MRI findings in people with epilepsy and nodding syndrome in an area endemic for onchocerciasis: an observational study.
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.


CONCLUSIONS
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.
Department of Neurology, Technical University of Munich, Germany ; Haydom Lutheran Hospital, Manyara Region, Tanzania.
A S
AS
Winkler
K
K
Friedrich
S
S
Velicheti
J
J
Dharsee
R
R
König
A
A
Nassri
M
M
Meindl
A
A
Kidunda
T H
TH
Müller
L
L
Jilek-Aall
W
W
Matuja
T
T
Gotwald
E
E
Schmutzhard
D000293:Adolescent; D000818:Animals; D001927:Brain Diseases / Q000175:diagnosis*; D020809:Central Nervous System Helminthiasis / Q000175:diagnosis*; D019353:Endemic Diseases; D004827:Epilepsy / Q000145:classification / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D064128:Nodding Syndrome; D017181:Onchocerca volvulus / Q000302:isolation & purification; D009855:Onchocerciasis / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000453:epidemiology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D013636:Tanzania / Q000453:epidemiology; D055815:Young Adult
Epilepsy; Onchocerca volvulus; cerebrospinal fluid; head nodding; magnetic resonance imaging