Causes of hypercalcemia in renal transplant recipients: persistent hyperparathyroidism and others

Electrolyte and Acid-Base Abnormalities After Kidney Transplantation

Kidney transplantation is the optimal therapeutic approach for individuals with end-stage kidney disease. The Scientific Registry of Transplant Recipients has reported a continuous rise in the total number of kidney transplants performed in the United States, with 25,500 new kidney recipients in 2022 alone. Despite an improved glomerular filtration rate, the post-transplant period introduces a unique set of electrolyte abnormalities that differ from those encountered in chronic kidney disease. A variety of factors contribute to the high prevalence of hypomagnesemia, hyperkalemia, metabolic acidosis, hypercalcemia, and hypophosphatemia seen after kidney transplantation. These include the degree of allograft function, immunosuppressive medications and their diverse mechanisms of action, and metabolic changes after transplant. This article aims to provide a comprehensive review of the key aspects surrounding the most commonly encountered electrolyte and acid-base abnormalities in the post-transplant setting.

Denosumab in a pediatric kidney transplant recipient with late, resistant hypercalcemia secondary to Pneumocystis jirovecii pneumonia

Kidney transplant recipients (KTR) are at an increased risk of developing Pneumocystis jirovecii pneumonia (PCP), especially during the first year after transplantation. This is the first reported pediatric KTR, with chronic kidney disease (CKD) secondary to kidney dysplasia and vesicoureteral reflux, who developed refractory and symptomatic hypercalcemia 5 years after transplantation. The hypercalcemia was resistant to treatment with intravenous hyperhydration, furosemide, and a low-calcium diet. A respiratory tract infection due to PCP treated with trimethoprim-sulfamethoxazole did not improve calcium levels. Due to the hypercalcemic symptom burden for the patient, a single dose of subcutaneous denosumab was used to achieve sustained clinical and biochemical improvement, without any severe adverse events. This case highlights the potential use of denosumab as a treatment option in pediatric KTR with refractory hypercalcemia related to PCP. Further study of denosumab in young people with CKD or kidney transplants is needed before routine use can be recommended.

Management of kidney transplant recipients for primary care practitioners

Patients with kidney transplants have a significant co-morbidity index, due to a high number of pre-existing conditions and use of immunosuppression medications. These patients are at higher risk of developing conditions such as hypertension, dyslipidemia, post-transplant diabetes, cardiovascular events, and anemia. Moreover, they are particularly susceptible to infections such as urinary tract infections or pyelonephritis, cancers, and gastrointestinal complications such as diarrhea, which in turn may be attributed to medication adverse effects or infectious causes. Along with these concerns, meticulous management of electrolytes and allograft function is essential. Prior to prescribing any new medications, it is imperative to exercise caution in identifying potential interactions with immunosuppression drugs. This review aims to equip primary care practitioners to address these complex issues and appropriate methods of delivering care to this rapidly growing highly susceptible group.

Transplant endocrinology

Solid organ transplants and stem cell transplants are becoming more common but a significant proportion of patients are still on waiting lists, awaiting transplants. When endocrinologists treat transplant recipients who have underlying endocrine problems, which might include endocrine emergencies, there are special clinical care considerations to be aware of. The stage of the transplant (pre-transplant, early post-transplant, and chronic post-transplant) must be taken into account. Additionally, it's crucial to be knowledgeable about immunosuppressive medications, their typical adverse effects and drug interactions. The review article addresses a number of endocrine and metabolic abnormalities that are reported after transplantation.

Timing of parathyroidectomy for kidney transplant patients with secondary hyperparathyroidism: A practical overview

Kidney transplantation remains the best treatment for patients with end-stage kidney disease, and it could partially mitigate systemic disorders of mineral and bone metabolism caused by secondary hyperparathyroidism. However, persistent hyperparathyroidism is still observed in 30-60% of patients 1 year after kidney transplantation, leading to impairment of allograft function and a disturbance of mineral metabolism. The timing of parathyroidectomy varies among transplant centers because the possible negative effects of parathyroidectomy on allograft outcomes are still unclear. This review provides a comprehensive and detailed overview of the natural course of hyperparathyroidism following kidney transplantation and the effects of the timing and extent of parathyroidectomy on allograft function. It aims to provide useful information for surgeons to propose an appropriate intervention strategy to break the vicious cycle of post-kidney transplantation hyperparathyroidism and deterioration of allograft function.

Case report: Histoplasmosis presenting as asymptomatic hypercalcemia detected on routine laboratory testing in a pediatric kidney transplant recipient

Among all infections occurring in pediatric kidney transplant recipients, approximately 1%-5% are fungal. Most fungal infections occur in the first 6 months following kidney transplantation. We present the case of a 15-year-old boy with a history of a kidney transplant 4 years ago, who was found to have asymptomatic moderate hypercalcemia on routine laboratory testing, along with an acute deterioration of his kidney function markers. The cause of his acute kidney injury was likely related to hypercalcemia. An extensive workup for hypercalcemia revealed infection with Histoplasma capsulatum (histoplasmosis) with multiple pulmonary nodules. Hypercalcemia that was initially refractory to medical management resolved after initiating the antifungal treatment. Fungal granulomatous infections such as histoplasmosis should be considered in the differential diagnosis of hypercalcemia in an asymptomatic pediatric kidney transplant recipient.