Cisticercosis

Cisticercosis is an infection caused by the larval form of Taenia solium, the pork tapeworm, which develops when humans ingest eggs shed in the feces of a person with taeniasis. After ingestion, oncospheres penetrate the intestinal wall and disseminate to various tissues, forming cysticerci. The disease most often affects the brain, eyes, muscles, and subcutaneous tissues.

The most common and clinically important form is neurocisticercosis, in which cysticerci inhabit the brain parenchyma, ventricles, or subarachnoid space. Symptoms vary by location and stage, but seizures are a frequent presenting feature; headaches, focal neurologic deficits, hydrocephalus, or intracranial hypertension may also occur. Subcutaneous or muscular cysticercosis can present as nodular or migratory lumps; ocular involvement may threaten vision.

Pathophysiology and imaging: cysticerci pass through several stages. In the brain, viable cysts may be asymptomatic; as they degenerate, inflammatory reactions provoke symptoms. Imaging with CT or MRI can show cystic lesions, often with a visible scolex, and eventually calcified nodules. Calcified lesions generally indicate non-viable infection.

Diagnosis relies on neuroimaging plus serologic tests. Serology (for example, antibody or antigen tests) supports the diagnosis, while stool examination helps identify a tapeworm carrier to prevent transmission.

Treatment depends on site and stage. Antiparasitic therapy (albendazole or praziquantel) is used for parenchymal neurocysticercosis in many cases, usually with corticosteroids to reduce inflammation. Antiseizure medications manage seizures; hydrocephalus or ventricular cysts may require surgical intervention. Calcified lesions are not treated with antiparasitics. Prevention focuses on sanitation, proper cooking of pork, meat inspection, and identifying/treating tapeworm carriers in the community.