Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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November 29, 2018
Varicella zoster virus vasculopathy (with proved positive VZV DNA in the CSF)
- Background
- Primary VZV infection results in varicella (chickenpox) and is followed by virus latency in neurons along the entire neuroaxis. As cell-mediated immunity declines with age or immunosuppression, VZV can reactivate and cause zoster (shingles), which may be followed by vasculopathy, myelopathy, retinal necrosis or cerebellitis.
- Reactivated VZV seems to infect the arterial wall through transaxonal spread to the adventitia, followed by transmural spread of the virus with disease progression.
- Clinical Presentation
- It usually presents with stroke or transient ischemic attacks and, less commonly, with cerebral hemorrhage or subarachnoid hemorrhage due to aneurysm rupture.
- Clinical presentation ranges from acute focal neurological deficits to more protracted neurological symptoms such as headache, cognitive impairment or altered mental status.
- VZV vasculopathy affects immunocompetent and immunocompromised individuals, but the risk of stroke after zoster is higher in immunocompromised. In 37% of cases, it develops without previous rash – zoster sine herpete – making the diagnosis even more challenging.
- Key Diagnostic Features
- Brain MRI is abnormal in most cases, revealing focal or multifocal areas of infarction in the distribution of small arteries and/or large arteries.
- Vascular imaging (MRA or angiography) usually demonstrates focal or diffuse areas of stenosis, with corresponding concentric thickening and contrast uptake in the vessel wall in high-resolution intracranial vessel wall MRI (VW-MRI).
- Most patients have moderate (<100 cells) CSF pleocytosis. Diagnosis requires virologic confirmation with detection of VZV DNA or anti-VZV IgG antibody (more sensitive) in the CSF.
- Differential Diagnoses
- Intracranial atherosclerotic disease – VW-MRI of intracranial atherosclerotic plaque typically demonstrates arterial wall thickening with eccentric involvement of the arterial wall, which may show a layered appearance: T2 hyperintensity with contrast enhancement in the more luminal aspect of the thickening (fibrous cap), adjacent T2 hypointense nonenhancing component (lipid core) and a third thin layer in the periphery that may enhance (possibly corresponding to increased vasa vasorum in the adventitia of the artery).
- Primary angiitis of the CNS (PACNS) and other secondary forms of CNS vasculitis – MRI and VW-MRI present with similar imaging features. Clinically, PACNS presents more frequently with subacute or chronic headaches and other forms of CNS vasculitis show evidence of systemic involvement, constitutional symptoms, elevated serum inflammatory markers and/or fever. Since VZV may mimic all features of PACNS, the CSF of all patients with suspected PACNS should be tested for VZV DNA and/or anti-VZV IgG antibody.
- Reversible cerebral vasoconstriction syndrome (RCVS) – Vasculitis and RCVS result in arterial wall thickening but the vessel wall in RCVS is typically nonenhancing.
- Arterial dissection – VW-MRI typically displays eccentric arterial wall thickening with spontaneous T1 hyperintensity consistent with intramural hematoma. It may also show a curvilinear hyperintensity on T2 (intimal flap), separating the true from the false lumen.
- Treatment
- Intravenous acyclovir, 10-15 mg/kg q8h for 14 to 21 days. A short course of oral prednisone, 1mg/kg for 5 to 7 days, is usually recommended. The use of oral antiviral therapies such as valaciclovir after the intravenous treatment is still a matter of debate.
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