Neurocysticercosis

B69.0

DESCRIPTION

Neurocysticercosis is caused by the cysticercal form, i.e. larval form of the pork tapeworm, Taenia solium . The larvae may locate in the brain parenchyma, intraventricular and meningeal areas, spinal canal/cord and eye, or a combination of these regions. Viable cysticerci incite little inflammatory response, but dead cysticerci elicit an increased inflammatory response.

Cysticerci in the brain may remain dormant or may cause complications such as:

  • headache,
  • focal neurological deficits,
  • behavioural disorders,
  • increased intracranial pressure,
  • visual disturbances,
  • hydrocephalus,
  • seizures,
  • meningitis,
  • meningo-encephalitis,
  • spinal cord compression.

DIAGNOSTIC CRITERIA

Clinical

  • Location and stage of the life cycle of the parasite in the brain determines the clinical features.
  • Suspect if child from endemic area, i.e. pig farming area, presents with neurological abnormalities such as:
    • seizures,
    • raised intracranial pressure/hydrocephalus,
    • focal neurological deficits,
    • meningo-encephalitis,
    • meningitis,
    • behavioural disorders,
    • headache,
    • cranial nerve palsies.

Investigations

  • Computed tomography (CT scan) and/or magnetic resonance imaging (MRI scan) of brain showing cysts, granulomas, peri-lesional oedema or calcification of cysts.
  • MRI scan may identify more lesions and viable cystic lesions than the CT scan.
  • Soft tissue radiology of muscles of lower limbs may demonstrate calcified cysticerci, i.e. “rice grain” calcifications in muscles.
  • Follow-up CT scans and/or MRI scans may help to assess the response to therapy.

GENERAL AND SUPPORTIVE MEASURES

Prevention:

  • Prolonged freezing or thorough cooking of pork to kill the parasite.
  • Thorough washing of fresh fruit and vegetables in T. solium endemic areas.
  • Attention to personal hygiene.
  • Proper sanitation facilities and safe water.
  • Avoid the use of human excreta as fertiliser.
  • Look for Taenia ova in the stools of the family members.

MEDICINE TREATMENT

Calcified cysticerci and a single dying lesion visible on CT scan require no anti-helminthic treatment.

Patients with multiple cysts usually have a mixture of live and dying cysts and are assumed to have active disease and require treatment.

  • Albendazole, oral, 7.5 mg/kg/dose 12 hourly for 7 days.
    • Maximum dose: 400 mg/dose.

Prevention of neurological manifestations

In massive infestations, cysticidal therapy may trigger an inflammatory response. Delaying anti-helminthic therapy and adding corticosteroids may lessen the risk.

24 hours prior to albendazole therapy:

  • Dexamethasone, IM, 0.15 mg/kg/dose 6 hourly.

Then follow with oral therapy as soon as possible:

  • Prednisone 1 mg/kg/day for the duration of albendazole therapy, and then taper and discontinue.

Seizure control

See: Epilepsy .
Treat according to the type of seizure.
AED treatment for 6–12 months after resolution of lesions on neuro-imaging.
Recurrent seizures require chronic treatment until seizure-free for 2 years.

REFERRAL

  • Neurocysticercosis not responding to adequate therapy.
  • Neurocysticercosis with complications, such as hydrocephalus.
  • Intractable epilepsy.