Severe Hypocalcemia and Dramatic Increase in Parathyroid Hormone after Denosumab in a Dialysis Patient: A Case Report and Review of the Literature.

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is frequently present in advanced stages of chronic kidney disease (CKD) patients with high risk of fracture and elevated socioeconomic burden. Denosumab, an injectable human monoclonal antibody with affinity for nuclear factor-kappa ligand (RANKL), is an effective treatment for osteoporosis in postmenopausal women and men. Unlike the bisphosphonates, the pharmacokinetics and pharmacodynamics of denosumab are not influenced by the renal function and are being increasingly used for patients having CKD-MBD with low bone mineral density (BMD) to reduce the risk of fragility fractures. Hypocalcemia is a known side effect of this drug along with compensatory increase in parathyroid hormone (PTH). However, limited information is available in the literature regarding this potentially life-threatening side effect with denosumab in end-stage renal disease (ESRD) patients on dialysis. We present a patient with ESRD on peritoneal dialysis who developed severe symptomatic hypocalcemia and dramatic increase in PTH following denosumab therapy. She was conservatively managed with calcium supplementation and appropriate adjustment in calcium dialysate. We have also reviewed the literature on the use of denosumab in dialysis patients and looked at additional factors that may precipitate severe hypocalcemia in these patients. We believe that denosumab should be used with caution in dialysis patients since it may lead to profound hypocalcemia. Clinicians should ensure special attention in recognizing patients at risk of developing this serious adverse effect, so that prompt treatment and preventive strategies can be implemented.

A Rare Case of Mediastinal Bronchogenic Cyst Infected by Salmonella enteritidis.

Bronchogenic cysts are rare congenital malformations which arise from abnormal budding of the primitive tracheobronchial tube and can localize to either the mediastinum or lung parenchyma. They remain clinically silent in most adults unless they become infected or are large enough to compress adjacent structures. Infections involving bronchogenic cysts are often polymicrobial. Gram-positive, Gram-negative, and mycobacterial infections have been reported, though frequently a pathogen is not identified. We present the case of a 46-year-old female with known history of bronchogenic cyst who presented with suspected postobstructive pneumonia. She underwent cyst excision with culture positive for Salmonella enteritidis, an extremely rare finding on review of the literature. The patient recovered following a three-week course of antibiotics for extraintestinal salmonellosis.