was significantly shorter in group B (5.9 ± 5.8 days) than in group A (11.9 ± 7.5 days) (P = .03). The total duration of pain was also significantly shorter in group B (18.5 ± 9.3 days) than in group A (31.6 ± 17.6 days) (P = .04).

Conclusions We believe that an epidural blockade combined with an antiviral agent is a very effective treatment modality for the pain of acute herpes zoster, and we recommend its use for the prevention of postherpetic neuralgia, with a view to shortening the total duration of pain, especially late residual pain.

POSTHERPETIC neuralgia (PHN) is the most common and feared complication of herpes zoster (HZ). Although PHN resolves spontaneously within the first year in the great majority of cases, the pain is often relentless and persists for years, or even a lifetime.1,2Thus, PHN is difficult to manage and, unfortunately, refractory to most forms of treatment modalities. It has been demonstrated that antiviral treatment,3- 6 cortcosteroids,7,8 sympathetic and regional nerve blockade,9,10 and a combination of these therapies 11,12 in the early stage of disease have preventive effects on PHN and reduce the duration of acute pain in HZ. Early therapeutic interventions with antiviral drags, particularly newly developed drugs, such as valacyclovir hydrochloride and famciclovir, allowed dramatic improvements of the skin lesions of HZ and reductions in the incidence of PHN.5,6 Corticosteroid therapy has also been postulated to be beneficial by some authors,7,8,11,12although there is controversy concerning the effectiveness of corticosteroids because of the immunosuppressive effects.

Although an epidural blockade is undeniably effective in providing relief of acute pain in HZ, the concept of its preventive action on PHN is intriguing, but unproved.9,10,13- 21Also, little information is available on the long-term efficacy of epidural blockade for the pain of HZ. Therefore, we designed this prospective interventional study to evaluate the effectiveness of epidural blockade on acute pain in HZ and the prevention of PHN.