Neurocysticercosis

Introduction

The primary cause of epileptic seizures in less developed countries is neurocysticercosis, which is caused when the larval stage of the pork tapeworm Taenia solium infects the central nervous system. It is endemic in most of Latin America, sub-Saharan Africa, and Asia, and has become more prominent in developed countries because of migration of people from these endemic areas. Humans typically become infected by the fecal-oral route, in which the life cycle of this tapeworm involves development of the tapeworm in the human small intestine after ingesting infected pork and eggs released in the stool, and then humans ingest stool containing the eggs of the tapeworm and the larva develops and disseminates within the human host. The clinical presentations of patients with neurocysticercosis include seizures, headaches, and intracranial hypertension, but can occur anywhere throughout the central nervous system and lead to diverse neurologic symptoms. The management includes surgery, drainage, and antiparasitic drugs. In this chapter, we present a case of a patient with a fourth ventricular neurocysticercosis.

Example case

Chief complaint: headaches and vomiting

History of present illness

A 37-year-old, right-handed man with no significant past medical history presented with progressive headaches and vomiting. Over the past 3 months, he complained of progressive headaches with more frequent nausea and vomiting. He also complained of some lethargy. He went to the emergency room where imaging revealed a brain lesion ( Fig. 74.1 ).

Medications: None.
Allergies: No known drug allergies.
Past medical and surgical history: None.
Family history: No history of intracranial malignancies.
Social history: Recent immigrant from Mexico, no smoking, occasional alcohol.
Physical examination: Awake, alert, oriented to person, place, time; Cranial nerves II to XII intact; No drift, moves all extremities with good strength; skin examination negative for lesions.
Imaging: Chest/abdomen/pelvis computed tomography negative for lesions, skeletal survey for calcified lesions.
Labs: Elevated eosinophils; blood, urine cultures pending.

	Pablo Augusto Rubino, MD, Román Pablo Arévalo, MD, Hospital El Cruce, Buenos Aires, Argentina	Javier Avendano Mendez-Padilla, MD, National Institute of Neurology and Neurosurgery, Tlalpan, Mexico	Jose Hinojosa Mena-Bernal, MD, PhD, Sant Joan de Deu, Barcelona, Spain	Isaac Yang, MD, University of California at Los Angeles, Long Angeles, CA, United States
Preoperative
Additional tests requested	None	Western blot for neurocysticercosisPET scan MRI Spectroscopy CSF analysis	Neuroophthalmology evaluation (fundoscopy) CT head Serologic testing	CT head
Surgical approach selected	Suboccipital craniotomy	Suboccipital craniotomy and EVD placement	ETV and endoscopic intraventricular	Suboccipital craniotomy and C1 laminectomy
Anatomic corridor	Telovelar	Telovelar	Right frontal transventricular	Telovelar
Goal of surgery	En bloc removal without cyst disruption, prevent hydrocephalus	Diagnosis, relieve hydrocephalus, restore CSF flow	Removal of cyst, restoration of CSF flow	Resection of lesion, resolve hydrocephalus
Perioperative
Positioning	Concorde	Prone	Supine neutral	Prone
Surgical equipment	IOM (SSEP, cranial nerve EMG) Surgical microscope	IOM (cranial nerve EMG) Surgical navigation Surgical microscope	Surgical navigation Endoscope with 30-degree lens	Surgical navigation Surgical microscope IOM (SSEP/EEG/MEP)
Medications	Mannitol	None	Steroids	Mannitol Steroids Antiepileptics
Anatomic considerations	Vertebral arteries, both PICA loops, floor of the fourth ventricle	Floor of the fourth ventricle, PICA	Fornix, venous system, mammillary bodies/hypothalamus/basilar artery, mass intermedia, periaqueductal gray, mesencephalon, fourth ventricular floor and choroid plexus	Floor of fourth ventricle, facial colliculi, PICA
Complications feared with approach chosen	CSF leak	Retraction injury, cranial nerve injury from injury to floor of fourth ventricle, hydrocephalus, hematoma	Avoid posterior fossa craniotomy	Brainstem injury, PICA injury
Intraoperative
Anesthesia	General	General	General	General
Skin incision	Midline linear	Midline linear	Linear	Midline linear
Bone opening	Midline suboccipital +/– C1 laminectomy	Midline suboccipital	Right frontal burr hole	Right frontal burr hole for EVD
Brain exposure	Cervicomedullary junction	Cervicomedullary junction, cerebellar hemispheres	Right frontal (MFG)	Cervicomedullary junction
Method of resection	Expose squamous part of occipital bones/posterior foramen magnum/posterior arch of C1, exposure of whole craniovertebral junction, medial suboccipital craniotomy +/– C1 laminectomy, Y-shaped dural opening, opening of inferior cerebellar cistern, telovelar opening with splitting of cerebellar amygdala, entry into fourth ventricle, handle cyst with care to not disrupt capsule, continuous irrigation, watertight dural closure	Midline opening, burr holes below transverse sinus bilaterally, craniotomy down to foramen magnum, Y-shaped dural opening, identify tonsils and cerebellomedullary fissure, open tela choroidea and inferior medullary velum, blunt dissection to dissect walls of cyst with continuous irrigation, remove en bloc, watertight dural closure	Entry of endoscope into right lateral ventricle, access to third ventricle and ETV, turn endoscope around to visualize posterior third and aqueduct, navigate to fourth ventricle, grab wall of cyst with endoscopic forceps, careful circular movements with mild retraction, and remove in single piece at same time as endoscope without working channel, visualize cavity, no EVD unless necessary. If cyst adherent, stop procedure and perform midline suboccipital craniotomy telovelar approach	EVD before surgery in supine, prone position for surgery, Y-shaped fascial opening, T-shaped muscle opening, periosteal dissection, C1 laminectomy, suboccipital craniotomy, release CSF from EVD, Y-shaped dural opening, elevate tonsils, telovelar approach, resect tumor, identify patency of aqueduct, watertight dural closure
Complication avoidance	Telovelar opening, continuous irrigation with cyst manipulation, avoid entering cyst, watertight closure	Telovelar opening, continuous irrigation with cyst manipulation, avoid entering cyst, watertight closure	ETV for hydrocephalus, gentle traction on cyst, EVD if surgical issues, stop procedure if cyst adherent	EVD before surgery, release CSF from EVD prior to dural opening, telovelar opening, evaluate patency of ventricular system
Postoperative
Admission	ICU	ICU	ICU	ICU
Postoperative complications feared	CSF leak	Injury to fourth ventricular floor, CSF leak, arterial injury	Memory loss, injury to fourth ventricular floor	Brainstem injury, PICA injury
Follow-up testing	CT immediately after surgery	MRI within 72 hours after surgery CSF analysis	MRI 1 month after surgery Infectious disease evaluation pending excision results of cyst	CT immediately after surgery MRI within 48 hours after surgery
Follow-up visits	14 days after surgery	14 days and 1 month after surgery	7 days after surgery	3–4 weeks after surgery