An elderly male with a history of prostate cancer presents with sudden onset weakness in one leg, what is the best course of action?

Urgent Neurological Emergency: Immediate MRI and Oncology Consultation Required

This elderly male with prostate cancer and sudden onset unilateral leg weakness requires immediate MRI of the entire spine to rule out spinal cord compression or cauda equina syndrome, followed by urgent oncology and neurosurgery consultation if metastatic disease is confirmed. 1, 2

Critical Clinical Context

This presentation is highly concerning for metastatic spinal cord compression (MSCC), which occurs in 1-12% of prostate cancer patients and represents an oncological emergency requiring treatment within hours, not days. 1, 2, 3

Why This is Likely Metastatic Disease Despite Normal Imaging

• Normal plain radiographs do not exclude spinal metastases or cord compression - X-rays of the hip, pelvis, and femur miss epidural disease, paraspinal masses, and early vertebral involvement that cause neurological symptoms. 2, 4

• Prostate cancer preferentially metastasizes to the lumbar spine through Batson's venous plexus in 15-30% of cases, causing lower extremity weakness before radiographic bone changes appear. 1

• Unilateral leg weakness with preserved reflexes suggests early cauda equina involvement or nerve root compression rather than upper motor neuron pathology, which is consistent with lumbar metastatic disease. 2, 5

Immediate Management Algorithm

Within 24 Hours (Ideally Within 4-6 Hours)

• Obtain urgent MRI of the entire spine (cervical through sacral) - this is the diagnostic test of choice and detects multiple asymptomatic compression sites in 51% of cases versus only 7% with myelography. 2

• Initiate high-dose intravenous corticosteroids immediately (dexamethasone 10-16 mg IV bolus, then 4-6 mg every 6 hours) while awaiting imaging, as this improves neurological outcomes. 1, 5

• Assess hormone therapy status - patients who have never received androgen deprivation therapy have significantly better outcomes (median survival 627 days versus 115 days overall) and should be considered for immediate bilateral orchiectomy or medical castration. 2, 4

Critical Prognostic Factors to Document

• Time from symptom onset to complete loss of ambulation - recovery is strongly associated with duration of paresis <48 hours in hormone-refractory patients. 4

• Current ambulatory status - 63% of non-ambulant patients become ambulant with treatment, but preoperative walking ability is the strongest predictor of postoperative function. 2, 4

• Performance status and PSA level - preoperative PSA <200 ng/ml and good performance status predict better neurological recovery. 4

Definitive Treatment Based on Findings

If MRI Confirms Spinal Cord Compression

• Radiation therapy (30 Gy or higher) is the standard definitive treatment for most patients with MSCC from prostate cancer. 2, 5

• Surgical decompression with posterior stabilization should be considered for patients with: single level compression, no prior hormone therapy, age <65 years, severe myelopathy, spinal instability, or neurological deterioration during radiation. 2, 4

• Combined laminectomy plus radiotherapy results in 89% ambulation rate (8/9 patients) versus 58% with radiotherapy alone (7/12 patients) in one series. 3

Hormone Therapy Considerations

• Immediate androgen deprivation is critical for hormone-naive patients - bilateral orchiectomy or LHRH agonist should be initiated urgently as these patients have dramatically better outcomes. 2, 3, 4

• Continue existing androgen suppression in castration-resistant patients while pursuing local treatment with radiation or surgery. 6

Common Pitfalls to Avoid

• Do not wait for plain radiographs to show abnormalities - back pain preceding neurological symptoms by an average of 60 days (range 10-840 days) is typical, and imaging may remain normal until cord compression is advanced. 3

• Do not delay imaging over weekends - studies show diagnosis rates peak on Fridays with few patients diagnosed during weekends, contributing to worse outcomes. 4

• Do not assume unilateral weakness excludes bilateral cord compression - 77% of patients who eventually improve show some motor improvement within 7 days, making rapid diagnosis essential. 2

• Do not overlook the 45% risk of recurrent cord compression at the same or different site within 2 years (median 236 days), requiring ongoing surveillance. 2

Long-Term Surveillance

• Patients with hormone-resistant disease and persistent back pain require prophylactic spine imaging (bone scan, CT, or MRI) and consideration of prophylactic local radiotherapy to prevent MSCC. 3

• Median survival after MSCC is only 4 months (range 2 weeks to 49 months), with 25% surviving 2 years, emphasizing the importance of early detection and treatment. 2, 3