Cysticercosis

Case contributed by Ashleigh Lynn Strange
Diagnosis almost certain

Presentation

First onset of generalized tonic-clonic seizures

Patient Data

Age: 35 years
Gender: Male

Disseminated cysticercosis

ct

Contrast-enhanced CT scan of the head demonstrates multi-stage parenchymal and subarachnoid neurocysticercosis with multiple vesicular, colloidal vesicular, granular-nodular and calcified nodular lesions scattered throughout bilateral cerebral hemispheres.

Further cystic, cyst-in-dot and calcified lesions are noted extensively within the extra-ocular muscles bilaterally. Sparing of the globes and optic nerves.

Further cysticerci noted in the posterior occipital muscles, anterior and posterior paraspinal muscles, the left temporalis muscle, bilateral masseters, left lateral pterygoid muscle, within the bilateral parapharyngeal spaces and the left carotid spaces.

Case Discussion

Cysticercosis is a parasitic infection caused by the pork tapeworm Taenia solium. It is the most common parasitic infection worldwide with the central nervous system involved in 60-90% of cases. Patients present clinically with seizures, headaches and hydrocephalus when there is CNS involvement.

There are 4 pathologic stages: Vesicular, colloid vesicular, granular nodular and nodular calcified. Lesions may be at different stages in the same patient. A cyst with a 'dot' inside is the best diagnostic clue on imaging.

Convexity subarachnoid spaces are the most common location. Infection may also involve the cisterns, parenchyma and ventricles. Intraventricular cysts are often isolated.

The size of cysts can be variable ranging from 5-20 mm. Cysts contain scolex, which is 1-4 mm. Cysts are usually round or ovoid in morphology. Cysts are solitary in 20-50% of cases; when multiple, usually a small number of cysts. Disseminated form is rare.

MRI is the most sensitive imaging modality. Calcified lesions are better seen on CT.

Diagnosis is confirmed by ELISA of serum or CSF.

Treatment includes Albendazole for parasitic burden and steroids for cerebral edema. Excision or drainage of parenchymal cysts can be considered.

Differential diagnoses include abscess, tuberculosis, neoplasm, arachnoid cyst, enlarged peri-vascular spaces and other parasitic infections.

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