Hypoparathyroidism

Last reviewed: 2 Nov 2022

Last updated: 27 Jul 2022

Hypoparathyroidism has wide variety of presentations: from the asymptomatic patient with dramatically low serum calcium to the acutely symptomatic patient with neuromuscular irritability, tetany, painful muscle cramps, stridor, and even seizures with low serum calcium in the accident and emergency department or recovery room.

Majority of cases are post-surgery for benign and malignant thyroid disorders, hyperparathyroidism, and laryngeal or other head and neck cancers.

Nonsurgical aetiologies include: rare genetic conditions and syndromes; autoimmune destruction of the glands; destruction or invasion due to tumour, radiation, or infiltration by iron or copper; hypomagnesaemia and magnesium depletion; and idiopathic.

Laboratory testing should confirm low ionised or albumin-corrected total calcium and low or inappropriately normal intact plasma parathyroid hormone, while also verifying normal serum magnesium and 25-hydroxyvitamin D levels.

If symptoms are present, replacement of calcium and/or magnesium should be promptly instituted with careful monitoring along with activated vitamin D metabolites for chronic treatment.

Definition

The disorder is caused by relative or absolute deficiency of plasma parathyroid hormone (PTH) synthesis and secretion. This leads to low albumin-corrected serum total calcium and elevated serum phosphate. Signs and symptoms can involve the neuromuscular, psychiatric, cardiac, ocular, dermatological, gastrointestinal, and renal/urological systems. Patients can also be asymptomatic.[1][2][3] Definitions of permanent post-surgical hypoparathyroidism vary, but persistently low intact PTH levels in the presence of hypocalcaemia requiring treatment for at least 6 months post-procedure generally indicates the condition is permanent.

History and exam

Key diagnostic factors

history of thyroid, parathyroid, or laryngeal surgery
chronic alcoholism
malnutrition, malabsorption, diarrhoea
muscle twitches, spasms, cramps
paraesthesias, numbness, tingling
poor memory, slowed thinking
Chvostek’s sign
convulsions
irregular heart beat, tachycardia
Trousseau sign

More key diagnostic factors

Other diagnostic factors

anxiety
dry hair, brittle nails
cataracts
history of mucocutaneous candidiasis
history of chronic transfusions in patients with thalassaemia
dyspnoea
laryngeal spasm

Other diagnostic factors

Risk factors

thyroid surgery
parathyroid surgery
hypomagnesaemia
moderate and chronic maternal hypercalcaemia (neonatal hypocalcaemia)
autosomal dominant conditions (e.g., mutations in CASR, GATA3)
hereditary haemochromatosis
transfusional iron overload in thalassaemia
Wilson's disease
metastatic cancer

More risk factors

Diagnostic investigations

1st investigations to order

serum calcium
serum albumin
ECG
plasma intact PTH
serum magnesium
serum 25-hydroxyvitamin D
serum phosphorus
serum creatinine

More 1st investigations to order

Investigations to consider

24-hour urine calcium, creatinine
24-hour magnesium, creatinine
liver function tests
arterial blood gases (ABGs)
serum free thyroxine, thyrotropin
morning cortisol and adrenocorticotropin (ACTH) stimulation testing
full blood count
serum iron, transferrin, ferritin
serum copper
ophthalmological examination
audiology
renal imaging
gene sequencing

More investigations to consider

Emerging tests

autoantibodies to 21-hydroxylase or type 1 interferons

Treatment algorithm

INITIAL

severe symptomatic hypocalcaemia (albumin-corrected serum total calcium <1.88 mmol [<7.5 mg/dL])

ACUTE

asymptomatic temporary postoperative hypocalcaemia

ONGOING

chronic hypoparathyroidism

Contributors

Authors

Dolores Shoback, MD

Professor of Medicine

University of California San Francisco

Endocrine Research Unit

San Francisco VA Medical Center

San Francisco

Disclosures

DS worked as a consultant for Takeda Pharmaceuticals, Ascendis, and Bridge Bio. She has received honorarium from Neopharma, and served as an expert witness for a patient-based malpractice case. For the past 5 years, DS was a speaker for the annual patients and caregivers conference on hypoparathyroidism for the US-based Hypoparathyroidism Association, and is an unpaid member of their medical advisory board. DS has given many CME lectures on hypoparathyroidism and calcium and bone and mineral disorders.

Quan-Yang Duh, MD

Professor of Surgery

Section of Endocrine Surgery

University of California San Francisco

San Francisco

Disclosures

QYD declares that he has no competing interests.

Acknowledgements

Professors Dolores Shoback and Quan-Yang Duh would like to gratefully acknowledge Professor Ronald Merrell, a previous contributor to this topic. RM declares that he has no competing interests.

Peer reviewers

Wail Malaty, MD

Adjunct Clinical Professor

Department of Family Medicine

University of North Carolina

Chapel Hill

Disclosures

WM declares that he has no competing interests.

Differentials
- Hypovitaminosis D
- Hypomagnesaemia
- Hypoalbuminemia
More Differentials
Guidelines
- Standards of care for hypoparathyroidism in adults: a Canadian and international consensus
- Postoperative hypoparathyroidism: diagnosis, prevention, and management in adults
More Guidelines
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Hypoparathyroidism

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Emerging tests

Treatment algorithm

severe symptomatic hypocalcaemia (albumin-corrected serum total calcium <1.88 mmol [<7.5 mg/dL])

asymptomatic temporary postoperative hypocalcaemia

chronic hypoparathyroidism

Contributors

Authors

Dolores Shoback, MD

Disclosures

Quan-Yang Duh, MD

Disclosures

Acknowledgements

Peer reviewers

Wail Malaty, MD

Disclosures

Differentials

Guidelines

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