Immediate line of management

1. Urgent admission or same-day oncology-neurology assessment.
   • Document full neurologic exam: reflexes, tone, plantar responses, sensory level, saddle sensation, anal tone, gait/transfer ability.
   • Measure post-void residual with bladder scan and assess for retention, UTI, and constipation/ileus.
2. Urgently exclude spinal cord, conus, or cauda equina involvement
   • Obtain urgent contrast MRI of the whole spine, or at minimum lumbosacral spine with extension according to examination.
   • The combination of bilateral leg weakness, sensory loss and bladder symptoms warrants this even without back pain. Spinal cord compression may present with progressive walking difficulty, sensory impairment and urinary dysfunction and can deteriorate rapidly. The Washington Manual of Medical Therapeutics, spinal cord compression section.
3. Hold further vincristine now, pending urgent review by the treating pediatric/hematology-oncology team.
   • Vincristine causes a dose-dependent, length-dependent sensorimotor neuropathy and can cause autonomic dysfunction including constipation, ileus and urinary retention. Early dose reduction or withdrawal commonly permits slow recovery, although residual deficits can persist. Bradley and Daroff's Neurology in Clinical Practice, p. 2710.
   • Given wheelchair dependence and 3/5 knee-extension strength, this is clinically consistent with at least severe motor neuropathy. The next vincristine dose should not simply be administered on schedule.
   • The final decision on omission, delay, or later dose reduction must follow the active COG protocol and leukemia team decision. Protocols commonly advise medical review and treatment delay/reduction/omission for grade 2 or higher neuropathy, though induction-phase modifications can differ by protocol, as noted in eviQ ALL induction guidance.
4. Neurology assessment and objective baseline testing
   • Nerve-conduction studies and EMG, if this will not delay urgent imaging or treatment decisions. Typical vincristine toxicity is an axonal neuropathy with reduced sensory amplitudes.
   • Check potentially reversible contributors: CBC, renal and hepatic function, electrolytes including Mg/Ca/K/phosphate, glucose/HbA1c, vitamin B12/folate, TSH, and medication reconciliation.
   • Specifically identify and avoid potentiators of vincristine neurotoxicity, particularly azole antifungals such as itraconazole, voriconazole, posaconazole, and strong CYP3A inhibitors, unless the oncology/pharmacy team makes a deliberate alternative plan.

Supportive treatment now

• Physiotherapy and rehabilitation urgently: transfer training, range-of-motion exercises, strengthening as safe, fall prevention, wheelchair assessment, and ankle-foot orthoses if foot drop develops.
• Occupational therapy for activities of daily living and upper-limb impairment.
• Pain treatment only if neuropathic pain is present: use an individualized regimen through oncology/pain/neurology. Duloxetine has the best evidence in adults for established painful chemotherapy-induced peripheral neuropathy, but evidence in children and for pure weakness is limited. Gabapentin/pregabalin are often used symptomatically, not to reverse nerve injury.
• Bowel and bladder care: aggressively prevent/manage constipation; involve urology if raised residual, retention, recurrent urinary symptoms, or neurogenic bladder concern.
• Avoid alcohol and unnecessary neurotoxic drugs. Ensure nutritional support.

What not to do routinely

• Do not give IVIG, steroids, or plasma exchange merely for presumed vincristine neuropathy. These are considered only if evaluation suggests an immune neuropathy such as Guillain-Barré syndrome/CIDP or another specific inflammatory diagnosis.
• No vitamin, supplement, or “neuroprotective” agent has established efficacy to reverse vincristine neuropathy.

Escalate immediately if present