Disseminated cysticercosis: a case report and review of treatment protocols

Abstract

Cysticercosis is caused by the larvae of Taenia solium and is a significant health problem. Disseminated cysticercosis is an infrequent manifestation of the same. A woman in her 30s presented to us with a history of seizures, outward protrusion of both eyes and multiple soft-tissue swellings over the face and tongue for 3 years. Imaging studies revealed multiple cystic lesions in the brain parenchyma, extraocular muscles, subcutaneous tissue, muscles of mastication and tongue. A high index of suspicion and a planned therapeutic approach is required in such cases.

Background

Cysticercosis is a parasitic infection caused due to infection by the larval form of Taenia solium (pork tapeworm). Humans are the definite host, harbouring the adult tapeworm in the intestine. The larval cysts can disseminate via the bloodstream to various organs like the brain, striated muscle, spinal cord, eye and skin.¹ It is a preventable cause of blindness and can have a varied presentation which may depend on the site of involvement, size and number of lesions, and the host response to the pathogen.

Case presentation

A woman in her 30s presented to our centre with a history of headache and outward protrusion of both eyes for the last 3 years. She also had a history of seizures, with the first episode (generalised tonic-clonic type) being 3 years back, for which she had undergone a CT scan and was diagnosed with neurocysticercosis; she was started on treatment with antiepileptics (clobazam and levetiracetam), along with a course of oral albendazole for 2 weeks in the previous hospital. The antiepileptics were continued for about a year, after which she discontinued and did not go for a follow-up visit. She presented to us with headache and dizziness and inability to close the right eye completely. On examination, was conscious and alert. No neurological deficits were noted. The physical examination revealed multiple soft-tissue nodules over the face and the tongue (figure 1B). The best-corrected visual acuity was 6/9 OU, with a normal colour vision OU and contrast of log 1.50 in both eyes. There was proptosis of both eyes. Anterior segment evaluation of the right eye revealed 3 subconjunctival cystic masses on the medial aspect of the right eye (figure 1A), along with incomplete closure of the right eye and limitation of extraocular movements (EOM) nasally. Eyelid closure and EOM in the left eye were normal. The rest of the anterior segment was within normal limits, fundus examination was within normal limits OU, with no signs of intravitreal or retinal cysticercosis.

Figure 1.

Slit lamp image showing subconjunctival cyst in the right eye (A); image showing multiple cysts involving the tongue muscles (B).

Investigations

Laboratory investigation showed a total leucocyte count of 7.9x10⁹/L, haemoglobin 11 g/L. Blood urea and serum creatine were normal. The stool examination did not reveal any ova or cyst.

An ultrasound b (USG B) scan of both the orbits revealed multiple hypoechoic areas with a few having high-amplitude spikes within them, mainly present in the extraocular muscles, suggestive of cysticercus cyst (figure 2A). One cyst was noted adjacent to the right optic nerve as well (figure 2B). MRI (brain, orbit and neck) showed multiple cysts of varying size in bilateral cerebral and cerebellar hemisphere, bilateral paraspinal muscle, supraclavicular, infraclavicular muscle, muscles of the chest wall, bilateral axilla, anterior and posterior part of the tongue, left submandibular gland, bilateral cervical region and bilateral extraocular muscles (figure 3).

Figure 2.

USG B scan showing multiple cysts in the extraocular compartment of the eye along with one present adjacent to the right optic nerve.USG B, ultrasound b.

Figure 3.

MRI images showing multiple hyperintense foci within the brain parenchyma, extraocular compartment and muscles of mastication, suggestive of cysticercus cysts.

Treatment

In view of the multiple intracranial cysts and orbital cysts, the patient was started on oral corticosteroids (Prednisolone 1 mg/kg) and antiepileptics.

As the patient had incomplete closure of the right eye, she was taken up for surgical removal of the subconjunctival cyst to prevent the development of exposure keratitis, which was done under topical anaesthesia, using blunt dissection. Three cysts were removed (in toto) one by one without rupturing the cyst wall, followed by local infiltration of triamcinolone acetonide (figure 4). Histopathological examination of the cyst confirmed the cysticercus cyst. To avoid the risk of extensive reaction by the multiple cysts present, antihelminthic therapy was avoided. The patient was continued on systemic steroids and was followed up in OPD, weekly for 3 weeks, and thereafter monthly. The steroids were tapered at a dose of 5 mg/week. There were no episodes of seizures at the 2-month follow-up.

Figure 4.

Intraoperative images: subconjunctival cysticercus cysts removed (in toto) (A, B). Notably, three cysts were removed, followed by local infiltration of triamcinolone acetate. The right lower figure represents immediate postoperative status(C).

Discussion

Human cysticercosis occurs after ingesting food contaminated with T. solium eggs or by reinfection by ingesting ova from larvae existing in the intestine. It may occur after consuming undercooked pork, raw vegetables, or fruit contaminated with T. solium eggs. These eggs mature, and the larvae penetrate the intestinal mucosa to disseminate via the bloodstream into various organs like the brain, striated muscle, spinal cord, eye and skin.¹ There are three stages of evolution of the cyst:

1. Vesicular/live cyst, which has a well-defined cyst wall and scolex, causes minimal or no inflammation.

2. Colloidal vesicular stage, where the larva begins to die and the cyst wall becomes leaky, resulting in inflammation of the surrounding tissues.

3. Calcified stage, where the larva dies and is either calcified or reabsorbed.²

Neurocysticercosis is the most common manifestation of cysticercus cellulosae, followed by ocular and adnexal cysticercosis, which represents 13%–46%.³ Disseminated cysticercosis is a rare manifestation, which was first reported as early as 1912 by Krishnaswamy CS, in a middle-aged man presenting with weakness of lower limbs and subcutaneous nodules. He died due to lobar pneumonia, and on autopsy, numerous cysticercus cysts were found in the heart, pancreas, brain and voluntary muscles.⁴ In 1926, Priest described a case of a 24-year-old British soldier presenting with muscle enlargement, subcutaneous nodules, seizures and subretinal cyst. The diagnosis was confirmed by removing two cysts from muscle and subcutaneous tissue, which contained a scolex surrounded by clear fluid.⁵ The clinical presentation depends on the parasitic burden, location of cysts in the body and the host reaction. The manifestations include subcutaneous and lingual nodules, seizures, dementia, pseudohypertrophy of muscles, myalgia, weakness and an absence of focal neurological signs.⁶

On investigations, a complete blood count may reveal eosinophilia. Serological tests like ELISA for anticysticercal antibodies, enzyme-linked immunotransfer blot and complement fixation test are available, but they may show high false-positive reports. More reliable are the imaging studies used for diagnosis, including USG B scan of orbit, CT scan and MRI. On USG B scan, a well-defined cystic lesion, with a hyperechoic area within it, corresponding to the scolex, is visualised. The cyst wall and scolex (due to calcareous corpuscles) have high amplitude spikes on A-scan.²

CT scan can demonstrate a hypodense mass with a hyperdense scolex, with or without surrounding soft-tissue inflammation. On MRI, a hypointense cyst with a hyperintense scolex is seen. Histopathological diagnosis would provide a definitive diagnosis.

Treatment of disseminated cysticercosis has no predetermined management protocol. Randomised controlled trials by Garcia et al have shown that antihelminthic drugs like praziquantel and albendazole are effective in neurocysticercosis, but they had only included patients with less than 20 lesions.^{7 8} There have been reports where the use of antihelminthic drugs has resulted in various adverse events like nausea, vomiting, seizures, raised ICT, altered sensorium, thrombosis, stroke and even death.^{9 10} These drugs may fasten the death of the cysts, but that may occur spontaneously as well. The adverse reactions are not per se due to the drug toxicity but because of the highly antigenic nature of the cystic contents, against which the host immune system mounts an inflammatory response.¹⁰ Currently, cysticidal therapy is indicated only after prior treatment with steroids which reduces inflammation and prevents serious adverse reactions. Albendazole is preferred over praziquantel as it is cheaper, has better CSF penetration and also destroys subarachnoid and ventricular cysts. Praziquantel has been known to interact with anti-epileptic drugs, which alters its bioavalibility.¹¹ Previously, one study tried to treat with lower doses of albendazole 12 mg/kg/day in place of standard 15 mg/kg/day, which showed improved symptoms post-treatment as well along with lesser side effects.¹² In a single-arm open-labelled prospective trial, 29 patients with disseminated cysticercosis (DCC) were given three cycles of albendazole 15 mg/kg/day for 28 days each, with adjuvant corticosteroids and antiepileptics. Oral methylprednisolone 0.75–1 mg/kg/day was started 3 days before and gradually tapered beyond the albendazole therapy. It showed promising results in terms of reduction of parasite load and was well tolerated with some patients having an asymptomatic rise in bilirubin and blood sugar levels. Patients with cysticercal encephalitis were excluded, and are best managed with corticosteroids. For patients with vitreoretinal cyst, surgical excision of the cyst, followed by albendazole after a 6 week interval is advised. Treatment of optic nerve cysticercosis is controversial due to the limited number of cases described. For patients with myocysticercosis with ≥3 lesions/ orbit, or >2 lesions in a single muscle, cysticidal therapy may be avoided.¹³

Conclusion

DCC is a rare manifestation of cysticercosis. Further studies are needed for a management protocol for DCC. Also, raising awareness concerning cysticercosis and the associated eating habits is imperative.

Learning points.

• Disseminated cysticercosis is a rare entity for which no definitive management protocol exists.

• Systemic corticosteroids (with or without antihelminthic therapy) are the mainstay for the management of disseminated cysticercosis.

• Ultrasound b scan is extremely helpful for the diagnosis of cysticercus cysts in and around the orbit.

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