Hypocalcemia: Difference between revisions

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==Background==
==Background==  
===Serum Levels===
''Normal value ranges may vary slightly among different laboratories''
*Low: <8.9 mg/dL<ref>Harbor-UCLA computer system accessed 08/15/2019</ref> (Ionized: <4.8 mg/dL or <1.20 millimol/L<ref>https://www.ucsfhealth.org/tests/003486.html</ref>)
*Critical low: <6.6 mg/dL<ref>Harbor-UCLA computer system accessed 08/15/2019</ref> (Ionized: <3.5 mg/dL<ref>http://www.clinlabnavigator.com/calcium-ionized.html</ref>)


Low <8.5 (<2.0 ionized)
Low! <6.5 (<1.5 ionized)


*Correct for hypoalbumimia
*Correct for hypoalbumimia
**Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca


===Fraction<ref>Yu, AS. Relation between total and ionized serum calcium concentrations. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on October 6th, 2016.)</ref>===
 
*15% bound to anions (phosphate, lactate, citrate)
==Diagnosis==
*40% bound to albumin
 
*45% free (regulated by PTH, Vit-D)
 
Symptoms
 
1) paresthesias
 
2) inc DTRs
 
3) cramps
 
4) weakness
 
5) confusion
 
6) sz
 
7) Chvostek's/Trouseau's
 
8) prolonged QT
 
 
==DDX==
 
 
1) Shock
 
2) sepsis
 
3) renal failure
 
4) cimetidine
 
5) hypoparathyroid
 
6) inc phos
 
7) vit D def
 
8) fat embolism
 
9) strychnine
 
10) hypomag
 
11) tetanus
 
 
==Treatment==
 


Asymptomatic
===Causes===
*Misc
**[[Shock]]
**[[Sepsis]]
**[[Pancreatitis]]
**[[Hypomag]]
**[[Rhabdo]] (phosphate overload)
**[[Massive transfusion]]
**Systemic [[Hydrofluoric Acid]] toxicity
**[[DiGeorge syndrome]]
*Decreased absorption
**[[Vitamin D deficiency]]
*Increased excretion
**[[Alcoholism]]
**[[Renal Failure]]
**[[Diuretics]]
*Endocrine
**[[Hypoparathyroidism]]
*Drugs
**[[Cimetidine]]
**[[Phenytoin]]
**[[Lasix]], loop diuretics
**[[Norepinephrine]]
**[[Glucagon]]
**[[Glucocorticoids]]
**[[Magnesium sulfate]]
**[[Nitroprusside]]


-calcium gluconate 1 gm PO Q6hrs
==Clinical Features==
{{Hypocalcemia clinical features}}


-vitamin D (calcitriol) 0.2 mcg BID
==Differential Diagnosis==
{{Movement disorder DDX}}
{{Jaw spasms DDX}}


==Evaluation==
===[[ECG]]===
[[File:ECG.png|thumbnail|Hypocalcemia with QTc prolongation]]
*[[QT Prolongation]] via increasing the ST length
**Only hypothermia and hypocalcemia prolong QT this way
===Trousseau's sign===
[[File:Hypocalcemia spasm.jpg|thumbnail|Spasm associated with symptomatic hypocalcemia]]
*Inflate BP cuff for 2-3 minutes
*Positive = Muscle contractions of the hand and wrist
*Specificity 99%, sensitivity 94%


Symptomatic
===Chvostek sign ===
*Tapping on the face just anterior to the ear and just below the zygomatic bone
*Positive = Ipsilateral facial twitching
*Specificity 96%, sensitivity 26%


-calcium gluconate/chloride 10mL of 10% sol over 10min IV
===Labs===
*BMP
*Mag, Phos
*PTH (secondary hyperparathyroidism)


==Management==
''Avoid empiric treatment in patients taking [[digoxin]] due to risk for [[Stone Heart]]''
*Asymptomatic
**[[Calcium gluconate]] 1 gm PO Q6hrs
**Vitamin D (calcitriol) 0.2 mcg BID
*Symptomatic
**[[Calcium gluconate]]/[[calcium chloride|chloride]] 10mL of 10% soln IV over 10min
*Correct [[hypomag]] at same time (otherwise PTH is inhibited)
*Avoid phenothiazine [[antipsychotics]] (may precipitate extrapyramidal symptoms)
*Avoid [[furosemide]] (may worsen hypocalcemia)


==Source ==


==Medication Dosing==
{{MedicationDose
| drug = Calcium gluconate
| dose = 1g PO Q6hrs
| route = PO
| context = Asymptomatic hypocalcemia
| indication = Hypocalcemia
| population = Adult
}}
{{MedicationDose
| drug = Calcium gluconate
| dose = 10mL of 10% solution
| route = IV
| context = Symptomatic hypocalcemia
| indication = Hypocalcemia
| population = Adult
| notes = Administer over 10 minutes
}}
{{MedicationDose
| drug = Calcium chloride
| dose = 10mL of 10% solution
| route = IV
| context = Symptomatic hypocalcemia (alternative to calcium gluconate)
| indication = Hypocalcemia
| population = Adult
| notes = Administer over 10 minutes; requires central access
}}


2/12/06 DONALDSON (adapted from Tintinalli)
==Disposition==
*Admit all symptomatic patients


== Calculators ==
{{Corrected_Calcium_Calculator}}


==See Also==
*[[Electrolyte Abnormalities (Main)]]


==References==
<references/>


[[Category:FEN]]
[[Category:FEN]]

Latest revision as of 16:31, 21 March 2026

Background

Serum Levels

Normal value ranges may vary slightly among different laboratories

  • Low: <8.9 mg/dL[1] (Ionized: <4.8 mg/dL or <1.20 millimol/L[2])
  • Critical low: <6.6 mg/dL[3] (Ionized: <3.5 mg/dL[4])


  • Correct for hypoalbumimia
    • Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca

Fraction[5]

  • 15% bound to anions (phosphate, lactate, citrate)
  • 40% bound to albumin
  • 45% free (regulated by PTH, Vit-D)

Causes

Clinical Features

Symptoms of hypocalcemia

Differential Diagnosis

Movement Disorders and Other Abnormal Contractions

Jaw Spasms

Evaluation

ECG

Hypocalcemia with QTc prolongation
  • QT Prolongation via increasing the ST length
    • Only hypothermia and hypocalcemia prolong QT this way

Trousseau's sign

Spasm associated with symptomatic hypocalcemia
  • Inflate BP cuff for 2-3 minutes
  • Positive = Muscle contractions of the hand and wrist
  • Specificity 99%, sensitivity 94%

Chvostek sign

  • Tapping on the face just anterior to the ear and just below the zygomatic bone
  • Positive = Ipsilateral facial twitching
  • Specificity 96%, sensitivity 26%

Labs

  • BMP
  • Mag, Phos
  • PTH (secondary hyperparathyroidism)

Management

Avoid empiric treatment in patients taking digoxin due to risk for Stone Heart


Medication Dosing

Calcium gluconate 1g PO Q6hrs PO Calcium gluconate 10mL of 10% solution IV — Administer over 10 minutes Calcium chloride 10mL of 10% solution IV — Administer over 10 minutes; requires central access

Disposition

  • Admit all symptomatic patients

Calculators

Corrected Calcium

Corrected Calcium for Hypoalbuminemia
Parameter Value
Serum Calcium (mg/dL)
Serum Albumin (g/dL)
Corrected Calcium mg/dL
Interpretation
8.5–10.5 Normal corrected calcium range.
<8.5 Hypocalcemia — Consider IV calcium if symptomatic.
>10.5 Hypercalcemia — Investigate underlying cause; consider IV fluids.
References
  • Formula: Corrected Ca = Measured Ca + 0.8 × (4.0 – Albumin)
  • Payne RB, et al. Interpretation of serum calcium in patients with abnormal serum proteins. BMJ. 1973;4(5893):643-646. PMID 4758544.

See Also

References

  1. ↑ Harbor-UCLA computer system accessed 08/15/2019
  2. ↑ https://www.ucsfhealth.org/tests/003486.html
  3. ↑ Harbor-UCLA computer system accessed 08/15/2019
  4. ↑ http://www.clinlabnavigator.com/calcium-ionized.html
  5. ↑ Yu, AS. Relation between total and ionized serum calcium concentrations. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on October 6th, 2016.)
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