Monday, April 22, 2024
HomeInfectious DiseasesVaricella-Zoster Virus (VZV)

Varicella-Zoster Virus (VZV)

Practice Essentials

Varicella-zoster virus (VZV) causes chickenpox and herpes zoster (shingles). Chickenpox follows initial exposure to the virus and is typically a relatively mild, self-limited childhood illness with a characteristic exanthem, but can become disseminated in immunocompromised children. Reactivation of the dormant virus results in the characteristic painful dermatomal rash of herpes zoster, which is often followed by pain in the distribution of the rash (postherpetic neuralgia). See the image below.

Typical zoster in the vicinity of right popliteal

Typical zoster in the vicinity of right popliteal fossa in a vertebral nerve L4 distribution.

View Media Gallery

Signs and symptoms

Pain and paresthesia are typically the first symptoms of VZV infection. Until the characteristic vesicular rash erupts, diagnosis may be difficult. A prodromal period during which symptoms may vary is common. Pain occurs in 41% of patients, itching in 27%, and paresthesias in 12%.

During the acute illness, patients may experience the following:

Pain (90%)

Helplessness and depression (20%)

Flulike symptoms (12%)

Herpes zoster (shingles)

The most common presentation is the shingles vesicular rash, which most commonly affects a thoracic dermatome

After a prodromal illness of pain and paresthesias, erythematous macules and papules develop and progress to vesicles within 24 hours

The vesicles eventually crust and resolve

Pain and sensory loss are the usual symptoms

Motor weakness also occurs and is frequently missed on examination

Cases of actual monoplegia due to VZV brachial plexus neuritis have been reported

Zoster multiplex

Shingles may appear in multiple dermatomes, both contiguous and noncontiguous, on either side of the body

Immunocompromised individuals are more susceptible

Terminology depends on the number of involved dermatomes and on whether the condition is unilateral or bilateral (eg, zoster duplex unilateralis refers to the involvement of 2 unilateral dermatomes)

Cases of zoster simultaneously occurring in 7 noncontiguous dermatomes have been reported

Zoster sine herpete

VZV infection may reactivate without causing cutaneous vesicles. These patients have severe dermatomal pain, possible motor weakness and possible hypesthesia, but no visible rash or vesicles.

VZV infection may present as acute peripheral facial palsy in 8-25% of patients who have no cutaneous vesicles. This is more common in immunosuppressed patients who use acyclovir (or other agents) as zoster prophylaxis.

Central nervous system deficits

More common in immunocompromised individuals, but do occur in the general population

CNS involvement may become apparent 3 weeks after the onset of the initial rash

The manifestations are usually bilateral

The physical findings may progress

The underlying pathology typically progresses for 3 or more weeks

Progression for 6 months in immunocompromised individuals has been reported

Recurrence is rare but has been reported

Zoster encephalitis is also rare but is reported in otherwise healthy individuals

Ramsay-Hunt syndrome

This syndrome occurs when the geniculate ganglion is involved. The clinical presentation includes the following:

A peripheral facial palsy

Pain in the ear and face

Vesicles in the external ear canal (not always present)

Additional auditory and vestibular symptoms in some cases

Keratitis (herpes ophthalmicus)

Caused by reactivation of VZV infection in the ophthalmic division of the trigeminal nerve.

The presentation may include conjunctivitis or corneal ulcers

Complications include blindness

Vesicles do not have to be present

Rarely, the virus migrates along the intracranial branches of the trigeminal nerve, causing thrombotic cerebrovasculopathy with severe headache and hemiplegia

See Clinical Presentation for more detail.

Diagnosis

When the presentation includes the typical dermatomal rash, additional studies are not required. Studies to consider in specific situations include the following:

If the diagnosis is in doubt, a Tzanck smear or culture of vesicular fluid can be performed

In cases of zoster sine herpete, DNA analysis via PCR can be used

In cases of acyclovir-resistant VZV, detections of mutations in thymidine kinase can be determined by PCR and sequence analysis

MRI may be useful if myelitis or encephalitis is suspected

Lumbar puncture may be helpful if signs suggest myelitis or encephalitis

See Workup for more detail.

Management

Treatment options are based on the following:

Patient age

Patient immune state

Duration of symptoms

Presentation

Antiviral medications decrease the duration of symptoms and the likelihood of postherpetic neuralgia, especially when initiated within 2 days of the onset of rash. Oral acyclovir may be prescribed in otherwise healthy patients who have typical cases. Compared with oral acyclovir, other medications (eg, valacyclovir, penciclovir, famciclovir) may decrease the duration of the patient’s pain.

Varicella zoster immune globulin (VariZIG) is indicated for administration to high-risk individuals within 10 days (ideally within 4 days) of chickenpox (VZV) exposure.
High- risk groups include the following:

Immunocompromised children and adults

Newborns of mothers with varicella shortly before or after delivery

Premature infants

Infants less than younger than 1 year of age

Adults without evidence of immunity

Pregnant women

See Treatment and Medication for more detail.

RELATED ARTICLES
- Advertisment -

Most Popular