Neurocysticercosis !
Neurocysticercosis is a brain infection by cysts of the pork tapeworm; it is a common cause of seizures in Latin America.
Updated 2026-10-30
Structures involved
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- Frontal lobe
- Parietal lobe
- Lateral ventricles
- Fourth ventricle
- Cerebral aqueduct
- Third ventricle
- Temporal lobe
- Choroid plexus
Microorganisms that cause it
In histology
In physiology
Why it happens
What it is
Infection of the brain by the larval cysts of the pork tapeworm Taenia solium. It is the commonest parasitic infection of the central nervous system.
Who gets it
Endemic in parts of Latin America, Africa and Asia where pigs roam freely and sanitation is poor. It is a leading preventable cause of acquired epilepsy in Latin America, including rural Colombia. Official records show its hospitalisation rate rising significantly in Colombia from 2009 to 2019, while it fell in Brazil, Ecuador and Mexico.
Causes
- Ingestion of Taenia solium eggs shed in the faeces of a human tapeworm carrier (faecal–oral route)
- Not caused by eating undercooked pork itself, which causes intestinal taeniasis
- A tapeworm carrier in the household is a common source
Risk factors
- Living in or travel to endemic areas
- Poor sanitation and open defecation
- Free-roaming pig raising
- Household contact with a tapeworm carrier
- Contaminated water or food, poor hand hygiene
Pathophysiology
Eggs hatch in the gut; larvae enter the blood and lodge in the brain, muscle and eye, forming cysts. Viable cysts provoke little reaction; when they degenerate, inflammation causes seizures and oedema. Dead cysts calcify, and calcifications can remain seizure foci. Ventricular or subarachnoid cysts can block CSF flow.
Classification
- Parenchymal: vesicular, colloidal, granular-nodular and calcified stages
- Extraparenchymal: ventricular (often fourth ventricle) and subarachnoid (including racemose)
- Spinal and ocular forms
Symptoms and signs
- Seizures (most common presentation in parenchymal disease)
- Headache
- Signs of raised intracranial pressure: vomiting, papilloedema, reduced consciousness (hydrocephalus)
- Focal deficits
- Cognitive or psychiatric symptoms
Diagnosis
- Clinical
- Seizures or raised pressure in a person from an endemic area. Diagnostic criteria combine imaging, serology, clinical and exposure data.
- Tests
- Serology (enzyme-linked immunoelectrotransfer blot) supports the diagnosis, less sensitive with a single cyst. Fundoscopy for papilloedema and ocular cysts. Stool tests and screening of household contacts for tapeworm carriers.
- Imaging
- CT shows cysts and is best for calcifications; MRI defines cysts, the scolex («cyst with a dot»), oedema and ventricular cysts better.
Differential diagnosis
- Tuberculoma
- Brain abscess
- Toxoplasmosis
- Primary or metastatic brain tumour
- Other parasitic cysts (echinococcosis)
Goal of treatment
Control seizures, treat hydrocephalus, kill viable cysts when appropriate while limiting inflammation, and break the transmission cycle.
Treatment
- Medical
- Antiseizure medicines for seizures.
- Medical
- Antiparasitic drugs (albendazole and/or praziquantel classes) for viable parenchymal cysts, with corticosteroids to limit inflammation; not for calcified-only disease.
- Acute
- Raised intracranial pressure is treated first: corticosteroids for diffuse oedema, and urgent CSF diversion for hydrocephalus before antiparasitic therapy.
- Surgical
- Endoscopic removal of ventricular cysts or ventriculoperitoneal shunt for hydrocephalus.
- Lifestyle
- Hand washing, safe water and treatment of tapeworm carriers in the household.
Drugs for this condition
Complications
- Chronic epilepsy
- Obstructive hydrocephalus and shunt failure
- Arachnoiditis and stroke from vasculitis
- Vision loss from ocular cysts
Prognosis
Most parenchymal cysts resolve and seizures are often controlled, though calcified lesions can cause lasting epilepsy. Extraparenchymal and subarachnoid forms are harder to treat and carry more complications.
Prevention
- Sanitation, latrines and safe disposal of faeces
- Hand washing and safe drinking water
- Detection and treatment of tapeworm carriers
- Pig confinement, meat inspection and pig vaccination or treatment programmes
Test yourself
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How do humans acquire neurocysticercosis?
By ingesting Taenia solium eggs from a human tapeworm carrier's faeces (faecal–oral), not from the pork itself.
What is the commonest presentation of parenchymal neurocysticercosis?
Seizures.
What is the typical imaging sign of a viable cyst?
A cyst with an eccentric dot, the scolex («cyst with a dot»).
Which imaging test is best for calcified lesions?
CT.
What must be treated before antiparasitic drugs in ventricular disease?
Hydrocephalus and raised intracranial pressure, e.g. with CSF diversion.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Tapeworm Infections and Cysticercosis (StatPearls (NCBI Bookshelf), 2026); Neurocysticercosis in Latin America: Current epidemiological situation based on official statistics from four countries (PLoS neglected tropical diseases, 2022) · adapted, CC BY 4.0.
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