Surgical case of subacute headache in a young Latin American woman

Abstract

Neurocysticercosis (NCC) is the most common helmintic disease affecting the central nervous system and a major cause of adult-onset epilepsy in the developing world. ¹ We describe a case of intraventricular NCC associated with hydrocephalus in a 28-year-old woman, Peruvian native, admitted to the emergency department for subacute headache and nausea. The cranial CT scan done showed asymmetric enlargement of the lateral ventricles which on cranial MRI was revealed to be due to an intraventricular cyst. An intraventricular endoscope was used to remove the cyst at the foramina of Monro, and therefore treat the obstructive hydrocephalus. NCC—a known cause of hydrocephalus in many Latin American countries—should be among the differential diagnosis in a patient with history of travel or residency in these countries. Treatment of choice for obstructive hydrocephalus caused by NCC is cyst removal with neuroendoscopy.

Background

Neurocysticercosis (NCC), the most common parasitic infection of the central nervous system (CNS), is quite rare in Europe but defined as emergent by the WHO.¹ Emerging infectious diseases are defined as diseases that have appeared recently or that have recently increased in their frequency, geographical distribution or both.² We present a case of intraventricular NCC causing obstructive hydrocephalus in a young Peruvian female living in Italy for 5 years treated using endoscopic cyst excision.

Case presentation

A 28-year-old Peruvian native woman was admitted to the emergency department due to the onset of progressive headache associated with nausea. She had been in good clinical condition until 1 week before the admission, when she developed fatigue, fluctuating blurred vision, impaired concentration, a progressive retro-orbital and bifrontal headache and nausea. The patient had no prior medical history except for a prolactin-secreting pituitary microadenoma, which had been diagnosed 2 years before because of galactorrhea and amenorrhea. Clinical signs and symptoms were successfully treated with cabergoline (Dostinex, dosage 0.50 mg twice a week) with normalisation of prolactin levels and tumour stability at MRI follow-up.

On admission, the patient was alert and oriented, though reaction to stimuli was slightly slow. Neurological examination did not show any meningeal signs (as nuchal rigidity). Fundoscopic examination documented bilateral papilledema. There was no impairment in visual acuity or visual fields. Neurological examination revealed mild cognitive deficits with a mini-mental status examination score of 24/30. The rest of the examination showed no focal neurological deficits. Systemic physical examination was normal.

Investigations

Emergent workup included complete blood count and chemistries including hormone levels, which showed mild anaemia with normal differential WBC count, pituitary hormones within normal range and no elevation of inflammatory markers. Cranial CT scan done showed asymmetrical dilation of the lateral ventricles with the left frontal horn slightly larger than the right. The size of the pituitary tumour was unchanged from previous imaging, with no evidence of apoplexy (figure 1A).

Figure 1.

(A) Brain computed tomography (CT) scan visualising distortion and dilatation of supratentorial ventricular system, primarily the left lateral ventricle containing an unusual lesion. (B) T1-weighted and contrast enhanced MRI of the brain, visualising a cyst with cerebro-spinal fluid (CSF)-like signal and a capsular nodule in the anterior horn of the left lateral ventricle. (C) Cerebral MRI, axial fiesta sequence, showing the radiological appearance of the cyst known as ‘hole with dot’, which corresponds to the vesicular stage of larval development. (D) Endoscopic view: a cyst with mucilaginous consistency appeared immediately after the introduction of the optic system representing the pathognomonic endoscopic sign called ‘full moon’ image. (E) Endoscopic view: endoscopic forceps removing the parasitic lesion. (F) Endoscopic view: exploring the left lateral ventricle after removal of the cyst the ependyma appeared diffusely bumpy. (G) Histopathological examination confirmed the diagnosis of intraventricular neurocysticercosis in the vesicular stage: the membrane of the cysticercal cyst with the outer layer covered with microvilli (H&E, ×200 and ×400 magnification). (H) Macroscopic appearance of the larval stage of the parasite. (I) Postoperative cerebral MRI, axial T1 contrast enhanced, showing resolution of hydrocephalus and no residual disease.

Cranial MRI with intravenous gadolinium (Gd) was subsequently done, revealing an expansive cystic lesion in the frontal horn of the left lateral ventricle, with a small capsular nodule, causing asymmetric obstructive hydrocephalus. No modification of microadenoma was detected, but an expansive cystic lesion located in the frontal horn of the left lateral ventricle, with CSF-like signal and a small capsular nodule, causing obstructive hydrocephalus was noticed (figure 1B,C).

Differential diagnosis

The differential diagnosis for an intraventricular cystic lesion is broad. It includes neoplastic lesions which could arise from the ventricular wall and septum pellucidum (eg, ependymoma, subependymoma, central neurocytoma and subependymal giant cell astrocytoma), choroid plexus (eg, papilloma and carcinoma) or metastasis from a distant primary. Non-neoplastic lesions appearing as an intraventricular cyst include congenital cysts (eg, colloid and arachnoid cysts) or infectious pathologies (eg, tuberculomas, hydatid cyst, NCC or other parasitic infections).

In the present case, the cranial MRI findings characteristic of viable (vesicular) cysts of NCC was noted. The T1-weighted Gd-enhanced sequence showed the so-called ‘hole with dot sign’ which represented a scolex as an eccentric hyperintense nodule within the hypointense cyst.³ Serological exams for cysticercosis were negative as well as direct and cultural stool examination.

Treatment

Due to progressive deterioration in sensorium, the patient underwent emergency endoscopic excision of the intraventricular cyst. Under general anaesthesia in the supine position, a 7 mm rigid endoscope with 30° lens (Karl Storz, Germany) was introduced in left lateral ventricle. At ventriculostomy, CSF pressure was high; a cyst with mucilaginous consistency was pushed towards the operating sheath by the pressure gradient and appeared immediately after the introduction of the optic system (figure 1D). The cyst with its content was then removed en-bloc by aspiration (figure 1E). Afterwards, the ventriculoscope was introduced deeper to inspect the ventricles: the ependyma of lateral ventricle appeared diffusely bumpy because of heavy inflammatory reaction (figure 1F). CSF examination showed pleocytosis. Histopathological examination of the cyst and its content confirmed the diagnosis of intraventricular NCC in the vesicular stage (figure 1G,H).

Outcome and follow-up

Postoperatively neurological condition of the patient markedly improved. Patient was treated with dexamethasone (8 mg/day) for 5 days, followed by prednisone 1 mg/kg/day for an additional week. Moreover, immediately after surgery, the patient started antihelminthic therapy with albendazole administered orally at 15 mg/kg/day for 3 weeks.

Postoperative brain CT scan and MRI with intravenous Gd documented total removal of the cyst and the resolution of hydrocephalus (figure 1I). The patient was discharged 10 days after surgery.

Follow-up MRIs at 1, 3, 6, 12 and 24 months after surgery showed no recurrence of NCC. At 30-month follow-up, the patient was in good general and neurological condition.

Discussion

To our knowledge, this case of intraventricular NCC is the third case of coincidental NCC and pituitary adenoma reported in literature.⁴ NCC is the most common helminthic disease of the CNS in humans, consisting in an infection by the larval stage of the pork tapeworm Taenia solium, acquired through fecal–oral contamination. The infective embryo (oncosphere) released from the egg in the intestine, passing through the mucosa to the bloodstream, may reach faraway locations, including CNS in the 4% of the cases. NCC predominantly affects people between 20 and 50 years and it is endemic in most Latin American countries, sub-Saharian Africa and large regions of Asia including the Indian subcontinent, most of Southeast Asia and China.⁵ Although accurate incidence data are not available, in the USA it is estimated 0.2–0.6 cases per 100 000 general population and 1.5–5.8 cases per 100 000 Hispanics, and that between 1320 and 5050 new cases of NCC occur every year, with a calculated annual age-adjusted mortality rate of at least 0.06 per million population.⁶ In the last decades, the prevalence of NCC has increased also in countries where local transmission is infrequent, due to immigration from endemic regions as well as recognition in international travellers. In Europe, 74.7% of NCC imported cases come from immigration and 17.6% from international travellers (mostly from Latin America): typically, symptoms of illness develop 2–5 years later.⁶

Common presenting symptoms of the disease include seizures (78.8%), headache (37.9%), intracranial hypertension, hydrocephalus, papilledema (11.7%) and focal deficits (16%). Clinical presentation depends on the location of the encysted organisms, according to which we distinguish intraparenchymal and extraparenchymal forms.⁷ The intraventricular form of NCC is relatively common (15%–54% of cases) and often determines rapidly progressive intracranial hypertension demanding prompt management. The most common sites in order of frequency are fourth ventricle (53%), third ventricle (27%), lateral ventricles (11%) and the aqueduct of Sylvius (9%).

Radiologically, the cysts within the ventricle have similar signal than the surrounding CSF, thus they are uncommonly detected on CT scan. MRI is therefore the gold standard for diagnosis: the best sequences to detail intraventricular cysts are Fluid Attenuated Inversion Recovery (FLAIR), Fast Imaging Employing Steady-state Acquisition (FIESTA), Constructive Interference in Steady-State (CISS) and Balanced Fast Field Echo (BFFE). Radiological appearance of the cyst changes according to the stage of larval development: the characteristic ‘hole with dot’ corresponds to the vesicular stage.⁸

Once confirmed radiologically, serology has limited value in diagnosis. The best documented serological test is enzyme-linked immunoelectrotransfer blot assay, which detects antibodies against T. solium. Its sensitivity is around 98% and its specificity is 100% for patients with two or more living parasites but it is lower in patients with one intracranial cysticercus.^{1 3} Other common laboratory findings are peripheral eosinophilia and CSF abnormalities, including mononuclear pleocytosis and a mild increase in protein level. Concurrent intestinal teniasis in patients with NCC is uncommon.⁵

Histopathology is essential and sufficient for definitive diagnosis.^{3 5}

Surgery is the first-line choice for treatment of intraventricular NCC, mainly through endoscopic removal of the cyst and, if needed, hydrocephalus treatment through endoscopic third ventriculostomy or CSF shunting. A pathognomonic endoscopic sign is the so-called ‘full moon’ image, depicting the endoscopic view of an intact cyst in the ventricle. The cyst should be removed ‘en-bloc’ when feasible; however, large cysts can be impossible to remove through endoscopic approach. Furthermore, unlike hydatid cysts, rupture of an intraventricular cysticercus does not lead to either dissemination of the disease or anaphylactic reaction.⁹ Because intraventricular cysts are free floating and can move around the ventricles depending on the position of the head, it has been suggested that a CT scan is performed just before the surgery.⁴

Endoscopic surgery is not only safe, but it is also efficacious to solve the associated hydrocephalus in most cases,¹⁰ thus avoiding the need of a permanent shunt. The latter can be necessary in cases of serious parasitic ependymitis. Tapia-Pérez et al ¹¹ have proposed an endoscopic scoring system for NCC, which allows to define the risk of persistent hydrocephalus. In our case, white bumpy ependymal lesions at ventricular exploration warranted a close clinical and radiological follow-up.

As concerns medical therapy, cysticidal drugs (praziquantel and albendazole) are known to destroy living larval cysts whether in the parenchyma, ventricles or the subarachnoid spaces and possibly to hasten the resolution of granulomas.¹² However, no consensus exists on indications for their use. Usually, albendazole is preferred over praziquantel for the lower cost and the more favourable safety profile. A dose of 15 mg/kg is the most commonly used regime. Caution must be taken in starting antihelmintic therapy before removal of the cysts, since cysticidal drugs can cause acute degeneration leading to exacerbation of intracranial hypertension: steroids are recommended during treatment with antiparasitic drugs at least in the first 3 days.

This case report explains a rare cause of obstructive hydrocephalus caused by NCC and treated with endoscopic removal of a cyst, with no need of a permanent ventriculoperitoneal shunt system.

Learning points.

• Physicians in non-endemic regions are increasingly dealing with neurocysticercosis cases due to increased global migration. Travel anamnesis is an important part of the clinical evaluation, especially with a patient presenting with atypical clinical and radiological features.

• Endoscopic surgery is not only safe but it is also efficacious in removing the cysts and in treating the associated hydrocephalus in most cases, avoiding thus the need of a permanent shunt.