An Evaluation of Emergency Department Patients Referred for Urgent Lumbar Magnetic Resonance Imaging with Suspected Cauda Equina Syndrome.

Purpose

Failing to correctly diagnose Cauda Equina Syndrome (CES) in the Emergency Department (ED) can have catastrophic consequences for the patient and be costly for the National Health Service (NHS). The ED clinician bears a weight of responsibility in the decision to refer for urgent Magnetic Resonance Imaging (MRI) in the presence of a plethora of potentially inconsistent Red Flags, whilst being mindful of limited MRI scanning resources.

The purpose of this study was to calculate the number of cases of suspected CES referred from the ED of a large teaching hospital for urgent MRI scanning over a six month period and to determine the percentage of positive diagnoses.

The secondary objective was to evaluate and compare the signs and symptoms of all suspected cases of CES.

 

Approach

One ED Physiotherapy Practitioner searched the local hospital Electronic Systems for clinical data and radiological data of patients referred for urgent lumbar MRI scans between June and November 2017.

Patients were included if they were over the age of 18 and were referred from ED for an urgent MRI scan within the same day for suspected CES.

Patients were excluded if they were under 18 or referred for a same day MRI for another reason.

Outcomes

A total of 75 patients were eligible for inclusion in the evaluation.

67% of the patients were female with a mean age of 45 years.

Mean pain score was 6.6 out of 10 on a numerical rating scale.

43 patients complained of back pain with referred pain in one or both legs, 44 had abnormal lower limb neurological findings, 38 complained of bladder and/or bowel dysfunction and 14 of saddle anaesthesia.

MRI scan results confirmed CES or central disc prolapse with bilateral nerve root compression in 15 cases, 5 of which were accepted for urgent transfer and surgical intervention by the neurosurgical team
 

These findings are consistent with previous work suggesting that only a small number of suspected CES cases are subsequently confirmed on MRI. Red flags commonly associated with CES such as bladder and bowel dysfunction and saddle anaesthesia were common findings in patients without CES and not always found in patients with a confirmed diagnosis.

The number of confirmed cases of CES were too small in this study to come to any robust conclusions regarding the predictive ability of any Red Flag or combination of Red flags. A further large scale study such as a national Audit is required to investigate the predictive ability of Red Flags to aid in the diagnosis of CES and support clinicians in their decision to refer for urgent imaging. 

Implications

Although numbers are small this study questions the clinical usefulness of performing a rectal examination to aid the decision making process.

This study highlights the many inconsistencies of signs and symptoms presenting in suspected CES but does reinforce the opinion that even in the absence of other red flags, patients presenting with bilateral leg pain with positive lower limb neurological symptoms should be considered as high risk.

Funding acknowledgements

This work was unfunded. 

Additional notes

This work was presented at Physiotherapy UK 2019