Herpes zoster: unusual cause of acute urinary retention and constipation.

Case A 67-year-old man presented to the emergency department with painful vesicular eruptions on his right buttock that had been present for about 24 hours. He was diagnosed with HZ and discharged with a prescription for 1000 mg of valacyclovir 3 times a day for 7 days. The next day he presented to our family practice clinic with urinary frequency of approximately 20 times per day, small volumes of urine, and suprapubic discomfort but no dysuria. He had no history of prostatic hypertrophy and he had never experienced similar symptoms before. The urinary symptoms had started 2 days earlier and had not changed. His last bowel movement had occurred 2 days previously and was normal. During examination, his bladder was percussed midway to his umbilicus and he found this palpation uncomfortable. Vesicles were present on his right buttock in the S2 to S4 dermatomal distribution and did not cross the midline. There were no vesicles on his genitals. Findings of the physical examination were otherwise unremarkable. Urine dip results were negative for nitrites, blood, and leukocytes. Urine culture results were also negative for bacterial infection. Because he was still passing urine, albeit small volumes, he was sent home with a prescription for 5 mg of terazosin every night. He was counseled to return to the emergency department for urinary catheterization if he failed to pass any urine for a 24-hour period. Five days later he again presented to our family practice clinic with constipation that had lasted 7 days. He reported that shortly after taking the terazosin, he had begun to urinate normally and as a result had stopped taking it after 3 days. However, he had felt no urge to pass stool since just before the herpetic eruption despite normal food intake. He was passing gas but with less regularity than usual. He admitted that he had been incontinent of small volumes of watery stool for the past week, which he attributed to his having taken senna concentrate to try and stimulate bowel function. Despite self-administered water enemas the previous day, he still had not passed any stool. He was otherwise well and did not have any abdominal pain or discomfort. A rectal examination revealed relatively poor resting anal tone, preserved voluntary squeeze, and an empty rectal vault. Abdominal x-ray scans obtained the next day revealed no abnormal gas pattern. He was prescribed 15 mL of lactulose twice a day until bowel movements returned to normal. Two days later he had his first normal bowel movement in 9 days. Editor’s kEy points • The effects of herpes zoster (HZ) are not always limited to the commonly seen skin eruption. Sacral HZ, which makes up approximately 8% of all HZ presentations, is associated about half of the time with some form of urinary dysfunction and constipation.