Ahmed T. El-Ghoneimy et al. 287 Neurological Complications Related to Treatment of Hepatitis C Virus Infection in Egyptian Patients Ahmed T. El-Ghoneimy 1 , Adel H. Gad 1 , Gihan M. Ramzy 1 , Mona A. Nada 1 , Montasser M. Hegazy 1 , Mohammed Ezz El-Arab 2 , Neveen M. El-Fayoumy 3 , Zeinab Shalaby 4 , Al-Metwally Youssof 1 Departments of Neurology 1 , National Hepatology and Tropical Medicine Research Institute 2 , Clinical Neurophysiology Unit 3 , Chemical Pathology 4 , Cairo University ABSTRACT Background: Treatment of hepatitis c virus (HCV) may induce or increase incidence of neurological side effects that may reduce adherence to therapy & result in dose modifications with less response or discontinuation of interferon therapy reducing quality of life. Objectives: To study central & peripheral nervous system complications related to treatment of chronic HCV infection. Methods: Forty Egyptian patients with chronic HCV infection were subdivided into 2 subgroups: Group  (20 patients with clinically apparent neuropsychiatric manifestation) & Group  (20 neurologically asymptomatic patients). Patients were subjected to clinical, neuropsychological evaluation with different scales, hepatitis markers, EEG & MRI brain. Results: The commonest pre-treatment disorder was sensory peripheral neuropathy (30%) followed by chronic sensory motor polyneuropathy & tension-type headache each (20%) while commonest post-treatment disorder was fatigue (25%), depression (20%) & tension-type headache (20%) followed by cognitive impairment & insomnia, each 15%. The most treatment-relieved disorders were cranial neuropathies (100%) followed by sensory PN (83.3%). EEG changes increased significantly after HCV treatment in both studied groups and significant improvement of SCV, DL & amplitude of SAP of ulnar nerve & sural nerve in group I. In group II, the SCV & amplitude of SAP of ulnar nerve got significantly worse after treatment. The results of neuropsychological scales got worse after treatment in both studied groups. Conclusion: In HCV patient, we found a wide range of central &peripheral nervous system disorders linked to treatment either these disorders are induced or improved by treatment assessed by clinical, laboratory, neurophysiological & MRI. (Egypt J. Neurol. Psychiat. Neurosurg, 2009, 46(2): 287-298) Key words: Hepatitis C infection treatment, Neuropsychiatric complications, Neuropathy related to interferon, Interferon Alfa. INTRODUCTION The treatment of hepatitis C virus (HCV) has dramatically improved over the past decade. Severe side effects may reduce adherence to therapy and may result in dose modifications which will result in less response or discontinuation of interferon Alfa (IFN) therapy, and will reduce the patients’ quality of life. Treatment of HCV and particularly IFN may induce an increase in the incidence of neuropsychiatric symptoms 1,2 . Neurological side effects have been reported in up to 33% of patients during IFN-α therapy. Parathesias, confusion, aphasia, cortical blindness, optic neuritis, delirium, dementia syndrome and extrapyramidal syndromes marked by ataxia and akathisia have been reported with IFN-α therapy 2,3 . Dizziness and vertigo are also common side effects associated with IFN-α treatment 4 . Seizures may occur in up to 1.3% of patients treated with IFN. While one-third of patients undergoing IFN therapy experience depression 5 and one-third suffer no neuropsychiatric symptoms 6 , the remaining 30%- 40% experience a variety of neuropsychiatric adverse effects that can be managed if identified early. Such adverse effects include fatigue, amotivation, apathy, lack of concentration, irritability, and anger, perceptual, cognitive, and affective symptoms 7 . Among psychiatric side effects of IFN-Alfa, psychosis seems to be a rare event. Correspondence to Mona Abdel Fattah, e-mail: mona_A_nada@yahoo.com. Contact number: +20189288848