Pseudohypoparathyroidism in a child

Abstract

Pseudohypoparathyroidism (Albright hereditary osteodystrophy) is a rare inherited disease of the skeletal system caused by impaired calcium and phosphorus metabolism that mimics hypoparathyroidism. It is often accompanied by mental and physical retardation. The disease is characterized by a pronounced clinical polymorphism, which is based on genetic heterogeneity. In the bone tissue there are changes typical of hyperparathyroidism: diffuse osteoporosis, the appearance of cysts (so-called brown tumors, giant cell tumors). Calcium, which is released from the bones, is deposited as calcifications in the subcutaneous tissue, as well as in the kidneys, muscles, myocardium, the walls of the large arteries, eye conjunctiva and periphery of the cornea. The cause of pseudohypoparathyroidism is a congenital defect — a genetically determined kidneys and skeleton resistance to parathyroid hormone. A diagnostic algorithm for monitoring of patients with pseudohypoparathyroidism is presented. In the presence of clinical symptoms that give reason to suspect pseudohypoparathyroidism, it is advisable to determine total and ionized calcium and phosphorus in the blood, urinary calcium excretion, as well as blood level of parathyroid hormone. Elevated blood parathyroid hormone and phosphorus along with low calcium in the blood and urine allow the diagnosis to be made. Timely diagnosis and clarification of the genesis of each syndrome are important for optimizing the treatment of these conditions and prevention of possible complications, as well as for determining the need for genetic counseling.