The incidence of spinal epidural abscess (SEA) has doubled in the past 2 decades due to the epidemic of MRSA infections, the spread of IV drug use, and the increased number of spinal and vascular access procedures. Delayed or missed diagnosis of SEA leads to profound disability or death; lawsuits in this arena are exceptionally costly.
5 Key Things You Should Know About Spinal Epidural Abscess
- The "Classic Triad" of back pain, fever and neurologic deficit is present in less than half of patients with spinal epidural abscess. Fever is only present in about 50% of SEA cases, whereas localized back pain is present in 75%. Neurologic findings vary greatly, with weakness found in 35% to 40% of patients and paralysis in 6% to 48%. Any complaint or finding regarding new onset of sphincter dysfunction (urinary retention or incontinence) should be considered a gigantic red flag for compression of the spinal cord or cauda equina.
- There may be NO identifiable risk factors! However, most patients found to have an SEA will have one or more risk factors. Therefore, risk factor analysis is essential in the evaluation of patients who present with neck or back pain, particularly if there is a history of fever or there are any neurologic complaints or findings. The list of known risk factors includes:
- Recent spinal surgery, instrumentation or epidural injection
- Immunosuppression (DM, cirrhosis, HIV, steroids)
- IV drug abuse
- Current MRSA infection, often on the skin
- Cognitive errors are your enemy. The multitude of patients with back pain can wear down your vigilance for high-risk conditions. Beware of the bias of labeling a patient with back or neck pain as just another “back pain,” “frequent flyer” or “drug seeker." Based on existing guidelines as well as from a practical standpoint, if SEA is suspected on the basis of history and exam, strongly consider diagnostic imaging with MRI and lab testing with CBC and ESR (sed rate) or CRP (C-reactive protein). Remember that the diagnosis of SEA is: 1) suspected on a clinical basis; 2) supported by lab and imaging studies; and 3) confirmed by surgical drainage.
- The symptoms and findings of SEA commonly progress from back or neck pain to paralysis over hours to days. Every practitioner should know the 4 stages of progression of symptoms and findings and the appropriate workup for SEA. The common sequence of events in the evolution of symptoms and signs of SEA is as follows:
- Stage 1: Localized spinal pain (pain in the neck or back), followed by:
- Stage 2: Radicular pain and paresthesia caused by irritation of a spinal nerve, followed by:
- Stage 3: Muscular weakness, sensory loss, and sphincter dysfunction caused by compression or spinal cord and/or its blood supply, followed by:
- Stage 4: Paralysis – permanent damage to the spinal cord
- In the event of litigation, your best defense is the documentation of a carefully performed history and neurological exam, particularly of everything below the waist. In the busy environment of an emergency department, urgent care center or private practice office, it is easy to shortcut the complete examination. However, the only chance of diagnosing an SEA in the early stages, when there is time to do something about it, is through a careful focused history and physical examination. Documentation should include detailed evaluation of mental status, sensation, motor strength, reflexes and gait.
In some cases, it is impossible to make the diagnosis of spinal epidural abscess before a patient suffers significant neurologic injury; for example, it may be too well disguised during early visits as recurrent musculoskeletal low back pain. In these cases, you may find yourself embroiled in a lengthy litigation process. The outcome of a medical malpractice suit is never certain; juries are often sympathetic when faced with a patient with a profound disability. When confronted with a patient with symptoms in or around the spine, take great care to identify pathology or document "spinal wellness."
Where potential spinal injury is possible, more extensive knowledge of SEA and awareness of key risk and documentation issues can significantly improve patient care and reduce the potential for litigation.