Introduction

Hypercalcemia is defined as a total calcium level in the plasma greater than 2.6 mmol/L. 

• Mild hypercalcemia =  2.7 – 2.9 mmol/L
• Moderate hypercalcemia = 3.0 – 3.4 mmol/L
• Severe hypercalcemia = greater than 3.4 mmol/L

Causes

• primary hyperparathyroidism
• malignancy
• excessive vitamin D intake
• thiazides or renal failure (secondary hyperparathyroidism)
• sarcoidosis
• multiple myeloma
• immobilization

Clinical presentation 

• Mild hypercalcemia - may be asymptomatic, nonspecific symptoms, such as constipation, fatigue, and depression
• Moderate hypercalcemia - polyuria, polydipsia, dehydration, anorexia, nausea, muscle weakness, and changes in sensorium
• Severe hypercalcemia - lethargy, confusion, stupor, coma and progression of symptoms above

ECG manifestation 

• short QT interval
• ST segment may be completely absent and replaced by inverted small T-wave directly after R-wave
• Osborn wave (usually a feature of hypothermia) - a positive deflection at the J point (negative in aVR and V1), most prominent in the precordial leads
• J-point elevation mimicking ST segment elevation is a common observation
• Ventricular irritability and VF arrest may occur in extreme hypercalcemia

 Picture 1 QT interval in serum calcium abnormalities 

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

Picture 2 Osborn wave‍

 ECG 1 Hypercalcemia (shortened QT interval, Osborn wave in V1) ‍

  
‍Management

 Treatment depends on the severity of symptoms and the underlying cause.

 avoid thiazide diuretics, prolonged inactivity, high calcium diet 

• adequate hydration minimises risk of nephrolithiasis
• saline hydration 
• bisphosphonates
• calcitonin

 References

1. Kelwade JV, Modi KD, Kumar N, Parekh H. Hypercalcemia and electrocardiogram changes. Indian J Endocrinol Metab. 2016;20(6):892-893. doi:10.4103/2230-8210.192900
2. Elizabeth Shane, Clifford J Rosen, Jean E Mulder.Diagnostic approach to hypercalcemia.: https://www.uptodate.com/contents/diagnostic-approach-to-hypercalcemia
3. Elizabeth Shane, Clifford J Rosen, Jean E Mulder.Clinical manifestations of hypercalcemia
4. Elizabeth Shane, Clifford J Rosen, Jean E Mulder. Treatment of hypercalcemia. https://www.uptodate.com/contents/treatment-of-hypercalcemia
5. https://litfl.com/hypercalcaemia-ecg-library/
6. https://www.techmed.sk/hyperkalcemia/
7. https://www.uptodate.com/contents/clinical-manifestations-of-hypercalcemia