Kristen Scheitler, MD Profile picture
PGY-6 #Neurosurgery Resident & #PhD Candidate @MayoClinic | interested in addiction neurobiology & psychiatric #DBS | erstwhile musician | views mine 🪐📚

May 13, 2022, 9 tweets

One of the most common consults we see in neurosurgery is the 'cauda equina syndrome (CES) rule-out.' CES can be diagnostically challenging & panic-inducing due to its highly variable presentation & grave consequences if missed.

How to evaluate suspected CES: a thread 🧵

(1/9)

(2/9) When cauda equina syndrome is suspected, investigate the following:

•History (always)
•Bladder function (PVR)
•Rectal exam (3 parts: perianal sensation, voluntary contraction, wink reflex)
•Neuro exam (sensorimotor, reflexes)
•Imaging (MRI)
 
Let’s dive in 👇

(3/9) We all learned:

bladder/bowel dysfunction + saddle anesthesia + severe leg/low back pain = slam-dunk diagnosis

...but the presentation is not always this clear.

Fortunately, cauda equina syndrome is RARE - annual incidence is approx. 5-10 cases per 1,000,000.

(4/9) HISTORY.

Listening to the patient is, & always will be, the first step. No skipping.

Ask:
❓onset, progression, severity, &c
❓NEW bladder/bowel dysfunction (retention, incontinence)
❓pain in low back or leg(s)
❓saddle anes.
❓PMH (blood thinners, infxn, cancer, &c)

(5/9) BLADDER DYSFUNCTION.

Not always present, but concerning when it is.
 
Impaired sensation of bladder filling, impaired micturition ➡️ retention ➡️ overflow incontinence.
 
Get PVR. Normal <50-100 cc. <200 cc has 97% neg pred value for CES.
 
🔴 PVR > 300 cc is concerning.

(6/9) RECTAL EXAM.

"Tone” is highly subjective & is NOT enough. The adequate rectal exam for CES has 3 components:
 
-perianal sensation
-wink reflex
-voluntary contraction
 
🔴 If any of the above are diminished/absent, that is concerning.

(7/9) NEURO EXAM.

CES affects lumbosacral nerve *roots* (*lower* motor neuron signs).
 
•Motor: weakness or ⬇️ tone in myotomes supplied by lumbosacral nerve roots

•Sensory: diminished/absent in lumbosacral dermatomes

•Reflexes: diminished

🔴 Any of these = concerning.

(8/9) IMAGING.

MRI w/wo contrast is first-line. If the patient can't tolerate being supine due to pain, sagittal & axial T2 sequences are the bare minimum.

If MRI unavailable or pt has contraindications (e.g., pacemaker), can do CT or CT myelogram.

(9/9) Summary:

•CES is a common consult but an uncommon condition

•H&P is your first step, always

•Diagnostic eval is incomplete without PVR, rectal exam, neuro exam, & imaging

•Back pain or bilateral leg pain is not reliably present

•Breathe - you got this :)

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