Thyroid & Adrenal
Following is indicative of hypercalcemia on ECG:
|A||Short QT interval|
|B||Bundle branch blocks|
|C||Paroxysmal atrial tachycardia|
|D||Prolonged PR interval|
a. Hypercalcemia is defined as a serum calcium level above the normal range of 8.5 to 10.5 mEq/L, or an increase in the ionized calcium level above 4.2 to 4.8 mg/dL.
b. Primary hyperparathyroidism in the outpatient setting and malignancy (associated bony metastasis or due to secretion of parathyroid hormone–related protein) in hospitalized patients account for most cases of symptomatic hypercalcemia. 12
c. Symptoms of hypercalcemia which vary with the degree of severity, include neurologic (depression, confusion, stupor, or coma), musculoskeletal (weakness and back and extremity pain), renal (polyuria and polydipsia as kidneys lose their ability to concentrate), and gastrointestinal (anorexia, nausea, vomiting, constipation, abdominal pain, and weight loss).
d. Cardiac symptoms also are present and can include hypertension, cardiac arrhythmias, and a worsening of digitalis toxicity.
e. ECG changes of hypercalcemia include:
i. Shortened QT interval
ii. Prolonged PR and QRS intervals
iii. Increased QRS voltage
iv. T-wave flattening and widening
v. AV block (can progress to complete heart block, then cardiac arrest with severe hypercalcemia)