Serotonin Syndrome Mimicking Intrathecal Baclofen Withdrawal in a Patient with Hereditary Spastic Paraparesis.

Context: Serotonin syndrome is a drug-induced condition related to an increased level of serotonin in the brain, which may induce neuromuscular, autonomic and mental symptoms.

Case report: A 40-year-old woman with hereditary spastic paraparesis (Strumpell-Lorrain disease) with an implanted intrathecal baclofen pump for severe spasticity. Two days after starting a medication known to inhibit serotonin re-uptake (paroxetine), she developed a sudden increase in lower limb spasticity with continuous spasms, fever, tachycardia and hypertension. Intrathecal baclofen withdrawal was excluded, confirming serotonin syndrome.

Conclusion: Medications that inhibit serotonin reuptake may induce serotonin syndrome, resulting in increased spasticity in patients with spinal cord lesions, and should be prescribed with caution.