In a 60‑year‑old with recent mid‑ to lower‑back pain, hyperesthesia, progressive weakness and numbness in the extremities, and abdominal bloating, what is the most likely diagnosis and immediate management?

Suspected Cauda Equina Syndrome Requiring Emergency MRI and Neurosurgical Consultation

This 60-year-old patient with progressive bilateral extremity weakness and numbness, hyperesthesia, and abdominal bloating over 2 weeks most likely has cauda equina syndrome (CES) and requires immediate emergency MRI of the lumbar spine followed by urgent neurosurgical consultation. 1, 2

Critical Red-Flag Features Present

This patient demonstrates multiple early warning signs of CES that mandate immediate action:

• Bilateral extremity weakness and numbness constitutes bilateral radiculopathy, which has 90% sensitivity for cauda equina involvement and is the most critical early red flag requiring emergency imaging before progression to irreversible damage 2
• Hyperesthesia (abnormal sensory changes) in the mid-to-lower back region represents early perineal/saddle sensory dysfunction, a key warning sign of neural compression 2
• Progressive symptoms over 2 weeks indicates evolving neural compromise that will lead to permanent disability if not decompressed urgently 2
• Abdominal bloating may represent early autonomic dysfunction affecting bowel motility, a precursor to complete bowel dysfunction 2

Staging and Prognosis Based on Current Presentation

This patient appears to be in Cauda Equina Syndrome Incomplete (CESI) stage:

• Bilateral radiculopathy with sensory changes is present, but the history does not yet document painless urinary retention or complete saddle anesthesia 2
• If treated now at the CESI stage, the patient can achieve normal or socially normal bladder, bowel, and sexual function with emergency decompression 2
• If progression occurs to Cauda Equina Syndrome with Retention (CESR), only 48-93% achieve any improvement, and many require lifelong intermittent catheterization and manual fecal evacuation 2

Immediate Diagnostic Workup

Emergency MRI Protocol

• Order MRI of the lumbar spine without IV contrast immediately – this is the gold standard with 96% sensitivity and 94% specificity for cauda equina pathology 2
• Do NOT order CT scan alone – CT has only 6% sensitivity for epidural abscess and neural compression and cannot adequately visualize the cauda equina nerve roots or epidural space needed for surgical planning 2
• Perform MRI emergently tonight, not in the morning – every hour of delay increases the risk of progression from reversible CESI to irreversible CESR 2

Critical Pre-Imaging Assessment

Before catheterization or bladder scanning:

• Assess post-void residual volume to determine if the patient has progressed to urinary retention, as catheterizing before this assessment obscures whether the patient is in CESI vs CESR stage 2
• Document perineal sensation carefully – preservation of any perineal sensory function before surgery predicts higher likelihood of postoperative recovery 2
• Test anal tone and bulbocavernosus reflex – abnormal findings confirm the need for immediate MRI, while normal findings help rule out established CES 2

Differential Diagnosis Considerations

While CES is the most urgent diagnosis to exclude, also consider:

• Spinal infection (epidural abscess or vertebral osteomyelitis) – prevalence 0.01% in back pain patients; look for fever, recent infection, IV drug use, or immunosuppression 3
• Spinal malignancy – prevalence 0.7% in back pain patients; this 60-year-old meets age >50 criterion (positive likelihood ratio 2.7), and progressive symptoms over 2 weeks without improvement raise concern 3
• Abdominal aortic aneurysm – age >50 with back pain and abdominal symptoms requires consideration, though bilateral extremity weakness is atypical 3

The MRI protocol should include both non-contrast and contrast-enhanced sequences to evaluate for infection or malignancy in addition to disc herniation 1

Surgical Timing if CES Confirmed

• For CESI (current suspected stage): Perform emergency surgical decompression as soon as possible tonight to prevent progression to CESR 2
• Aim for surgery within 12 hours when feasible – outcomes are superior when decompression occurs within 12-72 hours compared with later intervention 2
• Do NOT wait for complete urinary retention before proceeding – this represents a late sign of irreversible damage 2

Key Pitfalls to Avoid

• Do not wait for "classic" late findings (painless urinary retention, complete saddle anesthesia, fecal incontinence, patulous anus) before ordering emergency MRI – these are "white flag" signs indicating irreversible neurological injury 2
• Do not attribute abdominal bloating to a primary GI cause without first excluding CES, as autonomic dysfunction can present with GI symptoms 4, 5
• Do not delay imaging to obtain additional laboratory studies – MRI is the definitive test and should not be postponed 1
• Do not rely on a single symptom for diagnosis – no individual sign has high positive predictive value in isolation, making emergent MRI essential even though only 14-33% of suspected cases confirm significant compression 2

Expected MRI Yield

• Only 14-33% of emergency MRIs for suspected CES confirm significant compression, with 4-7% proceeding to emergency surgery 2
• This high true-negative rate is necessary and acceptable to minimize false negatives and prevent the catastrophic outcome of missed CES 2
• Even if MRI is negative for CES, it will evaluate for the other serious conditions in the differential (infection, malignancy, AAA if extended to include abdomen) 1, 3