Factors influencing the duration of treatment of acute herpetic pain with sympathetic nerve block: importance of severity of herpes zoster assessed by the maximum antibody titers to varicella-zoster virus in otherwise healthy patients

Hypovitaminosis Din Postherpetic Neuralgia-High Prevalence and Inverse Association with Pain: A Retrospective Study

Hypovitaminosis D (25-hydroxyvitamin D (25(OH)D) <75 nmol/L) is associated with neuropathic pain and varicella-zoster virus (VZV) immunity. A two-part retrospective hospital-based study was conducted. Part I (a case-control study): To investigate the prevalence and risk of hypovitaminosis D in postherpetic neuralgia (PHN) patients compared to those in gender/index-month/age-auto matched controls who underwent health examinations. Patients aged ≥50 years were automatically selected by ICD-9 codes for shingle/PHN. Charts were reviewed. Part II (a cross-sectional study): To determine associations between 25(OH)D, VZV IgG/M, pain and items in the DN4 questionnaire at the first pain clinic visit of patients. Independent predictors of PHN were presented as adjusted odds ratios(AOR) and 95% confidence intervals (CI). Prevalence (73.9%) of hypovitaminosis D in 88 patients was high. In conditional logistic regressions, independent predictors for PHN were hypovitaminosis D (AOR3.12, 95% CI1.73–5.61), malignancy (AOR3.21, 95% CI 1.38–7.48) and Helicobacter pylori-related peptic ulcer disease (AOR3.47, 95% CI 1.71–7.03). 25(OH)D was inversely correlated to spontaneous/brush-evoked pain. Spontaneous pain was positively correlated to VZV IgM. Based on the receiver operator characteristic curve, cutoffs for 25(OH)D to predict spontaneous and brush-evoked pain were 67.0 and 169.0 nmol/L, respectively. A prospective, longitudinal study is needed to elucidate the findings.

Patient characteristics and analgesic efficacy of antiviral therapy in postherpetic neuralgia

Postherpetic neuralgia (PHN) is the most common complication of shingles caused by reactivation of varicella zoster virus (VZV). Management of PHN is often suboptimal while using current conventional treatments. Antiviral therapy was used to reduce PHN-associated pain in two small trials which showed conflicting results. We hypothesize the analgesic efficacy of antiviral therapy on PHN is affected by patient characteristics including pathophysiology of the participants and serum vitamin D levels. Pathophysiology of PHN includes neuronal excitability and chronic VZV ganglionitis (persistent active VZV infection in ganglions). VZV-DNA positivity or a positive IgG coupled with a positive IgM indicates recent or current VZV infection. Positive VZV-DNA or IgG/IgM tests are used to confirm whether the patients experience chronic VZV ganglionitis. Antiviral therapy decreases pain in PHN patients with chronic VZV ganglionitis; whereas, antiviral therapy shows no effects in PHN patients with negative VZV-DNA or IgM. Vitamin D is a natural antiviral mediator. Studies show a high prevalence of vitamin D deficiency in hepatitis B/C virus-infected patients. Serum vitamin D levels and vitamin D supplementation are factors which affect the antiviral efficacy on hepatitis B/C virus infection. Serum 25-OHD levels of hospitalized patients with shingles were significantly lower compared to healthy controls. Accordingly, PHN patient may have a high prevalence of vitamin D deficiency which negatively affects the antiviral efficacy. Vitamin D supplementation may improve the antiviral efficacy on PHN. Future trials regarding antiviral therapy on PHN should consider patient characteristics and should be conducted among different subgroups of PHN patients.

Incidence of serum antibody titers against varicella zoster virus in Japanese patients with herpes zoster

Herpes zoster is an internal reactivation of varicella zoster virus following establishment of latent infection in the dorsal root ganglia during primary infection, which presents as chickenpox. Therefore, serologically, herpes zoster patients already have anti-varicella zoster virus immunoglobulin G at the onset of disease. Hence, positive serum antibody does not confirm the diagnosis of herpes zoster. We retrospectively investigated the incidence of varicella zoster virus-specific complement fixation in 865 zoster patients at initial presentation to a dermatology clinic. As a result, 66% of patients showed negative complement fixation, with patient numbers decreasing as titer increased. Paired complement fixation tests conducted within a short period showed a marked elevation in titer, and complement fixation titer gradually decreased after a year. Furthermore, incidence showed no correlation with patient age. These observations indicate that the complement fixation titer at first visit is mainly influenced by the duration from onset to presentation at clinic. Our findings indicate that a positive complement fixation result by single-point testing confirms at least recent onset of herpes zoster, while paired tests can confirm disease when primary tests are negative.

Persistence of varicella-zoster virus viraemia in patients with herpes zoster

BACKGROUND

Herpes zoster is caused by the reactivation of varicella-zoster virus from sensory neurons. The commonest complication following zoster is chronic pain termed post herpetic neuralgia.

OBJECTIVES

To investigate the dynamics of VZV viraemia and viral load following the resolution of zoster and its relationship to PHN development.

STUDY DESIGN

Blood samples were collected at baseline, 1 month, 3 months and 6 month from a prospective study of 63 patients with active zoster. Quantification of VZV DNA in whole blood was performed using a real-time PCR assay.

RESULTS

During acute zoster, all patients had detectable VZV DNA in their blood. VZV DNA remained detectable in the blood of 91% of patients at 6 months although levels declined significantly (p<0.0001). A history of prodromal symptoms (p=0.005) and severity of pain at baseline (p=0.038) as well as taking antivirals (p=0.046) and being immunocompromised (p=0.043) were associated, with longer time to recovery from PHN. Viral DNA loads were consistently higher in patients with risk factors for PHN and higher viral DNA loads over time were associated with longer time to recovery (p=0.058 overall and 0.038 in immunocompetent).

CONCLUSIONS

Based on these observations we hypothesise that VZV replication persists following acute shingles and that higher viral DNA loads contribute to the risk factors for PHN.

Herpes zoster and postherpetic neuralgia: optimizing management in the elderly patient

Herpes zoster (HZ) results from reactivation of varicella-zoster virus (VZV) that has been persistent and clinically dormant in spinal ganglia or cranial sensory nerves since primary infection with VZV. The most common reason for reactivation is a decline in zoster-specific cell mediated immunity as a result of aging (immunosenescence). More than two-thirds of HZ cases occur in people >or=60 years of age. HZ incidence is higher in persons who are immunocompromised as a result of disease (e.g. malignancies such as lymphoma, HIV/AIDS, diabetes mellitus) or treatments such as chemotherapy and radiotherapy. HZ incidence is also increased by therapeutic immune suppression following organ transplantation and in patients taking high-dose corticosteroids. However, HZ may occur in otherwise healthy young people. Although serious and life-threatening complications sometimes occur, the most common complication is postherpetic neuralgia (PHN), which may persist for months or years and is significantly resistant to treatment despite substantial advances in the understanding of its pathological mechanisms. The medical and social costs of HZ and PHN are high, particularly in older patients. Prevention of PHN in patients with HZ is unsatisfactory although antiviral drugs reduce the duration of pain after HZ. A live attenuated vaccine has been shown to reduce the incidence of HZ and PHN as well as the burden of illness in subjects aged >or=60 years. In view of the increasing numbers of elderly persons in the population and the poor outcomes of PHN treatment, vaccination against HZ at approximately 60 years of age appears to be an appropriate strategy.

Sympathetic nerve blocks in mandibular herpes zoster and postherpetic neuralgia

Sympathetic blocks have been indicated for the diagnosis and treatment of painful neuropathic conditions, such as herpes zoster (HZ) and postherpetic neuralgia (PHN). The purpose of this article is to report a case of mandibular HZ and PHN in an HIV-positive patient, and discuss the efficacy of sympathetic nerve blocks for pain relief and prevention of PHN.

Predicting postherpetic neuralgia in elderly primary care patients with herpes zoster: prospective prognostic study

Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster (HZ) and difficult to treat. Timely identification of high-risk HZ-patients enables physicians to focus on PHN prevention. To assess which simple to measure factors are independent predictors of PHN, and whether psychosocial and serological/virological parameters have additional predictive value, a prospective cohort study in primary care was conducted. We included 598 elderly (>50 years) consecutive patients with acute HZ (rash <7 days) below sixth cervical dermatome. At baseline demographic, clinical (e.g., duration and severity of pain and rash), psychological (Pain Cognition List [PCL] and Spielberger's Anxiety Inventory), serological (VZV-antibodies) and virological (viremia presence) variables were measured. Blood tests were performed in a random subset of 218 patients. Primary outcome was significant pain (VAS >30 on 0-100 scale) after three months. The final prediction model obtained from multivariable logistic regression was (internally) validated using bootstrapping techniques, and adjusted for optimism. Forty-six (7.7%) patients developed PHN. Independent predictors were age (odds ratio [OR]=1.08 per year), acute pain severity (OR=1.02 per unit), presence of severe rash (OR=2.31), and rash duration before consultation (OR=0.78 per day): area under receiver-operating-characteristic curve [ROC area]=0.77 (95% CI: 0.71-0.82). Of the five PCL scores, only factor V ('trust in healthcare') was an additional predictor (OR=1.01 per unit), though it increased the ROC area with only 0.01 to 0.78. The Spielberger's anxiety scores and serological and virological variables were no additional predictors. Thus, four simple variables can help physicians to timely identify elderly HZ-patients at risk of PHN.

Risk factors for postherpetic neuralgia in patients with herpes zoster

OBJECTIVES

To identify risk factors for postherpetic neuralgia (PHN) using a validated definition of this chronic neuropathic pain syndrome, to determine combinations of risk factors that identify patients with a high risk of developing PHN, and to examine the characteristics of patients with subacute herpetic neuralgia, that is, pain that persists beyond the acute phase of herpes zoster but that resolves before PHN can be diagnosed.

METHODS

The authors examined baseline and follow-up data from 965 herpes zoster patients enrolled within 72 hours of rash onset in two clinical trials of famciclovir.

RESULTS

Univariate and multivariate analyses indicated that older age, female sex, presence of a prodrome, greater rash severity, and greater acute pain severity made independent contributions to identifying which patients developed PHN. Patients with subacute herpetic neuralgia who did not develop PHN were significantly younger and had less severe acute pain than PHN patients but were significantly more likely to have severe and widespread rash than patients without persisting pain.

CONCLUSIONS

The independent contributions to the prediction of PHN made by older age, female sex, presence of a prodrome, greater rash severity, and greater acute pain severity suggest that these risk factors reflect different mechanisms that each contribute to the development of PHN. Subacute herpetic neuralgia that does not progress to PHN may reflect peripheral tissue damage and inflammation caused by a particularly severe or widespread rash.

Current management of postherpetic neuralgia

BACKGROUND

The herpes zoster rash occurs when a dormant varicella zoster virus reactivates in dorsal root and cranial nerve ganglia. Pain that persists in the region where this rash occurred after the cutaneous lesions have healed is termed postherpetic neuralgia (PHN). A wide variety of therapies has been used with varying degrees of success to prevent the occurrence of PHN and to reduce pain with established PHN.

REVIEW SUMMARY

In this review, we discuss the clinical presentation of PHN, current strategies for the prevention and management of this disease, and observations that have increased our understanding of the neural mechanisms involved in PHN.

CONCLUSIONS

Several classes of drugs are effective in attenuating the pain and hyperalgesia caused by PHN, but no single drug leads to the complete relief of symptoms. Additional research is needed to improve treatment strategies and define the role of invasive pain management techniques in cases where PHN is associated with intractable pain.

Clinical correlates of prolonged pain in Japanese patients with acute herpes zoster

To determine which risk factors are relevant to the occurrence of post-herpetic neuralgia in Japanese patients with acute herpes zoster, correlations between the prolongation of pain and various disease factors were examined in 263 adult patients presenting within 10 days of the onset of rash at 17 institutions in the Hyogo region of Japan. All patients in whom pain persisted for more than 3 months were over 60 years of age. The pain also tended to be more prolonged in those with clustered vesicles, disturbed sleep and hypanaesthesia. Other factors such as underlying disease states, critically involved regions, scar tissue, generalized rash and allodynia were not relevant to the duration of pain. Although decreased pain persistence was observed in patients in whom acyclovir therapy was initiated within 72 h of the onset of symptoms in comparison with those in whom it was initiated after this time, the difference between the two groups of patients was not statistically significant. Our results suggest that advanced age, the presence of clustered vesicles, and disturbed sleep and hypanaesthesia influence the prolongation of herpes zoster pain.

Acute pain in herpes zoster: the famciclovir database project

The results of a considerable number of recent prospective studies have demonstrated that greater acute pain severity in herpes zoster patients is associated with a significantly greater risk of developing postherpetic neuralgia (PHN). Only a few studies have examined the relationships between acute pain severity and demographic characteristics and clinical features of patients with herpes zoster, however, and the results of these studies have been inconsistent. To clarify these relationships, data from 1778 herpes zoster patients studied within 72 h of rash onset in four clinical trials of the antiviral agent famciclovir were examined. Univariate and multivariate analyses indicated that greater acute pain severity was significantly associated with greater age, female sex, greater rash severity, the presence of a prodrome, and primary involvement of non-trigeminal dermatomes. These results demonstrate that three of the established risk factors for PHN - older age, greater rash severity, and the presence of a prodrome - are also associated with more severe acute pain assessed soon after rash onset in patients with herpes zoster. The results of this study are consistent with the recommendation that herpes zoster patients who are older, who have had a prodrome, or who have severe rash or severe acute pain should be targeted for interventions designed to prevent PHN.

Allodynia and pinprick hypesthesia in acute herpes zoster, and the development of postherpetic neuralgia

Sensory loss and allodynia are hallmark signs of postherpetic neuralgia (PHN). We set out to investigate how frequently these signs are present in patients with acute herpes zoster (HZ) and what their prognostic value might be. We assessed pain, mechanical allodynia, and sensitivity to pinprick in 113 immunocompetent patients with HZ of a median duration of 5 days. Follow-up visits took place at 2 weeks, 6 weeks, 3 months, and 6 months. When first seen, 87 (77%) patients reported ongoing pain and 48/107 (45%) had allodynia. Twenty-eight (25%) patients had pain at 3 months (and were considered to have developed PHN), while 14 (12%) patients had pain at 6 months. Allodynia tended to subside quickly in most patients. Reduced sensitivity to pinprick was less common. Mechanical allodynia and pinprick hypesthesia were strongly associated with the development of PHN. They merit addition to the list of potential risk factors for PHN although they cannot be used as a predictive rule for an individual patient. By contrast, lack of allodynia in the early stages of HZ predicts good recovery by three months.

Pain and somatosensory dysfunction in acute herpes zoster

OBJECTIVE

To determine the nature of sensory change and its association with pain and allodynia in acute herpes zoster.

DESIGN

Prospective clinical study.

PATIENTS

One hundred thirteen immunocompetent patients with acute herpes zoster.

METHODS

Onset, intensity, and quality of pain and severity of rash were recorded. Quantitative somatosensory testing for tactile and thermal thresholds, qualitative pinprick testing, and testing of dynamic and static allodynia were performed within the affected dermatome, its mirror-image dermatome, and in an adjacent dermatome bilaterally.

RESULTS

Acute pain was reported as severe in 50%, moderate in 29%, mild in 12%, and absent in 9% of patients. Preherpetic pain (median = 4 days, range = 1-60 days) was experienced by 71%. Mechanical allodynia, dynamic, static, or both, was found in 37% of patients and was noted to extend one or more dermatomes outside the rash in 12%. In the affected dermatomes, thresholds were elevated for warmth and cold, lowered for heat pain, and unchanged for touch when compared with the contralateral side. Logistic regression analyses showed that compression-evoked allodynia, brush-evoked allodynia, and the history of preherpetic pain were more frequently encountered in patients with severe pain. Sensory threshold changes were not associated with the severity of pain or rash or with the presence of allodynia.

CONCLUSION

Pain, allodynia, and altered sensation are common features of acute herpes zoster. They are likely to result primarily from widespread neural inflammation within the affected afferent system. The sensory changes found in acute herpes zoster are different from those reported in published studies on postherpetic neuralgia and suggest sensitization phenomena and preservation of tactile functions rather than major neural damage. The exact mechanisms for acute herpes zoster pain, however, remain speculative.

Pain caused by herpes zoster infection

Postherpetic neuralgia (PHN) is a neuropathic pain disorder that occurs most often in the elderly. This painful condition is uniquely suited for clinical research, resulting in an emerging understanding of the pathophysiology of the persistent pain. Until recently, only the tricyclic antidepressants proved effective for PHN. Controlled trials of a wide variety of therapeutic strategies are in progress or have been recently completed.

Pain and its persistence in herpes zoster

The nature and duration of pain associated with herpes zoster is highly variable. This review of research on pain in acute herpes zoster and postherpetic neuralgia (PHN) explores those observations relevant to the definition and pathogenesis of PHN and the design of treatment trials. A model for the pathogenesis of PHN is presented, which gains support from studies of risk factors. Several directions for future research are identified.

[Ten years of therapy resistant intercostal neuralgia-suspected postherpetic neuralgia following herpes zoster sine herpete.]

We report the case of a 65 year old man who has been suffering from segmental back pain for 10 years. The diagnosis postherpetic neuralgia following herpes zoster sine herpete was fixed 9 years after the beginning of pain. All treatments prior to ours were ineffective. Acupuncture and the use of homeopathic drugs led to success at last.

T-lymphocyte subsets in otherwise healthy patients with herpes zoster and relationships to the duration of acute herpetic pain

T-lymphocyte subsets (CD3, CD4, and CD8 lymphocytes) in peripheral blood, parameters of cell-mediated immunity, were serially measured in 62 otherwise healthy Japanese patients with herpes zoster (HZ), and the findings were compared with those of 20 age-matched healthy controls who had had varicella but not HZ. Our objective was to elucidate whether there were changes in cell-mediated immunity, even in immunocompetent patients with HZ, and to investigate relationships between these variables and the duration of acute herpetic pain (AHP). All the patients underwent repeated sympathetic nerve blocks until pain was relieved. As compared with controls, there were slight increases in the percentages of CD4 lymphocytes (helper/inducer) and highly significant increases in the percentages of CD8 lymphocytes (suppressor/cytotoxic), resulting in marked decreases in CD4/CD8 ratios in the acute phase of HZ. The percentages of CD3 lymphocytes (pan-T lymphocytes) did not differ significantly. The duration of AHP was analyzed in 49 patients in whom T-lymphocyte subsets were measured more than twice. There was a weak but statistically significant positive linear correlation between age and the duration of AHP (r = 0.43, P < 0.01). There were statistically highly significant positive linear correlations between the number of days on which percentages of CD3 (r = 0.72, P < 10(-8)) and CD4 lymphocytes (r = 0.60, P < 10(-5)), and CD4/CD8 ratios (r = 0.62, P < 10(-5)) reached the maximum values after the onset of HZ and the duration of AHP. These correlation coefficients were higher than that between age and the duration of AHP.(ABSTRACT TRUNCATED AT 250 WORDS)

Somatosensory findings in postherpetic neuralgia

Somatic sensory perception thresholds (warm, cold, hot pain, touch, pinprick, vibration, two-point discrimination), allodynia and skin temperature were assessed in the affected area of 42 patients with unilateral postherpetic neuralgia (PHN) and 20 patients who had had unilateral shingles not followed by PHN (NoPHN), and in the mirror-image area on the other side. There was no difference between the two groups for age or length of time after the acute herpes zoster infection. The PHN group showed significant changes in all sensory threshold measurements when the affected area was compared with the mirror-image area on the unaffected side, while the NoPHN group exhibited no threshold changes. Mechanical allodynia was present in 87% of the PHN group; half of the 12 patients with ophthalmic PHN showed extension of allodynia to the maxillary distribution. No differences in skin temperature were recorded between affected and unaffected regions in either group. Our findings show a deficit of sensory functions mediated by both large and small primary afferent fibres and also suggest major central involvement in the pathophysiology of the condition. If PHN does not occur following acute herpes zoster, recovery of neural functions appears to be good.