What is a Stroke?

A stroke (cerebrovascular accident) occurs when blood flow to a region of the brain is suddenly interrupted, either by arterial occlusion (ischemic stroke — approximately 85% of cases) or by rupture of a blood vessel (hemorrhagic stroke — approximately 15% of cases). Deprivation of oxygen and glucose leads to neuronal death; it is estimated that approximately 1.9 million neurons die per minute during an untreated ischemic stroke.

"Time is brain" — early reperfusion therapy with intravenous thrombolysis (tPA) within 4.5 hours and mechanical thrombectomy within 24 hours in selected patients significantly improves functional outcomes.

Powers WJ, et al. 2019 AHA/ASA Guidelines for the Early Management of Patients with Acute Ischemic Stroke. Stroke. 2019;50(12):e344–e418. doi:10.1161/STR.0000000000000211

The BE-FAST Acronym (Updated from FAST)

Recent evidence supports the expanded BE-FAST acronym to identify additional stroke symptoms often missed by FAST alone:

• B — Balance: sudden difficulty with balance or coordination
• E — Eyes: sudden vision change, double vision, or loss of vision
• F — Face: facial drooping (ask patient to smile)
• A — Arms: arm or leg weakness (ask patient to raise both arms)
• S — Speech: slurred, confused, or no speech
• T — Time: time to call emergency services immediately

Transient Ischemic Attack (TIA)

Stroke symptoms that resolve completely within 24 hours (and typically within 1 hour) may represent a Transient Ischemic Attack (TIA). TIA is NOT benign — it carries a high short-term risk of completed stroke (up to 10–15% within 90 days, with highest risk in the first 48 hours). All TIA patients require urgent evaluation and secondary prevention.

Johnston SC, et al. Transient ischemic attack: part 1. Diagnosis and evaluation. N Engl J Med. 2002;347(21):1714–1721. doi:10.1056/NEJMcp020190

Treatment

• IV alteplase (tPA): eligible patients within 4.5 hours of symptom onset
• Mechanical thrombectomy: eligible patients within 6–24 hours depending on imaging criteria
• Blood pressure management per guidelines
• Antiplatelet therapy (aspirin / dual antiplatelet in TIA)
• Anticoagulation (in cardioembolic stroke/AF)
• Stroke unit admission
• Rehabilitation: physiotherapy, speech therapy, occupational therapy

What is Saddle Numbness?

Saddle numbness (perianal / perineal anesthesia) refers to sensory loss in the perineum, inner thighs, buttocks, and genital region — the anatomical areas that would contact a saddle. This symptom is the hallmark of cauda equina syndrome (CES), a rare but potentially devastating neurological emergency resulting from severe compression of the cauda equina nerve roots (L2–S5) at or below the conus medullaris.

Without timely surgical decompression, CES can result in permanent paralysis, loss of bladder and bowel control, and sexual dysfunction. Outcome is closely related to speed of diagnosis and intervention.

PRIMARY: Barraclough K. Cauda equina syndrome. BMJ. 2021;372:n32. doi:10.1136/bmj.n32 — Comprehensive review with management algorithm.

PRIMARY: British Association of Spinal Surgeons / SBNS. Standards of Care for Investigation and Management of Cauda Equina Syndrome. 2019. — Mandates emergency MRI within 1 hour for suspected CES.

SUPPORTING: Todd NV. Cauda equina syndrome: the timing of surgery probably does influence outcome. Br J Neurosurg. 2005;19(4):301–306. [PMID: 16455564]

SUPPORTING: Pace-Patterson AM, et al. Soft Tissue Extramedullary Plasmacytoma Leading to Cauda Equina Syndrome. Cureus. 2021;13(3):e14056. doi:10.7759/cureus.14056

Common Causes

• Large central lumbar disc herniation (most common; typically L4/5 or L5/S1)
• Severe lumbar spinal stenosis
• Spinal tumors (primary or metastatic)
• Spinal trauma with bone retropulsion
• Spinal epidural hematoma or abscess
• Cauda equina compression post-spinal procedure

Clinical Features of Cauda Equina Syndrome

• Saddle anesthesia (perianal / perineal sensory loss)
• Bladder dysfunction: urinary retention (most common), incontinence, or altered stream
• Bowel dysfunction: decreased rectal tone, incontinence, constipation
• Bilateral lower extremity weakness or asymmetric weakness
• Lower extremity sensory changes (numbness, tingling)
• Sexual dysfunction
• Reduced or absent lower limb reflexes (lower motor neuron pattern)
• Low back pain (often severe) with or without radicular leg pain

Investigations

• Emergency MRI Lumbar Spine (within 1 hour of presentation — British Association of Spinal Surgeons standard)
• CT Lumbar Spine (if MRI unavailable or contraindicated)
• Neurological examination
• Urological assessment (post-void residual ultrasound)

Plain X-rays are NOT adequate for diagnosing cauda equina syndrome. MRI is mandatory.

Management

• Emergency surgical decompression (ideally within 24–48 hours of symptom onset)
• Neurosurgical or spinal surgical consultation immediately
• Post-operative neurological rehabilitation
• Continence therapy and management