[Hereditary and acquired transthyretin-mediated amyloidosis]. / Erfelijke en verworven transthyretine-gemedieerde amyloïdose.

We describe three cases, two 70-year-old males with mainly cardiac symptoms and a 34-year-old male with gastro-intestinal and neurologic symptoms. Each patient was shown to have a distinctive type of transthyretin-mediated amyloidosis (ATTR). ATTR amyloidosis is a life-threatening disease characterised by the extracellular deposition of pathogenic transthyretin (TTR). A distinction is made between hereditary ATTR (ATTRv), in case of a pathogenic TTR mutation, and the acquired wild-type ATTR (ATTRwt). The prevalence of ATTR amyloidosis is probably underestimated. The variety of symptoms means that patients often visit several specialists, resulting in an average diagnostic delay of two to three years. Because of the development of new therapeutic possibilities, early diagnosis becomes more important to allow initiation of therapy at an early stage of the disease. Family members should be screened and asymptomatic carriers should undergo follow-up.

Metabolic aspects of tacrolimus in renal transplantation. Consequences for the choice of an immunosuppressive regimen and for the management of post-transplant diabetes mellitus.

The occurrence of post-transplant diabetes mellitus (PTDM) is an important complication after renal transplantation associated with an increased risk of chronic transplant dysfunction and of cardiovascular morbidity and mortality. Both tacrolimus and cyclosporine have been associated with PTDM. In the initial studies, PTDM seemed to occur more often in tacrolimus treated patients than in cyclosporine treated patients. The mechanism by which tacrolimus could cause PTDM was unknown and the relative roles of tacrolimus and corticosteroids, which are often prescribed concomitantly with tacrolimus, were unknown. In several studies we used fasting glucose and insulin levels to assess (peripheral) insulin resistance, and intravenous glucose tolerance tests to assess insulin secretion by the pancreatic b-cells in response to a stimulus (glucose load). Thus, we evaluated the mechanism by which tacrolimus causes glucose metabolic disorders, risk factors for glucose metabolic disorders during tacrolimus treatment, the relative roles of corticosteroids and tacrolimus trough levels in glucose metabolic disorders, and also differences in glucose metabolism between patients using tacrolimus versus patients using cyclosporine. Based on the results of these studies and the available literature, the consequences for the choice of a primary immunosuppressive agent and guidelines for the treatment of PTDM during tacrolimus-based immunosuppression are discussed.

Severe hypophosphataemia after intravenous iron administration.

Currently, in many centres, intravenous administration of iron is becoming increasingly popular because of higher efficacy and decreased side effects, mainly gastrointestinal, compared with oral iron therapy. Studies of intravenous ferric carboxymaltose administration in the postpartum setting and in patients with non-dialysis-dependent chronic kidney disease revealed a decrease in serum phosphate levels that was generally asymptomatic and transient. Here, we report four cases of severe and symptomatic hypophosphataemia after intravenous iron administration. All patients received this as therapy for iron deficiency anaemia due to heavy menstrual bleeding. In most cases, a pre-existent disorder in the phosphate homeostasis existed, such as a secondary (cases 3 and 4) or tertiary hyperparathyroidism (case 1). However, in the second case there were no risk factors for a dysregulation of the phosphate homeostasis. Based on these findings, we conclude that severe and symptomatic hypophosphatemia can occur as a side effect of intravenous iron administration and can persist for months after administration. Especially patients with low phosphate levels prior to therapy due to concomitant disorders in phosphate homeostasis (e.g. hyperparathyroidism, vitamin D deficiency) are at risk.