Introduction Toxocara infections can result in a variety of neurological conditions. Encephalomyelitis results from infection and inflammatory changes causing widespread central nervous system injury.

Case A 52 year old female presented to a peripheral hospital with headache and fevers. An initial CSF examination revealed a white cell count of 568×10^6/L (100% mononuclear) with elevated protein of 3200 mg/L. She developed flaccid paralysis of the lower limbs and urinary incontinence, and was transferred to our institution for ongoing management. While an infective screen was awaited, the patient had clinical deterioration with confusion and upper limb weakness, and radiological progression of extensive, patchy changes on medullary MRI T2-weighted sequences of the spinal cord from C1 to the conus medullaris. The neoplastic screen revealed a large pelvic mass with radiological features of neoplasia, and a thyroid nodule. A PET scan revealed non-specific avidity in the lower oesophagus and lower anal canal. Histology of the pelvic lesion revealed benign features. Toxocara IgG serology returned positive, and on repeat parallel testing revealed decreasing antibody titre.

Conclusions This case highlights this unusual infection for which 100 cases are reported in the literature. The diagnostic work-up for our patient included extensive search for infective, neoplastic and autoimmune causes. Treatment with intravenous corticosteroids resulted in clinical improvement, with the patient able to ambulate independently following a short rehabilitation stay.