Hypocalcemia: Difference between revisions
| Line 1: | Line 1: | ||
==Background== | ==Background== | ||
===Serum Levels=== | ===Serum Levels=== | ||
*Low <8.5 (<2.0 ionized) | *Low <8.5 (<2.0 ionized) | ||
| Line 7: | Line 7: | ||
**Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca | **Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca | ||
===Fraction | ===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) | *15% bound to anions (phosphate, lactate, citrate) | ||
*40% bound to albumin | *40% bound to albumin | ||
Revision as of 23:26, 6 October 2016
Background
Serum Levels
- Low <8.5 (<2.0 ionized)
- Low! <6.5 (<1.5 ionized)
- Correct for hypoalbumimia
- Corrected Ca = (0.8 *(Normal Alb - Patient's Alb)) + Serum Ca
Fraction[1]
- 15% bound to anions (phosphate, lactate, citrate)
- 40% bound to albumin
- 45% free (regulated by PTH, Vit-D)
Causes
- Misc
- Shock
- Sepsis
- Pancreatitis
- Hypomag
- Rhabdo (phosphate overload)
- Massive transfusion
- Systemic Hydrofluoric Acid toxicity
- DiGeorge syndrome
- Decreased absorption
- Vit D deficiency
- Increased excretion
- Endocrine
- Drugs
Clinical Features
- Paresthesias (mouth, fingertips)
- ↑ DTRs
- Cramps
- Weakness
- Confusion
- Seizures
- Chvostek/Trousseau signs, Tetany
- Hallucinations
Differential Diagnosis
Jaw Spasms
- Acute tetanus
- Akathisia
- Conversion disorder
- Drug toxicity (anticholinergic, phenytoin, valproate, carbamazepine)
- Dystonic reaction
- Electrolyte abnormality
- Hypocalcemic tetany
- Magnesium
- Mandible dislocation
- Meningitis
- Peritonsillar abscess
- Rabies
- Seizure
- Strychnine poisoning
- Stroke
- Temporomandibular disorder
- Torticollis
Evaluation
ECG
- QT Prolongation via increasing the ST length
- Only hypothermia and hypocalcemia prolong QT this way
Trousseau's Sign (Mod to high SN and SP)
- 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
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/chloride 10mL of 10% soln IV over 10min
- Correct hypomag at same time (otherwise PTH is inhibited)
Disposition
- Admit all symptomatic patients
See Also
References
- ↑ 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}}