Explore UAB

History:  70 year-old male admitted with a 5-month history of severe global headache and an episode of a partial seizure involving the left arm and left leg.  No fever, no systemic symptoms.

Epidemiology:  Farmer, born and lives in Cajamarca in the highlands.  Notravel.  No history of TB.  No HIV risk factors.

Physical Examination:  Afebrile, normal vital signs.  Enlargedthyroid gland.  No papilledema. Normal neurologic exam.

Laboratory Results:  Normal CBC and chemistries.  Thyroid functiontests normal.  MRI – T1 weighted images are shown [ImagesA & B].

Discussion:  The MRIs shown in Images A & B are diagnostic without any further testing; visualization of a fluid filled cyst with a scolex inside [arrow, Image A] is diagnostic.  The scolex is the head of the larval T. solium tapeworm.  Edema around a dying cyst is often the trigger for onset of seizures in infected individuals.  In this case a Western blot was performed and was positive.  Fortunately, no intraventricular lesions or signs of intracranial hypertension were seen in this patient, as such cysts are more difficult to manage.

Cysticercosis is infection with the larval stages of the human pork tapeworm Taenia solium.  Humans acquire cysticercosis after ingesting eggs of T. solium in material contaminated with feces originating in human tapeworm carriers.  Humans that do not eat pork can get cysticercosis.  Ingestion of contaminated pork results in humans getting an adult intestinal tapeworm, not cysticercosis.  Cysticercosis is common in many developing countries and very common in rural agricultural areas of Perú.  In developed countries the long-lived cysticerci are increasingly seen as immigration from affected areas rises.  Occasional transmission by tapeworm carriers to those who have never left non-endemic countries is reported.

Ingested T. solium eggs hatch in the stomach and are then carried to the muscles and other tissues where the larvae encyst and reach their usual size of about 1 cm within a few months.  Clinical manifestations depend on the affected organ but neurocysticercosis causes the most morbidity.  The cysticerci seem able to evade the immune system and are thought to remain viable for several years without causing any inflammatory response.  Most clinical symptoms are the direct result of inflammatory responses that accompany the eventual cyst degeneration.  Epileptic seizures are the primary or sole clinical manifestation in up to 80% of patients.  In endemic regions, new onset seizures in teenagers or young adults are most likely due to neurocysticercosis.  Cysticerci can also cause symptoms because of mass effect, impingement on a vital structure, or blockage of CSF circulation especially if the cyst is intraventricular.

In all cysticercosis patients, seizures need to be managed as per any other form of epilepsy.  Treatment of parenchymal neurocysticercosis with antiparasitic drugs such as albendazole is increasingly accepted even when there are few lesions.  Albendazole clearly kills the cysts, but may lead to added inflammation and exacerbation of symptoms, which is usually dealt with by empiric concomitant use of steroids.  Therapeutic decisions should be based on the number, location, and viability of the cysts.  Patients in whom all lesions are already calcified should receive no anti-parasitic treatment.  Recent work indicates that long-standing calcified lesions can sometimes provoke peri-lesional edema, which may need treatment with steroids as well as anti-seizure medication.  Intraventricular shunting may be necessary if intracranial hypertension results from treatment.  Neurocysticercosis is a variable disease and treatment approaches need to be individualized to a large number of differing clinical presentations [Neurology. 2006 Oct 10;67(7):1120-7].

Our patient was treated with albendazole 15mg/kg/d for one-month plus prednisone 1mg/kg/d tapering the dose progressively for a total duration of one month, and phenytoin.  After discussion with Gorgas Course professor and consultant Hector Hugo-García, the duration of treatment beyond the standard 8 days was undertaken, based on the proximity of one lesion to the 3rd ventricle [Image B].  He tolerated the therapy but his headache failed to resolve.  Repeat MRI 5 months later [Images C & D] showed good involution of the peri-ventricular lesion but little effect of treatment on the parenchymal lesions.  A further course of treatment was decided after follow-up consultation with Dr García.  His experience is that a significant resolution in the size of many lesions should have occurred in the 5-month follow-up period.  Not achieving that is an indication for longer duration of treatment and perhaps for combination therapy.  Our patient was started on a combination of albendazol 15mg/kg/d plus praziquantel 50mg/kg/d and steroids, with plan to give these drugs for at least one month; this regimen is currently being evaluated in a phase II clinical trial compared with albendazole.