Patient will present as → a 39-year-old woman after total thyroidectomy for papillary carcinoma of the thyroid is noted to have carpal spasm when her blood pressure is taken and facial muscle contractions with tapping over the facial nerve. You also note increased deep tendon reflexes along with perioral paresthesia. Lab work reveals decreased serum calcium, decreased parathyroid hormone, and elevated serum phosphate. On EKG there is a prolongation of the QT interval.
Hypoparathyroidism will present with a decreased parathyroid hormone (↓ PTH). This causes calcium levels in the blood to decrease
- Hypoparathyroidism is rare, you are much more likely to be tested on hyperparathyroidism
- The two most common etiologies are postsurgical (damage from neck or thyroid surgery) or autoimmune
- Accidental damage/removal of parathyroid during neck/thyroid surgery
- Autoimmune destruction of the thyroid gland
Patients will show signs of neuromuscular irritability with carpopedal spasm, laryngeal spasm, tingling, tetany, and facial grimacing.
Diagnosis is made by the triad: ↓ Ca+, ↓ PTH, and ↑ phosphate
- Why the low serum calcium? Calcium is low because the gland cannot secrete PTH (hence a low PTH) and PTH is responsible for the reabsorption of calcium from the bones, kidneys, and GI tract. Because you can't reabsorb calcium, your calcium will be low.
- Why the elevated phosphate? PTH normally inhibits the reabsorption of phosphate by the kidney. Therefore, without enough PTH there is more reabsorption of the phosphate leading to a high phosphate level in the blood.
- EKG = Prolonged QT
The following are signs of hypocalcemia:
Immediate: vitamin D and calcium to bring calcium levels back to normal
- Tetany - secure airway, IV calcium gluconate
- Long term: recombinant human parathyroid hormone to make up for bodies underproduction
Hyperventilation with panic attacks