Evidence-based Clinical Chinese Medicine

Volume 6: Herpes Zoster and Post-herpetic Neuralgia

Meaghan Coyle;Haiying Liang

• Publisher: WSPC
• Year: 2018
• eBook ISBN: 9789813209695
• Topic: Medicine
• Subtopic: Alternative & Complementary Medicine

Evidence-based Clinical Chinese Medicine provides a "whole evidence" analysis of the Chinese medicine management of herpes zoster and post-herpetic neuralgia. Evidence from the classical Chinese medicine literature, contemporary clinical literature, the outcomes of clinical trials and experimental studies are reviewed, analysed and synthesised. The data from all these sources are condensed to provide evidence-based statements which will inform clinical practice and guide future research.

This book has been designed to be an easy reference at the point of care. During a patient consultation, Chinese medicine practitioners can refer to this book for guidance on which Chinese herbal medicine formulas, specific herbs, or acupuncture points, can best treat their patient, and be confident there is evidence which supports its use.

Currently, Chinese medicine practitioners who develop a special interest in a particular health condition such as herpes zoster and its common sequelae post-herpetic neuralgia have to consult a variety of sources to further their knowledge. Typically, they use the contemporary clinical literature to understand the theory, aetiology, pathogenesis and obtain expert opinions on the Chinese medicine management of herpes zoster and post-herpetic neuralgia. They search the electronic literature to identify systematic reviews of clinical trials, if any exist, to obtain assessments of the current state of the clinical evidence for particular interventions. If they have the skills and resources, they may search the classical Chinese medicine literature for an historical perspective on treatments that have stood the test of time.

This book provides all of this information for practitioners in one handy, easy to use reference. This allows practitioners to focus on their job of providing high quality health care, with the knowledge it is based on the best available evidence.

Contents:

• Introduction to Herpes Zoster
• Herpes Zoster in Chinese Medicine
• Classical Chinese Medicine Literature
• Methods for Evaluating Clinical Evidence — Herpes Zoster
• Clinical Evidence for Chinese Herbal Medicine — Herpes Zoster
• Pharmacological Actions of Frequently Used Herbs — Herpes Zoster
• Clinical Evidence for Acupuncture and Related Therapies — Herpes Zoster
• Clinical Evidence for Combination Therapies — Herpes Zoster
• Summary and Conclusions — Herpes Zoster
• Introduction to Post-herpetic Neuralgia
• Post-herpetic Neuralgia in Chinese Medicine
• Methods for Evaluating Clinical Evidence — Post-herpetic Neuralgia
• Clinical Evidence for Chinese Herbal Medicine — Post-herpetic Neuralgia
• Pharmacological Actions of Common Herbs — Post-herpetic Neuralgia
• Clinical Evidence for Acupuncture and Related Therapies — Post-herpetic Neuralgia
• Clinical Evidence for Combination Therapies — Post-herpetic Neuralgia
• Summary and Conclusions — Post-herpetic Neuralgia

Readership: Chinese medicine practitioners and researchers, undergraduate and postgraduate Chinese medicine students, other health science students with interest in Chinese medicine.
Key Features:

• The inclusion of classical Chinese medicine literature, comprehensively reviewed using systematic methods, provides the readers with a history of changes in terminology and treatment approaches from pre Tang dynasty (before 618 AD) to modern times. Rigorous processes have been developed to ensure consistency of the search, extraction and synthesis of data from the classical literature into the body of evidence for herpes zoster. Systematic reviews of the clinical trial evidence and clinical practice guidelines tend to limit the evidence to that derived from randomised controlled trials. The books in this series take a broader view by including evaluations of controlled clinical trials and non-controlled studies, such as case series studies, in order to include the full scope of clinical studies and provide a clear insight into which Chinese medicine interventions have received clinical research attention
• This book integrates evidence from the contemporary and classical literatures with the results of clinical studies to make evidence-based statements for easy application at the point of care. In addition, the actions of the Chinese herbs most frequently used in controlled trials are discussed in light of the results of in-vivo and in-vitro studies. This provides the reader with an understanding of how these Chinese herbs exert their effects
• The authors are internationally recognized, well-respected leaders in the field of Chinese medicine and evidence based medicine with strong track records in research

1

Introduction to Herpes Zoster

OVERVIEW

Herpes zoster is a painful skin rash that develops in individuals who have been previously exposed to the varicella zoster virus. The rash is usually limited to the dermatome of the affected nerve. In young people and those with competent immune systems, herpes zoster usually resolves without any need for treatment. For older patients, antiviral therapies are recommended to aid recovery and inhibit the development of post-herpetic neuralgia. This chapter describes the characteristics, identified risk factors, pathological processes, and current management of herpes zoster.

Definition of Herpes Zoster

Herpes zoster, commonly known as shingles, is a painful skin rash caused by a reactivation of the latent varicella zoster virus.¹ Primary infection of the varicella zoster virus results in chickenpox.^2,3 The varicella zoster vaccine has been shown to be moderately effective in preventing primary infection of the varicella zoster virus,⁴ although it does not prevent all cases. Once the initial infection has resolved, the virus lies dormant in the dorsal root and cranial nerve ganglia.² Herpes zoster can occur at any age⁵ and the virus can lie dormant for several decades.¹ Factors such as age, immune suppression, or immunodeficiency can lead to a reactivation of the virus,¹ and the virus spreads along sensory ganglia to the neural tissue of the affected segment, resulting in localised skin eruptions.^1,3

Three clinical stages are usually seen in herpes zoster: the prodromal phase, acute phase, and healing phase.⁶ The prodromal phase occurs in 70–80% of patients² and can last from one day⁶ to more than 10 days.² The length of the prodromal phase usually relates to the amount of time the virus takes to travel from the dorsal ganglia to the cutaneous nerves and replicate in the skin.² Symptoms of the prodromal phase include pain or abnormal skin sensations, malaise, headache, and nausea.^2,3,6

During the acute phase, development of a painful, unilateral, and erythematous rash,⁶ typically in areas innervated by the thoracic, cervical, and trigeminal sensory nerves, is observed.⁷ Pain is usually described as burning, throbbing, or stabbing.² Small macules and papules appear in clusters which develop into vesicles after one to two days.² New vesicles can appear for a further three to five days.³ Pustulation occurs within one week of rash development, after which ulceration and crustation occurs.² Healing time can vary from two to four weeks in immunocompetent patients.^1,3

Presentation can be atypical in patients with a compromised immune system.¹ The rash may involve more than one dermatome and be of longer duration.¹ Patients with compromised immunity are at greater risk of disseminated and visceral zoster.²

While the disease is self-limiting,⁶ between 10% and 21% of people with herpes zoster go on to experience post-herpetic neuralgia (PHN).^5,6,8,9 Dubinsky et al.⁸ emphasised that there is no agreed definition of PHN, with definitions ranging from one month to six months after the rash has resolved. The definition provided by Dubinsky et al.^{8, p959} that PHN is the “persistence of the pain of herpes zoster more than 3 months after resolution of the rash” is generally accepted for clinical diagnosis and research. Pain arises due to sensory nerve damage, can be intermittent, and may be accompanied by allodynia (pain from stimuli that would not normally produce pain).

Complications of herpes zoster are not uncommon, and are grouped according to four categories: cutaneous, visceral, neurological, and ocular.⁷ PHN is the most common complication, affecting up to 21% of people with herpes zoster.⁶ Other common complications include opthalmic zoster, Ramsay Hunt syndrome (involving the geniculate ganglion of the facial nerve),² zoster encephalitis, disseminated zoster (defined as 20 or more lesions in a secondary dermatome),¹⁰ and visceral involvement. Further, bacterial infection of the rash may require antibiotic treatment.¹¹ For an extensive list of herpes zoster complications, see Volpi et al.⁶

Epidemiology

A global epidemiological review of herpes zoster found that the median incidence was 4–4.5 per 1,000 person-years.¹² Incidence has been reported to be higher in Germany (5.3–5.5 per 1,000 person-years)¹³ and in immunocompetent patients aged 50 years or older in Italy (6.31 per 1,000 person-years).¹⁴ Incidence of herpes zoster increases with age. The mean age of onset of herpes zoster is 59.4 years, with over two thirds of cases (68%) occurring in people aged 50 years or older.¹⁵ An early epidemiological peak at between 30–34 years was noted by Gialloreti et al.¹⁴, with a second peak at 75–79 years. Women are more likely to develop herpes zoster than men;^13,16 the age-adjusted incidence is 3.9 per 1,000 person-years for females and 3.2 per 1,000 person-years for males.¹⁵

Burden

Herpes zoster has a significant impact on health-related quality of life (HRQoL). Comparison with other chronic diseases showed that herpes zoster has a greater impact on the domain ‘role limitations due to physical problems’ of the Medical Outcome Study 36-item Short Form Health Survey (SF36; a HRQoL questionnaire) compared to hypertension, congestive heart failure, diabetes mellitus, myocardial infarction, and depression.¹⁷ Herpes zoster also led to poor quality of life (that is, a score of less than 50 out of 100) in infected individuals for four out of eight domains of the SF36.¹⁷ Herpes zoster has also been shown to be a risk factor for development of depressive disorders.¹⁸

HRQoL in acute stage herpes zoster decreases with increasing pain levels,¹⁹ and pain associated with PHN has a higher impact on HRQoL than pain due to herpes zoster in the acute stage.²⁰ The impact of herpes zoster on HRQoL can be felt long after the resolution of skin rash, with research showing that HRQoL was lower than baseline levels for up to 180 days of follow up.²¹ In addition to its impact on HRQoL, data from the European World Health Organization database shows that herpes zoster-related mortality ranged from 0 to >0.07 per 100,000.²² Herpes zoster-related mortality was higher in older women than men.^22,23

The economic burden of herpes zoster and PHN is considerable. The estimated total annual cost burden of herpes zoster and PHN in Europe ranges from €26.97 million in Sweden to €271.21 million in the UK.²³ Outpatient management costs are higher for PHN than herpes zoster.²³ This is likely related to the increased ut...

Table of contents

• Cover
• Halftitle
• Series Editors
• Title
• Copyright
• Disclaimer
• Foreword
• Purpose of the Monograph
• Authors and Contributors
• Members of Advisory Committee and Panel
• Professor Charlie Changli Xue, PhD
• Professor Chuanjian Lu, MD
• Acknowledgments
• List of Figures
• List of Tables
• 1. Introduction to Herpes Zoster
• 2. Herpes Zoster in Chinese Medicine
• 3. Classical Chinese Medicine Literature
• 4. Methods for Evaluating Clinical Evidence — Herpes Zoster
• 5. Clinical Evidence for Chinese Herbal Medicine — Herpes Zoster
• 6. Pharmacological Actions of Frequently Used Herbs — Herpes Zoster
• 7. Clinical Evidence for Acupuncture and Related Therapies — Herpes Zoster
• 8. Clinical Evidence for Combination Therapies — Herpes Zoster
• 9. Summary and Conclusions — Herpes Zoster
• 10. Introduction to Post-herpetic Neuralgia
• 11. Post-herpetic Neuralgia in Chinese Medicine
• 12. Methods for Evaluating Clinical Evidence — Post-herpetic Neuralgia
• 13. Clinical Evidence for Chinese Herbal Medicine — Post-herpetic Neuralgia
• 14. Pharmacological Actions of Common Herbs — Post-herpetic Neuralgia
• 15. Clinical Evidence for Acupuncture and Related Therapies — Post-herpetic Neuralgia
• 16. Clinical Evidence for Combination Therapies — Post-herpetic Neuralgia
• 17. Summary and Conclusions — Post-herpetic Neuralgia
• Glossary
• Appendix 1: References for Included Clinical Studies
• Index