One-year follow-up of patients with long-lasting post-herpetic neuralgia

BMC Infectious Diseases One-year follow-up of patients with long-lasting post-herpetic neuralgia Francesca Pica 3 Antonio Gatti 2 Marco Divizia 2 Marzia Lazzari 2 Marco Ciotti 1 Alessandro Fabrizio Sabato 2 Antonio Volpi 0 4 0 Dipartimento di Scienze Cliniche e Medicina Traslazionale, Universita di Roma Tor Vergata, Via Montpellier , 1 - 00133, Rome , Italy 1 Fondazione Policlinico Tor Vergata , Via Oxford 83, Rome , Italy 2 Emergency Care, Department of Intensive Care, Pain Medicine, and Anaesthesiology, Policlinico Tor Vergata, University of Tor Vergata , Rome , Italy 3 Dipartimento di Medicina Sperimentale e Chirurgia, Universita di Roma Tor Vergata, Via Montpellier , 1, 00133 Rome , Italy 4 Dipartimento di Scienze Cliniche e Medicina Traslazionale, Universita di Roma Tor Vergata, Via Montpellier , 1 - 00133, Rome , Italy Background: Recent information on epidemiology and management of post-herpetic neuralgia (PHN), a painful complication of zoster, is scarce. Methods: This study was conducted at the Pain Clinic of the Policlinico Tor Vergata, Rome, Italy, on eighty-five immunocompetent patients with a clinical diagnosis of PHN. At enrollment (time 0, T0), the patients were interviewed by physicians to obtain demographic data and information about their zoster clinical history and underwent a blood test for VZV-DNA research. DN4 and SF-12 questionnaires were used to assess the neuropathic nature of pain and the overall health status, respectively. A one-year follow-up was planned for enrolled cases, who were visited at regular intervals of at least 3 months. Results: At T0 all the patients were at least 6 months from the episode of acute zoster and still presented with intense pain (mean VAS =6.7; mean DN4 = 5.7). Using antivirals within 72 hours from the rash onset was associated to a significant reduction of pain at T0 (p = 0.006 vs untreated patients). Only 2.6% of patients treated with antivirals during acute zoster but 18.6% of the untreated ones presented with neuropathic pain at T12 (p =0.007), even though the two groups were similar at T0. VZV-DNA was found in 5 out of the 50 available blood samples. At the last follow-up visit, PCS and MCS scores of the PHN patients were found to be recovered over those of the historical age-matched healthy controls. Undesirable side effects of analgesic therapies were observed in 15.3 to 28.8% of the patients. Conclusions: Patients who six months after acute zoster still have significant neuropathic pain, have a high probability of suffering from chronic pain in the subsequent months/years. The initial antiviral treatment has a significant impact on the pain. Current strategies of analgesic therapy are effective to achieve relief of pain in PHN patients, but they are burdened with heavy and undesirable side effects. Chronic pain; Herpes zoster (HZ); Post-herpetic neuralgia (PHN); Quality of life - Background Post-herpetic neuralgia (PHN) is the most challenging and debilitating complication of herpes zoster (HZ) in immunocompetent hosts. It is characterized by constant or intermittent burning, itching or aching, with paroxysmal or lancinating pain. Other primary characteristic, such as numbness, tingling and allodynia, also contribute to the burden of PHN. Pain intensity at the rash onset, age, rash severity, length of prodromal pain and cranial localization are more frequently reported as predictors of PHN [1-14]. Several issues concerning diagnosis, prediction and prevention of PHN need, however, to be clarified in view of recent contributions [15-20]. Despite advances in antiviral therapy during acute HZ and the more recent introduction of vaccination against Varicella-zoster virus (VZV) [21], PHN continues to be a significant clinical problem, with up to 25% of patients over 60 years developing persistent neuropathic pain following acute HZ [22-24]. The estimated incidence of PHN varies with its definition [25-30]. PHN can persist, in some individuals, for months or years after the HZ rash has healed, causing suffering for the patient and a burden of economic cost on patient, care givers, and healthcare providers. Studies vary widely in the reporting of the duration of persistent pain [31]. Helgason et al. [32] found that of 13 subjects with persistent pain 12 months after HZ, 6 still reported pain after 6.3 years. In one study of patients aged over 65 years, the mean duration of pain was 3.3 years, and ranged from 3 months to more than 10 years [33]. A few recent prospective studies report on the persistence of symptoms up to and over 12 months after HZ onset. In detail, Bouhassira et al. [34] reported the presence of zoster-related pain in 6% of 1032 patients 12 months after HZ. McKendrick et al. [35] found that of 158 subjects assessed 9 years after HZ, 21% had experienced any pain during the past year; of these, 47% had been pain-free at the time of discharge from the acute study. This is the reason why, in the last years, PHN is emerging as a pr (...truncated)