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 a decreased serum calcium, decreased parathyroid hormone, and an 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
- 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 triad: ↓ Ca+ ↓ PTH ↑ phosphate
- EKG = Prolonged QT
- 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.
- This is easy to remember: Hyo-parathyroid literally causes a LOW PARATHYROID HORMONE. If you know that PTH is responsible for calcium reabsorption, you will know that CA+ will be low as well.
The following are signs of hypocalcemia:
- Chvostek's sign (watch video) is the twitching of the facial muscles in response to tapping over the area of the facial nerve.
- Trousseau's sign (watch video) is carpopedal spasm caused by inflating the blood-pressure cuff to a level above systolic pressure for 3 minutes.
- ↑ DTRs and carpopedal spasms
Treatment: Vitamin D and Calcium
- Tetany- secure airway, IV calcium gluconate
|An uncommon condition characterized by a low level of parathyroid hormone (PTH). Often caused by “accidental” removal of the parathyroid glands during thyroid surgery. Other causes of parathyroid deficiency include tumors and heavy metal poisoning. Treatment consists of taking supplements to normalize calcium and phosphorus levels.|
|The parathyroid gland is a series of four small glands located in the neck on the rear surface of the thyroid gland. It serves primarily in calcium homeostasis and has a blood calcium sensor that detects when blood calcium levels are abnormally low. It responds by releasing parathyroid hormone (PTH) which stimulates osteoclasts into action. Osteoclasts resorb bone and release a large amount of calcium. This calcium enters the blood and results in increased blood calcium levels. PTH can also activate vitamin D by promoting the activity of an enzyme that converts inactive vitamin D to active vitamin D|
Hyperventilation with panic attacks