Clinico-Radiological Profile of Neurocysticercosis in Children

Introduction: Neurocysticercosis (NCC) is the most common parasitic disease of the nervous system caused by the larval stage of Taenia solium (also known as pork tapeworm). Clinical manifestations are pleomorphic and determined mainly by the location, number and viability of cysts as well as by the host response. Neuroimaging is the most useful diagnostic study for parenchymal disease. Methods: The study was conducted in the Paediatric Ward of a tertiary care teaching institute, Bareilly, India. The study was conducted on 50 subjects. The study was a hospital based, prospective, observational study. All admitted children between one year to 18 years and diagnosed to have neurocysticercosis were included the study. Statistical analysis was done by single and double sample proportion test. P value of less than 0.05 was considered significant. Results: Maximum numbers of patients were in age group of five-14 years. Males (62%) were more commonly affected than females. Seizure was found to be the commonest presentation of NCC. In our study majority of cases were diagnosed by CT scan. 70% of the patients enrolled in this study demonstrated ring enhancing lesions on neuroimaging. Maximum number of patients had lesions in the parietal lobe followed by frontal lobe. Conclusions: NCC is common in the age group of five to 14 years. Focal seizures were the most common presentation. Other symptoms were headache and vomiting. Vegetarians were more commonly affected than non vegetarians. Single ring enhancing lesion in parietal area was the commonest neuroimaging findings.


INTRODUCTION
Neurocysticercosis (NCC) is the most common parasitic disease of the nervous system caused by the larval stage of the Taenia Solium (also known as pork tapeworm). 1 NCC is identified as the cause of active epilepsy in 26.3% to 53.8% of cases, in developing world. 2 Majority of cases with NCC present with seizures. Less-common manifestations include hydrocephalus, diffuse cerebral edema, or focal neurologic signs. 3 Neuroimaging is the most useful diagnostic study for parenchymal disease. It gives information about cyst location, viability, and associated inflammation. MRI also helps in better detection of basilar arachnoiditis, intraventricular cysts and cysts in the spinal cord. However, CT scan is the best modality to identify calcifications. The CT and MRI findings in parenchymal NCC depend on the stage of development of the parasites. 4 Prognosis and management vary with location. 5 NCC is rampant in the Rohilkhand region in Bareily, India despite the fact that it can easily be prevented by proper hygienic measures and health education. This work aimed to study the clinicoradiological profile of NCC in children to be able to gauge the magnitude of problem and to take adequate preventive measures as well as making public aware about the disease by appropriate methods.

METHODS
The study was conducted in the Paediatric Ward of a tertiary care hospital of Rohilkhand region from 1 November 2017 to 31 October 2018. It was a hospital based, prospective, observational study done for a period of 12 months period. All admitted children one year to 18 years and diagnosed as neurocysticercosis were included in the study. 5 Moribund cases and seizures due to any other cause were excluded. Statistical analysis was done by multivariate analysis. P-value of less than 0.05 was considered significant.

RESULTS
Maximum number of patients were in age group of five to 14 years. Males (62%) were more commonly affected than females (38%). Majority of lesions were diagnosed by the definite criteria given by Del Brutto criteria. Probable diagnosis of NCC was made in 36% of the cases. Seizure was the commonest presentation of NCC. Other manifestations include focal neurologic signs, recurrent vomiting and headache as a sign of raised intracranial pressure. In our study, majority of cases were diagnosed by CT scan. 70% of the patients enrolled in this study demonstrated ring enhancing lesions on neuroimaging. The other 30% cases showed either granulomatous lesions or the calcified stage of NCC without any ring enhancement. Single and non-calcified lesions were more common. It was found that only two patients had starry sky pattern on MRI brain and were diagnosed to have cysticercal encephalitis. Seizures was the most common presenting complaint. Maximum number of patients had lesions in the parietal lobe followed by frontal lobe. We found lesions in the brain parenchyma only. No lesions were found in the basal ganglia, brainstem or cerebellum. Similarly no cases of subarachnoid and intraventricular NCC was found. Majority of patients who presented with headache showed ring enhancing lesions (75%) and this observation is statistically significant.

DISCUSSION
Neurocysticercosis (NCC) is the most common parasitic disease of the nervous system. Larval stage of the Taenia Solium (also known as pork tapeworm) is the causative organism. 1 The cyst may remain dormant for many years. As soon as larval death occurs antigens are liberated leading to intense inflammatory reactions and onset of symptoms. Majority of cases of NCC present with seizures. Other features with which a child might present include hydrocephalus, diffuse cerebral edema, or focal neurologic signs. 4 CT scan and MRI help in identifying the number and topography of lesions, their stage of involution and degree of inflammatory reaction. CT scan is used for screening and MRI is used for confirming diagnosis. MRI is also superior in following up patients on therapy. 6 NCC usually has small cysts varying from 0.2 -0.5 cm in diameter and may be single or multiple. Maximum number (76%) of patients were in age group of five to 14 years and mean age being 8.7 years. Children above the age of 15 years had lesser also found nearly 70% cases between five to nine years age group and six to 10 years age group respectively. 5,7 A study in rural population of West Bengal found commonest age being a little higher than as observed by M.S Pandit et al. and Yadav et al. 54.9% cases were between 10 to 12 years of age. 8 A study done in Rohilkhand Medical College, Bareilly on 62 subjects in the year 2013 to 2014 observed that peak age of presentation was 5 to 12 years (80%) with 9.8 years being the mean age of NCC. 9 Thus, the mean age of presentation in our study was similar to that seen in other studies done in India and abroad.
In our study males were more commonly affected than females. 62% of affected children were males. A study done by Pandit MS et al. concluded that NCC didn't have any sex predilection and male: female ratio was 0.92:1. 10 However Yadav et al. conducted a study in 2012 in Saifai, Uttar Pradesh which concluded that 60.7% of affected individuals were males. 11 A study done on 40 patients in Andhra Pradesh also had male predominance with male : female ratio being 2.07:1. 12 In a study in West Bengal male predominance was observed with male : female ratio being 1.2:1. 54.9% of cases were boys and 45.1% were girls. 13 Male preponderance in our study might be possible because majority of the population presenting to our hospital was from rural and less literate areas where there is preferential treatment of male children at the best medical facility with negligence towards female health.  The symptoms and signs depend on the location, number and viability of the cysts, and the host immune response. Seizures are commonest presentation of parenchymal NCC. Involvement of frontal lobe can lead to cognitive impairment and loss of voluntary movement. Parietal lobe involvement will affect the temperature, taste and t o u c h s e n s a t i o n s a n d m o v e m e n t . Vi s u a l disturbances might be seen in occipital lobe involvement. Integration and processing of memories might be affected in temporal lobe involvement. It was found in our study that majority of lesions (56%) were seen in the parietal lobe on neuroimaging. No lesions were found in the basal ganglia, brainstem or cerebellum. Similarly no case of subarachnoid and intraventricular NCC was found.
A study done in a Medical College of Western Uttar Pradesh, India on 62 subjects found out that parietal lobe was most commonly involved (45%). 9 Similarly another study done in West Bengal, India concluded that parietal region specially on the right side was most commonly involved (61.1%). 8

CONCLUSIONS
NCC is common in the age group of five to 14 years. Focal seizures were the most common presentation. Other symptoms were headache and vomiting. Vegetarians were more commonly affected than non vegetarians. Single ring enhancing lesion in parietal area was the commonest neuroimaging findings. The belief that NCC is more common in non-vegetarians is not found to be true.