NEUROSARCOIDOSIS

Signs and symptoms of neurosarcoidosis are variable and depend on loca tion and size of granulomas. Clinical studies suggest a rate of 5% and autopsy results a rate of more than 25% of central nervous system (CN S) involvement in sarcoidosis. Statistical analysis of 57789 patients admitted to the Department of Medicine in Lucerne over an Ii-year peri od revealed 51 patients (0.9 parts per thousand) with the diagnosis of sarcoidosis. Six of these (12%) had sarcoidosis affecting the CNS. Ne urosarcoidosis presented as: leptomeningeal granulomas, cranial nerve palsy, hypothalamic-pituitary syndrome, diabetes insipidus, pareses,pa resthesia, pyramidal signs, dementia, urine retention, and asymptomati c granulomas. Neurosarcoidosis has predilections for the base of the b rain, cranial nerves (facial nerve palsy is the most common) and menin ges, but any part of the CNS may be affected. Therefore, the diagnosis of neurosarcoidosis may be extremely difficult, especially when it oc curs as an isolated finding. Positive findings in transbronchial biops y and lavage may demonstrate asymptomatic pulmonary involvement in as many as 50% of patients with neurosarcoidosis. Angiotensin-converting enzyme levels may be raised in the blood or cerebrospinal fluid in som e 50% of cases. Kveim test has a low sensitivity in neurosarcoidosis a nd thus is of little use. Gallium uptake may demonstrate extracranial granuloma available for biopsy. All these tests, and also computed tom ography and magnetic resonance imaging, may be helpful. However, when in selected cases with isolated CNS disease standard investigations ar e not conclusive, meningeal or cerebral biopsy may be required in orde r to exclude other causes such as other granulomatous disorders, tumor metastasis, lymphoma, vasculitis, Sjogren syndrome, infection, neurol ogic disease such as multiple sclerosis, or systemic diseases such as Whipple's disease. CNS involvement in the acute phase of the disease h as a favorable prognosis, while chronic courses respond less well to t herapy. Treatment is initiated most frequently with corticosteroids (0 .5-1 mg/kg body weight/day or pulses of 1 g/day of methylprednisolone in severe cases). Improvement is seen within 1-2 months. Side effects of corticosteroids, aggressive disease or frequent recurrences may req uire other immunosuppressive drugs (methotrexate, azathioprine, chlora mbucil, cyclosporine A). Cerebral irradiation may be successful in som e cases when other treatments fail.