Diagnosing Hypoparathyroidism
A diagnosis of hypoparathyroidisma requires either undetectable or inappropriately low levels of endogenous PTHb in the presence of hypocalcemia2,c
Lab tests can confirm hypoparathyroidism and rule out other conditions.2 Tests may include2,3:
- Serum total and ionized calcium levels
- Intact PTH
- Phosphorus/Phosphate
- Magnesium
- BUN/creatinine or eGFR (estimated glomerular filtration rate)
- 25-hydroxyvitamin D (25-OH vitamin D)
- 24-hour urinary calcium
In hypoparathyroidism, concentrations of active vitamin D and bone turnover markers are typically in the low-normal to low range.2
Following neck surgery, chronic hypoparathyroidism is established only after 6 months.
By second- or third-generation immunoassay.
(Albumin-adjusted) confirmed on at least two occasions separated by at least 2 weeks.
A physical examination should include testing for Chvostek’s and Trousseau’s signs2,3
Chvostek’s sign:
Tapping the patient's cheek over the path of the facial nerve causes twitching in the upper lip
Trousseau’s sign:
Inflating a blood pressure cuff on the patient's upper arm to a level above the systolic blood pressure for 3 minutes causes a painful carpal spasm
Neuromuscular irritability is the most common sign of hypocalcemia. Presentation depends on the severity and duration of hypocalcemia, and some patients may be asymptomatic
References: 1. NATPARA [package insert]. Shire-NPS Pharmaceuticals, Inc. 2. Brandi ML, Bilezikian JP, Shock D, et al. Management of hypoparathyroidism: summary statement and guidelines [published online ahead of print March 4, 2016]. J Clin Endocrinol Metab. 2016;101(6):2273-2283. doi: 10.1210/jc.2015-3907. 3. Shoback D. Clinical Practice. Hypoparathyroidism. N Engl J Med. 2008;359(4):391-403.