Neurocysticercosis is the infection of spinal and brain; Cysticercosis refers to tissue infection after exposure to eggs of Tania Solium, the pork tapeworm. The disease is spread via a faecal-oral route through contaminated food and water; is primarily a foodborne disease. The most common route is through raw vegetables which have been grown in the fields irrigated with untreated sewage water. That’s why it is important for you to properly clean the vegetable before cooking and proper sewage management.
The most people in the united states with neurocysticercosis are people who come from regions where the disease is common including Latin American.
Cause of neurocysticercosis
The cause of human Cysticercosis is the egg form of Taenia solium ( pork tapeworm) which is transmitted through oral-fecal route. T. solium is a member of phylum Platyhelminthes.
Human is a reservoir of T.solium. They are infected by eating undercooked pork that contains viable cysticerci. The cysticercus develops into an adult tapeworm in the gut and produces large number of eggs which pass out in the faeces. The presence of an adult tapeworm in the gut is reasonably harmless. The condition known as Cysticercosis in humans occurs due to ingestion of tapeworm eggs, either from an external source or from the person’s own faeces. The human has then become an accidental and dead end and intermediate host pigs which are the normal intermediate host of this parasite get infected with cyst cerci when they ingest human faeces. The incubation period ranges from months to over ten years.
Sign and symptoms
Clinical manifestations of Neurocysticercosis vary with the location of the lesion, the member of parasites and the host’s immune response. Many patients are asymptomatic, the possible symptomatic presentation includes; onset of most symptoms is usually subacute to chronic but present acutely.
Abnormal physical findings, which occur in 20% or fewer patients with Neurocysticercosis depend on where the cyst is located in the nervous system and include the following
- Cognitive decline
- Abdominal pain
- Constipation(difficulty passing stools/ solid waste)
- Extraocular movement palsy or paresis
- Hemiparesis or hemiplegia, which may be related to stroke or paralysis
- Hemi sensory loss
- Movement disorder
- Gait disturbances
- Meningeal signs
Neurocysticercosis is commonly diagnosed with the routine use of diagnostic methods such as computed tomography (CT) and magnetic resonance imaging (MRI) of the brain.
- CT findings vary as follows, depending on the stage of evolution of the infestation
- Vesicular stage (viable larva): hypodense, non-enhancing lesion
- Colloidal stage(larval degeneration): hypo dense/ isodense lesions with peripheral enhancement and perilesional oedema
- Nodular- granular stage: Nodular enhancing lesions
- Cysticercosis encephalitis: diffuse oedema, collapsed ventricles and multiple enhancing parenchymal lesions
- Active parenchymal stage: The scolex within a cyst may appear as a hyperdense dot
- Calcified Stage: When parasite dies nodular parenchymal calcification are seen
Cerebrospinal fluid (CSF) analysis for Neurocysticercosis is indicated in every patient presenting with new-onset seizures or neurologic deficit in whom neuroimaging shows a solitary lesion but does not offer a definitive diagnosis. CSF is contraindicated in case of large cyst causing severe oedema and displacement of brain structures, as well as in lesions causing obstructive hydrocephalus.
CSF finding includes following:
- Mononuclear pleocytosis
- Normal or low glucose level
- Elevated protein level
- High IgG index
- Oligoclonal bands in some cases
- CSF ELISA for NCC has sensitivity of 50% and specificity of 65%
Other tests are as follows:
- Stool examination: 10-15% Neurocysticercosis patients have taeniasis
- Brain biopsy can be done only in extreme cases
Treatment of Neurocysticercosis depends on the viability of the cyst and its complications. If the parasite is dead, the approach is as follows:
Treatment is directed primarily against the symptoms:
- Anticonvulsants are used for management of seizures, monotherapy is usually sufficient.
- Duration of the treatment remains undefined.
If the parasite is viable or active treatment varies as follows:
- Patient with vasculitis, arachnoiditis or encephalitis: A course of steroids or immune suppressants is recommended before the use of anticysticerol drug.
- Antiparasitic treatment with albendazole also useful in Cysticercosis of racemose type (i.e. multiple cysts in basal cisterns).
- Patient with parenchymal, subarachnoid spinal cysts or without complication (eg. Chronic epilepsy, headache neurologic deficits related to strokes and hydrocephalus). Anticysticerous treatment can be considered with the concomitant use of steroids.
- Patient with seizures due to viable parenchymal cysts-Antiparasitic.
- Surgical intervention and recommended procedures are: hydrocephalus due to intraventricular cyst placement of ventricular shunt, followed by surgical excision of cyst and subsequent medical treatment
Prognosis is best for those patients in whom imaging studies normalize for this albendazole and praziquantel are the best principal Antiparasitic drugs used to treat Neurocysticercosis.
Neurocysticercosis is the leading cause of epilepsy in the developing world. Infection from this tapeworm is preventable. Following measures can be used to prevent it.
- To avoid it, people should be sure the meat they eat is cooked completely hygiene is important
- Involves washing hands thoroughly after using the bathroom
- Proper sewage disposal and cattle should be kept away from the house.
- Health education campaigns are effective in the prevention and control of many infectious diseases. Participation of the community and schools in maintaining hygienic and sanitary conditions.
- Screening of farm workers for taeniosis, and treatment if warranted.
- Control of pig and cattle marketing systems, including the provision of incentives to ensure owner compliance
- Health education to both farmer and consumer, especially on the cooking of meat.
- Meat inspection to prevent infection.
- Improved farm management to ensure that pigs and cattle are protected from ingesting feed or water contaminated with human faeces to prevent Cysticercosis in animals.