The Beacon. Cauda Equina Syndrome: A Medical/Surgical Emergency. In This Issue. Case #1

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1 A Medical Mutual Insurance Company of Maine Publication The Beacon Second Quarter 2015 Cauda Equina Syndrome: A Medical/Surgical Emergency Cauda equina syndrome (CES) is a rare syndrome that has been described as a complex of symptoms and signs low back pain, unilateral or bilateral sciatica, motor weakness of lower extremities, sensory disturbance in saddle area, and loss of visceral function resulting from compression of the cauda equina. CES occurs in approximately 2% of cases of herniated lumbar discs and is one of the few spinal surgical emergencies. 3 Although symptoms can vary widely from individual to individual, common symptoms can include: severe low back pain (LBP); dysfunction or loss of control over the bladder or bowel; bilateral sciatica; decrease in rectal sphincter tone; analgesia or progressive loss of sensation in the legs, thighs, back of legs, hands or feet progressing to paralysis; saddle anesthesia (i.e., decreased sensation in the legs, buttocks, anus or perineum); and weakness or numbness in one or both legs that causes the individual to have sudden difficulty standing or walking. Symptoms often show up first in bladder and bowel function which are vulnerable to nerve damage. Being unable to empty the bladder is considered a hallmark symptom of the cauda equina compression. In other cases, the patient first reports symptoms of the loss of sensations and/or burning pain in the saddle region and inner thighs. Symptoms can quickly advance to extreme pain and loss of movement in the hips and legs. Unfortunately by the time the symptoms begin, the damage is already in progress. In This Issue Cauda Equina Syndrome: A Medical/Surgical Emergency pgs.1-4 References pg.4 Diagnosis University pg.6 Exams should include a full examination of the pelvis and lower extremities, including a neurologic examination to evaluate sensation, strength and reflexes as well as a straight-leg-raise test and a digital rectal exam (DRE) to evaluate anal tone. If urinary symptoms are present, a bladder ultrasound to identify residual urine is also appropriate. Diagnosis is usually confirmed by an MRI, the current study of choice in evaluating these patients. CT with myelography can be used when MRI is contraindicated. 3 The timeliness of diagnosis and intervention may determine the degree of permanent injury. Case #1 A 32-year-old female presented in the emergency department with a chief complaint of sudden onset of numbness and tingling in her legs. She reported waking up from a nap and sensing that her whole left leg and lower abdomen were numb. When seen in the emergency department, the patient reported that both legs felt numb from her waist/groin area to her knees. She reported a prickly feeling in the back of her legs. Because the patient also reported that she felt pressure in her groin and buttocks and cannot feel when she has to urinate the physician ordered a bladder scan. The bladder scan demonstrated that the patient was emptying her bladder. The exam notes also document that the patient was able to void without issue while in the emergency department. The physical exam revealed intact motor strength and reflexes in both legs. An x-ray of the lumbar spine revealed Schmorl s nodes at the L2-L3 level and also at L4-L5 and L1-L2 but was otherwise normal. The patient was assessed with acute right sided and left sided lumbar radiculopathy with sensory loss. The physician also noted that the patient might possibly have a centrally herniated disc, but was not reporting any back pain. Significantly, the patient had been seen six weeks earlier for a low back strain after slipping in the shower at home. Lastly, the physician noted a potential for Guillain-Barre disease. The physician prescribed a trial of steroids (prednisone) and a muscle relaxant (Valium). The discharge instructions informed the patient that she should follow up with her primary care provider the next day even if she was well. She was also advised to return to the continued on page 2

2 emergency department at any time should she get worse. The patient did not see her primary care provider the next day. She returned to the emergency department two days later reporting bladder dysfunction. An MRI was completed which demonstrated a free fragment coming into contact with the spinal canal and causing compression of the sacral nerve roots. The patient was assessed with acute cauda equina syndrome. The patient underwent emergent surgery to decompress a large central L5-S1 disc herniation causing the spinal cord compression. Following recovery and rehabilitation, the patient was left with perineal numbness and some incontinence. She was unable to continue in her regular employment because of its physical nature. Issues in the Case The physician had not performed a digital rectal exam to check for anal wink reflex and did not perform any perineal sensation evaluation such as pinprick testing of the perineal and perianal areas. The physician appeared to rule out cauda equina syndrome because of the absence of back pain even though cauda equina often will present without the presence of back pain. The absence of back pain also appears to have been the reason the physician did not order an MRI. Had the MRI been performed on the day the patient initially presented it is more likely than not it would have revealed the large central disc herniation at L5-S1 which would have led to emergent surgery. The physician agreed at his deposition that if a sensory exam yields abnormal results you are obliged to perform a complete neurological exam. The physician did not request a consult with a neurologist, a neurosurgeon or an orthopedic surgeon. The patient initially presented with partial cauda equina syndrome and surgery on that date might have limited her symptoms from progressing to those of complete cauda equina. Partial cauda equina had not been ruled out at the time of discharge of the patient from the emergency department. Close surveillance of the patient, as evidenced by the discharge instruction to follow up with the primary care physician the next day, was inadequate given the surgical emergency presented by a diagnosis of cauda equina syndrome. Case Resolution The case was resolved through voluntary settlement at mediation. 2 Case #2 The patient is a 46-year-old obese male with a longstanding history of low back pain for which he was under treatment by a chiropractor. He was employed as a carpenter and while at a construction job, he assisted in lifting a large, heavy structure that caused him to have immediate and intense shooting pain in his back radiating to his lower right extremity. The patient was unable to move so he was driven home by a fellow worker. The next day, with no improvement in his pain, the patient decided to seek treatment at his local hospital s emergency department. He described his pain to the ED physician as excruciating, starting in the lower back, traveling down his right leg with numbness in the lower half of the leg, inclusive of some of his toes on his right foot. The patient defined his pain as unlike any he had ever experienced but he did not report the lifting incident from the previous day. The ED physician diagnosed the patient with a possible herniated disk and made arrangements for him to undergo an MRI four days later when the imaging equipment would be at the facility. The patient was given prescriptions for oxycodone, Valium

3 and Aleve for his pain. The patient returned to the ED the next day reporting increased pain and increased numbness now extending into the buttocks and legs bilaterally with reported difficulty voiding, as recorded by the nurses. The ED physician who examined the patient on this visit found him to have a normal neurological exam but with acute low back and bilateral leg pain with paresthesia. The patient denied having bowel or bladder difficulties to the physician. Again, the patient did not disclose the lifting incident from two days prior. He did report having saddle pain, however, but he was not assessed for saddle anesthesia and a rectal exam was not performed. Despite the fact the medical record documentation did not capture the discussion, the ED physician recalled discussing with the patient his options for care including transfer to a tertiary care facility for further evaluation and treatment. The patient chose to continue with the current plan to treat his pain at home while awaiting the previously scheduled MRI. The patient was discharged from the ED with a final diagnosis of low back pain and radiculopathy with instructions to return to the ED with worsened symptoms. On the day of his MRI, the patient required ambulance transport from his home to the hospital because he was unable to ambulate. Upon arrival at the hospital, he was unable to wiggle his toes on his right foot and he reported the level of pain from his hips to his feet to be 10/10. His bladder control was intact but he reported that he was unable to detect when urination had stopped. After determining that the MRI machine could not accommodate the patient s size, he was transferred to a tertiary care facility for testing. There the MRI revealed a large L4-5 disk herniation causing severe spinal stenosis and cauda equina syndrome. The patient underwent urgent discectomy at L4-5. Post-operatively the patient recovered full bladder function and reduction in his pain but his right lower extremity foot drop was determined to be permanent, requiring use of an ankle orthotic and a walker. Issues in the Case The plaintiff alleged that his complaints of increased weakness, saddle anesthesia and difficulty voiding during his second ED visit warranted an emergent MRI. Furthermore, the assessment by the second ED physician should have included a rectal exam to assess anal tone and a neurological work-up to determine that the patient s condition had worsened in 24 hours. Had the ED physician recognized the signs and symptoms of cauda equina syndrome, the plaintiff alleged that he would have been transferred to a tertiary care facility three days sooner where MRI and neurosurgeons were available to emergently treat him to potentially avoid his permanent injury. This case illustrates the diagnostic difficulties facing providers when treating patients with chronic pain. Making the correct and prompt diagnosis was hindered not only by the providers failure to elicit a complete history but also in part by limited diagnostic MRI availability at the local hospital. The patient s preference to return for the testing three to four days later rather than be transferred to a tertiary care hospital further delayed the diagnosis. Case Resolution Considering the facts of the case and concerns with certain aspects of its defensibility, the defense agreed to participate in mediation and a settlement was reached. Case #3 The patient was a 40-year-old female that was seen in the ED for complaints of low back pain radiating to the front of her body. A CT scan showed a kidney stone but no other acute abdominal process. The patient was discharged and instructed to follow up with her PCP which she did that same day. Her PCP examined her and said that if her pain did not improve he would order an MRI. The patient s symptoms worsened the following day (Friday). She called her PCP who directed her to report to the ED. The PCP also called the ED and told them to expect a patient that had pain with ambulation and numbness down her legs. He also told the ED he wanted cauda equina ruled out via a CT scan of her lumbar spine. The patient reported to the ED approximately 30 minutes after the phone call from her PCP. She was seen by a physician s assistant. The patient reported a history of low back pain for 2 months. She had noticed a change in her symptoms which now included numbness in her buttock and vaginal area as well as tingling with a radiation of pain (9/10) down her left leg. She reported soreness in her right calf and numbness in her right upper leg. She also reported some twitching in her right toes. The PA performed a neurologic examination and noted 2 point discrimination intact in all extremities. The PA also performed a digital rectal exam (DRE) and found there was no loss of rectal tone and the exam was within normal limits. The PA determined that the patient s condition was unlikely cauda equina due to good rectal tone, no loss of bowel or bladder crease in deep tendon reflexes. The patient was discharged and told to follow up with her PCP the following Monday. 3

4 The claimant, as instructed, saw her PCP who ordered an immediate MRI. The MRI revealed a large central disc herniation at L4-5 and a large disc fragment obscuring the spinal canal causing bilateral compression on the L5 nerve roots. She underwent emergent lumbar laminotomy but was left with residual symptoms. Issues in the Case The above case highlights the need to adhere to accepted protocols for working up cases involving suspected cauda equina syndrome. Although the patient had a 2-month history of back pain, it s the change in her symptoms, specifically the saddle anesthesia, which should have raised a red flag for the practitioner. The PA was reluctant to order additional imaging as the patient had just undergone a CT scan the day before but the reality is that MRI is the gold standard and needed to be ordered due to the patient s saddle anesthesia. The resulting delay put the patient outside of the generally accepted 48-hour window. Her poor outcome was easily attributed to the delay. Conclusion Cauda equina syndrome, although infrequent, is a diagnosis that must be considered in patients who complain of low back pain coupled with neurologic complaints, especially urinary symptoms. Complete, thorough documentation of patient exam, findings, interventions and patient education is highly important. If a patient is discharged based on low suspicion of CES, strongly emphasize with the patient and document in the patient s discharge instructions the need to follow up promptly should the condition worsen or symptoms arise such as incontinence, saddle anesthesia, numbness or weakness in lower limbs. CES is a difficult diagnosis but one that falls into the can t miss category as it is a surgical emergency. The current belief is that surgery within a window of approximately 48 hours, but especially within 24 hours, of when the patient first experiences symptoms yields better results than waiting longer than 48 hours. This belief is evolving but it s hard to argue against early intervention when the resulting disability from cauda equina can be so profound. Case Resolution Settlement was achieved at a judicial settlement conference. References 1. Gardner, A., Gardner, E., & Morley, T. (2010). Cauda equina syndrome: A review of the current clinical and medico-legal position. European Spine Journal Eur Spine J, Robertson, J. (2014, January 29). Cauda Equina Syndrome. Retrieved from 3. Gitelman, A. et al (2008). Cauda Equina Syndrome: A Comprehensive Review. The American Journal of Orthopedics. 4

5 DIAGNOSIS Cauda equina syndrome is an error-prone diagnosis. The condition is high risk; it s rare; the symptoms unfold unevenly over time and can present like those of other more common conditions. Diagnostic error is the Number 1 or 2 cause of claims in nearly every specialty, and it is the top cause of claims associated with a death. With 8,000 disease conditions on the ICD-9/10 list and counting how can a physician keep up? One way MMIC of Maine helps is by providing access to the Diagnosis University (DxU) CME collection in Medical Interactive Community (MI). DxU is a subset of MI s risk management CME activities that contains nearly 30 CME activities by national experts, practicing physicians, and professional liability risk managers. These include a 3- part film series by Pat Croskerry, MD, an emergency physician and senior expert on the subject of cognitive bias and diagnostic error. Also included is a 6-part monograph series by Mark Graber, MD, the foremost leader in the field of diagnostic error, providing an introductory overview of diagnostic error and what can be done to reduce it. MI s CME activities are designed to aid physicians and hospitals launch initiatives to improve detection of certain common and high risk diagnoses. These activities include a 1-credit CME film available at no charge Early Recognition and Treatment of Severe Sepsis/Septic Shock: A New Paradigm by David Larson, MD, FACEP. Also presented by Dr. Larson is Evaluation and Risk Stratification of Patients with Acute Chest Pain. There are CME activities that address specific symptoms such as dizziness by David Newman-Toker, MD and sore throat by Robert Centor, MD. Disease-specific topics include obstructive sleep apnea, retinal tear, and melanoma. Specialty-specific activities provide an overview of claim experience and emerging risks in anesthesiology, radiology, pediatrics, plastic surgery, gastroenterology, and more. Diagnosis is often assumed to be the province of primary care and the medical specialties. While the surgical specialties are most often sued for improper performance of a procedure, a closer claim analysis reveals that failure to monitor and failure to recognize a post-operative complication is the highest risk to patients and most likely source of claims against surgeons. That s a diagnostic error. For access to the above resources, visit MMIC of Maine s website at Select the Risk Management tab, click on CME, then click on online courses under the MI logo. In addition to Dr. Larson s free 1-credit CME film on sepsis, the following resources are also available on the website free of charge: Access to Visual Dx s Emerging Global Disease Tool to help clinicians identify travel-related infectious diseases in their patients Understanding and Reducing Diagnostic Error, a 1-credit CME film by Mark Graber, MD, FACP 5

6 One City Center PO Box Portland, Maine The Beacon The Beacon is published by Medical Mutual Insurance Company of Maine for the benefit of our policyholders. We welcome your comments and feedback. Please direct correspondence to: The Editor Medical Mutual Beacon One City Center PO Box Portland, Maine Medical Mutual Insurance Company of Maine, Inc. Tel: (207) (800) Fax: (207) Risk Management Corporate Office: Cheryl Peaslee, Vice President - Risk Management Tel: (207) or (800) Claims Corporate Office: Mary Elizabeth Knox, Vice President - Claims Tel: (207) or (800) Follow us on The articles in this newsletter seek to raise the consciousness of clinicians who must apply their own experience, intuitions, and medical judgments to arrive at optimal care decisions. They do not constitute legal advice or practice standards. If you have any questions on any of the topics addressed by this publication, you should seek a qualified legal opinion.