Herpes Zoster (Shingles)

Herpes zoster, also known as shingles, is an acute unilateral and segmental inflammation of the dorsal root ganglia. It produces localized vesicular skin lesions confined to a dennatome. The patient with shingles may have severe neuralgic pain in the areas bordering the inflamed nerve root ganglia. The infection occurs only in someone who has had a previous infection of chickenpox, usually as a child, and is found primarily in adults over age 50; it seldom recurs. Herpes zoster may be more prevalent in people who had chickenpox at a very young age than in those who contracted chickenpox in adulthood. Herpes zoster is more common and severe in elderly, insulin-dependent patients and immunocompromised patients but is seldom fatal. It's also more severe in pregnant women than others of the same age, probably because of the mild immunosuppression and other factors associated with pregnancy. The prognosis is good and most patients recover completely unless the infection spreads to the brain.

What causes Herpes zoster ?

Herpes zoster is an infection caused by reactivation of the varicella-zoster virus (VZV), the same herpesvirus that causes chickenpox, which lies dormant in the cerebral ganglia (extramedullary ganglia of the cranial nerves) or the ganglia of posterior nerve roots. Although the cause for reactivation is unknown, it's thought to be associated with increasing age,
stress, illness or infection, and debilitation. Although the process is unclear, the virus may multiply as it reactivates. and antibodies remaining from the initial infection may neutralize it. Without opposition from effective antibodies, the virus continues to multiply in the ganglia, destroys neurons, and spreads down the sensory nerves to the skin.

Signs and symptoms of Herpes zoster

The typical patient reports no history of exposure to others with VZV She may complain initially of fever, malaise, unilateral stabbing pain that mimics appendicitis, tingling, itching, pleurisy, musculoskeletal pain, or other conditions. In 2 to 4 days, she may report severe, deep pain; reddening of the skin that's followed by blisters; and paresthesia or hyperesthesia (usually affecting the trunk and occasionally the arms and legs). Pain described as intermittent, continuous, or debilitating usually lasts from 1 to 4 weeks.

During examination of the patient within 2 weeks after her initial symptoms, you may observe small, red, nodular skin lesions spread unilaterally around the thorax or vertically over the arms or legs. Alternatively, instead of nodules, you may see vesicles filled with clear fluid or pus. About 7 to 10 days after they appear, these vesicles rupture and then dry, forming scabs.The lesions are most vulnerable to infection after rupture; some even become gangrenous. During palpation, you may detect enlarged regional lymph nodes. Herpes zoster may involve the cranial nerves (especially the trigeminal and geniculate ganglia or the oculomotor nerve). With geniculate involvement, you may observe vesicle formation in the external auditory canal and ipsilateral facial palsy. The patient may complain of hearing loss, dizziness, and loss of taste. With trigeminal involvement, the patient may complain of eye pain. She may also have corneal and scleral damage and impaired vision. Rarely, oculomotor involvement causes conjunctivitis, extraocular weakness, ptosis, and paralytic mydriasis.

Herpes zoster ophthalmicus may result in vision loss. Complications of generalized infection may involve acute urine etention and unilateral paralysis of the diaphragm. Another complication may be postherpetic neuralgia (most common in elderly patients), described as intractable neurologic pain that persists despite wound healing and that lasts more than 1 to 3 months after disease onset. In rare cases, herpes zoster may be complicated by generalized central nervous system (CNS) infection, muscle atrophy, motor paralysis (usually transient); acute transverse myelitis,and ascending myelitis.

Additional symptoms that may be associated with this disease:

• Fever, chills
• General feeling of malaise
• Headache
• Lymph node swelling
• Vision abnormalities
• Taste abnormalities

Diagnosis information

Diagnosis is usually based on appearance of the skin lesions and a patient's (past medical history of chickenpox. Tests, although usually unnecessary, may include viral culture of vesicular nuid and infected tissue analyses, which typically show eosinophilic intranuclear inclusions and varicella virus. Differentiation of herpes zoster from localized herpes simplex requires staining antibodies from vesicular fluid and identification under fluorescent light. Usually, though, the locations of herpes simplex and herpes zoster lesions are distinctly different. With CNS involvement, results of a lumbar puncture indicate increased pressure, and cerebrospinal fluid analysis demonstrates increased protein levels and, possibly, pleocytosis.

Treatment of Herpes zoster

Early treatment for herpes zoster, ideally within 48 to 72 hours of onset, provides the best chance of minimizing neurologic sequelae. Primary therapeutic goals include relief of itching with cool compresses and antipruritics (such as calamine lotion), relief of neuralgic pain with analgesics (such as aspirin [Bayer], acetaminophen [Tylenol] and, possibly, codeine), and preventing postherpetic neuralgia. A similar goal involves preventing secondary infection by applying a demulcent and skin protectant (such as collodion, compound benzoin tincture, and sulfonamide cream) to unbroken lesions. Other treatment measures include:

• Starting antiviral therapy within 2 to 3 days of onset usually provides early resolution of the skin blisters and shortens the duration of neurologic symptoms. Oral acyclovir therapy accelerates healing of lesions and resolution of oster associated pain. Famciclovir and valacyclovir have been effective and may be more effective than acyclovir. In the immunocompromised patient. herpes zoster should be treated with I.V. acyclovir.
• If bacteria infect ruptured vesicles. treatment includes an appropriate systemic antibiotic. Herpes zoster affecting trigeminal and corneal structures calls for instillation of idoxuridine ointment or another antiviral agent.
• To help a patient cope with the intractable pain of postherpetic neuralgia. a systemic corticosteroid, such as cortisone or corticotropin, may be ordered to reduce inflammation. The physician may also order tranquilizers, sedatives or tricyclic antidepressants with phenothiazines.
• As a last resort for pain relief, transcutaneous peripheral nerve stimulation. patient-controlled analgesia. or a small dose of radiotherapy may be considered.

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Is Herpes zoster contagious?

The virus that causes Herpes zoster can be passed on to others, but they will develop chicken pox, not zoster and only if they have not had chicken pox. Herpes zoster is much less contagious than chicken pox. Persons with zoster can only transmit the virus if blisters are broken and someone who never has had chicken pox or who already is ill is close by. Newborns or those who already are ill or immunosuppressed, such as cancer patients, are at the highest risk. Because of the risk of contagion for these people, these patients with herpes zoster are rarely hospitalized unless absolutely necessary.

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Special considerations or prevention

Administer topical therapies. If the physician orders calamine lotion, apply it liberally to the patient's lesions. Avoid blotting contaminated swabs on unaffected skin areas. Be prepared to administer drying therapies. such as oxygen. if the patient has severe disseminated lesions. Use silver sulfadiazine to soften and debride infected lesions.

• Give analgesics exactly as scheduled to minimize severe neuralgic pain. For a patient with postherpetic neuralgia. consult with a pain specialist. and follow his recommendations to maximize pain relief without risking tolerance to the analgesic.
• Maintain meticulous hygiene to prevent spreading the infection to other parts of the patient's body.
• Monitor tlle patient for complications associated with herpes zoster.
• Inspect the patient's skin lesions daily for signs of healing or infection.
• o decrease discomfort from oral lesions, instruct the patient to use a soft toothbrush. eat soft foods. and use a saline- or bicarbonate-based mouthwash and oral anesthetics.
• Stress the need for adequate rest during the acute phase.
• Avoid contact with the skin lesions of persons with known herpes zoster infection (shingles or chickenpox) if you have never had chickenpox or the chickenpox vaccine, or ESPECIALLY if your immune system is compromised.
• Stress the need for meticulous hygiene to prevent spreading infection to other body parts.
• Repeatedly reassure the patient that herpetic pain will eventually subside. Suggest diversionary or relaxation activities to take her mind off the pain and pruritus.
• Avoid drafts. Allow the affected area to be exposed to sunlight for fifteen minutes each day. Wash the blisters gently when bathing, and otherwise avoid touching or scratching them.