A Review of Herpes Zoster (Shingles) and the Geriatric Population
Pain.com recently asked Dr. Bernard Abrams about herpes zoster in the geriatric population. Following is an excerpt of our conversation in which Dr. Abrams identifies why healthcare professionals need to be up-to-date with information regarding HZ as well as treatment options and the potential complications of HZ.
Pain.com: Why is shingles such an important topic to consider in the geriatric population?
Dr. Abrams: There are three reasons healthcare providers need to be current on information related to shingles (or herpes zoster):
- Shingles has a much higher incidence in the 65 years+ population. In the general population, only two-to-three people per thousand will acquire shingles. However, in the population over 65 years of age, the incidence is approximately 12-per-thousand. Additionally, those people over 65 who do experience shingles are at an increased risk of experiencing postherpetic neuralgia (PHN), which occurs with increased frequency, severity, and duration in the older population and has been reported to occur in as high as 50% of patients over 65 with shingles.
- There is an FDA-approved preventative vaccine for shingles (Zostarax). This medication has been shown to have a 61% improvement rate in a person’s chance of not developing shingles.
3. There have been great strides in the development of treatments that are more effective in preventing PHN, as well as the potential for improvement of symptomatology in those patients developing postherpetic neuralgia.
Pain.com: What are the manifestations of acute herpes zoster?
Dr. Abrams: Acute HZ manifests as a characteristic maculopapular rash with crusting occurring in one-to-two weeks. You may also note vesicles, most commonly around the thorax in a unilateral radicular distribution, but it can also affect the cranial nerves, especially the VIIth & VIIIth, which can be devastating. More severe, acute pain, a more extensive rash, and a prodrome of pain in the dermatomal distribution indicate a greater likelihood of the development of postherpetic neuralgia.
Pain.com: What are the characteristics of postherpetic neuralgia?
Dr. Abrams: PHN has been defined as the persistence of pain of herpes zoster for more than four months after the rash disappears. Patients report a variety of pains in the distribution of the affected nerve root(s) including burning, throbbing, constant pain, or shooting, stabbing intermittent pain. Some patients also experience pain evoked by touching (allodynia). When PHN occurs in the ophthalmic division of the trigeminal nerve it can lead to ocular involvement and blindness. Severe ear pain and ipsilateral facial nerve palsy associated with a herpetic eruption of the external auditory meatus is known as Ramsay Hunt syndrome. Occasionally, acute herpes zoster may present as motor weakness as well as the usual sensory abnormality. This motor weakness has been estimated to occur in as many as 20% of herpes zoster patients, and may persist.
Pain.com: What is the treatment for acute herpes zoster?
Dr. Abrams: Physicians can prescribe an antiviral agent such as famciclovir or valacyclir to patients with acute HZ. Both medications have been shown to reduce the duration of postherpetic neuralgia in patients older than 50 years of age.
Pain.com: What can physicians do for patients who develop postherpetic neuralgia?
Dr. Abrams: The wide variety of treatments for postherpetic neuralgia testifies to the fact that no treatment is completely effective. In general, there are two types of treatment available: pharmacological or interventional. The pharmacological treatments include analgesics, membrane stabilizers, and antidepressants. Interventional procedures include sympathetic blockade, intrathecal injections, spinal cord stimulation, or as a last resort, surgical intervention.
Pain.com: Please describe the pharmacological agents available to treat PHN.
Dr. Abrams: Opioids have been a time-monitored standard treatment for postherpetic neuralgia. There is concern about using these agents over a long period of time due to the potential for addiction. While this fear may be overstated, due diligence before prescribing this agent would include a careful history to discern potential addictive tendencies.
There is currently much interest in using two membrane stabilizers: gabapentin and pregabalin. These meds act, in all likelihood, at the alpha2 delta1 voltage dependent calcium channel to decrease calcium influx and, hence, inhibit the release of glutamate, an excitatory neurotransmitter. Several double-blind placebo controlled studies have established the efficacy of gabapentin. Doses range from 100 mg t.id. to a maximum of 3600 mg a day in divided doses. Side effects include drowsiness, ataxia, dizziness, peripheral edema, and, especially in the elderly, a “dumbing down effect.” This significant cognitive effect has often been ignored, but is highly significant to the affected patient.
Pregabalin may have greater analgesic activity than gabapentin. Doses range from 150 to 600 mg per day. Again, dizziness, somnolence, and peripheral edema, are the most common side effects. Combinations of these medications with opioids will sometimes reduce the dose of both, making the side effects more tolerable.
Pain.com: What other pharmacological options exist?
Dr. Abrams: Antidepressants have been used to treat PHN, especially tricyclic antidepressants (TCAs). These drugs have norepinephrine reuptake and serotonin reuptake inhibition, and possibly affect the sodium channels. These drugs have strong anti-cholinergic affects, although some have less than the prototypical drug amitriptyline. Nonetheless, nortriptyline should be used with caution in the elderly and started at very small doses. Orthostatic hypotension, prolongation of the QT interval, blurred vision, precipitation of glaucoma, and urinary retention, especially in the presence of an enlarged prostate, remain the most common significant issues in the elderly.
Pain.com: Are there topical pharmacological options?
Dr. Abrams: A topical Lidoderm (5%) patch remains an option. This is especially true for the elderly population since there are relatively few side effects (mostly skin irritation). This patch is an attractive possibility since it has minimal systemic absorption of the drug, which makes drug interactions very unlikely. It can be applied efficaciously to the trunk. However, the cost may be prohibitive, especially if more than one patch is needed at a time.
Pain.com: Can you tell us about available interventional therapies for PHN?
Dr. Abrams: For a long time, sympathetic blockade, especially within the six-to-twelve week’s window of opportunity, was considered to be most efficacious. While meta-analysis of previous studies has disclosed numerous methodological weaknesses in prior studies, there may be efficacy in sympathetic blockade to specific regions, such as stellate ganglion block for facial herpes zoster.
There are at least some theoretical considerations for the use of sympathetic blockade in acute herpes zoster for preventing postherpetic neuralgia. Epidural nerve blocks have only anecdotal evidence to commend them, but they may be useful in acute situations. Intrathecal methylprednisolone has, at least in one study, shown to have an advantage over epidural methylprednisolone, and did provide a significant amount of relief. Because of the increase in interleukin-8 in the cerebrospinal fluid of patients with chronic postherpetic neuralgia, there is at least a theoretical basis for an intrathecal anti-inflammatory.
The use of spinal cord stimulation has not been studied enough for recommendation, and surgical sectioning of nerve roots or nerves affected by chronic postherpetic neuralgia has the potential for the development of anesthesia dolorosa, a dreaded complication even more refractory to treatment, and postherpetic neuralgia.
Pain.com: Dr. Abrams, can you sum up the current status of herpes zoster in the elderly?
Dr. Abrams: The old adage “an ounce of prevention is worth a pound of cure” probably applies more to this entity than most others. It is a disease of the elderly, and complications are more likely to occur in the elderly. The shingles vaccine should be considered in everyone over 60 without contraindications, probably those who have had previous chickenpox infections and certainly those who have had prior bouts of shingles.
Should shingles occur, it should be treated vigorously and early with antiviral compounds to prevent the development of postherpetic neuralgia. Should PHN occur, there are numerous treatment options, but the age and concurrent medical conditions of the patient should be taken into account.
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