A Medical Mutual Insurance Company of Maine Publication ...• analgesia or progressive loss of sensation in the legs, thighs, back of legs, hands or feet progressing to paralysis;

Cauda equina syndrome (CES) is a rare syndrome that hasbeen described as a complex of symptoms and signs—low backpain, unilateral or bilateral sciatica, motor weakness of lowerextremities, sensory disturbance in saddle area, and loss of vis-ceral function—resulting from compression of the caudaequina. CES occurs in approximately 2% of cases of herniatedlumbar discs and is one of the few spinal surgical emergencies.3

Although symptoms can vary widely from individual to indi-vidual, 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, but-tocks, anus or perineum); and

• weakness or numbness in one or both legs that causes theindividual to have sudden difficulty standing or walking.

Symptoms often show up first in bladder and bowel functionwhich are vulnerable to nerve damage. Being unable to emptythe bladder is considered a “hallmark” symptom of the caudaequina compression. In other cases, the patient first reportssymptoms of the loss of sensations and/or burning pain in thesaddle region and inner thighs. Symptoms can quickly advanceto extreme pain and loss of movement in the hips and legs.Unfortunately by the time the symptoms begin, the damage isalready in progress.

Exams should include a full examination of the pelvis andlower extremities, including a neurologic examination to evalu-ate sensation, strength and reflexes as well as a straight-leg-raisetest and a digital rectal exam (DRE) to evaluate anal tone. Ifurinary symptoms are present, a bladder ultrasound to identifyresidual urine is also appropriate. Diagnosis is usually con-firmed by an MRI, the current study of choice in evaluatingthese patients. CT with myelography can be used when MRIis contraindicated.3 The timeliness of diagnosis and interven-tion may determine the degree of permanent injury.

Case #1

A 32-year-old female presented in the emergency departmentwith a chief complaint of sudden onset of numbness and tin-gling in her legs. She reported waking up from a nap and sens-ing that her whole left leg and lower abdomen were numb.When seen in the emergency department, the patient reportedthat both legs felt numb from her waist/groin area to herknees. She reported a “prickly feeling” in the back of her legs.

Because the patient also reported that she felt pressure in hergroin and buttocks and “cannot feel when she has to urinate”the physician ordered a bladder scan. The bladder scan demon-strated that the patient was emptying her bladder. The examnotes also document that the patient was able to void withoutissue while in the emergency department. The physical examrevealed intact motor strength and reflexes in both legs.

An x-ray of the lumbar spine revealed Schmorl’s nodes at theL2-L3 level and also at L4-L5 and L1-L2 but was otherwisenormal. The patient was assessed with acute right sided and leftsided lumbar radiculopathy with sensory loss. The physicianalso noted that the patient might possibly have a centrally her-niated disc, but was not reporting any back pain. Significantly,the patient had been seen six weeks earlier for a low back strainafter slipping in the shower at home. Lastly, the physiciannoted a potential for Guillain-Barre disease. The physician pre-scribed a trial of steroids (prednisone) and a muscle relaxant(Valium). The discharge instructions informed the patient thatshe should follow up with her primary care provider the nextday even if she was well. She was also advised to return to the

Cauda Equina Syndrome: A Medical/Surgical Emergency

The Beacon

A Medical Mutual Insurance Company of Maine Publication

Cauda Equina Syndrome: A Medical/SurgicalEmergency — pgs.1-4

References — pg.4

Diagnosis University — pg.6

In This Issue

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Second Quarter 2015

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 laterreporting bladder dysfunction. An MRI was completed whichdemonstrated a free fragment coming into contact with thespinal 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 largecentral L5-S1 disc herniation causing the spinal cord compres-sion. Following recovery and rehabilitation, the patient was leftwith perineal numbness and some incontinence. She wasunable to continue in her regular employment because of itsphysical nature.

Issues in the Case

• The physician had not performed a digital rectal exam tocheck for anal wink reflex and did not perform any perinealsensation evaluation such as pinprick testing of the perinealand perianal areas.

• The physician appeared to rule out cauda equina syndromebecause of the absence of back pain even though caudaequina often will present without the presence of back pain.

• The absence of back pain also appears to have been the rea-son the physician did not order an MRI. Had the MRIbeen performed on the day the patient initially presented itis more likely than not it would have revealed the large cen-tral disc herniation at L5-S1 which would have led to emer-gent surgery.

• The physician agreed at his deposition that if a sensoryexam yields abnormal results you are obliged to perform acomplete neurological exam. The physician did not requesta consult with a neurologist, a neurosurgeon or an orthope-dic surgeon.

• The patient initially presented with partial cauda equina syn-drome and surgery on that date might have limited her symp-toms from progressing to those of complete cauda equina.Partial cauda equina had not been ruled out at the time ofdischarge of the patient from the emergency department.Close surveillance of the patient, as evidenced by the dis-charge instruction to follow up with the primary care physi-cian the next day, was inadequate given the surgical emergencypresented by a diagnosis of cauda equina syndrome.

Case Resolution

The case was resolved through voluntary settlement at mediation.

Case #2

The patient is a 46-year-old obese male with a longstandinghistory of low back pain for which he was under treatment bya chiropractor. He was employed as a carpenter and while at aconstruction job, he assisted in lifting a large, heavy structurethat caused him to have immediate and intense shooting painin his back radiating to his lower right extremity. The patientwas unable to move so he was driven home by a fellow worker.

The next day, with no improvement in his pain, the patientdecided to seek treatment at his local hospital’s emergencydepartment. He described his pain to the ED physician asexcruciating, starting in the lower back, traveling down hisright leg with numbness in the lower half of the leg, inclusiveof some of his toes on his right foot. The patient defined hispain as unlike any he had ever experienced but he did notreport the lifting incident from the previous day. The EDphysician diagnosed the patient with a possible herniated diskand made arrangements for him to undergo an MRI four dayslater when the imaging equipment would be at the facility.The patient was given prescriptions for oxycodone, Valium

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and Aleve for his pain.

The patient returned to the ED the next day reportingincreased pain and increased numbness now extending into thebuttocks and legs bilaterally with reported difficulty voiding, asrecorded by the nurses. The ED physician who examined thepatient on this visit found him to have a normal neurologicalexam but with acute low back and bilateral leg pain withparesthesia. The patient denied having bowel or bladder diffi-culties to the physician. Again, the patient did not disclose thelifting incident from two days prior. He did report having sad-dle pain, however, but he was not assessed for saddle anesthesiaand a rectal exam was not performed. Despite the fact themedical record documentation did not capture the discussion,the ED physician recalled discussing with the patient hisoptions for care including transfer to a tertiary care facility forfurther evaluation and treatment. The patient chose to con-tinue with the current plan to treat his pain at home whileawaiting the previously scheduled MRI. The patient was dis-charged from the ED with a final diagnosis of low back painand radiculopathy with instructions to return to the ED withworsened symptoms.

On the day of his MRI, the patient required ambulance trans-port from his home to the hospital because he was unable toambulate. Upon arrival at the hospital, he was unable to wigglehis toes on his right foot and he reported the level of painfrom his hips to his feet to be 10/10. His bladder control wasintact but he reported that he was unable to detect when uri-nation had stopped. After determining that the MRI machinecould not accommodate the patient’s size, he was transferred toa tertiary care facility for testing. There the MRI revealed alarge L4-5 disk herniation causing severe spinal stenosis andcauda equina syndrome. The patient underwent urgent discec-tomy at L4-5. Post-operatively the patient recovered full blad-der function and reduction in his pain but his right lowerextremity foot drop was determined to be permanent, requir-ing use of an ankle orthotic and a walker.

Issues in the Case

• The plaintiff alleged that his complaints of increased weak-ness, saddle anesthesia and difficulty voiding during his sec-ond ED visit warranted an emergent MRI. Furthermore,the assessment by the second ED physician should haveincluded a rectal exam to assess anal tone and a neurologi-cal work-up to determine that the patient’s condition hadworsened in 24 hours. Had the ED physician recognizedthe signs and symptoms of cauda equina syndrome, theplaintiff alleged that he would have been transferred to atertiary care facility three days sooner where MRI and neu-rosurgeons were available to emergently treat him to poten-

tially avoid his permanent injury.

• This case illustrates the diagnostic difficulties facingproviders when treating patients with chronic pain. Makingthe correct and prompt diagnosis was hindered not only bythe providers’ failure to elicit a complete history but also inpart by limited diagnostic MRI availability at the local hos-pital. The patient’s preference to return for the testing threeto four days later rather than be transferred to a tertiarycare hospital further delayed the diagnosis.

Case Resolution

Considering the facts of the case and concerns with certainaspects of its defensibility, the defense agreed to participate inmediation and a settlement was reached.

Case #3

The patient was a 40-year-old female that was seen in the EDfor complaints of low back pain radiating to the front of herbody. A CT scan showed a kidney stone but no other acuteabdominal process. The patient was discharged and instructedto follow up with her PCP which she did that same day. HerPCP examined her and said that if her pain did not improvehe 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. ThePCP also called the ED and told them to expect a patient thathad pain with ambulation and numbness down her legs. Healso told the ED he wanted cauda equina ruled out via a CTscan of her lumbar spine.

The patient reported to the ED approximately 30 minutesafter the phone call from her PCP. She was seen by a physi-cian’s assistant. The patient reported a history of low back painfor 2 months. She had noticed a change in her symptomswhich now included numbness in her buttock and vaginal areaas well as tingling with a radiation of pain (9/10) down her leftleg. She reported soreness in her right calf and numbness inher right upper leg. She also reported some twitching in herright toes.

The PA performed a neurologic examination and noted 2point discrimination intact in all extremities. The PA also per-formed a digital rectal exam (DRE) and found there was noloss of rectal tone and the exam was within normal limits. ThePA determined that the patient’s condition was unlikely caudaequina due to good rectal tone, no loss of bowel or bladdercrease in deep tendon reflexes. The patient was discharged andtold to follow up with her PCP the following Monday.

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The claimant, as instructed, saw her PCP who ordered animmediate MRI. The MRI revealed a large central disc hernia-tion at L4-5 and a large disc fragment obscuring the spinalcanal causing bilateral compression on the L5 nerve roots. Sheunderwent emergent lumbar laminotomy but was left withresidual symptoms.

Issues in the Case

• The above case highlights the need to adhere to acceptedprotocols for working up cases involving suspected caudaequina syndrome. Although the patient had a 2-monthhistory of back pain, it’s the change in her symptoms,specifically the saddle anesthesia, which should have raiseda red flag for the practitioner.

• The PA was reluctant to order additional imaging as thepatient had just undergone a CT scan the day before butthe reality is that MRI is the “gold standard” and needed tobe ordered due to the patient’s saddle anesthesia.

• The resulting delay put the patient outside of the generallyaccepted 48-hour window. Her poor outcome was easilyattributed to the delay.

Case Resolution

Settlement was achieved at a judicial settlement conference.

Conclusion

Cauda equina syndrome, although infrequent, is a diagnosisthat must be considered in patients who complain of low backpain coupled with neurologic complaints, especially urinarysymptoms. Complete, thorough documentation of patientexam, findings, interventions and patient education is highlyimportant. If a patient is discharged based on low suspicion ofCES, strongly emphasize with the patient and document inthe patient’s discharge instructions the need to follow uppromptly should the condition worsen or symptoms arise suchas incontinence, saddle anesthesia, numbness or weakness inlower limbs.

CES is a difficult diagnosis but one that falls into the “can’tmiss” category as it is a surgical emergency. The current beliefis that surgery within a window of approximately 48 hours,but especially within 24 hours, of when the patient first experi-ences symptoms yields better results than waiting longer than48 hours. This belief is evolving but it’s hard to argue againstearly intervention when the resulting disability from caudaequina can be so profound.

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, 690-697.

2. Robertson, J. (2014, January 29). Cauda Equina Syndrome. Retrieved from http://www.emdocs.net/cauda-equina-syndrome/

3. Gitelman, A. et al (2008). Cauda Equina Syndrome: A Comprehensive Review. The American Journal of Orthopedics.

References

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Cauda equina syndrome is an error-prone diagnosis. The condition is high risk; it’s rare; the symp-toms 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 topcause of claims associated with a death. With 8,000 disease conditions on the ICD-9/10 list—andcounting—how can a physician keep up?

One way MMIC of Maine helps is by providing access to the Diagnosis University (DxU) CME collec-tion in Medical Interactive Community (MI).

DxU is a subset of MI’s risk management CME activities that contains nearly 30 CME activities bynational 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 ofcognitive 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 diagnos-tic error and what can be done to reduce it.

MI’s CME activities are designed to aid physicians and hospitals launch initiatives to improve detec-tion of certain common and high risk diagnoses. These activities include a 1-credit CME film avail-able at no charge “Early Recognition and Treatment of Severe Sepsis/Septic Shock: A NewParadigm” by David Larson, MD, FACEP. Also presented by Dr. Larson is “Evaluation and RiskStratification of Patients with Acute Chest Pain.”

There are CME activities that address specific symptoms such as dizziness by David Newman-Toker, MDand sore throat by Robert Centor, MD. Disease-specific topics include obstructive sleep apnea, reti-nal tear, and melanoma. Specialty-specific activities provide an overview of claim experience andemerging 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 thesurgical specialties are most often sued for “improper performance of a procedure,” a closer claimanalysis reveals that failure to monitor and failure to recognize a post-operative complication is thehighest 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 www.medicalmutual.com. Selectthe 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 availableon 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

DDIIAAGGNNOOSSIISS

Tel: (207) 775-2791 • (800) 942-2791 • Fax: (207) 523-8300Email: [email protected]

Risk ManagementCorporate Office:Cheryl Peaslee, Vice President - Risk ManagementTel: (207) 775-2791 or (800) 942-2791

ClaimsCorporate Office:Mary Elizabeth Knox, Vice President - ClaimsTel: (207) 775-2791 or (800) 942-2791

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, youshould seek a qualified legal opinion.

The Beacon is published by Medical Mutual InsuranceCompany of Maine for the benefit of our policyholders. We welcome your comments and feedback.

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