Calcineurin-inhibitor induced pain syndrome after organ transplantation

Characterization of the calcineurin inhibitor pain syndrome in patients undergoing allogeneic hematopoietic cell transplantation

Calcineurin inhibitor pain syndrome (CIPS) is a rare complication of graft-vs-host disease prophylaxis following allogeneic hematopoietic cell transplant (alloHCT). CIPS presents as severe bilateral lower extremity pain, and the incidence, risk factors, and management of CIPS are poorly characterized.This is a single center retrospective study of patients who received tacrolimus (TAC) following alloHCT to describe the characteristics and management of CIPS and compare to a cohort who did not develop CIPS.Fifteen of 585 alloHCT patients (2.6%) developed CIPS at a median of 5 days following TAC initiation and a median level of 10.5 ng/mL. Severe bilateral foot, ankle, or leg pain were the primary symptoms. Patients with CIPS were younger and more frequently received myeloablative conditioning and total body irradiation compared to patients without CIPS. Analgesic regimens included dihydropyridine calcium channel blockers, gabapentinoids, topical diclofenac, and opioids.Clinicians should be aware of this uncommon but severe adverse effect.

Long-lasting severe knee pain in a SLE patient after renal transplantation: what is the reason? A case report and literature review

Musculo-skeletal complaints in a patient suffering from systemic lupus, with co-existing chronic renal failure, undergoing immunosuppressive treatment after kidney transplantation, can have a varied etiology. The aim of this work was to present a case based review of differential diagnosis of knee pain in such a patient. A literature search was carried out using MEDLINE/PubMed, Google Scholar and EBSCO, with no time limit. We undertook a systematic review of the literature published in English, limited to full-text publications of original articles, letters to the editor, and case reports in peer-reviewed journals, for a discussion and analysis of studies reporting arthralgia in patients with lupus after kidney transplantation. We present a case report of a 45-year-old woman with lupus nephritis, after kidney transplantation, who started to complain of increasing pain in the knees, most pronounced at night and after physical activity approximately 2 years after transplantation. Extensive causal diagnostics were carried out, which revealed bilateral extensive regions of bone infarction in the femur and tibia, chondropathy, degenerative changes of medial meniscuses in the body and posterior horn as well as chondromalacia of the patella. Establishing the right diagnosis is crucial for implementing appropriate treatment.

Prevalence of Musculoskeletal Manifestations in Adult Kidney Transplant's Recipients: A Systematic Review

Background and Objectives: The musculoskeletal (MSK) manifestations in the kidney transplant recipient (KTxR) could lead to decreased quality of life and increased morbidity and mortality. However, the prevalence of these MSK manifestations is still not well-recognized. This review aimed to investigate the prevalence and outcomes of MSK manifestations in KTxR in the last two decades. Materials and Methods: Research was performed in EBSCO, EMBASE, CINAHL, PubMed/MEDLINE, Cochrane, Google Scholar, PsycINFO, Scopus, Science Direct, and Web of Science electronic databases were searched during the years 2000–2020. Results: The PRISMA flow diagram revealed the search procedure and that 502 articles were retrieved from the initial search and a total of 26 articles were included for the final report in this review. Twelve studies reported bone loss, seven studies reported a bone pain syndrome (BPS) or cyclosporine-induced pain syndrome (CIPS), and seven studies reported hyperuricemia (HU) and gout. The prevalence of MSK manifestations in this review reported as follow: BPS/CIPS ranged from 0.82% to 20.7%, while bone loss ranged from 14% to 88%, and the prevalence of gout reported in three studies as 7.6%, 8.0%, and 22.37%, while HU ranged from 38% to 44.2%. Conclusions: The post-transplantation period is associated with profound MSK abnormalities of mineral metabolism and bone loss mainly caused by corticosteroid therapy, which confer an increased fracture risk. Cyclosporine (CyA) and tacrolimus were responsible for CIPS, while HU or gout was attributable to CyA. Late diagnosis or treatment of post-transplant bone disease is associated with lower quality of life among recipients

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Favorable Effects of Tacrolimus Monotherapy on Myasthenia Gravis Patients

Background and Purpose: Tacrolimus (TAC) has been proven to be a rapid-acting, steroid-sparing agent for myasthenia gravis (MG) therapy. However, evidence related to the effectiveness of TAC alone is rare. Therefore, this study was performed to investigate the effect of TAC monotherapy in MG patients.

Methods: Forty-four MG patients who received TAC monotherapy were retrospectively analyzed. A mixed effect model was used to analyze improvements in MG-specific activities of daily living scale (MG-ADL), quantitative MG score (QMG) and MG-ADL subscores. Kaplan-Meier analysis was used to estimate the cumulative probability of minimal manifestations (MM) or better. Adverse events (AEs) were recorded for safety analyses.

Results: Of the patients receiving TAC monotherapy, MG-ADL scores were remarkably improved at 3, 6 and 12 months compared with scores at baseline (mean difference and 95% CIs: −3.29 [−4.94, −1.64], −3.97 [−5.67, −2.27], and −4.67 [−6.48, −2.85], respectively). QMG scores significantly decreased at 6 and 12 months, with mean differences and 95% CIs of −4.67(−6.88, −2.45) and −5.77 (−7.55, −4.00), respectively. Estimated median period to achieve “MM or better” was 5.0 (95% CIs, 2.8, 7.2) months. Ocular MG (OMG) and generalized MG (GMG) showed similar therapeutic effects in cumulative probabilities of “MM or better” (P-value = 0.764). A better response was observed in MG-ADL subscores for ptosis and bulbar symptoms. AEs occurred in 37.5% of patients and were generally mild and reversible.

Conclusions: TAC monotherapy is a promising option to rapidly alleviate all symptoms of MG, especially for ptosis and bulbar symptoms.

Chronic pain 1-5 years after heart transplantation-A nationwide cross-sectional cohort study

Aim

To provide a multidimensional assessment of self-reported chronic pain 1-5 years after heart transplantation and its relationship with self-reported well-being, fatigue, recovery, self-efficacy and socio-economic factors and to explore differences between heart recipients and a cohort of lung recipients.

Design

This multicentre, cross-sectional, cohort study is a part of the Swedish national Self-management after thoracic transplantation study.

Methods

Six questionnaires were distributed at the heart recipients yearly follow-up (1-5 years) at three Swedish university hospitals 2014-2017.

Results

The study group comprised of 79 heart recipients, 25 women and 54 men with a mean age of 52.68 years. Chronic pain among heart recipients was common and those not in paid employment as well as those with low psychological well-being and high general fatigue reported significantly more pain. Female heart recipients were more affected by pain. General health and vitality, general fatigue, physical fatigue and reduced activity were related to the pain intensity score.

Relevance to clinical practice

As it is the duty of the healthcare system to provide adequate pain treatment, screening for pain should be a mandatory part of long-term follow-up.

Evaluation of the Renal Transplant Recipient in the Emergency Department

Renal transplants are becoming more and more frequent in the United States and worldwide. Studies demonstrate that these patients inevitably end up visiting an emergency department. In addition to typical medical and surgical problems encountered in the general population, this group of patients has unique problems arising from their immunocompromised state and also due to side effects of the medications required. This article discusses these risks and management decisions that the emergency department physician should be aware of in order to prevent adverse outcomes for the patient and transplanted kidney.

Neurologic complications of kidney transplantation

Renal transplant is the most common organ transplant in the United States, and the frequency of kidney transplants continues to rise as transplant offers improved survival and quality of life compared to dialysis. However, complications are not uncommon and patients frequently encounter issues requiring hospitalization, especially in the first year postoperatively. Complications that arise are typically related to surgical complications, immunosuppressive medications, or infection due to immunosuppression. Neurological complications are fairly common post-operatively, and are associated with increased morbidity and mortality in this population. This review discusses the most common etiologies of neurological complications after kidney transplant, including infection, malignancy, medication related, acute neuropathy, and other neurological pathology.

Bone infarction of the hip after hand allotransplantation: A case report

Vascularized composite allotransplantation represents as an emerging field in reconstructive surgery. However, some complications can be associated with the procedure. The authors describe a case of bone infarctions of the bilateral hip joints following the first hand allotransplantation in Taiwan. A 45-year-old man who experienced a traumatic amputation of the distal third of his forearm received a hand transplantation from a brain-dead donor. Immunosuppression included antithymocyte globulins, and bolus methylprednisolone (Solu-Medrol) was used for the induction. The maintenance therapy protocol included systemic tacrolimus, mycophenolate mofetil, and prednisone. The patient discontinued the systemic steroid 15 months after surgery. Two episodes of acute rejections were observed at 105 and 810 days after surgery. These signs disappeared after pulse therapy with Solu-Medrol, titration with tacrolimus, and topical immunosuppressive creams (tacrolimus and clobetasol). However, the patient felt pain in both hips after long periods of standing 30 months after the transplantation. A pelvic radiograph and magnetic resonance imaging revealed avascular necrosis (AVN) in both hip joints. Because of the progressive worsening of the pain, the patient underwent a decompression surgery on the left hip involving a fibula bone graft. The patient underwent a right hip hemi-arthroplasty with a bipolar prosthesis 3 months later. The patient remained in good health without major complications. These findings indicate that systemic steroids and tacrolimus might be the major predisposing factors for the induction of AVN after hand allotransplantation.

Calcineurin-inhibitor induced pain syndrome - Magnetic resonance imaging and scintigraphic findings illustrated through two cases

Calcineurin-inhibitor induced pain syndrome (CIPS) is a condition characterized by lower extremity pain in patients receiving tacrolimus or cyclosporine therapy following organ transplantation. Through two cases, we demonstrate key imaging findings in CIPS with bone scintigraphy and magnetic resonance imaging (MRI), which are those of increased scintigraphic activity and marrow edema in the lower extremities, respectively. CIPS is an important condition that has characteristic imaging findings, but is unfortunately underappreciated in the radiology literature. To our knowledge, this is the first article in the radiology literature presenting two cases of CIPS, as well as the first to present both scintigraphic and MRI findings in this condition.

Tacrolimus-Induced Pain Syndrome After Bone Marrow Transplantation: A Case Report and Literature Review

BACKGROUND

Calcineurin-inhibitor-induced pain syndrome (CIPS), a rare complication seen in patients with bone marrow transplants, is associated with the use of cyclosporine A (CsA) or tacrolimus (FK506). This case demonstrates the successful pain control of FK506-related CIPS in a 23-year-old male patient with previously reported characteristic clinical features of CIPS in addition to neuropathic symptoms and uncharacteristic imaging findings. On day 15 after the transplantation, the patient complained of severe pain in the lower limbs. Afterwards, the patient started to complain of pain on his hands and back too. During this period, FK506 levels ranged from 9.5 to 16.1 ng/mL. All laboratory exams were normal, except for an increased level of alkaline phosphatase (141 U/L). The pain was not ameliorated by various analgesic drugs. Although MRI done for our patient showed no typical radiological signs such as bone marrow edema, CIPS was suggested based on characteristic clinical features of CIPS. Of note, our patient's pain had neuropathic pain-like characteristics, unlike the pain in previously reported patients with CIPS.

CONCLUSION

The patient was treated successfully by switching FK506 to CsA and administrating gabapentin and nifedipine. Heightened awareness of this complication after bone marrow transplants may be needed for hematologists, otherwise CIPS can result in catastrophic consequences.

An Unusual Manifestation of Calcineurin Inhibitor-Induced Pain Syndrome in Kidney Transplantation: A Case Report and Literature Review

Patient: Female, 23

Final Diagnosis: Calcineurin inhibitor-induced pain syndrome

Symptoms: Back pain

Medication: —

Clinical Procedure: Supportive treatment

Specialty: Transplantology

Immunosuppressant Medication-Induced Lower Extremity Pain After Combined Liver and Kidney Transplant: A Case Report

Calcineurin inhibitors are imperative in the success of a transplanted organ. However, these immunosuppressants can lead to a rare complication known as calcineurin inhibitor-induced pain syndrome, which may not be recognized early and managed appropriately. We present a case of a 35-year-old woman who underwent a combined liver/kidney transplant and developed lower extremity pain while being maintained on tacrolimus. This case illustrates a patient with previously reported characteristic clinical features of calcineurin inhibitor-induced pain syndrome in addition to uncharacteristic neuropathic symptoms and imaging findings. The patient was treated successfully with gabapentin, calcitonin nasal spray, and acupuncture. Early recognition of this syndrome can help improve a patient's quality of life.

LEVEL OF EVIDENCE

V.

Renal association clinical practice guideline in post-operative care in the kidney transplant recipient

These guidelines cover the care of patients from the period following kidney transplantation until the transplant is no longer working or the patient dies. During the early phase prevention of acute rejection and infection are the priority. After around 3-6 months, the priorities change to preservation of transplant function and avoiding the long-term complications of immunosuppressive medication (the medication used to suppress the immune system to prevent rejection). The topics discussed include organization of outpatient follow up, immunosuppressive medication, treatment of acute and chronic rejection, and prevention of complications. The potential complications discussed include heart disease, infection, cancer, bone disease and blood disorders. There is also a section on contraception and reproductive issues.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and AD depending on the quality of the evidence that the recommendation is based on.

An unusual case of calcineurine inhibitor pain syndrome

Cyclosporine induced pain syndrome (CIPS) is a newly diagnosed complication of calcineurine inhibitors, mainly observed in solid organ and hematopoetic transplantations. The present case is a male child with steroid resistant nephrotic syndrome on low therapeutic level cyclosporine treatment. He presented with intractable and debilitating leg pain, with no reported history of previous injury or trauma. The pain was reluctant to antimicrobial and sedative treatment. MRI revealed bone marrow and soft tissue edema in the mid shaft of patient's right leg. Inspite of unusual manifestations, CIPS was suggested and cyclosporine discontinued. However, the pain did not improve and was resistant to calcium blocker. Subsequently, core decompression was performed as an unusual treatment of CIPS, revealing normal bone morphology. The pain improved rapidly and the patient was discharged a few days later.

Casein kinase II regulates N-methyl-D-aspartate receptor activity in spinal cords and pain hypersensitivity induced by nerve injury

Increased N-methyl-d-aspartate receptor (NMDAR) activity and phosphorylation in the spinal cord are critically involved in the synaptic plasticity and central sensitization associated with neuropathic pain. However, the mechanisms underlying increased NMDAR activity in neuropathic pain conditions remain poorly understood. Here we show that peripheral nerve injury induces a large GluN2A-mediated increase in NMDAR activity in spinal lamina II, but not lamina I, neurons. However, NMDAR currents in spinal dorsal horn neurons are not significantly altered in rat models of diabetic neuropathic pain and resiniferatoxin-induced painful neuropathy (postherpedic neuralgia). Inhibition of protein tyrosine kinases or protein kinase C has little effect on NMDAR currents potentiated by nerve injury. Strikingly, casein kinase II (CK2) inhibitors normalize increased NMDAR currents of dorsal horn neurons in nerve-injured rats. In addition, inhibition of calcineurin, but not protein phosphatase 1/2A, augments NMDAR currents only in control rats. CK2 inhibition blocks the increase in spinal NMDAR activity by the calcineurin inhibitor in control rats. Furthermore, nerve injury significantly increases CK2α and CK2β protein levels in the spinal cord. In addition, inhibition of CK2 or CK2β knockdown at the spinal level substantially reverses pain hypersensitivity induced by nerve injury. Our study indicates that neuropathic pain conditions with different etiologies do not share the same mechanisms, and increased spinal NMDAR activity is distinctly associated with traumatic nerve injury. CK2 plays a prominent role in the potentiation of NMDAR activity in the spinal dorsal horn and may represent a new target for treatments of chronic pain caused by nerve injury.

(99m)Tc-methylene diphosphonate bone scintigraphy findings in posttransplant distal limb syndrome

We report a case of posttransplant distal limb syndrome (PTDLS) representing a rare complication in kidney transplant recipients characterized by a pain syndrome of the distal extremities. A 68-year-old man with a history of kidney transplantation presented with symmetrical and incapacitating pain in the feet and knees and underwent whole-body Tc-methylene diphosphonate (MDP) scintigraphy for further evaluation. Planar scintigraphy demonstrated marked tracer uptake in the distal femoral and tibial epiphyses, and magnetic resonance imaging showed corresponding osteoedema. Tc-MDP scintigraphy is a valuable tool for evaluation of the etiology of musculoskeletal pain and may demonstrate typical findings in case of PTDLS.

Casein kinase II inhibition reverses pain hypersensitivity and potentiated spinal N-methyl-D-aspartate receptor activity caused by calcineurin inhibitor

Clinically used calcineurin inhibitors, including tacrolimus (FK506) and cyclosporine A, can induce calcineurin inhibitor-induced pain syndrome (CIPS), which is characterized as severe pain and pain hypersensitivity. Increased synaptic N-methyl-D-aspartate receptor (NMDAR) activity in the spinal dorsal horn plays a critical role in the development of CIPS. Casein kinase II (CK2), a serine/threonine protein kinase, can regulate synaptic NMDAR activity in the brain. In this study, we determined whether spinal CK2 is involved in increased NMDAR activity and pain hypersensitivity caused by systemic administration of FK506 in rats. FK506 treatment caused a large increase in the amplitude of NMDAR-mediated excitatory postsynaptic currents (EPSCs) evoked by primary afferent stimulation and in the frequency of miniature EPSCs of spinal dorsal horn neurons. CK2 inhibition with either 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB) or 4,5,6,7-tetrabromobenzotriazole (TBB) completely normalized the amplitude of evoked NMDAR-EPSCs of dorsal horn neurons in FK506-treated rats. In addition, DRB or TBB significantly attenuated the amplitude of NMDAR currents elicited by puff application of N-methyl-D-aspartate to dorsal horn neurons in FK506-treated rats. Furthermore, treatment with DRB or TBB significantly reduced the frequency of miniature EPSCs of spinal dorsal horn neurons increased by FK506 treatment. In addition, intrathecal injection of DRB or TBB dose-dependently reversed tactile allodynia and mechanical hyperalgesia in FK506-treated rats. Collectively, our findings indicate that CK2 inhibition abrogates pain hypersensitivity and increased pre- and postsynaptic NMDAR activity in the spinal cord caused by calcineurin inhibitors. CK2 inhibitors may represent a new therapeutic option for the treatment of CIPS.

Calcineurin inhibitor induces pain hypersensitivity by potentiating pre- and postsynaptic NMDA receptor activity in spinal cords

Calcineurin inhibitors, such as cyclosporin A and tacrolimus (FK506), have played a pivotal role in the preservation of allograft function. However, these drugs can cause unexplained severe pain in patients, often referred to as calcineurin inhibitor-induced pain syndrome (CIPS). Although calcineurin can regulate NMDA receptor (NMDAR) activity, the causal relationship between spinal synaptic plasticity and CIPS remains unknown. In this study, we showed that systemic administration of FK506 (1.5 mg kg(-1) day(-1)) for 7 days in rats led to long-lasting nociceptive and mechanical hypersensitivity. Whole-cell patch-clamp recordings in spinal cord slices revealed that FK506 treatment caused a large increase in the amplitude of NMDAR-mediated excitatory postsynaptic currents (EPSCs) of dorsal horn neurons evoked by dorsal root stimulation. The amplitude of NMDAR currents elicited by puff NMDA application to dorsal horn neurons was also significantly greater in FK506-treated than in vehicle-treated rats. The frequency of spontaneous and miniature EPSCs in most dorsal horn neurons was profoundly increased in FK506-treated rats and was reduced by blocking NMDARs. Furthermore, blocking GluN2A or GluN2B subunits similarly reduced the amplitude of evoked EPSCs and the frequency of miniature EPSCs in dorsal horn neurons of FK506-treated rats. In addition, intrathecal injection of an NMDAR antagonist or systemic administration of memantine effectively reversed nociceptive and mechanical hypersensitivity in FK506-treated rats. Our findings indicate that calcineurin inhibition increases glutamate-mediated nociceptive input by potentiating presynaptic and postsynaptic NMDAR activity in spinal cords. NMDAR antagonists may represent a new therapeutic option for the treatment of CIPS.

Case report: imaging features in a renal transplant patient with calcineurin inhibitor-induced pain syndrome (CIPS)

Post-transplant distal limb bone marrow edema syndrome or calcineurin inhibitor-induced pain syndrome (CIPS) is generally a self-limiting but debilitating acute pain syndrome that has been reported in 2-14 % of renal transplant recipients. The disease is extensively described in the transplant literature in patients receiving the calcineurin inhibitors cyclosporine and tacrolimus. We present a case of CIPS arising in a patient 73 days after renal allograft, review the imaging findings, and discuss proposed etiologies and differential diagnoses. To the authors' knowledge, CIPS has not been characterized as a distinct entity in the radiology literature.

Calcineurin-inhibitor pain syndrome

BACKGROUND

There has been increased recognition of calcineurin, a phosphoprotein serine/threonine phosphatase enzyme, in the regulation of many physiologic systems. Calcineurin mediates activation of lymphocytes, which play a role in immune response. Widely distributed in the central nervous system, calcinuerin also plays an important role in sensory neural function, via its role in the regulation of newly discovered 2-pore potassium channels, which greatly influence neuronal resting membrane potentials. Calcinuerin inhibition is the mechanism of action of immunomodulatory drugs such as cyclosporine and tacrolimus, which are widely used in transplantation medicine to prevent rejection. While important for immunosuppression, the use of calcineurin inhibitors has been associated with the development of a new pain syndrome called the calcineurin pain syndrome, which appears to be an untoward complication of the interruption of the physiologic function of calcineurin.

METHODS

This is a narrative review focusing on the epidemiology, pathophysiology, characterization of a newly recognized pain syndrome associated with the use of calcineurin inhibitors.

RESULTS

The use of immunosuppressants however is associated with several well-known toxicities to which the calcineurin pain syndrome can be added. The development of this syndrome most likely involves altered nociceptive processing due to the effect of calcineurin inhibition on neuronal firing, as well as effects of calcineurin on vascular tone. The most striking aspect of the treatment of this syndrome is the response to calcium channel blockers, which suggest that the effects of calcineurin inhibition on vascular tone play an important role in the development of the calcineurin pain syndrome.

CONCLUSION

The calcineurin syndrome is a newly recognized complication associated with the use of calcineurin inhibitors. There is no standard therapy at this time but anecdotal reports suggest the effectiveness of calcium channel blockers.

Immunosuppressant-related hip pain after orthotopic liver transplant

OBJECTIVES

Immunosuppressant-related hip pain can greatly affect a patient's mobility and increase the number of total hip arthroplasties. We investigated risk factors and causes of hip pain after orthotopic liver transplant.

MATERIALS AND METHODS

The medical records of 175 adult orthotopic liver transplant patients, who were followed-up for more than 2 years, were retrospectively reviewed. Data collected from the records included primary disease, medications, biochemical results, Child-Turcotte-Pugh score, death, rejection, and complications related to liver transplant.

RESULTS

A total of 11 patients (6.3%) complained of hip pain, which was diagnosed as calcineurin-inhibitor-induced pain syndrome in 4 patients (2.3%), osteonecrosis of the femoral head in 3 patients (1.7%), and osteoporosis in 2 patients (1.1%). The incidence of calcineurin-inhibitor-induced pain syndrome was related to the dosage of tacrolimus (P > .05) but independent of methylprednisolone use. The occurrence of osteonecrosis of the femoral head was independent of the dosage and early withdrawal of methylprednisolone (P > .05). Patients with methylprednisolone withdrawal within 6 months had significantly longer survival than those using methylprednisolone for more than 6 months (50 ± 15 vs 41 ± 18 mo; P = .007).

CONCLUSIONS

Calcineurin-inhibitor-induced pain syndrome and osteonecrosis of the femoral head are main causes of hip pain in adult orthotopic liver transplant patients. Osteonecrosis of the femoral head was not common, but the incidence of hip pain owing to calcineurin-inhibitor-induced pain syndrome was relatively high in orthotopic liver transplant patients. Early withdrawal of methylprednisolone could benefit the patients' survival.

Pain syndrome with stress fractures in transplanted patients treated with calcineurin inhibitors

Bone disease remains a major cause of morbidity after renal transplantation. Post-transplant osseous complications include osteoporosis and osteonecrosis, both historically associated with glucocorticoids, and a newer syndrome of bone pain associated with calcineurin inhibitors. Calcineurin inhibitor-induced pain syndrome (CIPS) is a reversible etiology of lower extremity bone pain and bone marrow edema reported in patients receiving cyclosporine or tacrolimus after solid organ or bone marrow transplantation. While the syndrome’s pathophysiology is unclear, bone insufficiency and epiphyseal impaction may play a role. We review the literature on this increasingly important post-transplant entity and describe a case illustrating the syndrome’s key features.

TRESK channel contribution to nociceptive sensory neurons excitability: modulation by nerve injury

Background

Neuronal hyperexcitability is a crucial phenomenon underlying spontaneous and evoked pain. In invertebrate nociceptors, the S-type leak K⁺ channel (analogous to TREK-1 in mammals) plays a critical role of in determining neuronal excitability following nerve injury. Few data are available on the role of leak K_2P channels after peripheral axotomy in mammals.

Results

Here we describe that rat sciatic nerve axotomy induces hyperexcitability of L4-L5 DRG sensory neurons and decreases TRESK (K2P18.1) expression, a channel with a major contribution to total leak current in DRGs. While the expression of other channels from the same family did not significantly change, injury markers ATF3 and Cacna2d1 were highly upregulated. Similarly, acute sensory neuron dissociation (in vitro axotomy) produced marked hyperexcitability and similar total background currents compared with neurons injured in vivo. In addition, the sanshool derivative IBA, which blocked TRESK currents in transfected HEK293 cells and DRGs, increased intracellular calcium in 49% of DRG neurons in culture. Most IBA-responding neurons (71%) also responded to the TRPV1 agonist capsaicin, indicating that they were nociceptors. Additional evidence of a biological role of TRESK channels was provided by behavioral evidence of pain (flinching and licking), in vivo electrophysiological evidence of C-nociceptor activation following IBA injection in the rat hindpaw, and increased sensitivity to painful pressure after TRESK knockdown in vivo.

Conclusions

In summary, our results clearly support an important role of TRESK channels in determining neuronal excitability in specific DRG neurons subpopulations, and show that axonal injury down-regulates TRESK channels, therefore contributing to neuronal hyperexcitability.

Neurologic manifestations of transplant complications

Neurologic complications affect posttransplant recovery of more than 20% of transplant recipients. Etiology is usually related to surgical procedure of transplantation, primary disorders causing failure of transplanted organ, opportunistic infections, and neurotoxicity of immunosuppressive medications. Risk of opportunistic infections and immunosuppressant neurotoxicity is greatest within the first six months, but it persists along with long-term maintenance immunosuppression required to prevent graft rejection. Neurotoxicity may require alteration of immunosuppressive regimen, and prompt therapy of opportunistic infections improves outcomes.

No major neurologic complications with sirolimus use in heart transplant recipients

OBJECTIVE

To determine whether sirolimus therapy is associated with neurologic complications, including stroke, among heart transplant recipients.

PATIENTS AND METHODS

We retrospectively studied patients who underwent heart transplant at Mayo Clinic's site in Rochester, MN, from January 1, 1988, through June 30, 2006.

RESULTS

Of 313 patients in the cohort, the medical regimen in 116 patients (37%) was switched from cyclosporine-based therapy to sirolimus. The hazard ratio of sirolimus for any neurologic or psychiatric event was 1.94 (95% confidence interval, 0.67-4.29). This hazard ratio was driven mainly by the association between sirolimus and the development of tremor and depression. Cerebrovascular events occurred with a cumulative incidence of 14% but did not occur in any of the patients who received sirolimus therapy. There were no cases of posterior reversible encephalopathy syndrome with sirolimus use.

CONCLUSION

No early or late episodes of major neurotoxicity occurred in heart transplant recipients using sirolimus immunosuppression. The absence of stroke and transient ischemic attacks in these high-risk transplant recipients treated with sirolimus is notable but needs confirmation in future studies.

Cyclosporine-induced pain syndrome in a child undergoing hematopoietic stem cell transplant

OBJECTIVE

To report a case of calcineurin-induced pain syndrome (CIPS) in a child undergoing his second hematopoietic stem cell transplant (HSCT).

CASE SUMMARY

A 6.1-year-old child received cyclosporine and methotrexate for acute graft-versus-host disease (aGVHD) prophylaxis after his first HSCT for acute myeloblastic leukemia. Amlodipine was given for the treatment of hypertension. Symptoms of CIPS were not observed. After the second HSCT at the age of 6.7 years, the child received cyclosporine (target trough whole blood cyclosporine concentration range 150-200 microg/L), starting on day -3, and mycophenolate mofetil for aGVHD prophylaxis. With the first cyclosporine dose, the patient complained of leg pain that was most severe during the cyclosporine infusion. Analgesic agents and a change from intravenous to oral administration of cyclosporine were ineffective in controlling the pain. Magnetic resonance imaging findings on day 10 showed periosteal soft tissue changes and mild bone marrow edema of the femora and tibiae. Tacrolimus was substituted for cyclosporine on day 20; on day 21 amlodipine was initiated to manage hypertension. Trough whole blood tacrolimus concentrations ranged from 1.7 to 6.2 microg/L. Pain was reduced in severity by day 29 and completely resolved once tacrolimus was discontinued on day 42. In this case, CIPS was considered to be probably associated with cyclosporine according to the Naranjo probability scale.

DISCUSSION

CIPS is hypothesized to result from calcineurin-induced vascular changes that disturb bone perfusion and permeability, leading to intraosseous vasoconstriction and bone marrow edema. In our patient, symptoms were most acute during the infusion, when whole blood cyclosporine concentrations were likely to be the highest. Our patient's symptoms were resolved when tacrolimus was substituted for cyclosporine and amlodipine was initiated.

CONCLUSIONS

Interventions aimed at reducing pain associated with CIPS may include the initiation of calcium-channel blocker therapy and conversion to an alternative calcineurin inhibitor.

Post-transplant distal limb syndrome: clinical diagnosis and long-term outcome in 37 renal transplant recipients

After the introduction of steroid sparing immunosuppressive protocols, osteonecrosis of the hip has become a rare entity in renal transplantation. Instead, an elusive bilateral pain syndrome of the distal extremities has gained more clinical attention. Because of the typical presentation, it is sometimes referred to as 'post-transplant distal limb syndrome' (PTDLS). The syndrome typically manifests during the first year after transplantation and may lead to significant morbidity because of pain induced immobilization. On MRI-scans, a characteristic bilateral patchy osteoedema can be demonstrated. The etiology of PTDLS has not been determined definitely so far. Over the last 8 years, we have seen the syndrome in 37 out of 639 renal transplant patients (5.8%). There was no association to steroid-medication, age, gender, PTH levels or delayed graft function. As an important finding, we saw a significant rise in alkaline phosphatase from 160 +/- 54 to 271 +/- 108 U/l (P = 0.001) and calcium from 2.46 +/- 0.18 to 2.58 +/- 0.18 mmol/l (P = 0.013) preceding the onset of pain by several weeks. Mean duration of clinical symptoms was 5.1 +/- 3.1 months; however, all patients experienced remission without signs of chronic damage on long-term follow up.