What are the diagnostic and management approaches for neurocysticercosis?

Diagnosis and Management of Neurocysticercosis

The diagnosis of neurocysticercosis requires both brain MRI and non-contrast CT scan, with enzyme-linked immunotransfer blot as the confirmatory serologic test, while treatment must be tailored to the specific form of neurocysticercosis, with albendazole as the primary antiparasitic agent for most cases. 1, 2

Clinical Presentation

• The two most common clinical presentations of neurocysticercosis are seizures and increased intracranial pressure 1, 2
• Other presentations may include focal neurological deficits, headache, and cognitive changes depending on location and number of lesions 3

Diagnostic Approach

Neuroimaging

• Both brain MRI and non-contrast CT scan are mandatory for complete evaluation 1, 2
  • MRI is superior for detecting viable cysts, especially in ventricular and subarachnoid locations 4
  • CT is better for identifying calcified lesions 4

Serologic Testing

• Enzyme-linked immunotransfer blot (EITB) is recommended as the confirmatory serologic test 1
• Enzyme-linked immunosorbent assays (ELISA) using crude antigen should be avoided due to poor sensitivity and specificity 1, 2

Diagnostic Criteria

• Absolute diagnostic criteria include histologic demonstration of the parasite, visualization of the scolex on neuroimaging, or direct visualization of subretinal parasites 5
• Major criteria include lesions highly suggestive of neurocysticercosis on neuroimaging, positive serum EITB, and resolution of lesions after antiparasitic therapy 5

Pre-Treatment Evaluation

Required Testing

• Fundoscopic examination is mandatory prior to initiating anthelmintic therapy to rule out retinal involvement 1, 6
• Screen for latent tuberculosis infection in patients likely to require prolonged corticosteroids 1, 2
• Screen for or provide empiric therapy for Strongyloides stercoralis in patients likely to require prolonged corticosteroids 1, 2
• Pregnancy testing for females of reproductive potential prior to therapy 7

Treatment Approach Based on NCC Type

Viable Parenchymal Neurocysticercosis (VPN)

• For 1-2 viable parenchymal cysticerci: albendazole monotherapy for 10-14 days (15 mg/kg/day divided into 2 daily doses, maximum 1200 mg/day) 1, 7
• For >2 viable parenchymal cysticerci: combination therapy with albendazole (15 mg/kg/day) plus praziquantel (50 mg/kg/day) for 10-14 days 1, 6
• Corticosteroids should be initiated prior to antiparasitic therapy to reduce inflammatory response 6, 7

Single Enhancing Lesions (SELs)

• Albendazole therapy is recommended 1
• Antiepileptic drugs for all patients with SELs and seizures 1
• Consider tapering off antiepileptic drugs after 6 months if seizure-free and lesion has resolved 1

Elevated Intracranial Pressure

• Manage elevated intracranial pressure first before antiparasitic treatment 1, 6
• For diffuse cerebral edema: anti-inflammatory therapy with corticosteroids 1, 6
• For hydrocephalus: surgical approach (shunt placement) 1, 6, 8

Ventricular Neurocysticercosis

• Surgical approach is often required, though medical therapy may be beneficial in some cases 8
• MRI should be repeated at least every 6 months until resolution of the cystic component 1, 6

Subarachnoid Neurocysticercosis

• Albendazole has shown effectiveness in treating giant subarachnoid cysts 8
• Longer courses of therapy may be needed compared to parenchymal disease 9

Monitoring During Treatment

Laboratory Monitoring

• Monitor blood counts at the beginning of therapy and every 2 weeks while on albendazole 1, 7
• Monitor liver enzymes (transaminases) at the beginning of therapy and at least every 2 weeks during treatment 6, 7
• Discontinue albendazole if clinically significant decreases in blood cell counts occur or if liver enzymes are significantly elevated 7

Imaging Follow-up

• Follow-up MRI should be performed at least every 6 months until resolution of the cystic component 1, 6
• Consider retreatment with antiparasitic therapy for parenchymal cystic lesions persisting for 6 months after initial therapy 1

Public Health Considerations

• Screen household members for tapeworm carriage in patients who likely acquired NCC in a non-endemic area 1, 2, 6
• This is a public health issue that can often be addressed by the local health department 1

Common Pitfalls and Caveats

• Diagnosis and management of neurocysticercosis can be challenging; clinicians with little experience should consult with disease experts 1, 6
• Attempted removal of inflamed or adherent ventricular cysticerci is associated with increased risk of complications 6
• Drug interactions: praziquantel interacts with steroids, decreasing its serum concentrations, and serum levels of phenytoin and carbamazepine may be lowered by praziquantel 6