Investigating cauda equina syndrome (summary)

This is a basic article for medical students and non-radiologists

Cauda equina syndrome (CES) is the compression of nerve roots within the cauda equina and a medical emergency that requires prompt diagnosis, investigation and treatment if prognosis is to be anything other than bleak ¹.

Assessment

The main urgent diagnostic symptoms of cauda equina syndrome are ¹:

• bladder, bowel and/or sexual dysfunction
• saddle/perianal parasthesia

Other signs and symptoms associated with CES are back pain and loss of power and sensation with reduced or lost reflexes - these can be unilateral or bilateral.

These symptoms which develop over a matter of hours manifest a surgical emergency. It is important to ask questions about these main symptoms - bladder dysfunction can present as painless urinary retention and not be acknowledged by the patient.

General history is also very important - any previous spinal issues (e.g. known disc protrusions) or history of malignancy?

Prompt, detailed neurological examination is vital, including intimate examination with perianal sensation and anal tone. Other useful assessments includes bladder scanning - they can typically hold up to 1500mL without any symptoms indicating denervation ¹.

Investigations

As stated, CES is a surgical emergency - if untreated, the nerves will cease to function entirely and the patient will be at risk of being permanently disabled and incontinent. Neurosurgery are usually the first phonecall you make when you suspect CES in a patient. They will request imaging and may start to arrange transport to a neurosurgical centre.

MRI lumbar spine is performed to locate ²:

• what lesion is causing this (disc/vertebral fracture/metastatic deposit
• the level of the lesion (although excellent examination should help determine this)
• if there is multi-level disease (may require input from oncology rather than neurosurgery)

Imaging should be prompt where ever you work as this is a diagnostic and management emergency and if out-of-hours will involve co-ordination between the radiologist, the radiology department and your ward team +/- transfer to another hospital ². Due to this, it is important to involve your seniors when dealing with a case like this.

Common pathology

Cauda equina syndrome is a subset of spinal cord compression commonly caused by:

• disc protrusion
• vertebral fractures/collapse
• malignant infiltration
• disc/vertebral infection

Teaching playlist

To follow

• spinal lesions playlist