Head nodding (HN) syndrome, a new epilepsy disorder in sub-Sahara Africa, is described in 62 patients studied prospectively at the University of Ulm, Germany; Haydom Lutheran Hospital, Tanzania; and other centers in Austria, Tanzania, and Canada. The onset of HN attacks was at 6 to 10 years in 50% cases, and at 11-15 years in 37%. At the time of diagnosis and evaluation, most patients were between 11 and 15 years of age. Twenty-eight (45%) patients had only HN attacks, and 28 had HN plus one other type of seizure, usually generalized or partial complex. HN was associated with loss of neck tone, and 37 (60%) patients had additional loss of tone of upper extremities. Consciousness was impaired in 11 (18%). Food was a provoking factor in 9 patients, and bathing in cold water caused HN in 2. A family history of epilepsy was present in 90%. EEGs in 10 patients were normal in 4 and showed abnormal slowing in 6, with sharp waves in 2. MRIs in 12 patients were normal in 4, and showed hippocampal sclerosis in 5 and gliotic changes in 5. Thirty-one (61%) of 51 patients had microfilariae visible on microscopic examination of the skin. Traces of Onchocerca volvulus DNA in the skin were identified by PCR in 12 of 20 without microscopically visible microfilariae. Skin PCR positivity was significantly associated with MRI abnormalities. Neutrophil counts were elevated in 14 (27%) patients and eosinophils in 28 (55%). O. volvulus serum ELISA test was positive in 44 (86%). CSF PCR was negative in all patients. HN seizures were 50% controlled by conventional antiepileptic drugs. [1]

COMMENT. The prevalence of epilepsy is reportedly higher in areas where onchocerciasis is endemic, eg Mexico, Sudan, Uganda, Tanzania, and S America, but meta-analysis fails to show a significant association between O. volvulus and epilepsy (Druet-Cabanac et al, 2004; cited by authors). The cause of the head nodding epilepsy syndrome in Tanzania and Sudan remains unclear. Alternative explanations offered include hippocampal sclerosis, and genetic susceptibility. Evidence of CNS invasion by O. volvulus was not supported by CSF PCR tests.

Onchocerciasis (River Blindness, Filariasis) involves skin, subcutaneous tissue, lymphatic vessels and the eyes. The AAP Red Book, 27^th ed. 2006 makes no mention of CNS invasion or epilepsy as a complication of onchocerciasis. Ivermectin, a microfilarial agent, and doxycycline are the drugs of choice for treatment of the infestation. Only anticonvulsant drug treatment is discussed in the article on HN syndrome. The effect of treatment with ivermectin on seizure frequency might be of interest.