Cysticercosis, popularly known as Tapeworm [Taenia solium] infection, is a very common disease where the patient would have consumed food or water infested with tapeworm eggs or larvae. These grow into adult tapeworms that cause an invasive infection by forming cysts in body tissues and organs outside the intestines or an intestinal infection by growing right inside the intestines.
These adult tapeworms have a head, neck and a series of segments called proglottids. A person with intestinal infection will have the tapeworm head stuck to the intestinal wall where the proglottids grow and multiply more eggs. At a given time, such tapeworms can live up to 30 years in the host.
The clinical conditions caused by Taenia solium are classified as either Cysticercosis (cysts in various tissues including the brain) or Taeniasis (intestinal tapeworm infection).
Taeniasis is usually mild, though persistent tapeworm infection can result in serious complications.
Cysticercosis is originates from the metacestode, (larval stage of Taenia solium), the pork tapeworm.
Neurocysticercosis refers to CNS infection with T solium. Neurocysticercosis is further classified into parenchymal and extraparenchymal disease. Parenchymal disease is distinguished by existence of cysticerci within the brain parenchyma. Extraparenchymal disease develops when cysticerci progress to the CSF of the ventricles, cisterns, and subarachnoid space or are seen within the eyes or spinal cord.
Usually, people with cysticercosis do not display any symptoms. It is actually the effects of the infection that lead people to go to doctors. Also, the type of infection and tapeworm, and the extent of infection and location determine most symptoms.
Intestinal Tapeworm Infection [Taeniasis]
- No appetite
- Abdomen – twinges of discomfort
- Weight loss
- Poor absorption of nutrients from food
Invasive Tapeworm Infection [Cysticercosis]
Besides cysts formation and causing organ and tissue damage, invasive larval infection results in the following symptoms:
Symptoms of cysticercosis may include seizures, elevated intracranial pressure (ICP), meningoencephalitis, psychiatric disorder, stroke, and/or radiculopathy or myelopathy, if the spinal cord is concerned.
The symptoms are primarily due to the effect of a mass, an inflammatory reaction, or impediment of the foramina and ventricular system of the brain. The most familiar symptoms include seizures, focal neurologic signs, and intracranial hypertension.
Parenchymal CNS Disease
- Seizures may be focal, focal with secondary generalization, or generalized.
- Headaches are regular and may be like a migraine.
- Neurocognitive deficits, while exceptional, may include learning disabilities, depression, or even neurosis.
- Most patients appear to have headaches or symptoms of hydrocephalus.
- Symptoms of augmented ICP may include headache, nausea or vomiting, distorted mental state, giddiness, and diminished visual acuity due to papilledema.
- Patients with numerous cysticerci in the basilar cisterns may build up communicating hydrocephalus, meningismus (without fever), signs of lacunar infarcts due to small-vessel vasculitis, or symptoms of large-vessel infarcts due to cysticercal corrosion into major arteries or rigorous inflammation of those arteries.
Those with spinal cysticerci typically appear with radicular symptoms, but rarely with motor or sensory shortage observable to a spinal level.
Cysticercosis Risk Factors
The following conditions put one to great risk of Taeniasis and Cysticercosis:
- Poor hygiene and sanitation Lack of the habit of bathing and not washing hands frequently and correctly with soap and water exposes one to consumption of contaminated matter that may contain larvae or eggs of tapeworm.
- Exposure to cattle and livestock Those having to deal with animal and human feces in farms and otherwise, are at great risk of contracting this infection.
- Consumption of raw and uncooked meats Poorly cooked meats do not kill the larvae or eggs attached to them thus increasing the risk of infection.
- Residing/travel in endemic countries Certain parts of Latin America, China, sub-Saharan Africa and South East Asia have a greater exposure tendency to tapeworm infection where pigs roam freely. If one happens to live/travel to these places, chances are high that one might contract this infection.
The diagnosis is fairly simple and the doctor will ask for the following tests:
- Stool analysis Doctors and labs may ask for more than one stool sample to check for the presence of tapeworm eggs and the extent of infection.
- Blood sample Once the infection has invaded tissues, doctors will ask for a blood sample to check antibodies in the blood which definitely indicate presence of infection.
- Imaging tests A CT scan or MRI, X-ray or an Ultrasound is required to confirm invasive tapeworm infection and the presence of cysts.
Once diagnosed with infection, doctors usually prescribe oral medicines to kill the tapeworm presence including larvae and follow it up with a stool examination which should not have tapeworm, larva or proglottids to double check that one is clear of the infection.
The effect of oral medications prescribed depends a lot on the type of tapeworm infection detected and the site of infection. The idea is to not re-infect oneself and therefore, hand sanitation and hygiene becomes very important.
Treatment for invasive tapeworm infection also depends on the type of tapeworm detected and the extent and site of infection- anthelminthic drugs, anti-inflammatory therapy, anti-epileptic therapy, shunt placement and surgery.
Neurocysticercosis treatment should be based on each individual and whether cysts are nonviable or active, which usually can be assessed by neuroimaging studies such as MRI or CT, and where they are located.
For patients with only nonviable cysts, treatment should be indicative and contain anticonvulsants for individuals with seizures and shunting for patients with hydrocephalus.
Corticosteroids are specified for all patients with multiple cysts and associated cerebral edema (“cysticercal encephalitis”). Hydrocephalus shunting is also important.
Ocular cysticercosis also is attended to by surgical elimination of the cysts, but not generally with antihelmintihc drugs, which could exacerbate ocular inflammation.