Tricyclic antidepressants reduce PHN pain, but their use is limited by side effects. Opioid medications are not generally recommended for treatment except in specific circumstances. Such cases should involve a pain specialist in patient care due to mixed evidence of efficacy and concerns about potential for abuse and addiction.PHN is the most common long-term complication of herpes zoster. The incidence and prevalence of PHN are uncertain due to varying definitions. Approximately 20% of people affected by herpes zoster report pain in the affected area three months after the initial episode of herpes zoster, and 15% of people similarly report this pain two years after the herpes zoster rash. Since herpes zoster occurs due to reactivation of the varicella zoster virus, which is more likely to occur with a weakened immune system, both herpes zoster and PHN occur more often in the elderly and in people with diabetes mellitus. Risk factors for PHN include older age, a severe herpes-zoster rash, and pain during the herpes zoster episode. PHN is often very painful and can be quite debilitating. Affected individuals often experience a decrease in their quality of life. Signs and symptoms
Symptoms:
With resolution of the herpes zoster eruption, pain that continues for three months or more is defined as postherpetic neuralgia. Pain is variable, from discomfort to very severe, and may be described as burning, stabbing, or gnawing.Signs:
Area of previous herpes zoster may show evidence of cutaneous scarring. Sensation may be altered over the areas involved, in the form of either hypersensitivity or decreased sensation.
The observable clinical manifestations may consist of rapid, hyperkinetic movements as well as tonic/dystonic posturing of the limbs. Other potential manifestations include brief arousals from sleep or wandering ambulatory behavior. Non-motor manifestations (such as sensory or emotional phenomenon) are common and retained awareness during seizures may occur. Seizures usually occur during non-REM sleep. The frequency of seizures can be very high and as many as dozens may occur every night which results in poor sleep quality. In addition, many patients with SHE suffer from cognitive impairment and have behavioral/psychological problems. There are many risks associated with nocturnal seizures including concussion, suffocation and sudden unexpected death (SUDEP). Cause
Approximately 86% of SHE cases are sporadic, 14% of patients have a family history of epilepsy and 5% are inherited in an autosomal dominant manner (i.e. autosomal dominant sleep-related hypermotor epilepsy). Both genetic, structural and multifactorial etiologies can occur. In structural cases, the most common pathology is focal cortical dysplasia.The first described mutation in SHE was found in genes coding for the neuronal nicotinic acetylcholine receptor. Since then multiple other genes have been identified including KCNT1, DEPDC5, NPRL2, NPRL3, PRIMA1, CABP4, CRH and others. In some cases, structural and genetic etiologies can coexist such as with mutations in DEPDC5. Diagnosis
The condition may be difficult to diagnose and misdiagnosis is common. The subject may be unaware they have a seizure disorder. To others, the involuntary movements made during sleep may appear no different from those typical of normal sleep.