Cystic Cerebellar Lesions Post Honeymoon: A Strange Case of Neurocysticercosis

CASE REPORT AND COMMENTARY

By Maria D. Mileno MD

Dr. Mileno is the Director, Travel Medicine, The Miriam Hospital and Associate Professor of Medicine, Brown University, Providence, RI.

Dr. Mileno reports no financial relationships to this field of Study

Synopsis: This case report of a US traveler is paired with a review of neurocysticercosis cases in Israel published in Journal of Travel Medicine illustrating the broad spectrum of clinical presentations that can be encountered with this disease.

Source: Leshem E, Kliers I, Bakon M et al. Neurocysticercosis in Travelers: A Nation-Wide Study in Israel. Journal of Travel Medicine. 2011; 18: 191-197.

Case Summary: A 27- year-old physical education teacher presented with two separate episodes of ill-defined dizziness and mild confusion over a period of one week. He was in good health, except for numerous upper respiratory infections during the months prior to his onset of dizziness. The first episode occurred while he was working in his basement. He described a feeling of "spaceyness" with difficulty forming words. This lasted roughly 90 minutes. He did not lose consciousness. The second episode occurred while he was playing basketball at the school where he is a physical education teacher, and it was quite similar to the first episode. The school nurse evaluated him and found an elevated blood pressure. He was sent by ambulance for hospital evaluation of hypertension and dizziness at which time CT imaging and an MRI revealed cystic cerebellar lesions. He had neither focal neurological symptoms nor fever in association with these episodes, and no nausea nor vomiting. Clinically the episode seemed most consistent with either a seizure aura or a true seizure. Further neurosurgical evaluation excluded a brain tumor, stroke or seizure disorder based upon his clinical examination, an EEG and the MRI appearance [see Fig 1A and 1B] of his lesions. He was referred for an outpatient infectious disease consultation to evaluate these symptoms and for further management of probable neurocysticercosis.

Fig. 1A Fig. 1B

His history included travel to Mexico on his honeymoon 6 months previously, at which time he ate undercooked meat, most likely prepared using the "Mayan methods" in which meat was "wrapped in banana leaves and baked in the earth." He also ate sushi occasionally at the time. He described no acute symptoms immediately after his honeymoon and states that he was at an upscale resort. There was no significant family history and his wife felt well, without any symptoms after the honeymoon. The patient denied tobacco, alcohol or recreational drug use.

An initial CT scan [not shown here] identified 2 small focal defects in the right cerebellum measuring 0.6 and 1.1 cm in diameter. The MRI scan shows the extent of the brain involvement without cerebral lesions. (See Fig 1A and 1B.) Clinically the episode seemed most consistent with a seizure aura or true seizure. (1A). The T2 weighted images showed a focus of five or six rounded areas of bright signal in the right posterior fossa of the cerebellum, the largest measuring approximately 8 mm with an internal nodular septate appearance. Post-gadolinium imaging showed a tiny nodule enhancing at the midparietal level to the right of the midline, not shown in this image.(1B)

Serological tests for cysticercosis were forwarded to the CDC, but given his ongoing symptoms and known risk of brain edema during treatment he was hospitalized for pre-treatment with dexamethasone and praziquantel 100 mg/kg/d, in 3 divided doses. He tolerated this well, but required diphenhydramine for skin redness with administration of his praziquantel. He completed 2 weeks of high dose corticosteroids. Almost daily he continued to have episodes of the "strange feeling" he found difficult to describe. Things seem to be "happening fast" and vision during this 10-minute period was less focused. He had to look away then refocus on TV for example. No loss of consciousness occurred. Episodes were sometimes more intense than his original presentation, but similar in nature. Final serological tests, including the Immunoblot assay for cysticercosis antibodies performed at CDC were negative. Upon follow up with the patient 6 months later (See Fig 2) he was well and without further episodes.

Fig. 2

The nine Israeli patients with neurocysticercosis described in the Journal of Travel Medicine had traveled to South Asia and /or southeast Asia1 and the most common presenting symptom at the time of diagnosis was a seizure. The average time interval from the suspected travel exposure and the onset of symptoms was 3.2 + 1.8 years. Two patients had multiple lesions; the others had a single lesion, and all were cerebral. Anti-helmintic therapy was given to most of these patients with resolution of symptoms. Antiepileptic treatment was utilized for 16 after albendazole was administered, and was eventually discontinued in all patients without any complications.

Other neurocysticercosis cases reported from Korea and Japan showed that very few had cerebellar involvement. The therapeutic approach ranged from neurosurgical intervention for impending brain herniation, to expectant treatment with steroids and albendazole for 28 days.

Commentary

Many features of our case were atypical including a presentation with ill-defined symptoms, the presence of lesions predominantly located in the cerebellum and the lack of confirmatory serology for cysticercosis. It was fortunate that a travel history was obtained and led to a consideration of neurocysticercosis in this patient. It is truly amazing to think that an upscale resort might convince honeymooners and others that eating in the dirt is probably safe!

Parasite immune evasion of the host immune system is one explanation why viable cystic neurocysticercosis lesions generally do not cause inflammation and are commonly asymptomatic.2 Parasite death leads to a breakdown of this protective mechanism and results in a profound inflammatory reaction; this can cause an encephalitic syndrome and clinical deterioration in patients who have primarily cerebral lesions. It can be provoked by cysticidal therapy.

An overriding concern that he might have had significant cerebellar inflammation and edema during degradation of the parasite and potentially herniate during treatment prompted me to initiate treatment in the hospital under observation with neurosurgical assistance available. He improved clinically, and the lesions evolved over six months into a calcified appearance, yet the case remained unsettling during that time.

Single-day praziquantel treatment regimens with favorable results have been published. They allowed us to complete anti-parasitic treatment during a short inpatient stay, followed by a prolonged course of cortiosteroids for two additional weeks to produce continued eradication of the parasites.

The paper by Leshem et al offers numerous references that explore the magnitude of neurocysticercosis as an emerging infection, and the various approaches to disease management in the summaries of case reports. The spectrum of treatment options has ranged from no treatment to neurosurgery and a panel of experts wrote consensus guidelines to set some basic principles of therapy.3 They concluded that each case must be individualized. Anti-parasitic agents should not be used in those cases showing already calcified parasites or during cysticercosis encephalitis. Importantly, antiparasitic treatment should be used to treat actively growing cysts and pre-treatment corticosteroids should be utilized, as well as anti-seizure medications. A growing lesion may require surgical excision. Cysts located in the ventricular system should be treated surgically if the necessary neuroendoscopic techniques are available. When hydrocephalus or intracranial hypertension is present management using a ventricular shunt is the top priority.

We had the benefit of follow-up neuroimaging technique. On a worldwide basis this may not be available nor performed for economic reasons. There are no studies showing long-term outcomes for neurocysticercosis. This case, in conjunction with the series published by Leshem et al, provides follow up that should be reassuring about the favorable course of this disease with medical management.4

References

  1. Leshem, E. et al. Neurocysticercosis in Travelers: A Nation-Wide Study in Israel. Journal of Travel Medicine 2011; 18 191-197.
  2. White AC, Robinson P, Kuhn R. Taenia solium cysticercosis: host-parasite interactions and the immune response. Chem Immunol 1997;66:209–30
  3. Garcia, Hector H., Current Consensus Guidelines for Treatment of Neurocysticercosis. Clin Micro Rev 2002;15:747-756
  4. Garcia HH, Gonzalez AE, Evans CA, et al. Taenia solium cysticercosis. Lancet 2003;362:547–56