Overview

• Abnormally high PTH levels in blood due to overactivity of the parathyroid glands
  • PTH → increases serum calcium & decreases serum phosphate. Secretion is stimulated by decrease in serum calcium.
• F>M (3:1), most cases occur >50 yrs old
• Primary HPT → parathyroid gland adenoma (benign tumour). High calcium levels.
• Secondary HPT → CKD, Malnutrition, Vitamin D Deficiency (reduced sunlight, nutritional deficiency). Low calcium levels.
• Tertiary HPT → caused by persistent sHPT. High calcium levels due to chronic increase in PTH. Hyerplasia of the parathyroid glands after correction of underlying renal disorder.

Making Diagnosis

Clinical Features:

• pHPT → polydipsia, polyuria, anorexia, nausea, constipation, bone pain (esp. back pain), renal stones, low mood. Majority of patients are asymptomatic.

  <aside> 💡 pHPT ⇒ painful bones, renal stones, abdominal groans & psychic moans (Symptoms of Hypercalcaemia)

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• sHPT + tHPT → symptoms related to underlying cause (ie. renal failure). Bone pain and increased risk of fractures.

Investigations:

• Primary vs Tertiary ⇒ PTH will be raised or inappropiately normal in primary, however will be markedly raised in tertiary.
• Secondary ⇒ low calcium. Low phosphate if vitamin D deficiency (osteomalacia), High phosphate if CKD.

• Ultrasound → look for parathyroid gland adenoma.