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Hypocalcemia
Aka: Hypocalcemia, Low Serum Calcium, Serum Calcium Decreased
- See Also
- Medication-Induced Hypocalcemia
- Causes
- Most common causes
- Hypoalbuminemia
- Vitamin D Deficiency
- Miscellaneous and Multifactorial causes
- Hypoalbuminemia
- Use Corrected Serum Calcium for albumin or Ionized Calcium to interpret Calcium level
- Gram-Negative Sepsis (Marker for increased Sepsis related mortality)
- Zaloga (1987) Ann Intern Med 107(1): 36-41 [PubMed]
- Low Parathyroid Hormone (or normal Parathyroid Hormone level)
- Hypomagnesemia
- Hypoparathyroidism
- Urine Calcium to Creatinine Ratio decreased
- Serum Phosphorus increased
- Calcium-sensing receptor activating mutation
- Serum Phosphorus increased
- Urine Calcium to Creatinine Ratio increased
- High Parathyroid Hormone (secondary Hyperparathyroidism as a reflex response to Hypocalcemia)
- Low Serum Phosphate
- See Medication-Induced Hypocalcemia
- Pancreatitis
- Vitamin D Deficiency
- Decreased 25-hydroxyvitamin D
- High or normal Serum Phosphate
- Rhabdomyolysis
- Tumor lysis
- Acute Renal Failure or Chronic Kidney Disease
- Decreased 1,25-dihydroxyvitamin D
- See Renal Osteodystrophy
- Pseudohypoparathyroidism (genetic PTH resistance)
- Associated with adequate PTH levels, but a PTH receptor defect
- Associated with a shortened fourth digits on the hands and feet
- Symptoms
- Cardiovascular (Systolic Dysfunction)
- Dyspnea
- Edema
- Palpitations
- Syncope
- Neurologic
- Headache
- Muscular fasciculations, Muscle cramping, Muscle spasms, Muscle stiffness
- Seizures
- Paresthesias
- Circumoral numbness
- Nervousness
- Weakness
- Decreased Vision
- Chronic Hypocalcemia may demonstrate Parkinsonism, Dementia
- Gastrointestinal
- Vomiting
- Diarrhea
- Dysphagia
- Abdominal Pain
- Psychiatric
- Anxiety
- Depressed Mood
- Signs
- Cardiovascular
- Hypotension
- Heart Failure
- Respiratory
- Bronchospasm (Wheezing)
- Laryngospasm (Stridor)
- Neurologic
- Tetany
- Carpopedal Spasm (Trousseau's Sign)
- Chvostek's Sign
- Skin
- Hair Loss (due to dry, brittle hair)
- Dry, puffy skin
- Eyes
- Premature Cataracts
- Papilledema
- Diagnostics: Electrocardiogram (EKG)
- Prolonged QTc with severe Hypocalcemia (may degenerate into Torsades de Pointes)
- Labs
- Serum Calcium low
- Total Corrected Serum Calcium (for Serum Albumin) or
- Ionized Calcium
- Serum Electrolytes
- Serum Phosphorus
- Serum Magnesium
- Serum Creatinine
- Serum Albumin (used for Corrected Serum Calcium)
- Parathyroid Hormone (PTH)
- Vitamin D
- 25-Hydroxyvitamin D
- 1,25-Dihydroxyvitamin D
- Urine Calcium to Creatinine Ratio (24 hour Urine Calcium and Urine Creatinine)
- Evaluation
- Confirm Hypocalcemia
- Obtain Corrected Serum Calcium (for Serum Albumin) or Ionized Calcium
- Correct Serum Calcium 0.8 mg/dl for every 1 gram Serum Albumin is below normal range
- Obtain labs to narrow causes (see labs above)
- Parathyroid Hormone
- Serum Electrolytes (Serum Phosphate, Serum Magnesium, Serum Creatinine)
- Vitamin D (25-Hydroxyvitamin D, 1,25-Dihydroxyvitamin D)
- Initial correction of abnormalities (if indicated)
- Treat severe, symptomatic Hypocalcemia (See Calcium Replacement)
- Correct Serum Magnesium if abnormal
- Parathyroid Hormone (PTH) Low or Normal
- Serum Magnesium Low
- Hypomagnesemia
- Serum Magnesium Normal
- Hypoparathyroidism
- Parathyroid Hormone (PTH) High
- Serum Creatinine increased
- Evaluate for Chronic Kidney Disease
- Manage as Renal Osteodystrophy
- Serum Creatinine normal
- Serum Phosphorus high
- Pseudohypoparathyroidism (genetic PTH resistance)
- Serum Phosphorus normal or low
- Treat as Vitamin D Deficiency if low 25-Hydroxyvitamin D
- Management
- See Calcium Replacement
- Consider replacement if Corrected Serum Calcium <10 mg/dl
- References
- Cooper (2008) BMJ 336(7656): 1298-302 [PubMed]
- Michels (2013) Am Fam Physician 88(4): 249-57 [PubMed]
- Sell (2022) Am Fam Physician 105(3): 289-98 [PubMed]