Back to: Endocrinology
Parathyroid conditions
a) Depletion of PTH
Hypoparathyroidism
This is a condition due to an impairment in PTH secretion
– Primary – due to autoimmune damage, congenital DiGeorge syndrome
– Secondary – due to radiation, surgery or low Magnesium (needed for synthesis)

Symptoms:
These resemble hypocalcaemia raising excitability of nerve and muscle:
– Tetany –> muscle twitching, cramping and spasm
– Gives numbness and tingling around mouth (circumoral)
– Trousseau sign – inflating cuff above systolic BP –> muscle contraction due to increase excitability
– Chvostek sign – tap on zygomatic bone –> twitching of facial muscle as it is more excitable.
Diagnosis:
Blood test shows decreased PTH and decreased Ca2+, but increased Phosphate
Management:
Calcium supplements + Alfacalcidol (synthetic Vitamin D3)
Pseudohypoparathyroidism
This occurs due to a failure of the organs to respond to PTH
– Can be autosomal dominant – characterized by short stature with short 4th and 5th digits, round face
– Alternate form is pseudopseudohypoparathyroidism – same features but with normal biochemistry
Diagnosis:
– Blood test shows decreased Ca2+, but increased Phosphate and PTH
– During infusion of PTH, urinary cAMP and Phosphate do not rise unlike in hypoparathyroidism.
Management:
Calcium supplements + Alfacalcidol (synthetic Vitamin D3)
b) Excess of PTH
Primary Hyperparathyroidism
This is a condition which leads to excess PTH due to a disorder of the parathyroid gland itself
Causes:
80% due to parathyroid adenoma, also due to parathyroid hyperplasia or parathyroid carcinoma
Symptoms:
It often feels asymptomatic, but there are signs related to high serum calcium:
– Bones –> Ectopic calcification (e.g. cornea) and bone pain (due to bone resorption)
– Stones –> Renal stones and renal failure
– Groans –> Abdominal pain, vomiting, constipation and weakness
– Psychic Moans –> Confusion + irritability + Depression
Diagnosis:
– Blood test increased PTH (can be normal), increased Ca2+, increased urinary cAMP, increased ALP and decreased Phosphate
– Urine Calcium: creatinine clearance ratio > 0.01
– X-ray –> osteitis fibrosa cystica of phalanges + “pepper-pot” skull appearance
Treatment:
– If Ca2+ is mildly raised and there is no organ damage, conservatively give fluids
– If moderate to severe, surgical total parathyroidectomy or cinacalcet if unsuitable for surgery.
Secondary Hyperparathyroidism
This is excess PTH due to a disease extrinsic to gland
– The most common cause is chronic renal failure.
– Renal insufficiency gives decreased phosphate excretion so Phosphate binds serum Ca2+
– Less free calcium stimulates parathyroid glands to secrete excess PTH
Diagnosis:
Blood test shows increased PTH + ALP + Phosphate but decreased Ca2+ and Vitamin D
Treatment:
Vitamin D supplements, else surgery if bone pain/pruritus/ectopic calcifications.
Tertiary hyperparathyroidism
This occurs after prolonged secondary hyperparathyroidism, causing glands to act autonomously after undergoing hyperplasia, which is seen in chronic renal failure
– Leads to increased Calcium from unlimited PTH secretion
– Increased PTH, Calcium, urinary cAMP, ALP
– Decreased Phopshate and Vitamin D
Malignant hyperparathyroidism
Parathyroid-related protein is produced by some squamous cell lung, breast and renal carcinomas
– This protein mimics PTH resulting in increased calcium
Treatment:
Need to treat the underlying cancer