“Ambulating with a cane…”
Presentation
Triage note: Had injection to treat sciatic nerve pain on Thursday. Has been having intermittent numbness to extremities and urinary incontinence. States that she has no sensation to genital area. Ambulating with a cane.
A 37-year-old female with a past medical history of hypertension, and sciatica presents to the emergency department with a complaint of back pain. She endorses that starting six days ago she “twisted her back” and began having increasing lower back pain which she describes as diffuse and right sided. She endorses chronic lower back pain but states that this episode was worse than usual. She presented to the hospital five days ago and received a sciatic nerve block for pain control and was discharged in stable condition. At the time, she did not have weakness, numbness, or incontinence present.
Since then, she reports progression of lower extremity weakness and numbness. She is able to ambulate with very unsteady gait with cane, and states that prior to last week she was ambulating without any difficulty without the cane. She also endorses urinary incontinence which initially “spilled out” but now states that she has to press on lower abdomen to void urine. Also endorses numbness in genital region when wiping after urinating.
Patient denies fever, history of IV drug use, trauma to back.
Vitals are within normal limits. On exam, the patient has almost complete loss of sensation of the lower extremities. She is able to stand with a cane but ambulates with broad based, very unsteady gait. Physical exam is otherwise normal with intact upper extremity sensation/strength and normal cranial nerve exam.
Workup/ED Course
EKG was without evidence of acute ischemia or arrhythmia. Chest x-ray was grossly unremarkable.
Labs demonstrated a WBC of 12.3 without neutrophilia. Hgb and platelets normal. Coags normal. CMP with glucose 303 with anion gap of 6, without electrolyte abnormalities. CK and CRP normal. Renal function normal.
MRI L-spine Radiology Impression:
“1. Early degenerative disc changes at L3-4, L4-5, and L5-S1.
2. There is congenital narrowing of the lower lumbar spinal canal due to short pedicles.
3. Small focal disc protrusion in the central and right paracentral zones of the L3-4 disc.
4. Large central disc extrusion at L4-5 which completely effaces the thecal sac and obliterates the central canal displacing the nerve root posteriorly. The extrusion extends below the L5 pedicle to the level of the mid L5 vertebra.”
A STAT MRI L spine was ordered due to concerns for cauda equina syndrome. Results were significant for “central disc extrusion at L4-5 which… obliterates the central canal.” These results are consistent with cauda equina syndrome.
Neurosurgery was consulted and recommended starting high-dose steroids with insulin given to control patient’s hyperglycemia. The patient was admitted for neurosurgical management.
Outcome
The patient was taken to the OR for emergent L3-4, L4-5 laminectomies/decompression. Afterwards, she endorsed improving sensation and strength in her lower extremities, and remains admitted. She is continuing to work with physical and occupational therapy on a daily basis.
Takeaway Points
While this a textbook example of cauda equina syndrome (sometimes patients do read the book!), there are important learning points from this case. First, the patient returned to the emergency department due to excellent return precautions given during her first ED encounter. This shows the importance of reviewing red-flag symptoms and return precautions in patients with benign presentations. Second, avoid anchoring on a benign diagnosis because of a patient’s medical history; this patient had a history of sciatic nerve pain that progressed into an emergent presentation. Third, in cauda equina syndrome, the “incontinence” often described is overflow incontinence, and begins with urinary retention. Finally, this patient was described in the triage note as “ambulating with a cane,” which may have led away from a cauda equina diagnosis. Clarifying a patient’s baseline ambulatory status and walking a patient during an exam will help avoid misdiagnoses.
Special thanks to all of the physicians who contributed to this interesting case!
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