Tacrolimus-induced neurotoxicity from bipolar disorder to status epilepticus under the therapeutic serum level: a case report

Late-onset tacrolimus-induced encephalopathy in lung transplant recipient: Case report

Background

Tacrolimus is regarded as a cornerstone of immunosuppressive therapy after lung transplantation. Tacrolimus-induced neurotoxicity is common, while late-onset severe encephalopathy is rare.

Case presentation

We report a case of a 61-year-old woman who presented with confusion and limb stiffness 29 months after undergoing bilateral lung transplantation for bronchiectasis. She received immunosuppressive regimen consisting of low-dose tacrolimus, sirolimus, mycophenolate mofetil, and prednisone due to renal insufficiency. Neurological examination revealed gaze deviation towards the right side in both eyes, as well as nuchal rigidity. The muscle strength of her extremities was at grade 1-2, and muscle tone was increased, with a bilateral positive Babinski sign. Blood tests revealed that tacrolimus and sirolimus levels were within the therapeutic range. Brain magnetic resonance imaging revealed that periventricular white matter lesions were slightly more extensive than those observed prior to transplantation. Lumbar puncture showed that cerebrospinal fluid pressure and composition were normal. A diagnosis of tacrolimus-induced encephalopathy was made after a thorough clinical examination. Subsequently, cyclosporine was administered instead of tacrolimus for anti-rejection therapy, and she has remained free of neurological symptoms since then. The improvement of clinical symptoms following the withdrawal of tacrolimus supports the drug-induced etiology of this neurological disorder.

Conclusions

We highlight that tacrolimus-induced encephalopathy can occur in a late stage after lung transplantation and may occur with tacrolimus whole blood concentrations within the therapeutic range.

Tacrolimus-Induced Neurotoxicity After Transplant: A Literature Review

Tacrolimus, a calcineurin inhibitor, is an immunosuppressant used globally to prevent rejection after organ transplantation. Although it significantly improves outcomes for solid organ transplant patients, it is associated with various side effects such as nephrotoxicity and neurotoxicity. Tacrolimus-induced neurotoxicity is frequently encountered in clinical practice and can present with a variety of symptoms that may occur even at therapeutic levels. Although tacrolimus-induced neurotoxicity is well documented, there is limited literature available on pharmacologic management. Twenty-eight case reports of tacrolimus-induced neurotoxicity were identified and analyzed in addition to other literature including reviews, retrospective studies, and animal model studies. The severity of cases of tacrolimus-induced neurotoxicity reported ranged from mild symptoms that could be managed with symptomatic treatment to conditions such as posterior reversible encephalopathy syndrome and chronic inflammatory demyelinating polyradiculoneuropathy that may require more immediate intervention. This information was utilized in addition to clinical experience to compile potential management options for prevention and treatment of neurotoxic adverse events. This review is limited by the utilization of primarily retrospective studies and case reports. The available literature on the subject is largely narrative and there are no guidelines on treatment of tacrolimus-induced neurotoxicity at the time of this research. This comprehensive review may guide further studies to investigate the pathophysiology of tacrolimus-induced neurotoxicity and to define patient-specific strategies for mitigation or minimization of neurotoxicity. This is especially important given that management of tacrolimus-induced neurotoxicity can include changes to immunosuppression that can result in an increased risk of rejection.

Delayed-Onset Psychosis Secondary to Tacrolimus Neurotoxicity After Lung Transplant: A Case Report and Systematic Review

BACKGROUND

Tacrolimus is the most common immunosuppressant used after transplant, yet it can result in moderate-to-severe neurotoxicity in up to 32% of patients. Signs of neurotoxicity can vary from mild (tremor or headache) to severe (posterior reversible encephalopathy syndrome or psychosis. Prompt recognition and management is needed to lead to symptom resolution.

OBJECTIVE

The objective of this study is to describe the clinical presentation of tacrolimus-induced psychosis, a type of tacrolimus-inducted neurotoxicity, and distinguish it from other central nervous system disturbances, including delirium.

METHODS AND RESULTS

We present a case of delayed onset tacrolimus-induced psychosis with focus on unique clinical features and management strategies. We conducted a systematic review of cases of tacrolimus-induced psychosis using the PubMed database and included 15 manuscripts in our review.

CONCLUSIONS

Tacrolimus-induced psychosis is a unique presentation of tacrolimus-related neurotoxicity and can present without the cardinal symptoms of delirium. The data on isolated psychotic symptoms are limited with current literature focusing on more common presentations of tacrolimus-induced neurotoxicity, such as delirium and tremor. Development of psychosis can occur later in the treatment course and at normal tacrolimus serum levels. It can improve with antipsychotic therapies, but primary management should include cross-titration to an alternate immunosuppressant regimen.