A wide variety of fungal and parasitic agents may involve the spinal meninges. Such infections are rare, and some do not occur at all in the United States or are limited to certain geographic areas, particularly among immigrant populations. Actinomyces, Blastomyces, Coccidioides, and Aspergillus may invade the spinal epidural space via intervertebral foramina or by extension from a vertebral osteomyelitic focus. Cryptococcus, which causes meningoencephalitis and, rarely, a cerebral granuloma, in our experience, seldom causes spinal lesions. Hematogenous metastases to the spinal cord or meninges may occur in both blastomycosis and coccidioidomycosis. Occasionally an echinococcal infection of the posterior mediastinum may extend to the spinal canal (epidural space) via intervertebral foramina and compress the spinal cord.
Schistosomiasis (bilharziasis) is a recognized cause of myelitis in the Asia, Africa, and South America. The spinal cord is a target for all three common forms of Schistosoma: S. haematobium, S. japonicum, and S. mansoni, but most particularly the last of these (see “Schistosomiasis” in
Chap. 31). The schistosomal ova evoke an intense granulomatous myelomeningoradiculitis. The lesions are destructive of gray and white matter, with ova in arteries and veins leading to vascular obstruction and ischemia (Scrimgeour and Gajdusek). Less often, a localized granuloma gives rise to a cord syndrome and, rarely, the disease takes the form of an acute transverse myelitis with massive necrosis of cord tissue (Queiroz et al). A pruritic “swimmer’s itch” at the site of entry of the parasite is reported by many patients in the days prior to the myelopathy. In the often cited review by Scrimgeour and Gajdusek, the latency between exposure and symptoms was 38 days to several years. We have cared for several patients over the years in whom the spinal cord in the low thoracic and lumbar region was infected approximately 3 weeks after they swam in contaminated water during an east African vacation and then returned home to the United States The CSF showed only a slight elevation of protein, but in almost all cases there is a pronounced pleocytosis ranging from 5 to 500 lymphocytes/mm3 and the glucose is normal or minimally reduced. Systemic and CSF eosinophilia are variable so are not dependable for diagnosis. The diagnosis is confirmed by the finding of elevated titers of antibody directed against the schistosome in the CSF or blood. There are usually oligoclonal bands of IgG in the CSF as well. The parasite can sometimes be found in biopsies of the rectosigmoid mucosa. The administration of praziquantel arrested the course of the illness, but all but one of our patients was left disabled.
Noninfectious Inflammatory Myelitis (Multiple Sclerosis and Acute and Subacute Transverse Myelitis) (See Chap. 35)