Hypoparathyroidism Flashcards
What is hypoparathyroidism?
An endocrine disorder characterised by low calcium, high phosphate, and ** low parathyroid hormone** levels.
What leads to decreased serum calcium levels in hypoparathyroidism?
Reduced/absent PTH secretion leads to:
* Decreased osteoclast activity
* Increased renal excretion of calcium
* Reduced renal excretion of phosphate
* Reduced activation of vitamin D
What are the acquired causes of hypoparathyroidism?
Acquired causes include:
* Anterior neck surgery
* Infiltration of parathyroid glands due to iron or copper deposits
* Functional causes due to hypermagnesaemia or severe hypomagnesaemia
* Transient causes like excess alcohol or severe acute illness
What congenital condition is the most common cause of hypoparathyroidism?
DiGeorge syndrome
What are the key features of DiGeorge syndrome?
Key features include:
* Hypoparathyroidism
* Abnormal facies
* Cardiac malformations
* Thymus underdevelopment
What clinical features result from neuromuscular excitability due to hypocalcaemia?
Clinical features include:
* Paraesthesia
* Muscle pains and cramps
* Stridor
* Tetany
* Seizures
What is Chvostek’s sign?
Tapping the facial nerve in front of the ear causes twitching of the corner of the mouth.
positive in hypocalcaemia
What is Trousseau’s sign?
Occluding blood supply to the arm results in carpopedal spasm.
positive in hypocalcaemia
What is a common finding on ECG in hypoparathyroidism?
Prolonged QT interval.
What is the priority in the acute management of hypoparathyroidism?
Correcting hypocalcaemia.
What treatment is given for severe hypocalcaemia (<1.9mmol/L) or symptomatic hypocalcaemia?
10% sodium gluconate in 5% glucose IV over 10 minutes.
What is the treatment for mild hypocalcaemia?
Oral calcium replacement.
What should be administered if concurrent hypomagnesaemia is present in acute hypoparathyroidism?
IV magnesium sulphate.
What is the management for chronic hypoparathyroidism?
Active vitamin D analogue therapy (e.g. calcitriol, alfacalcidol) and calcium-rich diet.
