Spinal cord schistosomiasis

Spinal cord schistosomiasis is a grave central nervous system form of this parasitic disease. In endemic areas, it should be included in the differential diagnosis of myelopathy, as early treatment is fundamental in the prevention of severe and irreversible injuries. 

This article discusses spinal cord schistosomiasis, a general view on this trematode infection is available in the main article on schistosomiasis.

Clinical presentation

Clinical features of schistosomal myeloradiculopathy include ^1-6:

• lumbar pain
• lower limb weakness, paraesthesia, paraparesis
• bladder, and intestinal dysfunction
• sexual impotence in men

In support of these clinical features for the diagnosis include ^1-6:

• positive epidemiology for schistosomiasis
• laboratory demonstration of exposure to schistosomiasis by serological techniques, parasitological stool examination or rectal biopsy
• elimination of other etiologiesaetiologies of transverse myelitis

Pathology

The species of the trematodes that infect the central nervous system are Schistosoma japonicum, Schistosoma haematobium, and Schistosoma mansoni. S. japonicum is usually implicated in cerebral involvement, while S. mansoni and S. haematobium most commonly affect the spinal cord, causing myeloradicular syndrome ^1-3,5,6.

Central nervous system infection occurs by the migration of pairs of adult worms or by embolisation of eggs of the schistosoma through retrograde venous flow into the Batson venous plexus, a valveless paravertebral venous system from the mesenteric venous system ^1-4. A granulomatous reaction marks the host inflammatory response to eggs of the schistosoma in nervous tissue ^1-3,5,6.  

Radiographic features

Intramedullary nodules with enhancing peripheral lesions, forming a granular or arborised pattern of enhancement are a possible pattern of the disease ^1-3,5,6. These changes usually regress with clinical improvement after treatment ^1,5. Atrophy of the spinal cord may occur in long term disease ⁵.

MRI

• T1: isointense and mild to moderate expansion of the distal spinal cord and conus medullaris
• T2: patchy hyperintense foci
• T1 C+ (Gd): types of contrast enhancement include intramedullary nodular, peripheral, and radicular

Treatment and prognosis

Medical treatment is with schistosomicides (praziquantel and ivermectin) and corticosteroids ^1-6. The role of surgery is limited for the cases that need decompression of CSF, particularly in large lesions ^1,3,5.

Differential diagnosis

As the imaging features are nonspecific, epidemiology is mandatory for schistosomiasis consideration. Differentials for other causes of myelitis should be considered.