Herpes simplex encephalomyeloradiculitis initially presents with urinary retention.

Herpes simplex virus (HSV) infections necessitate careful management of urinary dysfunction and retention, which are underestimated conditions. Here, we present a rare case of HSV encephalomyeloradiculitis in a 76-year-old man, whose initial symptoms included urinary dysfunction and retention that alone lasted for approximately 1 week. Unlike in meningoencephalitis, high fever and headache were absent; however, the patient subsequently developed cauda equina syndrome and consciousness disturbance. Gadolinium-enhanced spinal MRI suggested enhanced cauda equina at the L2/3 level. Upon admission, he was treated for meningoencephalitis with acyclovir and steroid pulse therapy. Subsequent cerebrospinal fluid analysis result was positive for HSV DNA. A ‍brain MRI conducted 1 week after admission displayed high-intensity lesions in the white matter of the right temporal lobe, confirming HSV encephalomyeloradiculitis. These treatments were highly effective and gradually improved the patient's condition. He was discharged 1 month after hospitalization, and the urinary catheter was removed 2 weeks later. HSV infections can cause life-threatening encephalomyeloradiculitis. Therefore, both neurologists and urologists must pay attention to their occurrence and characteristics in clinical settings.