Hypocalcemia 

Introduction 

Hypocalcemia is defined as calcium level in the plasma < 2.1 mmol/L. 

Severe hypocalcemia is defined as calcium level in the plasma < 1.9mmol/L.  

The majority of calcium in the body is within the skeletal system or bound to albumin in plasma, free calcium is tightly controlled by homeostasis affected by parathyroid hormone (PTH). 

Myocardial contraction is dependent on extracellular calcium because the myocardial sarcoplasmic reticulum cannot store sufficient quantities. As such, prolonged and significant hypocalcaemia can result in heart failure.

Causes

  • hypoalbuminemia (usually due to cirrhosis, nephrosis, malnutrition, burns, chronic illness, and sepsis) 
  • hypoparathyroidism or PTH resistance
  • hyperventilation
  • vitamin D deficiency or resistance
  • abnormal magnesium metabolism
  • diuretics intake (furosemide)
  • extravascular deposition of calcium (acute pancreatitis)

Clinical presentation

  • acute hypocalcemia:
    - tetany 
    - seizures
    - papilledema 

  • chronic hypocalcemia:
    - ectodermal and dental changes
    - cataracts
    - basal ganglia calcification
    - extrapyramidal disorders

Chvostek’s sign (normal in 10% of people).

Trousseau’s sign - very specific for hypocalcemia.


ECG manifestation 

  • prolongation of the QT interval (increased risk of Torsade de Pointes)

https://litfl.com/hypocalcaemia-ecg-library/


ECG 1 Hypocalcemia in a patient with postoperative hypoparathyroidism and furosemide treatment (long QT interval) 


Management 

  • vit. D
  • calcium per os or i.v.
  • if hypomagnesemia is severe - firstly magnesium  

References

  1. RUDUSKY, Basil M. ECG Abnormalities Associated With Hypocalcemia. Chest [online]. 2001, 119(2), 668-669 [cit. 2021-02-06]. ISSN 00123692. doi:10.1378/chest.119.2.668-a
  2. Chorin E, Rosso R, Viskin S. Electrocardiographic Manifestations of Calcium Abnormalities. Ann Noninvasive Electrocardiol. 2016;21(1):7-9. doi:10.1111/anec.12316
  3. David Goltzman, Clifford J Rosen, Jean E Mulder. Diagnostic approach to hypocalcemia. https://www.uptodate.com/contents/diagnostic-approach-to-hypocalcemia#H7
  4. https://litfl.com/hypocalcaemia-ecg-library/
  5. David Goltzman, Clifford J Rosen, Jean E Mulder. Clinical manifestations of hypocalcemia. Dostupné z: https://www.uptodate.com/contents/clinical-manifestations-of-hypocalcemia?topicRef=837&source=see_link
  6. Nijjer S, Ghosh AK, Dubrey SW. Hypocalcaemia, long QT interval and atrial arrhythmias. BMJ Case Reports 2010; doi:10.1136/bcr.08.2009.2216