Supplementary Material for: Hyponatremia-induced epileptic seizure provoked by levetiracetam and pain medication intake in a patient with central diabetes insipidus

Introduction: Causes of epileptic seizures are often multifactorial but for an effective therapy they should be uncovered in detail.
Case presentation: We present a 67-year old male patient with a central diabetes insipidus, who experienced a generalized tonic-clonic seizure. The patient was treated with levetiracetam for prevention of further seizures, opioids and non-steroidal anti-inflammatory drugs [NSAID], i.e. ibuprofen because of severe back pain due to vertebral compression fractures. In this setting, he developed significant hyponatremia and experienced another epileptic seizure. After stopping analgesics and switching from levetiracetam to lacosamide, sodium levels returned to normal and the patient remained free of seizures since then.
Conclusion The interrelationships of medical therapy, sodium levels and epileptic seizures in the context of central diabetes insipidus are discussed.