Nodding syndrome.

Area of Science:

• Neurology
• Epidemiology
• Infectious Diseases

Background:

• An epidemic illness, nodding syndrome, has affected children in Eastern Africa since the 1960s.
• Characterized by head nodding, cognitive impairment, and atonic seizures, its incidence is rising in Uganda and South Sudan.
• The syndrome's onset is often triggered by eating or cold temperatures.

Purpose of the Study:

• To summarize published reports and recent studies on nodding syndrome.
• To investigate potential causes and associations of this unexplained epidemic epilepsy.
• To consolidate current understanding of nodding syndrome's clinical presentation and epidemiology.

Main Methods:

• Review of published literature and recent studies on nodding syndrome.
• Analysis of case-control studies investigating potential etiological factors.
• Examination of neuroimaging (MRI), cerebrospinal fluid (CSF), and electroencephalography (EEG) findings.
• Testing for infectious agents, nutritional deficiencies, and toxicities.

Main Results:

• Nodding syndrome presents as atonic seizures in children aged 5-15 years.
• Extensive testing ruled out associations with various infections (e.g., trypanosomiasis, cysticercosis), nutritional deficiencies, and toxicities.
• Magnetic resonance imaging showed nonspecific lesions, cerebrospinal fluid analysis revealed no inflammation, and electroencephalography results were markedly abnormal.
• A consistent, though enigmatic, association was found with onchocerciasis, detected via skin snip or serologic analysis.

Conclusions:

• Nodding syndrome is an unexplained epidemic epilepsy.
• Onchocerciasis remains a consistent, yet not fully understood, associated factor.
• Further research is needed to elucidate the precise mechanisms underlying nodding syndrome.