Increased weakness after pancreas and kidney transplantation

The neurology of solid organ transplantation

Transplantation is the rescue treatment for end-stage organ failure with more than 110,000 solid organs transplantations performed worldwide annually. Recent advances in transplantation procedures and posttransplantation management have improved long-term survival and quality of life of transplant recipients, shifting the focus from acute perioperative critical care needs toward long-term chronic medical problems. Neurologic complications affect up to 30-60 % of solid organ transplant recipients. Common etiologies include opportunistic infections and toxicities of antirejection medications, and wide spectrum of toxic and metabolic disturbances. Most complications are common to all allograft types, but some are relatively specific for individual allograft types (e.g., central pontine myelinolysis in liver transplant recipients). Close collaboration between neurologists and other transplant team members is essential for effective management. Early recognition of complications and accurate diagnosis leading to timely treatment is essential to reduce the morbidity and improve the overall transplant outcome.

Neurologic aspects of multiple organ transplantation

Complex multiorgan failure may require simultaneous transplantation of several organs, including heart-lung, kidney-pancreas, or multivisceral transplantation. Solid organ transplantation can also be combined with hematopoietic stem cell transplantation to modulate immunologic response to a solid organ allograft. Combined multiorgan transplantation may offer a lower rate of allograft rejection and lower immunosuppression needs. In recent years, intestinal and multivisceral transplantations became viable as a rescue treatment for patients with irreversible intestinal failure who can no longer tolerate total parenteral nutrition with 70% survival after 5 years which is comparable to other types of solid organ allografts. Post-transplant neurologic complications were reported in up to 86% of allograft recipients and greatly overlap in intestinal and multivisceral allograft recipients, without a significant effect on the outcome of transplantation. Other common organ combinations in multiorgan transplantation include kidney-pancreas, which is mostly used for patients with renal failure and uncontrolled diabetes, and heart-lung for patients with congenital heart disease and idiopathic pulmonary arterial hypertension. Kidney-pancreas transplantation frequently results in an improvement of diabetic complications, including diabetic neuropathy. Heart-lung allograft recipients have very similar clinical course and spectrum of neurologic complications to lung transplant recipients. At this time there are no reports of an increased risk of graft-versus-host disease with combined transplantation of solid organ allograft and hematopoietic stem cells. Chronic immunosuppression and complex toxic-metabolic disturbances after multiorgan transplantation create a permissive environment for development of a wide spectrum of neurologic complications which largely resemble complications after transplantations of individual components of complex multiorgan allografts.

Neurologic complications of pancreas and small bowel transplantation

In the past decade, substantial improvements in patient and graft survival for pancreas and small bowel transplants have been achieved. Despite this progress, many patients still develop neurologic complications in the course of their illness. Small bowel transplants produce more neurologic complications because of the complex metabolic environment in which the procedure is performed and because of the intense immune suppression necessitated by the greater immunogenicity of the intestinal mucosa. Pancreas transplants stabilize and/or improve the signs and symptoms of diabetic neuropathy over time. Because transplantation of the pancreas is often coupled with a kidney transplant and small intestine with liver, neurologic complications in these patients sometimes reflect problems involving the organ partner or both organs. The spectrum of neurologic complications for pancreas and small bowel transplant recipients is similar to other organ transplants but their frequency varies depending on the type of transplant performed.

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.

History of standard scoring, notation, and summation of neuromuscular signs. A current survey and recommendation

In this article, we trace the history of scoring, notation, and summation of the neuromuscular signs of muscle weakness and decrease of tendon reflexes and sensation. We recommend a standard system to promote consistency in the effort introduced by Mitchell and Lewis to "represent systems and force by their signs." The scoring of neuromuscular signs began with Mitchell and Lewis in the 19th century who used pluses, minuses, and N (for normal) to express the activity of muscle stretch reflexes. Henry Plummer introduced an ordinal scoring approach for muscle weakness, reflex decrease and increase, and sensation loss. In 1919, he and Walter Sheldon and Henry Woltman introduced standard pre-printed examination forms with written instructions for notation and scoring. Robert Lovett, a Boston orthopedist, scored weak muscles of poliomyelitis patients from 2 (mild weakness) to 6 (paralyzed), 1 being normal. Lovett's approach was used, after reversing the order of the grades and decreasing each grade by 1, by a Committee of the Medical Research Council for evaluating return of muscle weakness after nerve injury. Despite dissimilarity to existing reflex and sensation scores and uneven width of grades, this approach was widely adopted for use in neurologic practice. We introduced the Neuropathy Impairment Score using a combination of the Mitchell, Plummer, and Lovett approaches, summing all individual scores of a standard set of neuromuscular examinations. In a non-representative survey of 19 neuromuscular physicians from different countries, we find that there is a considerable variability in the approaches used for grading. Assuming that scoring is useful, we herein suggest (a) impairments should be scored separately from hyperfunction and (b) for the scoring of impairments (muscle weakness, reflex decrease, and sensation loss), the same ordinal scoring approach should be used with 0 as normal and 1, 2, ... representing increasing impairment based on the judgment of percentage abnormality with corrections made for age, sex, physical fitness, and physical characteristics.

Pancreas transplantation: indications and consequences

Pancreas transplantation continues to evolve as a strategy in the management of diabetes mellitus. The first combined pancreas-kidney transplant was reported in 1967, but pancreas transplant now represents a number of procedures, each with different indications, risks, benefits, and outcomes. This review will summarize these procedures, including their risks and outcomes in comparison to kidney transplantation alone, and how or if they affect the consequences of diabetes: hyperglycemia, hypoglycemia, and microvascular and macrovascular complications. In addition, the new risks introduced by immunosuppression will be reviewed, including infections, cancer, osteoporosis, reproductive function, and the impact of immunosuppression medications on blood pressure, lipids, and glucose tolerance. It is imperative that an endocrinologist remain involved in the care of the pancreas transplant recipient, even when glucose is normal, because of the myriad of issues encountered post transplant, including ongoing management of diabetic complications, prevention of bone loss, and screening for failure of the pancreas graft with reinstitution of treatment when indicated. Although long-term patient and graft survival have improved greatly after pancreas transplant, a multidisciplinary team is needed to maximize long-term quality, as well as quantity, of life for the pancreas transplant recipient.

Natural progression of diabetic peripheral neuropathy in the Zenarestat study population

OBJECTIVE

The aim of this study was to report the baseline and natural progression of diabetic peripheral neuropathy over 12 months in a large mild-to-moderate neuropathy population.

RESEARCH DESIGN AND METHODS

Patients from a multicentered trial of zenarestat, an aldose reductase inhibitor, had serial measures of neurologic function, including nerve conduction studies (NCSs), quantitative sensory testing (QST), and clinical neuropathy rating scores at baseline and at 12 months. Baseline population descriptors and changes in neurologic function in placebo-treated patients were analyzed.

RESULTS

Sural sensory velocity (P = 0.0008 [95% CI -1.04 to -0.27]), median sensory amplitude (P = 0.0021 [-1.3 to -0.29]), median distal motor latency (P = 0.002 [0.09-0.28]), cool thermal QST (P = 0.0005 [0.27-0.94]), and Michigan Neuropathy Screening Instrument results (P = 0.0087 [0.04-0.30]) declined significantly from baseline in the placebo population. NCS changes from baseline were independent of baseline HbA1c stratification.

CONCLUSIONS

The neurologic decline over 12 months is evident when measured by NCS and cool thermal QST. Other measures (vibration QST, neuropathy rating scores, monofilament examination) are insensitive to changes over 12 months in a mild-to-moderate affected population of this size.