Adult onset seizures in a patient with neurocysticercosis

Clinical History

A young adult Indian man presented with increasing confusion and acute onset of tonic clonic seizures followed by unconsciousness. He showed no signs of meningism with bilaterally equal and reactive pupils. Laboratory findings depicted normal blood and cerebrospinal fluid (CSF) and negative polymerase chain reaction for mycobacterium tuberculosis.

Imaging Findings

Initial non-enhanced computed tomography (NECT) brain showed multiple variable-sized, wide-spread, well-defined, hypo-dense lesions with high density eccentric nodules and associated hydrocephalus. Magnetic resonance imaging (MRI) was also performed the same day showing hypo-intense lesions on T1W and FLAIR and hyper-intense on T2WI with a central nodule. Acute moderate hydrocephalus was also visualized with transependimal
oedema. CSF drainage was done by Ventriculo-peritoneal (VP) shunt insertion along with medical management with Albendazole. Follow-up CT confirmed decreased size of the lesions and resolution of hydrocephalus. VP shunt placement associated oedema was seen at the operative site as irregular hypo-dense area on CT examination.

Discussion

Neurocysticercosis is caused by infestation with Taenia solium - a tapeworm endemic in many parts of the developing world. The disease burden is spreading to non-endemic areas because of increasing migration. Humans are thought to be definite hosts in its life cycle, giving years of thriving before final overpower by host defenses and ultimately calcification [1]. Ingested eggs in undercooked pork meat or contaminated food lose their protective capsule in the stomach and turn into larval cysts which cross the intestinal barrier and migrate via the vascular system to the brain, muscle, eyes, spine (1-5% in adults) and other structures [2]. It is most common in patients in their early 30s with equal gender distribution and 4-8% prevalence in general population [3].
Neurocysticercosis may involve ventricles, cisterns, sub-arachnoid space, spinal cord or the eyes in 10-20% along with parenchymal lesions especially at grey-white junction. Clinical manifestations include seizures, hydrocephalus associated headaches, arteritis associated infarcts and strokes, cord compression, intra-vitreal or sub-retinal cysticercosis, cysticercal encephalitis, meningo-encephalitis, granulomatous meningitis and focal abscess or granulomas. Seizures and headache are related to active disease [4] whereas calcified granulomas present as chronic epilepsy [5]. Colloidal cysts cause recurrent seizures and are the most symptomatic and survive up to a year [6]. Almost 80 % of infections are asymptomatic [7].
Contrast-enhanced CT or MRI can differentiate four stages of the disease entity as follows: I) Vesicular - the viable larval cyst with identifiable scolex as an eccentric nodule, II) Colloidal - enhancing cyst without a well defined scolex, III) Nodular/granular - an enhancing but degenerating nodule and IV) a non-enhancing calcified granuloma. MRI is better for detecting intra-ventricular, extra-parenchymal disease and visualizing the scolex within the cysticercus. CT examination is better for detecting intra-cerebral calcifications.
Albendazole or praziquantel is the specific treatment used along with corticosteroids to reduce cerebral oedema or vasculitis. Surgical excision is required in giant cysts or a cyst at a critical location such as fourth ventricle, middle cerebral artery or optic chiasma along with ventriculo-peritoneal (VP) shunting for hydrocephalus [8].
Prognosis is the best for patients in whom imaging studies normalize after treatment. Neurocysticercosis is a leading cause of epilepsy in the developing world and is increasingly prevalent in the developed countries. Better understanding of the mechanisms of neurocysticercosis and the life cycle of T. solium is needed to develop appropriate intervention and prevention programs.

Differential Diagnosis List

Final Diagnosis

Adult onset seizures in a patient with neurocysticercosis

URL:	https://eurorad.org/case/11375
DOI:	10.1594/EURORAD/CASE.11375
ISSN:	1563-4086