Irreversible neurotoxicity with acyclovir treatment of acute retinal necrosis

Abstract

Sir, Irreversible neurotoxicity with acyclovir treatment of acute retinal necrosisNeurotoxicity is a rare but recognised side-effect of acyclovir, which typically occurs in those with cancer or renal failure. We report a case of hand paraesthesia in a man who received intravenous acyclovir for acute retinal necrosis. This case is unusual in that it occurred in a healthy man and its effects did not completely reverse. Case reportA previously healthy right-handed 50-year-old toolmaker presented to us with a 10 day history of blurred vision in his right eye. Visual acuity in this eye was 6/18 unaided, improving to 6/9 with a pinhole, and there was a granulomatous anterior uveitis, papillitis, retinal necrosis, localised retinal detachment and vasculitis. The left eye was never involved. He had no history of neurological disease, previous hand trauma and was on no medication. Acute retinal necrosis was diagnosed and the patient was admitted and received a week's course of intravenous acyclovir 850 mg t.d.s. (32 mg/kg/ day) plus 80 mg prednisolone orally. The intravenous cannula was placed in a vein in the antecubital fossa of his left hand. Approximately 3 days later he developed numbness and tingling over the palmar surface and fingers of his right hand. The patient did not inform the staff of these symptoms and the acyclovir was continued. His ocular condition improved and he was discharged on va1cyclovir 1 g t.d.s. (which was continued for 6 weeks) and prednisolone 60 mg for the right eye. Having stopped the acyclovir his neurological symptoms improved over 3-4 months but currently, 2 years later, he still suffers residual stable paraesthesia. Current neurological assessment indicates reduced pinprick sensation over the ulnar region of the right palmar surface but no muscle weakness. Unaided visual acuity in his right eye is counting fingers improving to 3/60 with a pinhole. Comment Acyclovir selectively inhibits viral DNA polmerase. Its side-effects include neurotoxicity,l-7 nephrotoxocitys and hypotension.9 Neurological effects include alterations in mental status (commonest), myoclonic jerks, action tremors, hallucinations, convulsions, ataxia, dysarthria and hemiparaesthesia.l In Haefeli et al.'s4 review of 24 patients only 13% of the reported

Neurotoxicity associated with acyclovir and valacyclovir: A systematic review of cases

“…All patients suffered neurological alterations, and the majority recovered their baseline state (93.3%). Only 3 cases had an incomplete reversal of symptoms 61,75,93 . Lastly, 5 patients died, of those, 4 were older than 65 years with significant comorbidity and 3 presented ESRD under renal replacement therapy.…”

“…Ninety‐seven of those were included in the analysis, representing a total of 119 independent patients (Figure 1). The cases were extracted from 86 clinical cases 9‐35,37‐48,50‐54,56‐63,65‐71,73,75‐77,80‐83,85‐100,102,103 and 11 case series 36,49,55,64,72,74,78,79,84,101,113 . Figure 1 shows the case selection flow diagram.…”