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Endocrinology & Metabolic

Hypoparathyroidism

Hypoparathyroidism is deficient parathyroid hormone secretion or action, most often after neck surgery, causing hypocalcaemia with hyperphosphataemia; acute symptoms need emergency calcium treatment, while chronic care balances active vitamin D and calcium against hypercalciuria and renal injury.

In a nutshell

Hypoparathyroidism is low calcium with high phosphate and an inappropriately low or normal PTH, usually after neck surgery. Acute tetany, seizures, laryngospasm or QT prolongation needs monitored IV calcium. Chronic treatment uses active vitamin D and calcium, targeting the lower calcium range while monitoring urinary calcium and renal function.

Classic presentation

A patient after total thyroidectomy develops perioral tingling and carpopedal spasm with low calcium, high phosphate and an inappropriately normal PTH.

Key points

  • Low calcium plus inappropriately low/normal PTH is hypoparathyroidism; correct magnesium before confirming chronic disease.
  • Post-surgical disease may recover; chronic postsurgical hypoparathyroidism is defined after 12 months in the 2025 ESE guideline.
  • Use alfacalcidol or calcitriol plus calcium, not native vitamin D alone as the main treatment.
  • Aim for symptom-free calcium in the lower reference range and avoid treatment-induced hypercalciuria.
  • PTH replacement is specialist therapy for selected patients inadequately controlled on optimised conventional treatment.

First-line investigation

Concurrent adjusted or ionised calcium, phosphate, PTH, magnesium, vitamin D and renal function, with ECG if symptomatic.

Management

Treat the calcium emergency

  • Give monitored IV calcium for tetany, seizure, laryngospasm, significant QT prolongation/arrhythmia or marked symptomatic hypocalcaemia, while correcting magnesium.2,4

Confirm the PTH phenotype

  • Measure concurrent calcium, phosphate, PTH, magnesium, vitamin-D status and renal function; low/normal PTH is inappropriate when calcium is low.1

Replace active vitamin D and calcium

  • Use alfacalcidol or calcitriol with adequate calcium intake/supplements, titrated to symptoms and lower-range calcium rather than high-normal calcium.1,4

Protect the kidneys

  • Monitor urinary calcium, phosphate, magnesium and renal function; adjust treatment and consider specialist thiazide therapy if hypercalciuria develops.1,4

Refer refractory disease

  • Refer for specialist PTH-replacement assessment when symptomatic or biochemical control remains inadequate despite optimised conventional therapy, especially with renal complications or poor quality of life.1

Monitor recovery and safety

  • Recheck biochemistry after treatment changes, monitor stable disease regularly, assess PTH recovery after surgery and safety-net for hypo- or hypercalcaemia symptoms.1,2

Exam traps

  • A normal-range PTH is inappropriate when calcium is low.
  • Low magnesium can mimic hypoparathyroidism and must be corrected before diagnosing chronic disease.
  • Native vitamin D may not replace the missing renal activation; active vitamin D is usually required.
  • Chasing a high-normal calcium increases hypercalciuria and renal risk.
  • Do not assume postoperative hypoparathyroidism is permanent before the appropriate recovery period.

Illustrations

Signs of hypocalcaemia: Chvostek and TrousseauA clinical illustration of Chvostek's sign and Trousseau's sign as bedside manifestations of neuromuscular hyperexcitability in hypocalcaemia.Tmdswan, Wikimedia Commons · CC-BY-SA-4.0
ECG showing a prolonged QT intervalAn ECG example with a prolonged QT interval, illustrating the cardiac effect that increases urgency in symptomatic hypocalcaemia.Bionerd, Wikimedia Commons · CC-BY-3.0

Key sources

  1. European Society of Endocrinology: revised clinical practice guideline for treatment of chronic hypoparathyroidism in adults (Current international guideline used because no dedicated UK chronic hypoparathyroidism guideline was identified; covers diagnosis, lower-range calcium targets, active vitamin D/calcium, PTH replacement assessment, urinary calcium and biochemical monitoring; published 13 November 2025 and accessed 4 August 2026.)Updated 13 Nov 2025
  2. Society for Endocrinology: emergency management of acute hypocalcaemia in adult patients (UK endocrine emergency guidance for acute symptomatic hypocalcaemia, with 2019 dose addendum; accessed 4 August 2026.)
  3. Society for Endocrinology: Hypoparathyroidism patient information (UK Society for Endocrinology information on causes, symptoms and conventional treatment of hypoparathyroidism; accessed 4 August 2026.)
  4. British National Formulary (BNF) (Current UK prescribing information for calcium salts, alfacalcidol, calcitriol, cholecalciferol, magnesium and thiazide diuretics; product-specific doses, contraindications, interactions and monitoring must be checked at the point of care; accessed 4 August 2026.)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.