ISPUB.COM The Internet Journal of Neurology Volume 5 Number 2 1 of 7 Electrophysiological Evaluation Of Adolescents Presenting With Chloroquine Toxicity Due To Persistent Malaria Infections E Anyanwu, I Kanu, J Nnadozie Citation E Anyanwu, I Kanu, J Nnadozie. Electrophysiological Evaluation Of Adolescents Presenting With Chloroquine Toxicity Due To Persistent Malaria Infections. The Internet Journal of Neurology. 2005 Volume 5 Number 2. Abstract Most drugs used in the treatment of malaria produce phototoxic side effects in both the skin and the eye. These effects are evaluated electrophysiologiclly. The EEG examination was abnormal in 7 out of 10 of the patients compared to the controls with only 1 in 10 with episodes of bi-hemispheric sharp activity. It was later found that this particular control subject has had seizures of unknown etiology in the past. There was fronto-temporal theta wave activity that seemed to indicate diffuse changes characteristic of metabolic encephalopathies. There was scattered and slowing of the alpha rhythm with subsequent appearance of theta and delta activity. The P100 latency was markedly prolonged with mainly the left eye stimulation at an avrage of 143.62 msec and the amplitude of response decreased at 1.26 microvolts. Overall results provided evidence of left optic nerve dysfunction in chloroquine retinopathy. INTRODUCTION When patients are attacked by malaria (disease caused by plasmodia and transmitted by anopheles mosquito in the tropics) or have rheumatic disorders, they are generally treated with quinine or its derivatives. Almost all patients with hydroxychloroquine (HCQ) retinopathy complain of altered central vision as their first symptom and a normal optic fundus does not exclude the diagnosis HCQ retinopathy (Bienfang et al., 2000). Chloroquine retinopathy (CR) is a major complication of long-term malaria prophylaxis (LTMP) causing permanent visual dysfunction and occasionally blindness. The risk of retinopathy in subjects receiving LTMP is limited to a cumulative dose that does not exceed 140 g. CR that occurred after 8 years of malaria prophylaxis with chloroquine at a cumulative dose of 125 g. Because a threshold dose of chloroquine for retinal toxicity has not been established, careful, ongoing screening is required, especially as the cumulative dose increases (Bertagnolio, et al., 2001). Although, very few patients with mild chloroquine retinopathy may show normal visual acuity, visual fields and full-field electroretinogram, however, retinal dysfunction may be indicated by color vision disturbances. Those with moderate chloroquine retinopathy with normal visual acuity, visual fields and dark- adapted full-field electroretinogram, light-adapted and flicker full-field electroretinogram responses are, however, borderline and color vision was abnormal. While those with severe chloroquine retinopathy show reduced visual acuity, visual field and color vision defects, and a reduced full-field electroretinogram and if color vision defects are detected in patients at risk of developing chloroquine retinopathy, additional testing is indicated to rule out toxicity (Vu et al., 1999; Kellner et al., 2000). Cutaneous and ocular effects that may be caused by light include changes in skin pigmentation around the ocular adnexia, corneal opacity, cataract formation and other visual disturbances including irreversible retinal damage (retinopathy) leading to blindness (Motten et al., 1999). The most effective quinine derivative regarded as the drug of choice is choroquine. In treating malaria, chloroquine is used for prevention, treatment of symptomatic attacks of malaria. It is also used for the eradication of plasmodia (radical cure). Other derivatives, which equally are good but not as effective as chloroquine, are amodiaquine, mefloquine and primaquine. Low dose of chloroquine are sometimes given to patients during the symptomatic stage thereby relieving the episodes of fever and chills. However, these medicines do not completely destroy all the malarial parasites remaining in the liver. Hence the attack may re-occur some months or years later. In order to avoid this from happening, patients are usually given the full doses of chloroquine or