Alternative tacrolimus and sirolimus regimen associated with rapid resolution of posterior reversible encephalopathy syndrome after lung transplantation

Should Calcineurin Inhibitors/Sirolimus Be Ceased Completely In Posterior Reversible Encephalopathy Syndrome?

BACKGROUND

To investigate the relationship between immunosuppressive treatments and posterior reversible encephalopathy syndrome (PRES) in transplant patients.

METHODS

We presented a retrospective study of 4 cases of PRES in transplant patients. Patient records were reviewed to identify potential risk factors, clinical presentations, radiological findings, and immunosuppressive treatments used.

RESULTS

Our analysis revealed a potential association between immunosuppressive treatments and the development of PRES in transplant patients. Specifically, we found that adjusting or switching immunosuppressive treatments can improve outcomes and prevent the recurrence of PRES.

CONCLUSION

Our findings highlight the importance of recognizing PRES as a potential complication of immunosuppressive treatments in transplant patients. Early detection and management, including a review of immunosuppressive treatments, may improve patient outcomes and prevent further complications.

Precision sirolimus dosing in children: The potential for model-informed dosing and novel drug monitoring

The mTOR inhibitor sirolimus is prescribed to treat children with varying diseases, ranging from vascular anomalies to sporadic lymphangioleiomyomatosis to transplantation (solid organ or hematopoietic cell). Precision dosing of sirolimus using therapeutic drug monitoring (TDM) of sirolimus concentrations in whole blood drawn at the trough (before the next dose) time-point is the current standard of care. For sirolimus, trough concentrations are only modestly correlated with the area under the curve, with R 2 values ranging from 0.52 to 0.84. Thus, it should not be surprising, even with the use of sirolimus TDM, that patients treated with sirolimus have variable pharmacokinetics, toxicity, and effectiveness. Model-informed precision dosing (MIPD) will be beneficial and should be implemented. The data do not suggest dried blood spots point-of-care sampling of sirolimus concentrations for precision dosing of sirolimus. Future research on precision dosing of sirolimus should focus on pharmacogenomic and pharmacometabolomic tools to predict sirolimus pharmacokinetics and wearables for point-of-care quantitation and MIPD.

Identifying the association between tacrolimus exposure and toxicity in heart and lung transplant recipients: A systematic review

AIMS

Tacrolimus is the cornerstone of immunosuppression management in heart and lung transplant recipients, improving overall survival. However, tacrolimus-associated toxicities, including nephrotoxicity, neurotoxicity, new-onset diabetes mellitus after transplant (NODAT), and gastrointestinal toxicity, are known contributors to increased post-transplant morbidity outcomes and reduced graft and recipient survival rates. The aim of this systematic review was to identify correlations between pharmacokinetic measures of tacrolimus exposure in heart and lung recipients and tacrolimus toxicities.

METHODS

MEDLINE, Embase, the Cochrane Library, CENTRAL and WHO Clinical Trial Registries were searched for published studies evaluating tacrolimus toxicities and their correlation to pharmacokinetic monitoring parameters in thoracic transplant recipients. Studies were reviewed by two authors, with data extracted for evaluation. Risk of bias was assessed using the PEDro scale for randomised control trials and the Newcastle Ottawa Scale for non-randomised cohort studies.

RESULTS

Eighteen studies were eligible; a randomised control trial, 11 observational cohort studies, and 6 case series or studies. Of these, 9 studies were in heart transplant recipients alone and 5 in lung transplant recipients alone, 2 studies were in heart and lung transplant recipients and 2 were heart, lung, liver or renal transplant recipients. Studies used variable criteria to define toxicities. Tacrolimus trough concentration (C₀) was the marker of tacrolimus exposure most commonly used. Ten studies reported on nephrotoxicity. Elevated tacrolimus C₀ was associated with acute kidney injury occurrence and severity in three observational studies. Increasing C₀ was a predictor of renal impairment in 6 studies. One study found that for each 5 ng/mL per year of tacrolimus exposure, defined by consecutive AUC, eGFR declined by 1.3 mL/min/1.73m² (p < 0.001). Comparatively, 2 studies failed to find a significant association between nephrotoxicity and tacrolimus exposure. Seven studies reported on neurotoxicity, including neuro-encephalopathies, polyneuropathies and symptomatic change in neurological status. Neurotoxicity occurred both with tacrolimus C₀ within therapeutic range and with supratherapeutic C₀. No significant association was found between NODAT and tacrolimus C₀ in two studies. One study reported on gastrointestinal toxicity, with supratherapeutic C₀ and elevated peak concentration in one lung transplant recipient three days prior to symptom development.

CONCLUSION

No clearly defined relationship between tacrolimus exposure and toxicities is described in the literature. Studies with clear toxicity criteria and pharmacokinetic markers of tacrolimus exposure are required to provide valuable information that may optimise tacrolimus therapy, helping to reduce toxicities in heart and lung transplant recipients.

Etiologies, Cerebral Vasomotion, and Endothelial Dysfunction in the Pathophysiology of Posterior Reversible Encephalopathy Syndrome in Pediatric Patients

The posterior reversible encephalopathy syndrome was characterized by Hinchey and colleagues in the 1990s. The condition frequently afflicts patients suffering from hematologic and solid organ malignancy and individuals undergoing transplantation. Cases are more frequently described in the adult population compared with children. In the pediatric population, malignancy, transplantation, renal disease, and hypertension represent the most common etiologies. Theories on pathogenesis have centered upon cerebrovascular dysautoregulation with increases in blood–brain barrier permeability. This generates vasogenic edema of the cerebral parenchyma and consequent neurologic deficits. The parietal and occipital lobes are affected with greatest prevalence, though frontal and temporal lobe involvement is frequent, and that of the contents of the infratentorial posterior cranial fossa are occasionally described. The clinical presentation involves a characteristic constellation of neurologic signs and symptoms, most typically inclusive of headache, visual-field disturbances, abnormalities of visual acuity, and seizures. Supportive care, withdrawal of the offending agent, antihypertensive therapy, and prophylactic anticonvulsants affect convalescence in majority of cases. The principal challenge lies in identifying the responsible agent precipitating the condition in patients with malignancy and those having undergone transplantation and thus deciding which medication among a multidrug treatment regimen to withhold, the duration of drug cessation required to effect clinical resolution, and the safety of resuming treatment with the compound. We accordingly reviewed and evaluated the literature discussing the posterior reversible encephalopathy syndrome in children.

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.

Immunosuppression-associated posterior reversible encephalopathy syndrome in an acute leukemia case

Posterior reversible encephalopathy syndrome (PRES) was described in 1996. Herein, we aimed to report an immunosuppression- related PRES case. A 34-year-old woman was diagnosed as t-cell acute lymphoblastic leukemia and allogeneic hematopoietic stem cell transplantation (HSCT) was performed. Cyclosporine was given for GVHD prophylaxis in addition to the other routine medications of HSCT. She was hospitalized for acute renal failure and due to the possible contribution of acute renal failure cyclosporine was stopped. Tacrolimus was started for GVHD prophylaxis at a dose of 1 mg/day. However, fifteen days after the initiation of tacrolimus, blurred vision occurred in our patient. Petechial bleeding sites were detected in bilateral cerebral and cerebellar hemisphere by MR imaging. Tacrolimus dosage was reduced to 0.5 mg/day. She had hypertension which was difficult to control and followed-up in the intensive care unit. She had seizures. Control cranial MR resulted as diffusion limitation in bilateral cerebellar hemisphere, bilateral occipital and frontal-parietal regions with vasogenic edema findings; contrast involvement in left frontal-parietal and right cerebellar regions. She had vision loss and lethargy. Control cranial MR favored PRES syndrome secondary to immunosuppression. Hypertensive state was taken under control with antihypertensive treatment and all immunosuppressive agents were stopped. Two weeks later her clinical condition was slightly improved. MR test which was conducted 2 weeks after the diagnosis revealed the regression of PRES lesions. The characteristic signs on neuroimaging are the symmetrical white matter edema in the posterior cerebral hemispheres, particularly the parietal- occipital regions. In conclusion, PRES rarely develops secondary to the immunosuppressive agents and the clinicians should suspect and promptly diagnose PRES which might cause otherwise serious irreversible clinical complications.

Tacrolimus-induced parkinsonism in a patient after liver transplantation - case report

BACKGROUND

Hepatic encephalopathy may manifest by a wide spectrum of neuropsychiatric symptoms, including cognitive impairment, seizures or extrapyramidal symptoms. The liver transplant can lead to improvement of the signs of encephalopathy but subsequent immunosuppressive treatment might possess pronounced neurotoxicity.

CASE PRESENTATION

We present a case report of a patient with chronic liver disease who developed signs of Parkinsonism after an orthotopic liver transplant, with consecutive immunosuppressant treatment with tacrolimus. Despite the improvement of liver functions due to the cytostatic treatment, a progressive worsening of neuropsychiatric symptoms associated with the presence of tremor was observed. Metabolic as well as endocrine dysfunctions were excluded as the primary causes of this condition. A brain CT did not reveal structural pathology. Signs of severe, symmetric Parkinsonism - with resting tremor, bradykinesia, rigidity and severe postural instability were observed. A brain MRI was performed with the presence of T2- hyperintensities in basal ganglia bilaterally. Tacrolimus blood concentration was elevated; hence the dose was reduced and later switched to less toxic sirolimus. Subsequently, clinical signs markedly improved after treatment modification. Improvement of clinical symptomatology after tacrolimus discontinuation supports the drug-induced etiology of this neurological condition.

CONCLUSIONS

Cytostatic treatment after solid organ transplantation often leads to signs of encephalopathy. If necessary, the dose of cytostatics needs to be reduced, or a less toxic agent must be chosen for the therapy. This modification is usually efficient with no further need for neurological intervention.

New Developments in Hypertensive Encephalopathy

PURPOSE OF REVIEW

This review summarizes the latest science on hypertensive encephalopathy and posterior reversible encephalopathy syndrome (PRES). We review the epidemiology and pathophysiology of these overlapping syndromes and discuss best practices for diagnosis and management.

RECENT FINDINGS

Diagnosis of hypertensive encephalopathy largely relies on exclusion of other neurological emergencies. We review the extensive causes of PRES and its imaging characteristics. Management strategies have not changed substantially in the past decade, though newer calcium channel blockers simplify the approach to blood pressure reduction. While this alone may be sufficient for treatment of hypertensive encephalopathy in most cases, management of PRES also depends on modification of other precipitating factors. Hypertensive encephalopathy and PRES are overlapping disorders for which intensive blood pressure lowering is critical. Further research is indicated to both in diagnosis and additional management strategies for these critical conditions.

Posterior reversible encephalopathy syndrome following a thoracic discectomy–induced dural leak: case report

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological syndrome characterized by headaches, altered mental status, seizures, and visual disturbances. Classic MRI findings include white matter changes of the parieto-occipital regions. This syndrome has been encountered in myriad medical illnesses, including hypertension, preeclampsia/eclampsia, and immunosuppressive conditions. While the pathogenesis of the disorder is unclear, vasoconstriction and hypoperfusion leading to brain ischemia and vasogenic edema have been implicated as potential mechanisms. The authors present, to the best of their knowledge, the first case of PRES following a thoracic spinal surgery–induced dural leak noted on resection of the fifth rib during a thoracotomy for a T4–5 discectomy. Brain MRI revealed large areas of increased FLAIR and T2 hyperintensity in the superior posterior frontal lobes, superior and medial parietal lobes, and bilateral occipital lobes. Following repair of the CSF leak, the patient's symptoms resolved. Spinal surgeons should be alert to the potentially life-threatening condition of PRES, especially in a hypertensive patient who experiences surgery-induced dural leakage. The development of a severe positional headache with neurological signs is a red flag that suggests the presence of PRES. Prompt attention to the diagnosis and treatment of this condition by repairing the dural leak via surgery or expeditious blood patch increases the likelihood of a favorable outcome.

[Posterior reversible encephalopathy syndrome]

Posterior reversible encephalopathy syndrome refers to a neurological disorder characterized by headache, disorders of consciousness, visual disturbances, epileptic seizures, and subcortical vasogenic edema. About two thirds of patients develop neurological symptoms, which are associated with blood pressure fluctuations. One hypothesis is that hypertensive episodes cause autoregulatory failure, and values above the upper limit of cerebral autoregulation result in a breakthrough followed by hyperperfusion and blood-brain barrier dysfunction. In another hypothesis, endothelial dysfunction triggered by numerous factors including preeclampsia, immunosuppressive agents, chemotherapeutics, sepsis, or autoimmune disorders is thought to be the key pathomechanism. Endo- or exogenic toxic agents including pharmacological substances, cytokines, or bacterial toxins are supposed to trigger endothelial activation and dysfunction resulting in the release of vasoconstrictors, pro-inflammatory mediators, and vascular leakage. Diagnosis is usually based on clinical and neuroimaging findings that frequently show a bilateral, symmetric, and parietooccipital pattern. However, the diagnosis can often only be confirmed during the course of disease after excluding important differential diagnoses. Currently, there is no specific treatment available. Lowering of arterial blood pressure and eliminating the underlying cause usually leads to an improvement of clinical and neuroradiological findings. Admission to a critical care unit is required in about 40 % of patients due to complicating conditions including status epilepticus, cerebral vasoconstriction, ischemia, or intracerebral hemorrhage. Prognosis is favorable; in the majority of patients neurological deficits and imaging findings resolve completely.

Calcineurin Inhibitors Associated Posterior Reversible Encephalopathy Syndrome in Solid Organ Transplantation: Report of 2 Cases and Literature Review

Posterior reversible encephalopathy syndrome (PRES) is a rare neurologic side effect of calcineurin inhibitors (CNIs) with poorly understood clinical features.We report cases of 2 patients with PRES developing after kidney transplantation and summarize PRES clinical features through a literature review.The 1st case was a 28-year-old man who received a kidney transplant from a deceased donor. Initial immunosuppressive therapy consisted of tacrolimus/mycophenolate mofetil/prednisolone. He developed headache and blurred vision with visual field loss15 days after transplantation and generalized seizures 4 days later. The 2nd case was a 34-year-old man who received a living kidney transplant. His initial immunosuppressive therapy comprised tacrolimus/mycophenolate mofetil/prednisolone. Two months after transplantation, he developed seizures. Both patients were diagnosed with PRES based on neurological symptoms and magnetic resonance imaging (MRI) findings; they recovered after switching from tacrolimus to either a cyclosporine or a lower tacrolimus dose. CNI-associated PRES is an acute neurological syndrome with seizures, encephalopathy, visual abnormalities, headache, focal neurological deficits, and nausea/vomiting. It is always accompanied by hypertension. A fluid-attenuated inversion recovery signal MRI scan typically shows reversible subcortical white matter changes in the posterior cerebral hemisphere that usually occur within the 1st month after transplantation. CNI-associated PRES has a generally favorable prognosis with early diagnosis and prompt treatment including alternating or discontinuing CNIs and blood pressure control.CNI-associated PRES should be considered in patients exhibiting acute neurological symptoms after transplantation. Early diagnosis and immediate treatment are critical for a favorable prognosis.

Posterior Reversible Encephalopathy Syndrome After Transplantation: a Review

Posterior reversible encephalopathy syndrome (PRES) is a rare neurological disease. Recently, an increase in the number of transplantations has led to more cases being associated with PRES than what was previously reported. Calcineurin inhibitors (CNIs) are major risk factors for PRES in posttransplantation patients. The mechanisms of the development of PRES remain to be unclear. The typical clinical symptoms of PRES include seizures, acute encephalopathy syndrome, and visual symptoms. The hyperintense signal on fluid-attenuated inversion recovery image is the characteristic of the imaging appearance in these patients. In addition, other abnormal signals distributed in multiple locations are also reported in some atypical cases. Unfortunately, PRES is often not recognized or diagnosed too late due to complicated differential diagnoses, such as ischemic stroke, progressive multifocal leukoencephalopathy, and neurodegenerative diseases. Thus, this review emphasizes the importance of considering the possibility of PRES when neurological disturbances appear after solid organ transplantation or hematopoietic cell transplantation. Moreover, this review demonstrates the molecular mechanisms of PRES associated with CNIs after transplantation, which aims to help clinicians further understand PRES in the transplantation era.