A 36-year-old man presented with five days of progressive buttock and scrotum numbness and decreased urinary and fecal urgency. His history revealed L5 herniated disc with sciatica, cervical radiculopathy, hypertension, depression and gastric bypass. Neurologic exam was normal except for mildly decreased rectal tone, no cremaster reflex and decreased pinprick sensation in dermatomes S2-S5. Anal wink was preserved and no other sensory loss was found. 

Working diagnoses included abscess, radiculopathy, myelopathy. MRI of the lumbar and sacral spine showed enhancement in the conus medullaris with a broad differential. Disease processes included HIV, HSV, VZV, CMV, sarcoidosis, coccidiomycosis, nutritional deficiency or a neoplastic source.  CSF showed WBC of 75 with 94% lymphocytes, glucose 59 mg/dl, protein 43 mg/dl and positive HSV. Labs for HIV, TB, cocci, VZV, CMV and HSV serum were negative. Acyclovir was started the day after admission and 36 hours later the patient had improved perineal and bladder sensation. Post void scans showed 40 and 0 ml on the day of discharge. We concluded this to be a typical presentation of Elsberg syndrome secondary to HSV infection, considering the absence of alternative diagnostic possibilities particularly cauda equine compression.

Elsberg syndrome is an acute lumbosacral radiculitis with myelitis related to a herpes infection and is often an unrecognized disease entity.  It is specifically a cauda equina syndrome lacking compression. Clinicians may not consider this syndrome in the differential resulting in diagnostic delay thereby missing the ability to provide a favorable outcome.  This patient is a reminder to consider Elsberg syndrome as a differential.