hypoparathyroidism

see also:

• parathyroid hormone (PTH)

• hypoparathyroidism is usually due to excision of parathyroid glands and causes slowly developing hypocalcaemia over days/wks leading to tetany

• surgical
  • post-thyroidectomy with incidental removal of parathyroid glands or their blood supply
  • parathyroidectomy
• rare causes:
  • Kenny-Caffey Syndrome
  • automimmune destruction of glands
  • haemochromatosis causing gland dysfunction
  • genetic disorders involving chromosome 22q11 microdeletion syndrome (eg. DiGeorge syndrome)
  • hypomagnesaemia
  • rare congenital form due to defect in calcium receptor
  • Barakat syndrome - may be familial, a genetic development disorder resulting in hypoparathyroidism, sensorineural deafness and renal disease

• low serum parathyroid hormone (PTH) levels in cases of hypocalcaemia

• Rx episodes of hypocalcaemia with iv calcium and then oral calcium
• there is no readily available replacement PTH Rx although injectable recombinant PTH may be available
  • teriparatide (Forteo), a biosimilar peptide to parathyroid hormone, may be given by injection
• long term Rx is usually with vitamin D analogs and oral calcium supplements