- Hypoparathyroidism is a relative or absolute deficiency of parathyroid hormone due to disease, surgical injury, congenital absence or malfunction of parathyroid glands. Manifested as hypocalcemia, producing symptoms ranging from paresthesias to tetany.
- Parathyroid hormone (PTH) mobilizes calcium from bone, stimulates reabsorption of calcium in distal nephron, and enhances formation of the active vitamin D metabolite, 1,25-dihydroxy-vitamin D.
- Acquired hypoparathyroidism
- Accidental removal or damage to parathyroid glands or their blood supply during neck surgery. Decreased parathyroid levels may be transient or permanent.
- Autoimmune: May develop as isolated destruction of parathyroid or part of autoimmune polyendocrine syndrome 1 (APS-1).
- Deposition of heavy metals in gland (copper or iron), radiation-induced destruction, and metastatic infiltration are less common acquired forms of hypoparathyroidism.
- Genetic hypoparathyroidism: May be a manifestation of multiple genetic aberrancies. Most commonly involves calcium-sensing receptor.
- Functional hypoparathyroidism: May be secondary to either hyper- or hypomagnesemia (seen in alcoholics). Parathyroid adenoma may suppress normal parathyroid gland.
- Acquired hypoparathyroidism
- System(s) affected: Endocrine/Metabolic; Musculoskeletal; Nervous
- May occur in premature infants
- Neonates born to hypercalcemic mothers may experience suppression of developing parathyroid glands.
- Congenital absence of parathyroids
- May appear later in childhood as autoimmune or APS-1
Hypocalcemia is fairly common in the elderly; however, it is rarely secondary to hypoparathyroidism.
Use of magnesium as a tocolytic may induce functional hypoparathyroidism.
Thyroid and parathyroid disease conditions resulting in surgical intervention are more common in women. More than 250,000 individuals undergo thyroid or parathyroid procedures. Affects individuals of all ages.
Estimated to occur after 0.5–6.6% of total thyroidectomies; varies depending on skill and experience of surgeon and extent of surgical procedure
Varies widely depending upon etiology
- Neck surgery, especially thyroid
- Neck trauma
- Head and neck malignancies
- Family history of hypocalcemia
- Autoimmune endocrinopathy
- Mutations in transcription factors or regulators of parathyroid gland development:
- Hypoparathyroidism may present as a component of a larger genetic syndrome (APS-1 or DiGeorge Syndrome) or in isolation (x-linked hypoparathyroidism)
- May be autosomal dominant (DiGeorge), autosomal recessive (APS-1), or x-linked recessive (x-linked hypoparathyroidism)
- PTH gene mutations:
- Hypoparathyroidism presents in isolation
- May be autosomal dominant or autosomal recessive
- Mitochondrial disorders with hypoparathyroidism:
- Typically hypoparathyroidism exists in conjunction with other congenital anomalies or metabolic derangements
- Maternal transmission
Intraoperative identification and preservation of parathyroid tissue
- PTH is involved in the control of serum ionized calcium levels. PTH:
- Mobilizes calcium and phosphorus from bone stores
- Stimulates formation of 1,25-dihydroxy-vitamin D
- Stimulates reabsorption of calcium in the distal nephron and phosphate excretion
- Loss of PTH action results in hypocalcemia, hyperphosphatemia, and hypercalciuria
- Magnesium is crucial for PTH secretion and activation of the PTH receptor; hypo- or hypermagnesemia may result in functional hypoparathyroidism.
- Postsurgical: Transient or permanent
- Metastatic carcinoma
- Wilson disease
- Hypo- or hypermagnesemia
Commonly Associated Conditions
- DiGeorge syndrome
- Autoimmune polyendocrine syndrome type 1 (APS-1). Features include:
- Chronic yeast infections
- Addison disease
- Chronic hypocalcemia may be asymptomatic.
- Circumoral or distal extremity paresthesias
- Muscle cramps
- Neuropsychiatric symptoms
- Previous neck trauma or surgery
- Head and neck irradiation
- Family history of hypocalcemia
- Presence of other autoimmune endocrinopathies
- Surgical scar on neck
- Chvostek sign: Positive sign is ipsilateral twitching of the upper lip upon tapping the facial nerve on the cheek.
- Trousseau sign: Positive sign is painful carpal spasm after 3-minute occlusion of brachial artery with blood pressure cuff.
- Laryngo- or bronchospasm
- Cardiac arrhythmias or failure
- Dry hair, brittle nails
Diagnostic Tests & Interpretation
Initial lab tests
- Blood work ()[C]:
- Calcium: Total and ionized (low)
- Albumin (correct serum calcium level for albumin)
- Corrected serum calcium = Total serum calcium + 0.8 (4.0 – serum albumin)
- Phosphorus (high)
- Intact PTH (low or inappropriately normal)
- Magnesium (low or high may cause hypoparathyroidism; may also be normal)
- BUN, creatinine (normal)
- 25 OH vitamin D level
- Urinary calcium (normal or high) (1)[C]
Follow-Up & Special Considerations
- EKG may show prolonged QT and ST (secondary to hypocalcemia) (1)[C].
- Gene sequencing may be required to diagnose genetic causes.
- Evaluation of other hormone levels may be required to diagnose APS-1.
Radiographs may show absent tooth roots, calcification of cerebellum, choroid plexus, or cerebral basal ganglia.
Parathyroid gland parenchymal tissue completely or almost completely replaced by fat
- Vitamin D deficiency/resistance
- Pseudohypoparathyroidism: Resistance of end organs to PTH resulting in hypocalcemia with high PTH
- Renal failure
- Familial hypocalcemia
- No formal guidelines for treatment exist at this time.
- Severe symptoms (tetany, seizures, cardiac failure, laryngospasm, bronchospasm):
- Short-term management (1)[C]
- IV calcium gluconate: 1 or 2 g, each infused over a period of 10 minutes. Central venous catheter preferred because calcium-containing solutions can irritate surrounding tissues.
- Follow with infusion 10 g calcium gluconate in 1 L 5% dextrose water at a rate of 1–3 mg calcium gluconate/kg of body weight/hour
- Long-term management
- Oral calcium carbonate: 500–1000 mg of elemental calcium 3 times a day. Constipation is a common side effect (2)[C]
- Calcitriol: Start at 0.25 mcg once to twice daily. Max dose 2 mcg daily (1)[C].
- Short-term management (1)[C]
- Asymptomatic, mildly symptomatic, or mild hypocalcemia
- Oral calcium: as above. Adjust to control symptoms and achieve target serum calcium.
- Calcitriol: As above
Oral vitamin D: 25,000–100,000 units/day (1)[C]
- Monitor EKG during calcium repletion.
- Maintenance therapy:
- May require lifelong treatment with calcium and calcitriol
- Maintain serum calcium in low normal range: 8.0–8.5 mg/dL (2.0–2.12 mmol/L) (1,2)[C]
- Adequate control requires careful attention to avoid over- or undertreatment.
- If hypercalcemia occurs, hold therapy until calcium returns to normal.
- Treat magnesium deficiency if present.
- Phosphate binders required if high calcium-phosphate product
- Thiazide diuretics combined with low-salt diet may be used to prevent hypercalciuria, nephrocalcinosis, and nephrolithiasis.
- Oral calcium administration and vitamin D supplementation post-thyroidectomy may reduce risk for symptomatic hypocalcemia after surgery (3)[C].
Issues for Referral
May require referral to endocrinologist
Parathyroid hormone 1–34 (subcutaneous) (4)[C]
- May be as effective as calcitriol for maintaining growth and serum calcium levels in children with chronic hypoparathyroidism
- Unproven method of treatment at this juncture; further study required
See Treatment, Medications
- QT prolongation
Monitor for hypocalcemic symptoms.
- Resolution of hypocalcemic symptoms
- Patient educated on hypoparathyroidism and treatment protocol
- Outpatient follow-up scheduled
- Goal of treatment is to reach a total corrected serum calcium level in low normal range (8.0–8.5 mg/dL or 2.0–2.12 mmol/L), 24-hour urine calcium below 300 mg and calcium-phosphate product below 55.
- Outpatient measurement of serum calcium, phosphorus, and creatinine weekly to monthly during initial management
- Once regimen stable, measure serum calcium, phosphate, and creatinine twice yearly.
- Measurement of urine calcium and creatinine twice yearly
- Annual slit lamp and ophthalmologic evaluation are recommended.
Low phosphate diet in patients with hyperphosphatemia
- Provide careful and detailed instructions about maintenance therapy.
- Explain importance of periodic blood chemistry evaluations.
- Instruct patient to watch for signs and symptoms of over- and undertreatment.
- Hypoparathyroidism following neck surgery is often transient.
- Length of required treatment may vary depending on origin.
- Symptoms and serum calcium can be well controlled with treatment.
- Neuromuscular symptoms (resolve with treatment)
- Hypercalciuria, nephrocalcinosis, nephrolithiasis
- Hypercalcemia with excessive treatment
- Calciphylaxis with high calcium-phosphate product
- Basal ganglia calcifications with Parkinsonian symptoms
- If condition starts early in childhood: Stunting of growth, malformation of teeth, mental retardation
1. Shoback D. Clinical practice. Hypoparathyroidism. N Engl J Med. 2008;359:391–403.
2. Cooper MS, Gittoes NJ. Diagnosis and management of hypocalcaemia. BMJ. 2008;336:1298–302.
3. Roh JL, Park CI et al. Routine oral calcium and vitamin D supplements for prevention of hypocalcemia after total thyroidectomy. Am J Surg. 2006;192:675–8.
4. Winer KK, Sinaii N, Reynolds J, Peterson D, Dowdy K, Cutler GB et al. Long-Term Treatment of 12 Children with Chronic Hypoparathyroidism: A Randomized Trial Comparing Synthetic Human Parathyroid Hormone 1–34 versus Calcitriol and Calcium. The Journal of clinical endocrinology and metabolism. 2010
Betterle C, Zanchetta R. Update on autoimmune polyendocrine syndromes (APS). Acta Biomed Ateneo Parmense. 2003;74:9–33.
Gunn IR, Gaffney D. Clinical and laboratory features of calcium-sensing receptor disorders: a systematic review. Ann Clin Biochem. 2004;41:441–58.
Thakker RV. Genetics of endocrine and metabolic disorders: parathyroid. Rev Endocr Metab Disord. 2004;5:37–51.
36976004 Hypoparathyroidism (disorder)
- The most common etiology of hypoparathyroidism is damage to the parathyroid glands or blood supply during neck surgery; other causes include congenital and infiltrative disease.
- Patients with hypoparathyroidism may be asymptomatic or present with symptoms of hypocalcemia, including paresthesias, tetany, or laryngospasm.
- In the presence of severe neuromuscular or cardiac symptoms, emergent treatment should begin with parenteral calcium.
- Treatment with calcium and calcitriol may be required transiently or permanently depending on origin of hypoparathyroidism.
- Treatment goal is total serum calcium in low-normal range: 8.0–8.5 mg/dL (2.0–2.12 mmol/L).