American Journal of Neuroradiology

Case of the Month

Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO

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January 2021

Next Case of the Month Coming February 2...

Varicella Zoster Virus Vasculopathy

Background:
- Varicella zoster virus (VZV) is a human DNA virus that causes a primary infection characterized by diffuse and typical skin lesions, usually in the pediatric population.
- After the initial disease, the virus persists as a latent infection in the dorsal root ganglia and cranial nerves of the CNS.
- Impaired immunity will cause the reactivation of the virus, causing secondary infection or herpes zoster, which generally occurs in adults. This condition may produce different types of neurologic complications, including vasculopathy.
- Vasculopathy appears to be caused by transaxonal spread from afferent fibers of the trigeminal and other ganglia to the arterial adventitia, with the ensuing transmural propagation of the virus.
Clinical Presentation:
- VZV vasculopathy indistinctly affects both immunocompetent and immunodeficient patients.
- The clinical presentations vary from acute focal neurologic deficits that resemble ischemic pathology to more lengthening neurologic symptoms with cognitive impairment.
- Both subarachnoid and cerebral hemorrhage are less frequent.
- Presumed spinal cord infarction is an atypical complication of VZV vasculopathy, and it has been diagnosed based on acute-onset myelopathy associated with zoster in the literature. Severe hemorrhagic myelitis has been described even in immunocompetent patients.
- Many patients with VZV vasculopathy (37% of cases) present without the characteristic accompanying zoster rash, making diagnosis difficult.
Key Diagnostic Features:
- When a clinical diagnosis of VZV vasculopathy is suspected, virologic confirmation is required. In the samples of CSF, the detection of VZV IgG antibody has proven to be more sensitive than VZV for diagnosis. The CSF will usually show modest pleocytosis, increased concentrations of proteins, and normal glucose levels.
- MRI usually demonstrates lesions in both gray and white matter and their junctions. Ischemic lesions are more frequent than hemorrhagic lesions. Enhancement due to the breakdown of the blood-brain barrier also occurs.
- T2 hyperintensities in the pons or trigeminal pathways may be present in early stages of the disease, helping the diagnosis. MRI patterns of meningoencephalitis with gyral and leptomeningeal enhancement may coexist.
- Angiographic studies generally demonstrate segmental stenosis with the involvement of both large and small arteries. Enhancement of the arterial wall is also common.
Differential Diagnoses
- Acute hemorrhagic leukoencephalitis or Hurst disease: MRI will show large tumefactive and hemorrhagic lesions affecting the white matter with relative sparing of the cortex. Leptomeningeal enhancement is unusual.
- Neurosarcoidosis: Meningeal involvement with a predilection for the basal leptomeninges is typical. Perivascular and cranial nerve enhancement is common. Spinal involvement may occur.
- Primary angiitis of the CNS (PACNS) and other secondary vasculitides: They present with very similar MRI patterns. A correct clinical history and a CSF analysis are crucial to confirm or exclude these diagnoses.
- Reversible cerebral vasoconstriction syndrome (RCVS): Ischemic and hemorrhagic infarcts and arterial wall thickening, with a similar appearance as VZV vasculopathy; RCVS will typically resolve in the following months and will not show enhancement of the arterial walls.
Treatment:
- Intravenous aciclovir is the treatment of choice in all patients.
- A short period of steroid administration is recommended to diminish the inflammatory changes.