Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Hypocalcemia Testing Algorithm
Clinical Background
Hypocalcemia may be noted either acutely or chronically in hospitalized patients and outpatients.
Epidemiology
- Prevalence - occurs in 12-80% of critically ill patients
Etiology
- Acute hypocalcemia - intensive care unit patients (acute pancreatitis, sepsis)
- Hypoparathyroidism
- Autoimmune hypoparathyroidism
- Associated with polyglandular syndrome 1
- Symptoms - chronic mucocutaneous candidiasis, alopecia and vitiligo
- Autosomal recessive inheritance
- Acquired
- Surgical removal of parathyroids
- Radiation-induced parathyroid destruction
- Pseudohypoparathyroidism
- Resistance to parathyroid hormone (PTH)
- DiGeorge and velocardiofacial syndrome
- Rare congenital disorder
- Symptoms - cardiac, facial, thymic and thyroid abnormalities
- Severe early childhood infections
- Learning disorders
- Genetics - rearrangements on chromosome 22
- Vitamin deficiency
- Malabsorption
- Inadequate diet/sunlight
- Magnesium deficiency
- Malabsorption
- Inadequate diet
- Alcoholism
Pathophysiology
- Serum calcium concentration kept within a narrow physiologic range
- Control of calcium by parathyroid hormone, vitamin D (1,25), calcium and phosphate
Clinical Presentation
- Acute
- Neuromuscular - tetany, paresthesias, muscle spasms (Chvostek and Trousseau signs)
- Neuropsychiatric - anxiety, hallucinations, confusion
- Cardiovascular - bradycardia, ventricular arrhythmias, cardiac collapse
- Chronic
- Neuropsychiatric - cognitive deficits, extrapyramidal symptoms
- Dermatologic - dermatitis, dry skin
- Dental - enamel hypoplasia
- Ophthalmologic - cataracts
Treatment
- Treat according to etiology
- Calcium (may require intravenous calcium depending on calcium level) and vitamin D analogues
See Also
Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Hypocalcemia Testing Algorithm
Diagnosis
Diagnosis
- Indications for testing
- Suspect when symptoms occur and serum calcium is low
- Laboratory testing
- Repeat serum ionized calcium testing
- Intact PTH
Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Hypocalcemia Testing Algorithm
Tests generally appear in the order most useful for common clinical situations
| Test name: Calcium, Serum or Plasma
|
| ARUP #: 0020027 |
| Methodology: Spectrophotometry
|
| Use:
Diagnose hypocalcemia
|
| Limitations: |
| Follow-up:
|
| Test name: Parathyroid Hormone, Intact
|
| ARUP #: 0070346 |
| Methodology: Electrochemiluminescent Immunoassay
|
| Use:
Diagnose hypoparathyroidism
|
| Limitations: |
| Follow-up:
|
| Test name: Magnesium, Plasma or Serum
|
| ARUP #: 0020039 |
| Methodology: Spectrophotometry
|
| Use:
Differential diagnosis of hypocalcemia
|
| Limitations: |
| Follow-up:
|
| Test name: Albumin, Serum or Plasma by Spectrophotometry
|
| ARUP #: 0020030 |
| Methodology: Spectrophotometry
|
| Use:
Differential diagnosis of hypocalcemia
|
| Limitations: |
| Follow-up:
|
| Test name: Vitamin D, 25-Hydroxy
|
| ARUP #: 0080379 |
| Methodology: Chemiluminescent Immunoassay
|
| Use: Differential diagnosis of hypocalcemia |
Additional Tests Available
| Test name: Parathyroid Hormone, Intact with Calcium
|
| ARUP #: 0070172 |
| Methodology: Electrochemiluminescent Immunoassay
|
| Comments: |
| Test name: Calcium, Ionized, Whole Blood
|
| ARUP #: 0020140 |
| Methodology: Ion-Selective Electrode/pH-Electrode
|
| Comments: |
| Test name: Calcium, Ionized, Serum
|
| ARUP #: 0020135 |
| Methodology: Ion-Selective Electrode/pH-Electrode
|
| Comments: |
| Test name: Parathyroid Hormone-Related Peptide (PTHrP)
|
| ARUP #: 0093014 |
| Methodology: Immunoradiometric Assay
|
| Comments: |
References
General References
Arnold A, Shattuck TM, Mallya SM, Krebs LJ, Costa J, Gallagher J, Wild Y, Saucier K. Molecular pathogenesis of primary hyperparathyroidism. J Bone Miner Res.
2002;
17 Suppl 2:
N30-N36.
Clement B. Parathyroid pathophysiology. Semin Perioper Nurs.
1998;
7(
3):
186-192.
Dickerson RN. Treatment of hypocalcemia in critical illness--part 1. Nutrition.
2007;
23(
4):
358-361.
Dickerson RN. Treatment of hypocalcemia in critical illness--part 2. Nutrition.
2007;
23(
5):
436-437.
Maeda SS, Fortes EM, Oliveira UM, Borba VC, Lazaretti-Castro M. Hypoparathyroidism and pseudohypoparathyroidism. Arq Bras Endocrinol Metabol.
2006;
50(
4):
664-673.
Marx SJ. Hyperparathyroid and hypoparathyroid disorders. N Engl J Med.
2000;
343(
25):
1863-1875.
Murphy E, Bassett JH, Williams GR. Disorders of calcium metabolism. Practitioner.
2006;
250(
1686):
4-6, 8.
Silverberg SJ, Bilezikian JP. The diagnosis and management of asymptomatic primary hyperparathyroidism. Nat Clin Pract Endocrinol Metab.
2006;
2(
9):
494-503.
Younes NA, Shafagoj Y, Khatib F, Ababneh M. Laboratory screening for hyperparathyroidism. Clin Chim Acta.
2005;
353(
1-2):
1-12.
Medical Reviewers
Lehman, Christopher M., M.D. Co-Medical Director, University Hospital Clinical Laboratory; Associate Professor, Clinical Pathology, University of Utah
Meikle, A. Wayne, M.D. Medical Director, RIA and Endocrinology at ARUP Laboratories; Professor of Internal Medicine and Pathology, University of Utah
Roberts, William L. , M.D., Ph.D. Medical Director, Automated Core Laboratory at ARUP Laboratories; Professor, Pathology, University of Utah
Comprehensive Review: March 2008
Last Update: March 2008
