Chapter 51F Vascular Diseases of the Nervous System
Central Nervous System Vasculitis
Isolated vasculitis of the central nervous system (CNS) is rare. Although only one or two cases may be seen in a year even in large referral centers, isolated CNS vasculitis is nonetheless frequently invoked in the differential diagnosis of obscure neurological illnesses (Berlit, 2004). The process of diagnosing and treating isolated CNS vasculitis often places the neurologist on the horns of serial dilemmas. There are no characteristic clinical features; the results of routine laboratory investigations, both medical and neurological, are either normal or nonspecific. Short of brain biopsy, only one test may be helpful—catheter cerebral angiography—but this invasive procedure has the additional drawbacks of low sensitivity and specificity. It is all too often negative in pathologically documented cases of the disease. Angiographic changes deemed “typical” or even “classical” of vasculitis prove just as often to be the result of entirely different disease processes. The consequence of missing the diagnosis of CNS vasculitis is the death of the patient; the consequence of delay in diagnosis is likely to be severe disability. Current therapies are highly toxic. Use of newer, less toxic alternatives is still dependent on limited anecdotal evidence.
Types of Central Nervous System Vasculitis
When vasculitis is clinically and pathologically restricted to the CNS, it is referred to as a primary or isolated CNS vasculitis. Early descriptions of this disorder included the term granulomatous, but this histological feature, although frequent, is not required for diagnosis (Miller et al., 2008). This chapter covers isolated CNS vasculitis and the CNS vasculitides associated with cutaneous herpes zoster infections, drug abuse, lymphoma, and amyloid angiopathy.
The CNS also may be involved in widespread systemic vasculitis, usually polyarteritis nodosa or Wegener granulomatosis. These disorders, which are discussed in Chapter 49A, rarely present with isolated CNS manifestations. Although vasculitis is often proposed as the explanation for CNS dysfunction in systemic lupus erythematosus, it is actually quite rare in this disease (Ramos-Casals et al., 2006).
Isolated Central Nervous System Vasculitis
Clinical Findings
The mode of onset is acute or subacute. Although the classic picture is one of progressive, cumulative, and multifocal neurological dysfunction, there are abundant exceptions, including patients whose presentation suggests cerebral tumor, chronic meningitis, demyelinating disease, acute encephalitis, myelopathy, simple dementia, and even degenerative disorders. Although often mentioned in the differential diagnosis, especially in patients without risk factors, isolated CNS vasculitis rarely causes stroke (Wiszniewska et al., 2003). When isolated CNS vasculitis presents as a stroke, it is usually due to intracerebral hemorrhage, which occurs in approximately 15% of patients at some time in the illness. The disease rarely causes single cerebral infarcts or transient ischemic attacks in the absence of clinical or laboratory evidence of widespread CNS inflammation, verified by cerebrospinal fluid (CSF) pleocytosis.
Nonfocal symptoms such as headache and confusion are the most common presenting complaints. Aside from confusion, the most common sign at presentation is hemiparesis. Ataxia of limbs or gait, focal cortical dysfunction including aphasia, and seizures are also frequent. Virtually every neurological sign or symptom has been reported at least once (Schmidley, 2000). Nonspecific visual complaints occur in approximately 15% of patients, but disorders of specific ocular motor nerves, optic nerve, or visual fields are much less common. Systemic symptoms are generally absent. Fully developed cases almost invariably show signs and symptoms of progressive, widespread neurological dysfunction; however, occasional patients present with a multiple sclerosis–like course of early relapses and partial remissions or clinical manifestations largely restricted to one part of the nervous system, such as the spinal cord or cerebellum.
