II. Causes

  1. Most common causes
    1. Hypoalbuminemia
    2. Vitamin D Deficiency
  2. Miscellaneous and Multifactorial causes
    1. Hypoalbuminemia
      1. Use Corrected Serum Calcium for albumin or Ionized Calcium to interpret Calcium level
    2. Gram-Negative Sepsis (Marker for increased Sepsis related mortality)
      1. Zaloga (1987) Ann Intern Med 107(1): 36-41 [PubMed]
  3. Low Parathyroid Hormone (or normal Parathyroid Hormone level)
    1. Hypomagnesemia
    2. Hypoparathyroidism
      1. Urine Calcium to Creatinine Ratio decreased
      2. Serum Phosphorus increased
    3. Calcium-sensing receptor activating mutation
      1. Serum Phosphorus increased
      2. Urine Calcium to Creatinine Ratio increased
  4. High Parathyroid Hormone (secondary Hyperparathyroidism as a reflex response to Hypocalcemia)
    1. Low Serum Phosphate
      1. See Medication-Induced Hypocalcemia
      2. Pancreatitis
      3. Vitamin D Deficiency
        1. Decreased 25-hydroxyvitamin D
    2. High or normal Serum Phosphate
      1. Rhabdomyolysis
      2. Tumor lysis
      3. Acute Renal Failure or Chronic Kidney Disease
        1. Decreased 1,25-dihydroxyvitamin D
        2. See Renal Osteodystrophy
      4. Pseudohypoparathyroidism (genetic PTH resistance)
        1. Associated with adequate PTH levels, but a PTH receptor defect
        2. Associated with a shortened fourth digits on the hands and feet

III. Symptoms

  1. Cardiovascular (Systolic Dysfunction)
    1. Dyspnea
    2. Edema
    3. Palpitations
    4. Syncope
  2. Neurologic
    1. Headache
    2. Muscular Fasciculations, Muscle cramping, Muscle spasms, Muscle stiffness
    3. Seizures
    4. Paresthesias
    5. Circumoral numbness
    6. Nervousness
    7. Weakness
    8. Decreased Vision
    9. Chronic Hypocalcemia may demonstrate Parkinsonism, Dementia
  3. Gastrointestinal
    1. Vomiting
    2. Diarrhea
    3. Dysphagia
    4. Abdominal Pain
  4. Psychiatric
    1. Anxiety
    2. Depressed Mood

IV. Signs

  1. Cardiovascular
    1. Hypotension
    2. Heart Failure
  2. Respiratory
    1. Bronchospasm (Wheezing)
    2. Laryngospasm (Stridor)
  3. Neurologic
    1. Tetany
    2. Carpopedal Spasm (Trousseau's Sign)
    3. Chvostek's Sign
  4. Skin
    1. Hair Loss (due to dry, brittle hair)
    2. Dry, puffy skin
  5. Eyes
    1. Premature Cataracts
    2. Papilledema

V. Diagnostics: Electrocardiogram (EKG)

  1. Prolonged QTc with severe Hypocalcemia (may degenerate into Torsades de Pointes)

VII. Evaluation

  1. Confirm Hypocalcemia
    1. Obtain Corrected Serum Calcium (for Serum Albumin) or Ionized Calcium
    2. Correct Serum Calcium 0.8 mg/dl for every 1 gram Serum Albumin is below normal range
  2. Obtain labs to narrow causes (see labs above)
    1. Parathyroid Hormone
    2. Serum Electrolytes (Serum Phosphate, Serum Magnesium, Serum Creatinine)
    3. Vitamin D (25-Hydroxyvitamin D, 1,25-Dihydroxyvitamin D)
  3. Initial correction of abnormalities (if indicated)
    1. Treat severe, symptomatic Hypocalcemia (See Calcium Replacement)
    2. Correct Serum Magnesium if abnormal
  4. Parathyroid Hormone (PTH) Low or Normal
    1. Serum Magnesium Low
      1. Hypomagnesemia
    2. Serum Magnesium Normal
      1. Hypoparathyroidism
  5. Parathyroid Hormone (PTH) High
    1. Serum Creatinine increased
      1. Evaluate for Chronic Kidney Disease
      2. Manage as Renal Osteodystrophy
    2. Serum Creatinine normal
      1. Serum Phosphorus high
        1. Pseudohypoparathyroidism (genetic PTH resistance)
      2. Serum Phosphorus normal or low
        1. Treat as Vitamin D Deficiency if low 25-Hydroxyvitamin D

VIII. Management

  1. See Calcium Replacement
  2. Consider replacement if Corrected Serum Calcium <10 mg/dl

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Related Studies

Ontology: Hypocalcemia (C0020598)

Definition (MSH) Reduction of the blood calcium below normal. Manifestations include hyperactive deep tendon reflexes, Chvostek's sign, muscle and abdominal cramps, and carpopedal spasm. (Dorland, 27th ed)
Definition (CSP) reduction of the blood calcium below normal; manifestations include hyperactive deep tendon reflexes, muscle and abdominal cramps, and carpopedal spasm.
Concepts Pathologic Function (T046)
MSH D006996
ICD9 275.41
ICD10 E83.51
SnomedCT 154752005, 267505006, 5291005
English Hypocalcemias, CALCIUM BLOOD DECREASED, HYPOCALCAEMIA, HYPOCALCEMIA, hypocalcemia, hypocalcemia (diagnosis), Hypocalcemia, Hypocalcemia [Disease/Finding], abnormally low blood calcium levels, Calcium deficiency disease, Hypocalcemia syndrome, Hypocalcaemia, Hypocalcaemia syndrome, Hypocalcemia (disorder), hypocalcaemia
Spanish HIPOCALCEMIA, CALCEMIA DISMINUIDAD, enfermedad por deficiencia de calcio, hipocalcemia (trastorno), hipocalcemia, síndrome de hipocalcemia, síndrome hipocalcémico, Hipocalcemia
German HYPOKALZAEMIE, KALZIUMBLUTSPIEGEL VERMINDERT, Hypokalzaemie, Hypocalcaemia, Hypokalzämie
Japanese 低カルシウム血症, テイカルシウムケツショウ, テイカルシウムケッショウ
Swedish Hypokalcemi
Czech hypokalcémie, Hypokalcemie
Finnish Hypokalsemia
Polish Hipokalcemia
Hungarian Hypocalcaemia
Norwegian Hypokalsemi
Dutch hypocalciëmie, Calciëmie, hypo-, Hypocalciëmie
Italian Ipocalcemia

Ontology: Serum calcium decreased (C0595882)

Concepts Finding (T033)
English Calcium Serum Decreased, Calcium serum decreased, Serum calcium decreased
Dutch calcium serum verlaagd, serum calcium verlaagd
French Calcium sérique diminué
German Kalzium im Serum erniedrigt
Italian Calcio sierico diminuito
Portuguese Cálcio do soro diminuído, Cálcio sérico diminuído
Spanish Calcio disminuido en suero
Japanese 血清カルシウム減少, ケッセイカルシウムゲンショウ
Czech Snížené kalcium v séru
Hungarian Kalcium szérumszint csökkent, Szérum kalcium csökkent