Intramedullary spinal schistosomiasis in a child with acute myelopathy: A case report

INTRODUCTION

Rarely, neuroschistosomiasis presents a parasitic infection of the lower thoracic area, conus medullaris, and/or cauda equina. Notably, schistosomiasis is endemic to South America, Africa, and certain Asian areas and infects at least 200 million people worldwide.[6,10]

Typically, the infection occurs secondary to exposure to water that contains snails with cercariae. The cercariae penetrate the skin and travel through the venous system in which they become adult worms that are capable of releasing eggs. Once in the bloodstream, they are frequently deposited in the gastrointestinal or urinary tract and also rarely in the central nervous system.[1] Due to the presence of valveless venous anastomosis between the pelvic and spinal cord venous plexus, an increase in abdominal pressure may lead to egg migration to spinal cord vessels.[9]

As the parasite reaches the spinal cord, symptoms may appear secondary to the resultant immune response and/ or inflammatory process.[6,7,9,10] The clinical presentation and imaging characteristics may mimic tumors, making the establishment of the diagnosis of neuroschistosomiasis challenging even in endemic areas.[3,5]

CASE REPORT

A 4-year-old autistic male from São Paulo presented with a 1-month history of a progressive paraparesis associated with fecal incontinence and urinary retention.

On examination, he was alert, the cranial nerves were intact, and he exhibited a Grade 3/5 motor paraparesis with urinary retention. The thoracolumbar magnetic resonance image (MRI) showed a conus medullaris mass; T2-weighted images demonstrated a T9-T12 syrinx, while the enhanced T1 study showed a heterogeneously enhancing mass [Figure 1].

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Figure 1:: Preoperative magnetic resonance imaging (MRI). (a) Sagittal view of the lumbosacral spine T1-weighted without contrast showing an isointense signal lesion in the conus medullaris. (b) MRI sagittal view of the T2-weighted lumbosacral spine showing hyperintense conus medullaris signal. (c) Sagittal MRI of the lumbosacral T1-weighted spine after gadolinium injection, heterogeneous contrast enhancing in conus medullaris, an apparently infiltrative lesion. (d) Sagittal section of the dorsal column and lumbosacral showing extensive syringomyelia in the thoracic spinal cord.

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Surgery and outcome

When the T12-L2 laminectomy was performed, the lesion appeared reddish and infiltrative, simulating a high-grade glioma. The intraoperative frozen sections revealed a chronic granulomatous infectious process. The patient was discharged 5 days later with the same preoperative paraparesis; when the final pathology confirmed conus medullaris schistosomiasis, the patient underwent subsequent treatment with praziquantel (20 mg/kg) [Figure 2]. Three months later, the postoperative MRI showed no residual lesion [Figure 3]. At 4 postoperative months, motor strength in the lower extremities improved to the 4/5 level, and he no longer required a urinary catheter.

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Figure 2:: (a-c) Hematoxylin and eosin (H&E) staining showing numerous granulomatous fragments of fibrotic and neural tissue and lymphomononuclear inflammatory infiltrate rich in eosinophils forming granulomatous nodules with necrotic center enclosing parasites with the characteristic spicula of consistent in appearance with Schistosoma mansoni.

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Figure 3:: Postoperative magnetic resonance image of the thoracolumbar spine showing the absence of anomalous contrast areas in addition to the absence of recurrence of the lesion.

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DISCUSSION

In Brazil, 5.6% of inflammatory myelopathy can be attributed to Schistosoma mansoni infection; it must be included among the differential diagnostic considerations for children presenting with acute paraplegia.[1,2,6,9] Typically, schistosomal myelopathy is symptomatic early on, resulting in acute myelopathy and/or radiculopathy.[2,3,6] In this study, our patient experienced the abrupt onset of paraparesis without systemic signs of schistosomiasis. Symptoms are typically attributed to an inflammatory response against schistosome eggs deposited within the conus through the valveless venous plexus of Batson. They result in local tissue edema and/or a granulomatous inflammatory response (e.g., with eosinophils and tissue fibrinoid necrosis around the eggs).[1,4,7,8,10] The differential diagnosis typical includes; an acute vascular event and/or tumor, especially in children from endemic areas for schistosomiasis (Africa and others).[10]

MRI

On MRI, neuroschistosomal infection may mimic intramedullary tumors.[1,2,3,5] The MRI studies in our patient consisted of an expanded/intramedullary spinal cord/conus lesion extending from T12 to L2; it was hyperintense on T2-weighted sequences and heterogeneously enhanced with contrast.

Drug protocol to treat neuroschistosomiasis

The drug protocol for treating neuroschistosomiasis includes praziquantel with corticosteroids; patients on this regimen typically show neurological improvement in 50.0%–60.3% of cases.[2,8] Another alternative medication is oxamniquine [Table 1].[1,4,8]

Table 1:: Cases of spinal cord schistosomiasis.

CONCLUSION

Schistosomal myeloradiculopathy should be considered in children with infiltrative lower thoracic, conus medullaris, and/or cauda equina lesions who present with myelopathy particularly in endemic areas.