Cysticercosis is a systemic parasitic infestation by pork tapeworm known as Taenia solium. It is an infection of the tissue which occurs after exposure to the eggs of Taenia solium. This disease is spread through fecal-oral route through contaminated food and water since it is a food borne disease. This larval cyst infects brain, muscle or other tissues.
People living in the same household with a tapeworm carrier carry a greater risk of developing cysticercosis. A person with a poor hygiene might accidentally contaminate food while preparing it for others.
The disease is a rare occurrence in the United States, but is found in several developing countries.
Based on the location of the infections, the condition is divided into various types like:
This term is usually used to refer to cysts in the parenchyma of the brain. It presents with seizures and sometimes headaches.
This refers to cysts in the subarachnoid space. These can occasionally grow into large globulated masses, exerting pressure on surrounding structures.
Cysticercosis in muscles
They develop inside voluntary muscles in humans. This condition can cause myositis, with fever, eosinophilia, and muscular pseudohypertrophy which begin with muscle swelling and later develop into atrophy and fibrosis.
It refers to cysts located within the ventricles of the brain which can block the flowing out of cerebrospinal fluid and manifest with increased intracranial pressure.
Subcutaneous cysts refer to the type of firm but mobile nodules that arise mainly on the trunk and extremities. The nodules are sometimes painful.
It involves the spinal cord and usually results in symptoms like back pain and radiculopathy.
This condition is found inside the globe of the eye, in extraocular muscles and subconjunctiva. It can cause visual complications which fluctuate with eye position, retinal edema, hemorrhage and decreased vision or even a visual loss based on the location.
This disease is caused by swallowing of eggs from T. solium which are found in contaminated foods. Risk factors of contamination include eating pork, fruits and vegetables contaminated with T. solium due to unhealthy cooking or food preparation. After ingestion of the eggs, they pass through the lumen of the intestine into the tissues. They migrate preferentially to the brain and muscles. Once there, they form cysts and can survive for years. In some cases, the cysts get inflamed and form painful nodules in the muscles. The incubation period for the worms varies from months to ten years. Pigs get infected by consuming tapeworm eggs in the feces of the human tapeworm carrier.
The worms that stay in muscles do not show any symptoms. The signs in this condition depend on the areas of the body that have been infected. The disease is generally characterized by:
Infection in brain
It is marked by seizures or symptoms similar to those of a brain tumor, nausea and vomiting tendency and headache.
Infection in eyes
It is exhibited by reduced vision or blindness.
Infection in heart
It gives rise to abnormal heart rhythms or heart failure in some cases.
Infection in spine
It is marked by weakness or changes in walking due to damaged nerves in the spine.
Other symptoms include lethargy, confusion and weakness. If other body tissues are involved, it may cause skeletal muscle swelling, subcutaneous cysts and vision changes from cysts which infect the eyes.
The tests that are performed to diagnose the condition are:
- Spinal tap
- Blood tests to detect count of antibodies in comparison to the parasite.
- In rare cases biopsy of the affected area may be done.
- Examination of the eye by ophthalmologist which will look inside the fundus of the eye.
- Testing of stool samples which contain tapeworm eggs.
- Imaging studies such as CT scan, MRI scan are done to detect the lesion. CT scans provide images for calcified and uncalcified cysts. They also help in distinguishing between active and inactive cysts. MRI detects intraventricular cysts.
The treatment of this disorder is based on numerous factors which include location and number of cysticerci and the stage of cyst development.
Asymptomatic patients do not require any treatment. The immediate therapy for this disease is anticonvulsant medications. Once the seizures are brought under control, anti-helminthic treatments are provided. Anti-parasitic treatment is provided on the basis of:
- The number of cysts
- The stage of the disease
- The location of infection
Anticonvulsants reduce the inflammation which surrounds the cysts and lower the chances of seizures. Albendazole is a drug reasonable priced to treat this disease. This medication may be prescribed for more than one course to completely remove active cysts. Corticosteroids are used in combination with anti-parasitic medications. They are used to reduce the inflammation but are not that active against parasites. Anticonvulsant medications are prescribed in patients who suffer from neurocysticercosis and experience seizures. Medications such as carbamazepine (Tegretol) or phenytoin (Dilantin) are usually recommended in such situation.
In some cases of the condition, surgical management may be required. Cases like intraventricular, spinal neurocysticercosis and racemose require surgical treatment. The treatment consists of direct excision of ventricular cysts, shunting processes and removal if cysts through endoscopy. Surgical removal is required when the central nervous system has cysts or to place a brain shunt to release pressure. Subcutaneous cysts also require surgery to help patients get rid of the painful symptoms.
The possible complications of this condition include:
- Cognitive problems
- Hydrocephalus or accumulation of fluid in one part of the brain, often with increased pressure
- Blindness or decreased vision
The occurrence of this disease can be avoided in various ways which include:
- Avoidance of raw or uncooked meat especially pork.
- Inspection of meat and proper disposal of infected meat in endemic areas.
- Maintaining good personal hygiene and proper handling of foods.
- Improvising sanitary measures for disposal of human waste in endemic areas.
- Washing of fruits and vegetables properly.
- Examination of people who are infected and administering proper treatment.
- Widespread public education regarding the parasite and its route of transmission.
- Banning of trading cyst infected pigs in regions where food is scarce.
Here are some pictures to help you take a look at the way this disease manifests itself.
Picture 1 – Cysticercosis
Picture 2 – Cysticercosis Image