More unusal organisms can be encountered in the setting of immune suppression, particularly in patients with HIV infection. Chronic spinal meningitis demonstrates enhancement of the leptomeninges. The enhancement is usually relatively smooth and of even thickness, lining the cord surface and dura. Chronic infections can lead to a myelitis, cord abscess, or a vasculits and cord infarction. Sarcoidosis Sarcoidosis is a granulomatous disease of unknown etiology.
Intramedullary involvement can occur in severe cases.
The meningeal inflammation enhances brightly with gadolinium. A nodular enhancement pattern usually distinguishes it from the infectious varieties. In the setting of immune suppression, particularly in AIDS patients, CMV can produce a progressive polyradiculopathy. The clinical syndrome consists of progressive ascending weakness, lower extremity pain and sensory disturbance, saddle anesthesia, and urinary retention. Acute and chronic inflammation of the cauda equina and lumbosacral nerve roots results in destruction of axons and myelin.