Home | | Medicine and surgery: Principles and practice of medicine and surgery | Secondary hyperparathyroidism - Disorders of the parathyroids

Chapter: Medicine and surgery: Endocrine system

Secondary hyperparathyroidism - Disorders of the parathyroids

This is a syndrome of appropriately raised parathyroid hormone (PTH) in response to hypocalcaemia. - Definition, Incidence, Aetiology, Pathophysiology, Clinical features, Complications, Investigations, Management, Prognosis.

Secondary hyperparathyroidism

 

Definition

 

This is a syndrome of appropriately raised parathyroid hormone (PTH) in response to hypocalcaemia.

 

Incidence/prevalence

 

Increasing because of survival of renal patients on dialysis.

 

Aetiology

 

Common causes of chronic hypocalcaemia are chronic renal failure and vitamin D deficiency.

 

Pathophysiology

 

1. Chronic renal failure leads to reduced hydroxylation of inactive vitamin D (25-hydroxycholecalciferol 25(OH)D3) to the active vitamin D (calcitriol or 1,25(OH)2D3) in the kidney, and hence a functional vitamin D deficiency.

 

2. Chronic hypocalcaemia caused by vitamin D deficiency stimulates chronically increased parathyroid hormone secretion, which may cause some restoration of serum calcium. The failing kidney also retains phosphate which binds calcium, reducing serum levels further.

 

3. The pathological effects are due to raised PTH levels which cause loss of calcium from the skeleton.

 

Clinical features

 

This condition is usually asymptomatic and chronic, although hyperparathyroidism may cause vague bone pains. Hypocalcaemia is rarely severe.

 

Complications

 

Tertiary hyperparathyroidism (hypercalcaemia due to autonomous parathyroids).

 

Investigations

 

Low or normal serum calcium, with a raised PTH. Phosphate is high. Skeletal X-ray classically shows subperiosteal erosions, ‘brown tumours’ which are areas of radiolucency which mimic lytic bone lesions and a ground-glass appearance of the skull.

 

Management

 

Dietary calcium and Vitamin D supplements. For renal patients alfacalcidol and calcitriol are suitable forms of vitamin D, as they do not require hydroxylation by the kidney to become active.

Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
Medicine and surgery: Endocrine system : Secondary hyperparathyroidism - Disorders of the parathyroids |


Privacy Policy, Terms and Conditions, DMCA Policy and Compliant

Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.