Parathyroid Flashcards
Where are the parathyroid glands and what is there main role?
You have 4 parathyroid glands, located next to the 2 thyroid lobes in the neck.
Their main role is calcium homeostasis. They contain Chief cells which secrete PTH. This works to raise blood calcium.
Role of PTH?
In the bones it increases osteoclast activity, leading to Ca2+ and PO4- release into the blood.
In the kidneys it increases calcium reabsorption.
In the gut it activates vitamin D enabling more GI Ca2+ absorption.
Primary hyperparathyroidism - causes and symptoms
Solitary adenoma, hyperplasia, carcinoma.
Symptoms of hypercalcaemia: Bones, stones, moans and groans.
Typically elderly women with excessive thirst and polyuria.
Primary hyperparathyroidism- test results
Ca2+ raised
PO4- low
PTH raised or normal.
Primary hyperparathyroidism- treatment
Total parathyroidectomy.
Conservative management with cinacalcet.
Secondary hyperparathyroidism - cause
Excess PTH production, secondary to low serum Ca2+.
Typically in CKD.
Secondary hyperparathyroidism- test results
PTH- raised
Ca2+ low
PO4- raised
Tertiary hyperparathyroidism- cause and test results
Due to hyperplasia of PT gland after correction of renal disorder.
PTH- raised
Ca2+ raised
PO4- low/normal
Hypoparathyroidism- cause
Primary- due to gland failure. Secondary to thyroid surgery.
Pseudo and psueodopseudohyperparathyroidism- genetic conditions. Failure of target cells to respond to PTH. Also see short stature, short 4th and 5th metacarpals, low IQ and a calcified basal ganglia. In pseudo you see a high PTH, low Ca2+ and high PO4-.
Hypoparathyroidism- tests and treatment
PTH - low
Ca2+ low
PO4- raised
Treatment is alfacalcidol
Hypothyroidism- symptoms
Hypocalcaemia causes tetany, muscle spasms, paraesthesia, pins and needles in hands and feet, Trousseau’s sign- carpel spasm if you occlude the brachial artery.
Chvostek’s sign- tapping over parotid causes facial spasm
ECG- prolonged QT
