Seizure in Organ Transplant Patients: Diagnosis and Management

Seizure is the second most common neurologic complication after solid organ transplantation. The reported incidence of seizures among organ transplant recipients is variable, ranging from 1 to 20%. Both focal and generalized seizures may occur but, in most instances, they are a non-specific symptom of cerebral dysfunction. In this article, we provided the major causes of seizure in the setting of organ transplantation, according to available case series; seizures may result from drug-induced neurotoxicity, electrolyte derangements, central nervous system (CNS) infections, malignant hypertension, stroke (ischemic or hemorrhagic) or CNS malignancies. Drug toxicity from anti-rejection agents is the most common cause of seizures and is the cause in about 25% of cases. Post-transplant drug-induced seizures (and encephalopathy) occur mostly within the early post-operative period (first month) due to high loading doses and the calcineurin inhibitors (such as cyclosporine or tacrolimus) are mostly responsible. So, it is important to closely monitor drug levels during early phase of maintenance immunosuppression. Other main causes of early post-transplant seizures are electrolyte disturbances (especially hyponatremia) and cerebrovascular disease but causes such as CNS infection or post-transplant malignancy are rare during early post-transplant phase and most commonly occur a few months to years following solid organ transplantation. The stepwise approach to the evaluation of seizures in this population differs little from the general population and includes: (1) acute seizure control in order to minimize neurologic and systemic complication, (2) identifying and treating the underlying etiology when possible, and (3) to determine the need for long term anti-epileptic drugs (AED). A few specific considerations are also provided in this article.In patients who have recurrent seizures or single seizure with uncontrollable metabolic disturbances or structural CNS lesions, AEDs should be started. In most patients,AEDs can be discontinued after 3 months without risk of recurrence, but patient with untreatable underlying etiology,long term AED therapy may be considered.In this review article, we also provide some especial consideration in selecting AEDs in organ transplant patients.