Cauda equina syndrome (CES) is a “can’t miss” diagnosis in the emergency department characterized by lower back pain. It is associated with red flag symptoms such as urinary retention or incontinence, saddle anesthesia, and weakness or sensation changes in the lower extremities.
Most providers consider the common textbook differential diagnoses for CES such as spinal epidural abscess, multiple sclerosis, and local spinal tumors, but many are unaware of another rare cause of CES: herpes simplex virus (HSV), also known as Elsberg syndrome.
Case Report
A 39-year-old female — with a history of a recent genital herpes infection diagnosed a month prior and treated with oral valacyclovir — presented to the ED with chief complaints of lower back pain, weakness and sensation changes in the right leg, and urinary retention. The back pain was described as a burning and tingling sensation in her sacral region that had been progressively getting worse over the past week, with radiation to the lower extremities. Urinary retention began on the day of presentation. She denied any recent travel, intravenous (IV) drug use or smoking history.
On physical examination, the patient’s vitals were all within normal limits without a fever or tachycardia. Otherwise, her examination was significant for 4/5 strength, decreased sensation to light touch, and pain in the left lower extremity.
The patient was started on broad spectrum anti-infectives including vancomycin, ceftriaxone, and acyclovir despite being afebrile because there was significant concern for a potential infectious etiology of her symptoms, with HSV highest on the differential.
ED workup consisted of basic laboratory values including complete blood count (CBC), comprehensive metabolic profile (CMP), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), as well as magnetic resonance imaging (MRI) of the full spine and a lumbar puncture (LP) with cell count, cultures, HSV polymerase chain reaction (PCR), and opening pressure. Basic laboratory values were unremarkable, and the MRI of the full spine was within normal limits. The LP was significant for lymphocytic pleocytosis with 85% lymphocytes and negative for HSV.
Given the patient’s history and lymphocytic pleocytosis, a clinical diagnosis of Elsberg syndrome was made, and the patient was admitted to the floor and started on IV acyclovir every eight hours, later switching to oral valacyclovir at a dose of 1 gram three times per day. After 21 days, she was discharged after clinical improvement in her urinary retention.
Discussion
Elsberg syndrome is a clinical diagnosis that is a presumed infectious syndrome most commonly secondary to herpes simplex virus 2. It consists of acute or subacute lumbosacral radiculitis that must be considered in all patients presenting to the ED with CES.1 The exact pathophysiology of Elsberg syndrome is not completely understood. However, it is hypothesized that the initial viral infection causes an inflammatory reaction that results in myelitis and radiculitis. Literature review reveals some case reports of Elsberg syndrome published over the years, but only one study from the Mayo Clinic retroactively found 30 patients suspected of having Elsberg syndrome through chart review from 2000 to 2016. In this study, urinary retention and weakness in the lower limbs were the most common clinical presentations (77% and 40% of patients, respectively).1 Furthermore, most patients tested positive for HSV; however, other viruses such as varicella-zoster, cytomegalovirus, West Nile, and COVID-19 have been associated with the syndrome.2-5
Recorded cases of Elsberg syndrome show that it tends to present within a week of the initial viral infection, but this may be confounded by missed diagnoses in the subacute or late stages.1 Furthermore, our patient presented subacutely, almost an entire month after initial HSV-2 infection, although this may be attributable to the oral valacyclovir she had been taking.
When it comes to diagnostic criteria and findings, the data is also limited and scarce. On spine MRI, there are no pathognomonic findings. MRI can either be negative or there can be findings of spinal cord lesions that are commonly multiple, discontinuous, and centrally or ventrally positioned on the cord.1 Cerebrospinal fluid (CSF) examination tends to show lymphocytic pleocytosis; however, CSF PCR detection of specific viruses can be negative and cannot be used to exclude presence of an infection.6 Due to the wide range of diagnostic findings, a broad workup is recommended.
Lastly, in terms of treatment, there is no documentation regarding the best window for treatment or efficacy of different treatments. Most prior cases either turn to intravenous high-dose steroids or intravenous acyclovir to treat the inflammatory and viral components, respectively.1
Our patient did not receive steroids inpatient and had a slow resolution of symptoms with only IV acyclovir, whereas in other case reports, some patients only got IV steroids and no antivirals.1
Nevertheless, the current recommendation is to proceed with these treatments, as both treatments are relatively well tolerated and there have been several case reports of Elsberg syndrome causing permanent neurological deficits in patients.7
Importance of Awareness
Emergency physicians must consider Elsberg syndrome in their workup of CES because the condition is treatable, and discharge of these patients without full workup and treatment with acyclovir can result in potentially devastating permanent neurologic deficits.
References
- Savoldi F, Kaufmann TJ, Flanagan EP, Toledano M, Weinshenker BG. Elsberg syndrome: A rarely recognized cause of cauda equina syndrome and lower thoracic myelitis. Neurol Neuroimmunol Neuroinflamm. 2017;4(4):e355.
- Saito H, Ebashi M, Kushimoto M, et al. Elsberg syndrome related to varicella zoster virus infection with painless skin lesions in an elderly woman with poorly controlled type 2 diabetes mellitus. Ther Clin Risk Manag. 2018;14:1951-1954.
- Garcia Ruiz M., Portocarrero Sanchez L., Sanchez Boyero M., et al Cauda equina syndrome caused by cytomegalovirus infection (Elsberg syndrome) in an immunocompetent patient. Eur. J. Neurol. 2021;28(SUPPL 1):618.
- Hawkes MA, Toledano M, Kaufmann TJ, Rabinstein AA. West Nile Neuroinvasive Disease Presenting as Elsberg Syndrome. Neurolog. 2018;23(5):152-154.
- Abrams RMC, Desland F, Lehrer H, et al. A Case of Elsberg Syndrome in the Setting of Asymptomatic SARS-CoV-2 Infection. J. Clin. Neuromuscul. Dis. 2021;22(4):228-231.
- Davies NW, Brown LJ, Gonde J, et al. Factors influencing PCR detection of viruses in cerebrospinal fluid of patients with suspected CNS infections. J Neurol Neurosurg Psychiatry 2005;76:82–87.
- Desai R, Welsh C, Schumann S. Elsberg Syndrome, Lumbosacral Radiculopathy, and Myelitis Due to Herpes Zoster in a Patient With Smoldering Myeloma. Journal of Investigative Medicine High Impact Case Reports 2022 Jan-Dec.