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36 year old male with seizure/

Infectious

Neurocysticercosis

Other parasites (amebiasis, echinococcus, paragonimiasis)

Metastases -- squamous cell carcinoma

Enlarged perivascular spaces.

Pork tapeworm Taenia solium

Endemic in parts of Mexico, Central and South America, Asia and Africa

In the US

Most infections within the immigrant population

Locally acquired infection is rare and associated with contact with a tapeworm carrier.

Two clinical syndromes

Intestinal tapeworm infection

Neurocysticercosis.

Humans are the only known definitive hosts for the adult tapeworm

Pigs are the intermediate hosts (larval stage)

Mode of transmission

humans are infected by eating raw pork containing the larvae (cysticerci) which attach to the gut and develop into adult worms

Intermittent fecal shedding of eggs occurs, pigs ingest the excreted eggs in contaminated food or water

embryos penetrate the GI mucosa of the pig and are hematogenously disseminated to peripheral tissues with resultant formation of larval cysts.

NCC occurs when T solium eggs are ingested via fecal-oral transmission from a tapeworm host

The human then becomes an intermediate host with development of cysticerci within organs (skin, skeletal muscle, eye, CNS)

Encysted larvae inhibit the host inflammatory response

Acute inflammatory reaction occurs when the larvae die -- patient develops seizures

Variable range from date of infection to development of symptoms -- 1 to 30 years (average 5 years).

Parenchymal disease is most common

seizure or headache

NCC is the leading cause of adult-onset seizures worldwide

Extraparenchymal ventricular and subarachnoid cysts

Higher morbidity and mortality

intraventricular NCC -- obstructive hydrocephalus

Basilar cisterns involvement -- vasculitis, stroke

Acute encephalitis

Rare; more common in children

diffuse cerebral edema.

Cyst location

Grey-white matter junction, deep grey matter nuclei

Convexity sulci > cisterns > ventricles

Cysts typically 0.5 to 2.0 cm with eccentric scolex within cyst

Four imaging stages based on development stage and host immune response

1) Vesicular stage

2) Colloidal vesicular stage

3) Granular nodular stage

4) Nodular calcified stage

All stages may be present in single patient

Racemose pattern -- “grape-like” multiloculated cysts in cisterns and/or sylvian fissures, typically lack scolex.

3) Granular nodular stage

Retracted cyst wall

Nodular or ring-enhancement

Decreasing edema

4) Nodular calcified stage

Shrunken calcified lesion

No enhancement.