Elsberg syndrome (ES) is a rarely recognized cause of cauda equina syndrome and lower thoracic myelitis, which was first described in 1913 as acute urinary retention accompanied by subacute lumbosacral radiculitis and cerebrospinal fluid (CSF) pleocytosis.1,2 Nowadays, ES is presumed to have an infectious etiology, and has been mainly linked to reactivation, or occasionally primary, infection with herpes simplex virus type 2 (HSV-2).3
West Nile virus (WNV) epidemics have occurred in the United States since 1999. Around 20% of infected patients will develop a self-limited flu-like disease known as West Nile fever and at most 1% will have West Nile neuroinvasive disease (WNND).4
A 63-year-old man with pancreatic cancer in remission (treated with Whipple surgery, chemotherapy, and radiotherapy) and polymyalgia rheumatica on low-dose prednisone presented with a 10-day history of low-back pain and a viral-type illness with low-grade fever, nausea, and vomiting. Days later, he developed slowly progressive monoparesis in his left lower extremity. His neurological examination revealed flaccid and arreflexic paralysis of the left leg. He also developed neurogenic bladder and bowel.
Brain magnetic resonance imaging (MRI) was unrevealing. MRI of the lumbar spine, performed only without IV gadolinium contrast, depicted hyperintense signal abnormality on T2-weighted sequences within the central spinal cord and conus medullaris with mild swelling of the conus (Fig. 1). There were no abnormal vascular flow voids in the spinal canal. Cells, protein, and glucose in CSF were 67/mm3, 70 mg/dL, and 58 mg/dL, respectively. Serology was positive for WNV IgM. WNV polymerase chain reaction in the CSF was negative. Nerve conduction studies and electromyography showed an acute motor neurogenic process affecting left lumbosacral segments.
Repeated electromyography examination at 3 months revealed a severe neurogenic process affecting bilateral lumbosacral motor neurons and roots, more severe on the left. Three months follow-up thoracolumbar spine MRI without and with IV gadolinium contrast depicted resolution of most of the signal abnormality within the spinal cord, though subtle signal abnormality persisted in the mid-lower thoracic spinal cord, with very subtle associated spinal cord contrast enhancement (Figs. 2A, B). The conus medullaris signal abnormality had resolved. There was also mild diffuse enhancement of cauda equina nerve roots throughout the lumbar spine, without significant nerve root thickening (Figs. 2C, D).
We present a case of clinically definite ES secondary to WNND based on recently proposed diagnostic criteria.3
ES may account for ∼5% to 15% of patients with cauda equine syndrome and myelitis.3 Even though usually self-limited, it can cause permanent neurological deficit.3 Proposed etiologies are heterogenous, but infections are thought to be the predominant cause.
While HSV-2 infection is believed to be responsible for the majority of ES cases2,5,6 a large proportion of patients are never tested for it.3 Furthermore, HSV is only detected in a minority of those who are tested.3 Yet, additional viral etiologies, including WNV, are rarely considered.
WNND is rare, although possibly underdiagnosed.4 Older age and chemotherapy for malignancy have been reported as risk factors. These patients can present with meningitis, encephalitis, acute flaccid paralysis or combined symptoms. A prior history of a flu-like disease in a patient who presents acute flaccid paralysis in the summer months should raise suspicion for this condition. Positive IgM antibodies in serum or CSF are needed for diagnosis.4 A positive polymerase chain reaction in serum or CSF is diagnostic too, but its yield is much lower due to rapid viral clearance once specific antibodies are produced.7
WNND is an uncommon condition that should be considered in patients with ES. Determining the etiology of ES in the acute setting may avoid unnecessary diagnostic investigations and treatments.
1. Elsberg CA. Experiences in spinal surgery. Observation upon 60 laminectomies for spinal disease. Surg Gynecol Obstet. 1931;16:117–135.
2. Oates JK, Greenhouse PR. Retention of urine in anogenital herpetic infection. Lancet. 1978;1:691–692.
3. Savoldi F, Kaufmann TJ, Flanagan EP, et al. Elsberg syndrome
. A rarely recognized cause of cauda equina syndrome and lower thoracic myelitis. Neurol Neuroimmunol Neuroinflamm. 2017;4:e355.
4. Petersen LR, Brault AC, Nasci RS. West Nile virus: review of the literature. JAMA. 2013;310:308–315.
5. Eberhardt O, Kuker W, Dichgans J, et al. HSV-2 sacral radiculitis (Elsberg syndrome
). Neurology. 2004;63:758–759.
6. Caplan LR, Kleeman FJ, Berg S. Urinary retention probably secondary to herpes genitalis. N Engl J Med. 1977;297:920–921.