Summary Purpose: In the 1960s in Tanzania, L. Jilek‐Aall observed a seizure disorder characterized by head nodding (HN). Decades later, “nodding disease,” reminiscent of what was seen in Tanzania, was reported from Sudan. To date this seizure disorder has not been classified and possible causes still remain obscure. Methods: In a prospective study in southern Tanzania, we evaluated 62 patients with HN. Selected patients underwent blood (n = 51) and cerebrospinal fluid (CSF) (n = 48) analyses. Others were chosen for MRI (n = 12) and EEG (n = 10). Results: Seizure type was classified as “head nodding only” and “head nodding plus,” the latter being combined with other types of seizure (n =34). During HN, consciousness was impaired in 11 patients (17.7%) and supportive signs of epileptic seizures were described by 15 (24.2%) patients. Precipitating factors were confirmed by 11 (17.7%) patients. Fifty‐six (90.3%) patients had at least one relative with epilepsy. EEG confirmed interictal epileptic activity in two patients and unspecific changes in four patients. MRI showed hippocampus pathologies (n = 5) and gliotic changes (n = 5). Skin polymerase chain reaction (PCR) positivity for Onchocerca volvulus was significantly associated with lesions on MRI. However, PCR of the CSF was negative in all cases. Conclusions: We present a comprehensive clinical description of the “HN syndrome,” possibly a new epilepsy disorder in sub‐Saharan Africa. MRI lesions and their association with positive skin PCR for O. volvulus despite negative PCR of the CSF is intriguing and deserves attention. Furthermore, the high prevalence of hippocampus sclerosis and familial clustering of epilepsy may point toward other potential pathogenetic mechanisms.
Background: Onchocerciasis has been implicated in the pathogenesis of epilepsy. The debate on a potential causal relationship between Onchocerca volvulus and epilepsy has taken a new direction in the light of the most recent epidemic of nodding syndrome. Objective: To document MRI changes in people with different types of epilepsy and investigate whether there is an association with O. volvulus infection. Methods: In a prospective study in southern Tanzania, an area endemic for O. volvulus with a high prevalence of epilepsy and nodding syndrome, we performed MRI on 32 people with epilepsy, 12 of which suffered from nodding syndrome. Polymerase chain reaction (PCR) of O. volvulus was performed in skin and CSF. Results: The most frequent abnormalities seen on MRI was atrophy (twelve patients (37.5%)) followed by intraparenchymal pathologies such as changes in the hippocampus (nine patients (28.1%)), gliotic lesions (six patients (18.8%)) and subcortical signal abnormalities (three patients (9.4%)). There was an overall trend towards an association of intraparenchymal cerebral pathologies and infection with O. volvulus based on skin PCR (Fisher's Exact Test p=0.067) which was most pronounced in children and adolescents with nodding syndrome compared to those with other types of epilepsy (Fisher's Exact Test, p=0.083). Contrary to skin PCR results, PCR of CSF was negative in all patients. Conclusion: The observed trend towards an association of intraparenchymal cerebral pathological results on MRI and a positive skin PCR for O. volvulus despite negative PCR of CSF is intriguing and deserves further attention.
Our results do not give evidence of a relationship between O. volvulus and epilepsy. Despite the fact that 2 participants had raised antibody index, the existence of cerebral onchocerciasis caused by migration of microfilariae into the CSF appears unlikely. However, to date unexplored reactions to the infestation with O. volvulus causing epilepsy cannot be excluded.
SUMMARYPurpose: The main aim of this door-to-door-study was to determine the prevalence, incidence, and clinical characteristics of epilepsy in northern Tanzania. Methods: A total of 7,399 people were screened with a standardized questionnaire using ''multistage random sampling.'' Results: The prevalence rate of epilepsy was 11.2/ 1,000 [95% confidence interval (CI) 8.9-13.9/ 1,000] and the age-adjusted prevalence rate was 13.2/1,000. The prevalence of active epilepsy was 8.7/1,000 (95% CI 6.7-11/1,000). There was a preponderance of women. The average retrospective incidence including the last 5 years was 81.1/ 100,000 (95% CI 65-101/100,000). Fifty-four percent (45 of 83) of the people with epilepsy had generalized seizures without any identifiable cause; 71% (59 of 83) of the epilepsy patients had not visited health institutions prior to the study and 76% (63 of 83) had never received treatment. Discussion: Our study shows that the prevalence and incidence of epilepsy in northern Tanzania are higher compared to developed countries and that the majority of people with epilepsy do not access treatment.
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