Expressive dysphasia possibly related to FK506 in two liver transplant recipients

Tacrolimus-associated neurotoxicity isolated to the brainstem: two illustrative cases and a systematic review of the literature

INTRODUCTION

Tacrolimus-associated neurotoxicity (TAN) manifests with wide clinical spectrum, ranging from mild tremors to severe encephalopathy. The isolated involvement of the brainstem is a rarely documented presentation of TAN, and its clinical and diagnostic characteristics are unclear.

METHODS

We report two cases of brainstem-isolated TAN (bi-TAN). Moreover, we performed a systematic review of the literature on bi-TAN and extracted data concerning demographics, clinical characteristics, radiological features, and management. The systematic literature search followed PRISMA guidelines and a pre-defined protocol.

RESULTS

Eleven patients, including our two, were identified (mean age: 41.3 years, ± 18.8; five males, 45%). Speech disturbance was the most common clinical presentation (45%). The mean latency from Tacrolimus initiation to bi-TAN onset was 26 days (± 30.8). Tacrolimus serum level tested above the reference range in three patients (mean: 26.83 ± 5.48). Brain MRI showed T2-FLAIR hyperintensities; three showed restricted diffusion on ADC maps. Neurological symptoms resolved completely in seven patients (63%) after Tacrolimus withdrawal or dose reduction.

CONCLUSIONS

Our findings suggest that bi-TAN could represent a brainstem variant of posterior reversible encephalopathy syndrome. Recognition of bi-TAN as a potential cause of isolated brainstem lesions is crucial to disentangle the diagnostic work-up and ensure prompt withdrawal or reduction of the offending agent.

Tacrolimus induced diffuse pontine hyperintensity in status epilepticus: a rare entity

Posterior Reversible Encephalopathy Syndrome resulting from the hypertension-induced Failure of cerebral autoregulation, is a well-described neuro-imaging finding resulting from vasogenic oedema. Pontine Hyperintensities resulting from this condition need recognition to prognosticate and avoid unnecessary investigations.  We report a 48 year old male with chronic diabetes mellitus, Hypertension, and chronic kidney disease, and history of liver transplantation who presented with established status epilepticus. He was on Tacrolimus for prophylaxis for graft rejection. His MRI brain showed diffuse pontine and predominantly left thalamic hyperintensity, which suggested the diagnosis of central PRES. His evaluation for CNS infections and autoimmune encephalitis was negative.  On stopping Tacrolimus, the imputed drug, and control of hypertension, along with dialysis, and symptomatic management for seizures, a complete recovery was observed over one week. Repeat MRI also showed partial regression of the pontine hyperintensity. This report documents the importance of this less described neuroradiological finding that can change the management significantly and have a bearing on the prognosis.

Different Effects of Tacrolimus on Innate and Adaptive Immune Cells in the Allograft Transplantation

While tacrolimus (FK506) is currently used as immunosuppression therapy in transplant recipient, the immunological mechanism remains unknown. Herein, the immunoregulatory effects of FK506 were investigated in the physiological status and allogeneic skin transplantation. FK506 cannot significantly alter the functions of innate immune cells (macrophages and neutrophils) and adaptive immune cells (T cells) in the physiological status. However, it can effectively delay allogeneic skin-graft rejection through ameliorating the T cell responses, but not myeloid-derived innate immune cell responses. Importantly, it did not affect the allograft recipient macrophage innate immune defence capacity to bacteria. In clinics, FK506 treatment can significantly control the cytokine production in T cells, but not non-T cells. This study shows targeting calcineurin signalling, FK506, to be essential in inducing allograft tolerance, but not to damage the innate defence capacity, validating the immune cell phenotypes as a potential marker in transplantation following FK506 treatment.

One thousand consecutive primary liver transplants under tacrolimus immunosuppression: a 17- to 20-year longitudinal follow-up

BACKGROUND

Tacrolimus has proven to be a potent immunosuppressive agent in orthotopic liver transplantation (OLT). The aim of this study is to examine its long-term efficacy and safety.

METHODS AND RESULTS

One thousand consecutive primary OLTs performed between August 1989 and December 1992 and maintained under tacrolimus-based immunosuppression were followed up until January 2009. Patient and graft survivals with corresponding causes of death and retransplantation, maintenance immunosuppression, and adverse effects were examined. The study population includes 600 males and 400 females comprising 166 children, 630 adults, and 204 seniors. The mean follow-up was 17.83 (range, 16.1-19.50) years. The overall 20-year actuarial patient and graft survivals were 35.8% and 32.6%, respectively. At the last follow-up, 442 patients were alive; 133 (77.1%) children, 265 (34.5%) adults, and 44 (16.1%) seniors (P=0.0001). After the first post-OLT year, cardiopulmonary events, recurrence of primary disease, and malignancy were the main causes of death. Overall, 183 recipients underwent retransplants; mainly for primary nonfunction, hepatic artery thrombosis, and recurrent primary disease, 180 required dialysis, and 45 underwent kidney transplant. A total of 97.7% of the survivors were on tacrolimus and 26.2% were also receiving adjunctive immunosuppressants at the last follow-up.

CONCLUSIONS

The overall 20-year actuarial patient and graft survivals were 35.8% and 32.6%, respectively, with significantly better survival among children. Age-related complications, recurrence of primary disease, and malignancy were the major causes of late graft loss. Graft loss related to immunologic reasons was rare. The prevention of recurrent disease and newer immunosuppressive regimen will further improve these results.

Mutism and persistent dysarthria due to tacrolimus-based immunosuppression following allogeneic liver transplantation

Tacrolimus is a potent immunosuppressant medication with a low therapeutic index. We report a case of mutism with persistent dysarthria in a patient receiving tacrolimus-based immunosuppression following allogeneic liver transplantation. A 59-year-old female patient with end-stage liver disease secondary to primary sclerosing cholangitis underwent successful allogeneic liver transplantation. The patient was started on tacrolimus for prevention of allograft rejection and subsequently developed complete mutism. Following consultation of the medical toxicology service, tacrolimus was discontinued and the patient's mutism gradually improved. However, the patient still has moderate dysarthria more than 2 years after tacrolimus discontinuation. The Naranjo probability scale revealed a probable adverse reaction of mutism and dysarthria associated with tacrolimus therapy. Mutism is an uncommon complication of calcineurin inhibitors. Both cyclosporine and tacrolimus have been associated with mutism, though mutism may be more common in patients treated with tacrolimus. The mechanism of injury has not been delineated, although liver transplant patients and patients with preexisting hepatic encephalopathy or neurologic disease may be at increased risk for this complication. The mainstay of treatment is tacrolimus dose reduction or discontinuation, although benzodiazepine therapy may be beneficial in the treatment of this disorder. Clinicians should be aware of the potential adverse effects associated with calcineurin inhibitor toxicity in transplant patients and should advocate for aggressive and rapid treatment of this serious adverse drug effect.

Neurologic complications in adult living donor liver transplant recipients

BACKGROUND

Neurologic complications (NC) after liver transplantation are not uncommon, with serious complications such as central pontine myelinolysis (CPM), often causing disability.

OBJECTIVE

We investigated the incidence and features of NC following liver transplantation in adult recipients.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 319 adult patients who underwent liver transplantation between January 2004 and May 2005 at the Asan Medical Center.

RESULTS

Neurologic complications developed in 49 of 319 patients (15.4%). Although most of these complications were minor, including tremor and foot drop, three patients developed CPM, and one each developed posterior leukoencephalopathy, cerebral hemorrhage, and cerebral infarction. One-yr survival rates were 95.9% in patients without NC and 83.7% in patients with NC (p = 0.004). Hospital stay was prolonged in patients with NC. Graft-to-recipient body weight ratio (GRWR) did not affect occurrence of NC.

CONCLUSIONS

Neurologic complications were not uncommon in liver transplant recipients. These complications contributed to prolongation of hospital stay, increased in-hospital mortality, and decreased graft and patient survival. Every effort should be made to prevent NC, as well as to detect and treat them as soon as possible.

Neuropsychiatric complications after liver transplantation: role of immunosuppression and hepatitis C

Neuropsychiatric complications are an important source of morbidity following orthotopic liver transplantation. Etiology of liver disease and type of immunosuppression are possible related factors. The aim of this study was to describe the prevalence of neuropsychiatric complications after liver transplantation, the role of immunosuppression, and the association between these and specific liver diseases such as hepatitis C. One hundred twenty-eight patients with liver transplants were studied. Tacrolimus was the primary immunosuppressant in 101 patients and cyclosporine in 27 patients. Seventy-five complications in 49 patients (38.2%) were reported. In 43 patients, the etiology was associated with immunosuppression: 36 on tacrolimus and 7 on cyclosporine (P = 0.34). Seventeen and four-tenths percent of patients with hepatitis C and 4.6% of patients without hepatitis C developed depression (P = 0.02). There is no difference between types of primary immunosuppression and neuropsychiatric complications. There is a significantly greater incidence of depression in patients transplanted for hepatitis C.

Cyclosporine-Associated Leukoencephalopathy in Organ Transplant Recipients: Experience of Three Clinical Cases

Leukoencephalopathy is a structural alteration of cerebral white matter mainly involving damage to myelin. Several reports have linked cyclosporine (CsA) with this alteration. The clinical features vary from qualitative alterations of consciousness to neurological deficits. Magnetic resonance imaging (MRI) of the brain demonstrates the damage to the white matter, which is essential for the differential diagnosis. We describe three clinical cases of leukoencephalopathy. The first case is a 43-year-old man received a cadaveric kidney transplant using immunosuppression with of mycophenolate mofetil, prednisone, and CsA. Four months later he developed meningism and bilateral sixth nerve palsy. The second case is a 50-year-old man with a cadaveric kidney transplant received immunosuppressive treatment with azathioprine and prednisone. As a result of gouty arthritis of the ankle, azathioprine was replaced with CsA to allow addition of allopurinol. Two weeks later he developed confusion and personality changes. The third case is a 16-year-old man received a orthotopic liver transplant. Postoperatively he suffered generalized tonic-clonic seizures. In all patients the CsA levels were toxic and signs of neurological alterations were present on MRI. All patients recovered rapidly after CsA withdrawal.

Tacrolimus (FK506)-induced mutism after liver transplant

Tacrolimus (FK506), an immunosuppressant, has been associated with mutism in adults after liver transplant. Speech arrest, agitation, tremor, ataxia, and downward gaze deviation in a 5-year-old female 13 days after orthotopic liver transplant are reported. FK506, which began to be administered 12 days earlier, rose to a level of 44 ng/mL (normal range, 10-20 ng/mL) 1 day before neurologic abnormalities began. FK506 dose level was maintained and then reduced. Three days later the patient could say a few single words and extra-ocular movement returned to normal. Four months later, she continued to exhibit decreased fluency and dysarthria with ataxia. One year later, decreased fluency and mild ataxia persists. Rapid identification of speech loss linked to FK506 may be important because reduction or cessation of the drug may be associated with reverse of speech loss.

Neurologic complications of transplantation

BACKGROUND

Organ transplantation is one of the most dynamic fields in medicine and has evolved into a life-saving option for thousands of patients with previously fatal conditions. The posttransplantation clinical course is frequently associated with neurologic complications that are usually related to pretransplant morbidity, the surgical procedure of transplantation, immunosuppression, and opportunistic infection.

REVIEW SUMMARY

Neurologic complications of organ transplantation may be divided into complications common to all types of allografts and complications that are specific for a particular type of organ transplantation. The most common complications include seizures, opportunistic central nervous system (CNS) infection, metabolic encephalopathy, stroke, intracranial hemorrhage, and drug-related adverse events. Opportunistic CNS infection may have a subtle presentation and should not be overlooked, as the consequences of delayed treatment may be grave. Neurotoxicity of immunosuppressive agents is also a frequent cause of neurologic complications and may occur in the setting of normal serum drug levels. The clinical course of transplant patients is frequently complex, requiring close cooperation between the transplant team and specialty consultants. Prolonged survival of transplant patients will shift the focus of neurologic complications from acute, perioperative to chronic complications of immunosuppression.

CONCLUSIONS

Neurologic complications of organ transplantation are commonly related to opportunistic infection or neurotoxicity of immunosuppressive agents, requiring careful titration of immunosuppression. Timely diagnosis of CNS infection or other causes of neurologic dysfunction may significantly improve recovery and outcome in these patients.

Neurological examinations after liver transplantation concerning patients under corticosteroid immunosuppression and either FK 506 or cyclosporin

To study the neurological sequelae in liver transplanted recipients, 25 patients were followed up between 5 and 30 months after transplantation and another 14 patients were seen before and after transplantation. Physical examination took special note of tremor and polyneuropathy; additionally, patients estimated concentration and memory, tremor, paraesthesias and sleep disturbances on a self-rating scale. Tremor was reported to be preexistent in 50% of the later FK 506 and cyclosporin group and only temporarily rose afterwards. Twenty-eight percent complained of tremor and 20% said that it interfered mildly with daily activity. Only 2 of 39 patients showed new signs of polyneuropathy. Concentration and memory improved significantly after transplantation. In the second group of patients, MRI, EEG, lumbar puncture and neuropsychological tests were done just before and routinely after transplantation, revealing numerous preexisting neurological deficits with only singular changes afterwards.

Reversible tacrolimus-induced neurotoxicity isolated to the brain stem

Diplopia, nystagmus, visual hallucinations, and internuclear ophthalmoplegia developed in a 30-year-old woman 84 days after she received a matched, unrelated bone marrow transplant for chronic myeloid leukemia. A regimen of tacrolimus had been administered since the transplantation was performed. MR imaging revealed bilaterally symmetric regions of signal abnormality with abnormal contrast enhancement in the brain stem. No supratentorial abnormality was present. Tacrolimus therapy was discontinued, and the symptoms resolved. MR imaging that was performed 10 days after tacrolimus was discontinued showed resolution of the abnormalities.

Cortical laminar necrosis caused by immunosuppressive therapy and chemotherapy

We report three patients in whom neurologic symptoms and cortical laminar necrosis developed after immunosuppressive treatment (cyclosporin A and FK 506) and polychemotherapy (vincristine and methotrexate). Initial neuroradiologic studies showed cortical and white matter involvement. Follow-up studies showed cortical hyper-intense lesions on T1-weighted MR images, consistent with cortical laminar necrosis. The clinical and radiologic data indicate that a transient hypoxic-ischemic process could have been responsible for the encephalic lesions in these three patients.

Immunosuppressive-associated leukoencephalopathy in organ transplant recipients

Immunosuppressive-associated leukoencephalopathy is a significant complication of cyclosporine (CsA) or tacrolimus therapy. However, the precise time of onset, role of putative risk factors, differences, if any, in presentation in various types of organ transplantation and outcome of this entity, remain poorly defined. Fifty cases of immunosuppressive-associated leukoencephalopathy reported in the literature in organ transplant recipients, were reviewed. Of 50 cases, 31 occurred in liver, 8 in renal, 6 in lung, and 5 in heart transplant recipients. Median time to onset was 28 days (range 3-1512 days); 82% occurred within 90 days of transplantation. Lesions tended to occur earlier in the liver transplant recipients, compared with other organ transplant recipients (median 9 vs. 29 days, P=.19). Seizures 74%, altered mental status 50%, and visual abnormalities 28% were the most frequently presenting features. Ten percent of the patients had fever with no documented source of infection. Systemic hypertension (P=.001), and lesions in the presence of therapeutic drug levels (P=.11) were more likely to occur with CsA than tacrolimus. Neuroimaging and clinical abnormalities were reversible on cessation or reduction of CsA or tacrolimus in all but two cases. Resolution of neurologic signs/symptoms occurred a median of 4 days and neuroimaging abnormalities in a median of 20 days on reduction/cessation of the drug. Immunosuppressive-associated leukoencephalopathy is a unique entity that can usually be diagnosed on the basis of its distinctive time of onset, and clinical and neuroimaging characteristics, and it is potentially reversible if promptly diagnosed. Despite identical clinical presentation of this syndrome in the recipients of CsA and tacrolimus, above noted variations in risk factors suggest that a difference in pathophysiologic mechanism may exist.

What have we learned about primary liver transplantation under tacrolimus immunosuppression? Long-term follow-up of the first 1000 patients

OBJECTIVE

To summarize the long-term efficacy and safety of tacrolimus in orthotopic liver transplant (OLT) recipients, as well as to examine the factors that influence long-term morbidity and mortality rates.

BACKGROUND

Tacrolimus (FK506, Prograf) was introduced as primary immunosuppression for primary liver transplantation in 1989; many subsequent trials have verified the association of tacrolimus with decreased rates of acute rejection and steroid-resistant rejection after OLT. Cumulative experience with tacrolimus has also defined its short- and intermediate-term toxicity.

METHODS

One thousand consecutive patients undergoing primary OLT at a single center from August 1989 to December 1992, under tacrolimus immunosuppression, were followed until January 1999. Patients were categorized by age. Mean follow-up was 93.4+/-11 months after OLT. Patient survival, graft survival (with corresponding causes of death and retransplantation), and rejection rates (and corresponding doses of immunosuppression) were examined as efficacy parameters. Hypertension, renal function, incidence of malignancies, incidence of diabetes, and other toxicities were examined as safety parameters.

RESULTS

Actual 6-year overall patient survival rate was 68.1% and graft survival rate was 62.5%, with significant differences in the patterns of survival among the different age groups. After the first post-OLT year, infection, recurrence of disease, de novo malignancies, and cardiovascular events were the main causes of graft loss and death during the long-term follow-up. Graft loss related to either acute or chronic rejection was rare. The rate of acute rejection beyond 2 years was approximately 3% per year, and most were steroid-responsive. Approximately 70% of the patients were receiving tacrolimus monotherapy beyond year 1; at the latest follow-up, 74.2% were maintained on tacrolimus alone. In 6.1% of the survivors, end-stage renal disease developed during the follow-up period, requiring either dialysis or kidney transplantation. Hyperkalemia and hypertension was observed in approximately one third of the patients. Insulin-dependent diabetes mellitus (including patients who had diabetes before the transplant) was observed in 14% in year 1, dropping to 11% in year 7. In 82 patients, de novo malignancies developed; in 41 patients, lymphoproliferative disorders developed during the entire follow-up period.

CONCLUSIONS

Long-term patient and graft survival rates are excellent under tacrolimus immunosuppression. Pediatric patients have a better long-term outcome than adults, in part because of the limited recurrence of the original disease, which was the most common cause of late graft loss (other than patient death, most commonly the result of late de novo malignancies and cardiovascular events). Graft loss from late rejection was rare.

Early complications after orthotopic liver transplantation

The cost and impact of early post-transplant complications continue to be high. Diagnosis and management involves a high index of suspicion, rapid diagnostic and therapeutic interventions, and elimination of technical problems. Preoperative assessment of the donor and recipient medical condition and meticulous attention to detail during the technical performance of OLTx are the mainstays in achieving a good outcome.

Central nervous system lesions in liver transplant recipients: prospective assessment of indications for biopsy and implications for management

BACKGROUND

Precise diagnosis of central nervous system (CNS) lesions in liver transplant recipients remains problematic. Brain biopsies are often not feasible as a result of coagulopathy. We sought to determine whether selected clinical or radiologic characteristics can predict the likely etiology of CNS lesions in liver transplant recipients and thus obviate the need for diagnostic brain biopsies.

METHODS

A 4-year prospective, observational, cohort study was conducted at liver transplant centers at four geographically diverse medical institutions. A total of 1730 consecutive liver transplant recipients were evaluated for CNS lesions; 60 patients with radiologically documented CNS lesions comprised the study sample.

RESULTS

Vascular events (52%, 31/60), infections (181%, 11/60), immunosuppressive associated leukoencephalopathy (12%, 7/60), central pontine myelinolysis (8%, 5/60), and malignancy (3%, 2/60) were the predominant etiologies of CNS lesions. CNS lesions were most likely to occur within 30 days of transplantation (43%, 26/60); central pontine myelinolysis, subdural hematoma, acute infarcts, and Aspergillus brain abscesses were the predominant etiologies during this time. All brain abscesses were fungal; 73% (8/11) of these patients concurrently had documented extraneural (pulmonary) infection as a result of the same fungal pathogen. Thus, a diagnostic brain biopsy is not warranted in these patients. Patients on dialysis were more likely to have ischemic or infectious CNS lesions (P=0.03). Vascular events were more likely to occur in repeat transplant recipients (P=0.03). Twenty-five percent (15/60) of the CNS lesions occurred more than 1 year after transplantation; small vessel ischemic lesions, malignancy, or non-Aspergillus fungal brain abscesses accounted for all such lesions.

CONCLUSIONS

A presumptive etiologic diagnosis can be established in a vast majority of CNS lesions in liver transplant recipients based on identifiable presentation that includes time of onset, unique risk factors, and neuroimaging characteristics. Empiric therapy of brain abscesses in liver transplant recipients should include antifungal and not antibacterial agents.

The neuropathology of organ transplantation: comparison and contrast in 500 patients

The main objective of this report is to compare and contrast the type and frequency of neuropathological findings following liver, heart, lung, heart-lung, kidney and bone marrow transplantation and to provide an overview of the major systemic complications in patients that received allografts. This is a retrospective analysis of the complete autopsy records and clinical histories of 500 adults who underwent organ transplantation at the University of Pittsburgh Medical Center during the interval of March, 1981 through July, 1997. This study is based on the neuropathological and systemic findings among 225 liver, 101 heart, 40 lung, 28 heart-lung, 74 kidney and 32 bone marrow transplants. Clinico-pathological correlations were made. All patients received base-line immunosuppressive therapy with one or more of the following drugs: cyclosporine, corticosteroids and azathioprine. Since August, 1989, the primary immunosuppressive agent is FK-506 (Tacrolimus). Some patients received antilymphocyte globulin (OKT3), when acute rejection was imminent. Light microscopic examination of tissue sections, stained with hematoxylin and eosin and in some cases with special stains were made. Ultrastructural evaluation were also performed in selected cases. All of the studies were carried out at the University of Pittsburgh Medical Center, Department of Pathology, Neuropathology Division. Cerebrovascular complications were the most frequent and were seen in 51% of the liver, 59% of the heart, 58% of the lung, 50% of the heart-lung, 49% of the kidney and 44% of the bone marrow allografts. Aspergillus sp. infection was the most common of all CNS infections followed by viral, bacterial and protozoal. Primary Central Nervous System Lymphoma (PCNSL) was seen in 2% of the liver, and 2% of the heart recipients. Post transplant lymphoproliferative disorder (PTLD) involving the brain was seen in 2% of the liver allografts, 3% of the heart, and 7% of the heart-lung recipients. PTLD systemically was seen in 6% of the liver, 7% of the heart, 5% of the lung, 11% of the heart-lung and 4% of the kidney allografts. Graft-versus-host disease was seen only in 41% of the bone marrow recipients. There was no statistically significant difference between the incidence of the total CNS complications among the different organ transplant groups (p value > 0.10), but there was a statistically significant difference in the systemic complications among the organ transplant groups (p value < 0.001). In conclusion that immunocompromised patients with impaired cellular and humoral immunity are at risk for the development of opportunistic infections and hematologic abnormalities. PTLD appears to be different in its pathogenesis from that of PCNSL which occurs anew in the brain of these patients. The neurological complications may be reduced by earlier recognition and better understanding of their etiopathogenesis.

FK506-induced fulminant leukoencephalopathy after single-lung transplantation

FK506 is being used increasingly to prevent rejection after organ transplantation. Its use is associated with a wide spectrum of neurotoxicity, which has been described after most solid organ transplantations, but reports after lung transplantation are extremely rare. This is a report of the pathologic correlation of the clinical and radiologic features of delayed FK506-induced fulminant leukoencephalopathy after single-lung transplantation. The patient presented with neurologic symptoms that progressed to seizure activity. Neuroimaging showed diffuse changes in the brain, and results of a brain biopsy were consistent with leukoencephalopathy with microglial and astrocytic activation. The patient had a remarkable improvement in clinical status after discontinuation of FK506 administration, with resolution of the changes seen on neuroimaging.

Immunosuppression-induced leukoencephalopathy from tacrolimus (FK506)

Tacrolimus (FK506) has recently been approved for immunosuppression in organ transplantation, although its use is accompanied by a wide spectrum of neurotoxic side effects. We describe the clinical, radiological, and pathological features of 3 cases of tacrolimus-related leukoencephalopathy. The syndrome of immunosuppression-related leukoencephalopathy is proposed as an uncommon neurological syndrome occurring in patients with organ transplants involving demyelination, in particular in the parieto-occipital region and centrum semiovale. Although the syndrome is not associated with a particular (absolute) serum level of tacrolimus, it resolves spontaneously upon decreasing the dose. The tacrolimus-related syndrome has a similar radiographic and pathologic appearance as the analogous syndrome that occurs in patients taking cyclosporine.

Dysarthria and apraxia of speech associated with FK-506 (tacrolimus)

The immunosuppressive agent FK-506 (tacrolimus) is one of the agents most commonly used to prevent rejection after liver transplantation. Neurologic toxicity related to FK-506 has been reported, including speech disorders; however, a detailed analysis of the speech disorder associated with use of FK-506 has not been presented. Herein we describe a patient who exhibited mutism, then severe apraxia of speech with a concomitant hypokinetic, spastic, and ataxic dysarthria after administration of FK-506. His residual mixed dysarthria, without radiographic evidence of a structural lesion, suggests dysfunction of one or more neurochemical systems. The pathophysiologic mechanisms underlying this intriguing entity remain obscure.

Acute disseminated encephalomyelitis (ADEM) or ADEM-like inflammatory changes in a heart-lung transplant recipient: a case report

Acute disseminated encephalomyelitis (ADEM) is a white matter inflammatory disease which usually follows a viral infection or pharmaceutical intervention. We describe a case of presumed ADEM in a heart/lung transplant patient, the etiology of which cannot be elucidated. The fascinating aspect is the mode of clinical presentation and the rapid resolution of radiologic abnormalities. Histologic examination of the brain is provided in an attempt to elucidate the radiographic abnormalities.

FK506-induced neurotoxicity in liver transplantation

We report FK506-induced neurotoxicity in 14 of 44 consecutive patients following orthoptic liver transplantation. In 10 of these 14 patients, postural hand tremors were found in the first weeks following surgery, transient apraxia of speech in 3, and generalized tonic-clonic seizures were noted in 2 patients. Other manifestations included nightmares, agitation, and acute delirium. Reduction of the FK506 dose resulted in resolution of symptoms, but in 1 patient mild speech difficulties and in 3 patients a fine tremor remained. Blood and plasma levels of FK506 were similar in patients with and without neurotoxicity. FK506 neurotoxicity in patients with liver transplantation commonly results in transient neurological manifestations. The incidence of neurotoxicity in FK506 is dramatically reduced in maintenance doses of 0.075 mg/kg twice a day.

Tacrolimus. A review of its pharmacology, and therapeutic potential in hepatic and renal transplantation

Tacrolimus (FK 506) is a macrolide immunosuppressant which possesses similar but more potent immunosuppressant properties compared with cyclosporin, inhibiting cell-mediated and humoral immune responses. Like cyclosporin, tacrolimus demonstrates considerable interindividual variation in its pharmacokinetic profile. This has caused difficulty in defining the optimum dosage regimen and has highlighted the usefulness of therapeutic drug monitoring. Most clinical studies with tacrolimus have neither been published in their entirety nor subjected to extensive peer review; there is also a paucity of published randomised investigations of tacrolimus versus cyclosporin, particularly in renal transplantation. Despite these drawbacks, tacrolimus has shown notable efficacy as a rescue or primary immunosuppressant therapy when combined with corticosteroids in adult and paediatric recipients following liver or kidney transplantation. Indeed, graft salvage rates in patients experiencing rejection or drug-related toxicity were > or = 50%, although data in renal transplantation are limited. Compared with cyclosporin as a primary immunosuppressant, tacrolimus showed comparable or greater patient/graft survival rates in liver allograft recipients (where cost savings associated with reduced hospitalisation costs were evident in one study), and comparable patient/graft survival in patients following kidney transplantation. Worthy of note was the efficacy of tacrolimus as a primary immunosuppressant in patients who received en bloc kidney allografts. The incidence of rejection was largely reduced following rescue therapy with tacrolimus and was generally lower (notably for refractory rejection) than that observed for cyclosporin, at least in liver allograft recipients. This was reflected in less need for adjunct immunotherapy including antilymphocyte preparations for the treatment of rejection episodes. The potential for reduction or withdrawal of corticosteroid therapy with tacrolimus appears to be a distinct advantage compared with cyclosporin, and this may be enhanced by the reduced incidence of infectious complications and of hypertension and hypercholesterolaemia reported by some investigators. In other respects, however, the tolerability profile of tacrolimus appears to be broadly similar to that of cyclosporin. Against this background, preliminary data indicate that tacrolimus provides a valuable therapeutic alternative to retransplantation in patients experiencing liver or kidney graft rejection or drug-related toxicity. Pending confirmation of initial randomised studies and preliminary results from large randomised investigations, tacrolimus may well be considered as an alternative primary immunosuppressant to cyclosporin in hepatic (particularly) and renal transplantation. Furthermore, the steroid-sparing effects of tacrolimus, although of benefit to all patient groups, may prove to be of particular worth in children and in en bloc kidney recipients. In these patients tacrolimus may well emerge as the drug of choice.(ABSTRACT TRUNCATED AT 400 WORDS)

Pontine myelinolysis following liver transplantation: a report of two cases

Two cases of central pontine myelinolysis (CPM) following orthotopic liver transplantation (OLT) are reported. Several months after the onset of this neurological syndrome, the two patients are still alive but with severe neurological sequelae. Some patients undergoing emergency OLT present a high risk of CPM because of pre-existing malnutrition, encephalopathy, and hepatic insufficiency. All of these are associated with an inevitable abrupt rise in sodium serum concentration due to intraoperative compensation of blood losses with high-sodium content blood products. Whenever the renal capacity to excrete sodium is impaired by the surgical procedure, continuous intraoperative venovenous hemofiltration is recommended.

The effect of graft function on FK506 plasma levels, dosages, and renal function, with particular reference to the liver

Plasma FK506 was studied in 49 liver, 13 heart, 3 double-lung or heart-lung, and 21 kidney recipients. The levels were correlated with the drug doses used, kidney function, and liver function. In all varieties of recipients, there was an early rise in the FK506 plasma levels that occurred at the time of intravenous administration of the drug. At the same time or shortly after, there were increases in serum creatinine that were transitory except in liver recipients with continuing suboptimal graft function. The quality of hepatic function dominated all aspects of FK506 management in the liver recipients. Those who received well-functioning grafts could be given about the same drug doses as recipients of kidneys and the thoracic organs. Liver recipients with defective grafts had astronomical rises in plasma FK506, a high incidence of renal failure, and probably increased neurotoxicity. In kidney transplant recipients, the FK506 plasma levels and doses were essentially the same in patients with prompt versus delayed renal function. These studies have highlighted the necessity, first, of close pharmacologic monitoring of patients who are given FK506 in the presence of abnormal liver function, and second, of using smaller intravenous induction doses than in past practice.