Late-onset Tacrolimus-associated Cerebellar Atrophia in a Heart Transplant Recipient

Recent Topics on The Mechanisms of Immunosuppressive Therapy-Related Neurotoxicities

Although transplantation procedures have been developed for patients with end-stage hepatic insufficiency or other diseases, allograft rejection still threatens patient health and lifespan. Over the last few decades, the emergence of immunosuppressive agents such as calcineurin inhibitors (CNIs) and mammalian target of rapamycin (mTOR) inhibitors have strikingly increased graft survival. Unfortunately, immunosuppressive agent-related neurotoxicity commonly occurs in clinical practice, with the majority of neurotoxicity cases caused by CNIs. The possible mechanisms through which CNIs cause neurotoxicity include increasing the permeability or injury of the blood–brain barrier, alterations of mitochondrial function, and alterations in the electrophysiological state. Other immunosuppressants can also induce neuropsychiatric complications. For example, mTOR inhibitors induce seizures, mycophenolate mofetil induces depression and headaches, methotrexate affects the central nervous system, the mouse monoclonal immunoglobulin G2 antibody (used against the cluster of differentiation 3) also induces headaches, and patients using corticosteroids usually experience cognitive alteration. Therapeutic drug monitoring, individual therapy based on pharmacogenetics, and early recognition of symptoms help reduce neurotoxic events considerably. Once neurotoxicity occurs, a reduction in the drug dosage, switching to other immunosuppressants, combination therapy with drugs used to treat the neuropsychiatric manifestation, or blood purification therapy have proven to be effective against neurotoxicity. In this review, we summarize recent topics on the mechanisms of immunosuppressive drug-related neurotoxicity. In addition, information about the neuroprotective effects of several immunosuppressants is also discussed.

Treatment of methylmalonic acidemia by liver or combined liver-kidney transplantation

OBJECTIVE

To assess biochemical, surgical, and long-term outcomes of liver (LT) or liver-kidney transplantation (LKT) for severe, early-onset methylmalonic acidemia/acid (MMA).

STUDY DESIGN

A retrospective chart review (December 1997 to May 2012) of patients with MMA who underwent LT or LKT at Lucile Packard Children's Hospital at Stanford.

RESULTS

Fourteen patients underwent LT (n = 6) or LKT (n = 8) at mean age 8.2 years (range 0.8-20.7). Eleven (79%) were diagnosed during the neonatal period, including 6 by newborn screening. All underwent deceased donor transplantation; 12 (86%) received a whole liver graft. Postoperative survival was 100%. At a mean follow-up of 3.25 ± 4.2 years, patient survival was 100%, liver allograft survival 93%, and kidney allograft survival 100%. One patient underwent liver re-transplantation because of hepatic artery thrombosis. After transplantation, there were no episodes of hyperammonemia, acidosis, or metabolic decompensation. The mean serum MMA at the time of transplantation was 1648 ± 1492 μmol/L (normal <0.3, range 99-4420). By 3 days, post-transplantation levels fell on average by 87% (mean 210 ± 154 μmol/L), and at 4 months, they were 83% below pre-transplantation levels (mean 305 ± 108 μmol/L). Developmental delay was present in 12 patients (86%) before transplantation. All patients maintained neurodevelopmental abilities or exhibited improvements in motor skills, learning abilities, and social functioning.

CONCLUSIONS

LT or LKT for MMA eradicates episodes of hyperammonemia, results in excellent long-term survival, and suggests stabilization of neurocognitive development. Long-term follow-up is underway to evaluate whether patients who undergo early LT need kidney transplantation later in life.

BK virus-induced acute motor-axonal polyneuropathy in a renal transplant patient

Neurological complications are not uncommon in patients with renal transplantation, mostly affecting the central nervous system, and less frequently the peripheral nerves. BK virus infection is relatively common in transplant recipients and in some cases may lead to neurological complications. In this report, we present an interesting case of a patient who developed acute axonal motor polyneuropathy in the course of BK virus infection 3 months after kidney transplantation. After BK virus clearence in blood, a significant improvement was noted in her polyneuropathy. In patients with acute axonal motor polyneuropathy after transplantation BK virus-induced polyneuropathy should be excluded.

Tacrolimus-induced encephalopathy and polyneuropathy in a renal transplant recipient

Tacrolimus is an immunosuppressant frequently used following solid organ transplantation, including renal transplantation. Peripheral neuropathy is an uncommon neurological side effect of tacrolimus and has rarely been reported in renal transplantation. We report a patient who received a living-related donor kidney transplant and presented with altered mental status and new-onset bilateral foot drop. Laboratory tests including cerebrospinal fluid tests excluded infection, and MRI of the brain showed chronic microvascular ischaemic changes. Electromyography and nerve conduction study confirmed bilateral common peroneal nerve demyelination. He was also found to have inadvertently overdosed on tacrolimus at home. After switching from tacrolimus to cyclosporine, the patient's symptoms improved within 5 months. His renal function was maintained with an immunosuppressant regimen of cyclosporine, prednisone and mycophenolic acid. The prompt recognition of tacrolimus as a potential neurotoxic drug in a patient with renal transplant and substituting tacrolimus with a different immunosuppressant may prevent permanent neurological damage.

Reversible posterior leukoencephalopathy syndrome (RPLS) in a heart transplant recipient treated by substitution of cyclosporine A with tacrolimus

Reversible posterior leukoencephalopathy syndrome (RPLS) is one of the important adverse events following organ transplantation, associated with calcineurin inhibitors (CNIs). We describe a case of 54-year-old woman, who was diagnosed with RPLS within weeks after transplantation. Considering the risk of causing fatal rejection by discontinuation of CNIs, the immunosuppressive regimen of the patient was switched from a cyclosporine A-based regimen to a tacrolimus-based regimen. The patient recovered rapidly from RPLS following the switch to tacrolimus. This case demonstrated that not only discontinuation but also a substitution of CNIs would be a valid treatment option for RPLS in transplant recipients.