Cerebral paragonimiasis mimicking tuberculoma: First case report in India.

An 8-year-old male child of Tuensang District, Nagaland, India, attended Civil Hospital, Tuensang, complaining of cough, fever, headache, and inability to move right arm since one month. On clinical suspicion of tubercular meningitis, anti-tubercular therapy was initiated and the patient was referred to the Naga Hospital Authority. A brain computed tomography scan revealed an isodense area with surrounding edema on the left parietal lobe, which was diagnosed as tuberculoma and the anti-tubercular therapy was continued. As there was no sign of clinical improvement on completion of the three-month-ATD regimen, the patient was investigated for paragonimiasis. Laboratory investigations revealed peripheral blood eosinophilia, raised ESR, Paragonimus egg-positive sputum, and positive Enzyme-linked immunosorbent assay (ELISA) and ID tests for paragonimiasis. The Bacillus Calmette-Guérin (BCG) test and Acid Fast Bacilli (AFB) sputum smears were negative. Chest roentgenogram showed no abnormal findings. A final diagnosis of pulmonary paragonimiasis associated with cerebral paragonimiasis was made. The patient responded to praziquantel therapy. Cerebral paragonimiasis is a serious extrapulmonary form of paragonimiasis, sometimes life-threatening, but curable with praziquantel. It should be included in the differential diagnosis of cerebral granulomatous and other space-occupying lesions.

INTRODUCTION

Paragonimiasis is commonly manifested as pulmonary paragonimiasis, but extrapulmonary forms are not infrequent in humans. Singh et al., in a review of 45 cases of paragonimiasis in children, found 20 (44.4%) extrapulmonary cases.[1] In another review of 247 cases in adults, the extrapulmonary forms were found in 2% of all the cases.[2] Extrapulmonary forms resulted from the erratic migrations of juvenile worms, which deviated from the normal route of migration to the lungs through the intestinal wall, peritoneal cavity, and diaphragm. The cerebral form is one of the typical examples of extrapulmonary forms due to erratic migrations. In this form, the worms enter the cranial cavity through the jugular or carotid foramen and commonly invade the temporal and occipital lobes.[3] Cerebral paragonimiasis is a serious and sometimes fatal disease, although the symptoms are solely dependent on the site of localization and number of parasites.[4] Cerebral paragonimiasis have been reported mainly from China;[5] Korea;[6] Formosa;[78] and Japan.[9] We report the first case of cerebral paragonimiasis in India, which was combined with the pulmonary form.

CASE HISTORY

An 8-year-old boy of Tuensang district, Nagaland, India was admitted to the district hospital of Tuensang on 15 October, 2007, with chief complaints of cough, fever, headache, and inability to move the right arm since one month prior. The patient was provisionally diagnosed as a case of tubercular meningitis. Without any laboratory investigations, he was discharged on 22 October, 2007 to be admitted in a Civil Hospital, Tuensang, on 25 October, where he was given antitubercular therapy (Cat-II). In the absence of any appreciable improvement, the patient was transferred on 6 November, 2007 to the Naga Hospital Authority, where specialists and facilities for laboratory investigations, including computed tomography (CT) / X-ray / Ultrasonography were available. On 13 November, 2007, few laboratory investigations and CT scan of the brain were performed. The routine hematological test revealed Hb 11gm%, total leucoctye count 8800 per cumm, neutrophils-58%, lymphocytes-25%, eosinophil-17%, and ESR (Westergren) 60 mm, at the end of the first hour. The BCG test was negative. A CT scan of the brain showed an isodense area with surrounding edema in the left parietal lobe [Figure 1]. A diagnosis of tuberculoma in the left parietal lobe was made and antitubercular therapy was continued. Sputum samples were negative for AFB, but positive for Paragonimus eggs [Figure 2]. Micro-ELISA and double immunodiffusion tests of the serum were positive for paragonimiasis. Paragonimus heterotremus adult extract was used for these tests, as an antigen. The patient gave a history of consumption of mountainous crabs. Based on these findings, the case was finally diagnosed as pulmonary paragonimiasis with cerebral involvement. The morphological and molecular characterizations of eggs from the sputum sample revealed features of P. heterotremus. Hence, the causative agent was identified as P. heterotremus. A high incidence of P. heterotremus metacercariae in mountainous crabs (Singh TS et al., manuscript in preparation) supports this conclusion. A course of praziquantel was given in doses of 25 mg per kg body weight, thrice a day, for five days. Following the praziquantel therapy, the patient showed dramatic improvement clinically, during the follow-up period of three months post therapy.

Figure 1

CT scan of the brain showing an isodense area surrounded by edema (arrow) in the left parietal lobe

Figure 2

Paragonimus egg seen in the sputum smear (40×) not to be scaled

DISCUSSION

Cerebral paragonimiasis is one of the important extrapulmonary forms with serious consequences and high mortality compared to the pulmonary form, which is usually benign. Most cases of cerebral disease are associated with chronic morbidity due to epilepsy, dementia, and various neurological sequelae. Rarely, the patient may die of cerebral hemorrhage. A rare case of cerebral paragonimiasis combined with cerebral hemorrhage was reported by Choo et al.[3] Cerebral paragonimiasis is usually diagnosed with the help of imaging techniques, such as, X-ray, Computerized Axial Tomography (CAT) scan, and magnetic resonance (MRI), and serodiagnosis (ELISA and others) is complemented. The CT and MRI of cerebral paragonimiasis generally show as conglomerates of multiple ring-shaped shadows or enhancements, called the ‘grape cluster’ or ‘soap bubble’ forms, in one hemisphere.[10] The present case is an exception of cerebral paragonimiasis with a granulomatous lesion in the left parietal lobe. As the case was associated with pulmonary paragonimiasis, the causative agent was identified as P. heterotremus, based on the morphological and molecular characterization of the eggs from the sputum sample. This case emphasizes the need for differential diagnosis between tuberculoma and cerebral paragonimiasis by careful history taking and laboratory investigations. If the clinicians were aware of the prevalence of paragonimiasis and its various clinical presentations, the delay in the correct diagnosis and therapy for cerebral paragonimiasis could have been avoided.