House MD: Season 1, Episode 1 – A young kindergarten teacher presents after a seizure and progressive deterioration of mental status. Final diagnosis is neurocysticercosis.
Cysticercosis is a parasitic infection that results from the ingestion of eggs from the adult tapeworm, Taenia soium (T. solium), found in pork. Neurocysticercosis occurs when the infection involves the brain and central nervous system. It is the leading cause of seizures and epilepsy in the developing world, especially Latin America, India, Africa, and China, but is a growing health concern in the United States.
Overall, there are approximately 1000 cases annually in the United States. Cysticercosis accounts for 2 to 10% of emergency room visits for seizures in the southwestern US, primarily due to immigration from Latin American countries.
After ingestion, when exposed to stomach acid, the eggs of the tape worm lose their protective capsule and turn into larval cysts called oncospheres. These cross the gastrointestinal tract and migrate through the blood stream to the brain, muscle, eyes, and other structures.
Unless there are large amounts of cysts, the body’s immune system doesn’t react and cysts can live for many years undetected. A live cyst can live for as long as 5 years before dying or causing symptoms in the body.
Neurocysticercosis is usually benign. The first symptom is usually a seizure or headache. Less commonly, a patient presents with hemiparesis, visual changes, progressive obtundation (reduction in mental capacity) and other sensory disturbances.
Albendazole and praziquantel are the main anti-parasitic drugs used to treat neurocysticercosis. Some physicians and researchers suggest that this treatment may expose patients to increased risk , such as those who also have hydrocephalus. The risks include gastrointestinal side effects (nausea), seizures, increased intracranial pressure and rarely, death (1 to 4%).
Cysts that do not respond to medication can be removed surgically.
Neurocysticercosis is endemic in countries where sanitation is poor, sewage is used for fertilizer, or there is a lack of controlled pens for pigs. A person can also swallow the tapeworm eggs in food, water, or surfaces contaminated with feces. To prevent contracting cysticercosis:
- Avoid eating raw or undercooked pork and other meats.
- Don’t eat meat of pigs that are likely to be infected with the tapeworm.
- Wash hands with soap and water after using the toilet and before handling food, especially when traveling in developing countries.
- Wash and peel all raw vegetables and fruits before eating. Avoid food that may be contaminated with feces.
- Drink only bottled or boiled (1 minute) water or carbonated (bubbly) drinks in cans or bottles. Do not drink fountain drinks or any drinks with ice cubes. Another way to make water safe is by filtering it through an “absolute 1 micron or less” filter AND dissolving iodine tablets in the filtered water. “Absolute 1 micron” filters can be found in camping/outdoor supply stores.
Journal: Epilepsy Currents, May 2004
eMedicine from WebMD
Centers for Disease Control and Prevention