Timely Diagnosis of Acyclovir-Induced Neurotoxicity During Acute Care Surgery Resuscitation: A Rare Complication of Common Herpes Zoster Treatment.

Acyclovir-induced neurotoxicity is a serious adverse effect of acyclovir, which is widely utilized to treat herpes zoster, and presents with diverse neuropsychiatric symptoms. However, cases where psychiatric manifestations have resulted in self-inflicted abdominal injuries are extremely rare. Moreover, obtaining detailed medical and medication histories during trauma resuscitation is often difficult. A 58-year-old man with a history of diabetes mellitus and chronic kidney disease on maintenance dialysis was found at home in a stuporous state after stabbing his abdomen and was transported in hemorrhagic shock. Emergency laparotomy showed transverse colonic and mesenteric injuries, which were treated with hemostasis and repair. During trauma resuscitation, it was discovered that the patient had ingested three days' worth of valacyclovir, prescribed two days earlier for herpes zoster, inappropriately over a short period. The patient's acute psychiatric manifestations were attributed to acyclovir-induced neurotoxicity in the absence of a psychiatric history. Hemodiafiltration was performed because the postoperative disturbance of consciousness persisted, and this resulted in rapid improvement. The patient was extubated on postoperative day 2, the neuropsychiatric symptoms resolved, and the patient was discharged on day 10. At admission, the whole blood acyclovir concentration was 6.45 μg/mL, and the concentration of its metabolite, 9-carboxymethoxymethylguanine, was 10.5 μg/mL, both of which were substantially elevated. This case report underscores a rare presentation of Acyclovir-induced neurotoxicity in which neuropsychiatric symptoms led to self-inflicted abdominal injury and hemorrhagic shock. Even in the acute setting of trauma resuscitation, careful history-taking, including medication use, can be crucial for timely diagnosis and effective treatment. Clinicians should remain vigilant of acyclovir despite it being commonly prescribed for herpes zoster because of its potential to cause severe psychiatric manifestations, and sufficient patient education is essential to prevent its misuse.