Hypocalcemia: Difference between revisions
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==Background==
==Background==  
*Low <8.5 (<2.0 ionized)
===Serum Levels===
*Low! <6.5 (<1.5 ionized)
''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>)
 


*Correct for hypoalbumimia
*Correct for hypoalbumimia
**Corrected Ca = (0.8 * (Normal Alb - Pt's Alb)) + Serum Ca
**Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca
 
==Clinical Features==
#Paresthesias (mouth, fingertips)
#Incr DTRs
#Cramps
#[[Weakness]]
#[[Confusion]]
#[[Seizures]]
#Chvostek/Trousseau, Tetany
#[[Hallucinations]]
 
==Diagnosis==
*[[ECG]]
**[[QT Prolongation]]


*Trousseau's Sign (Mod to high SN and SP)
===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>===
**Inflate BP cuff for 2-3 mins
*15% bound to anions (phosphate, lactate, citrate)
**Positive = Muscle contractions of the hand and wrist
*40% bound to albumin
*45% free (regulated by PTH, Vit-D)


*Chvostek's Sign (Low SN and SP)
===Causes===
**Tapping on the face just anterior to the ear and just below the zygomatic bone
**Positive = Ipsilateral facial twitching
 
==Differential Diagnosis==
*Misc
*Misc
**[[Shock]]
**[[Shock]]
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**[[Rhabdo]] (phosphate overload)
**[[Rhabdo]] (phosphate overload)
**[[Massive transfusion]]
**[[Massive transfusion]]
**Systemic [[Hydrofluoric Acid]] toxicity
**[[DiGeorge syndrome]]
*Decreased absorption
*Decreased absorption
**Vit D deficiency
**[[Vitamin D deficiency]]
*Increased excretion
*Increased excretion
**[[Alcoholism]]
**[[Alcoholism]]
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**[[Cimetidine]]
**[[Cimetidine]]
**[[Phenytoin]]
**[[Phenytoin]]
**[[Lasix]]
**[[Lasix]], loop diuretics
**[[Norepinephrine]]
**[[Glucagon]]
**[[Glucocorticoids]]
**[[Magnesium sulfate]]
**[[Nitroprusside]]
 
==Clinical Features==
*[[Paresthesias]] (mouth, fingertips)
*↑ DTRs
*Cramps
*[[Weakness]]
*[[Confusion]]
*[[Seizures]]
*Chvostek/Trousseau signs, Tetany
*[[Hallucinations]]
*Laryngospasm
*Bronchospasm
*Cardiac [[dysrhythmias]]


==Differential Diagnosis==
{{Jaw spasms DDX}}
{{Jaw spasms DDX}}


==Treatment==
==Evaluation==
*Avoid empiric treatment in patients taking digoxin due to risk for [[Stone Heart]]
===[[ECG]]===
#Asymptomatic
[[File:ECG.png|thumbnail|Hypocalcemia with QTc prolongation]]
##Calcium gluconate 1 gm PO Q6hrs
*[[QT Prolongation]] via increasing the ST length
##Vitamin D (calcitriol) 0.2 mcg BID
**Only hypothermia and hypocalcemia prolong QT this way
#Symptomatic
===Trousseau's Sign (Mod to high SN and SP)===
##Calcium gluconate/chloride 10mL of 10% soln IV over 10min
[[File:Hypocalcemia spasm.jpg|thumbnail|Spasm associated with symptomatic hypocalcemia]]
*Inflate BP cuff for 2-3 mins
*Positive = Muscle contractions of the hand and wrist
===Chvostek's Sign (Low SN and SP)===
*Tapping on the face just anterior to the ear and just below the zygomatic bone
*Positive = Ipsilateral facial twitching
===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)
*Correct [[hypomag]] at same time (otherwise PTH is inhibited)
*Avoid phenothiazine [[antipsychotics]] (may precipitate extrapyramidal symptoms)
*Avoid [[furosemide]] (may worsen hypocalcemia)
==Disposition==
*Admit all symptomatic patients


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


==Source ==
==References==
*Tintinalli
<references/>
 
==Video==
{{#widget:YouTube|id=6QrzmVYMkWc}}


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

Revision as of 16:06, 29 September 2019

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

Differential Diagnosis

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 (Mod to high SN and SP)

Spasm associated with symptomatic hypocalcemia
  • Inflate BP cuff for 2-3 mins
  • Positive = Muscle contractions of the hand and wrist

Chvostek's Sign (Low SN and SP)

  • Tapping on the face just anterior to the ear and just below the zygomatic bone
  • Positive = Ipsilateral facial twitching

Labs

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

Management

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

Disposition

  • Admit all symptomatic patients

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.)

Video

{{#widget:YouTube|id=6QrzmVYMkWc}}

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