Central Nervous System

All schistosome spp. can affect the central nervous system, causing myelopathy or arachnoiditis. The granulomatous reaction can be demonstrated by MRI or CT scanning, and there may be a block on myelography (Figs. 2.65, 2.66). Cerebral schistosomiasis has occurred, but is most common in schistosomiasis japonica (see later). There is frequently a response to appropriate treatment but intramedullary granulomas, usually affecting the lower part of the cord and the conus, can be acute and necrotizing and may not respond to treatment. In the absence of CT or MRI, myelography is important, but may be normal. If there is acute paraplegia, surgical decompression may be required because the response to chemotherapy may not be immediate.

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Fig. 2.65 A-G. Spinal cord schistosomiasis: S. mansoni granulomas can cause spinal cord symptoms. A, B PA and lateral radiographs from a myelogram showing partial extradural block and spinal cord compression at the T12-L1 level. (Courtesy of Dr. Ehrlich, San Juan) C A similar granuloma due to S. haematobium. This was a young African male with paraplegia of relatively sudden onset: he had early calcification in the bladder and his clinical condition responded to antischistosomal therapy. D A sagittal T 2-weighted MR image shows enlargement of the conus medullaris with a central hyperintense signal. E A T 1-weighted image following gadolinium injection reveals heterogenous enhancement of the conus and confirms the enlargement. There was eosinophilia of the blood and CSF and intrathecal antibodies for S. mansoni. Four months after treatment the MRI was normal and there was no enhancement. (Courtesy of Dr. S. Grand et al. and Clin Radiol, 1996.) F The myelogram of a young Zulu male with spinal cord schistsomiasis. There is marked swelling of the conus medullaris. G The CT myelogram of the same patient. In many patients the cord swelling will resolve quite rapidly with treatment, usually with matching clinical improvement. However, in some patients the cord may shrink and there will be residual neurological changes. In others there may be the added complication of arachnoiditis. In a minority of patients atrophy of the cord occurs. (F, G courtesy of Prof. P.L.A. Bill, Natal).

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Fig. 2.66 A-E. Spinal cord schistosomiasis: a granulomatous intramedullary mass in a 7-year-old girl. A Myelography showing partial blockage at the level of T11-12. B Post-myelography axial CT scan showing the swollen cord, confirmed on the sagittal scan (C). D Pre- and E post-gadolinium sagittal T 1-weighted MR scans show the markedly enlarged conus medullaris, with heterogenous enhancement; the T 2-weighted scans (not shown) had images with inhomogenous signal intensity. None of these images provide a specific indication of schistosomiasis: the clinical history and examination need to be correlated in order to make the diagnosis. (Courtesy of Drs. R. Silbergleit and AJR, 1992).