Endocrine #3 (Parathyroid/Calcium Disorders)

Question 1

What does the parathyroid gland do?

Answer 1

Produces PTH in response to low serum Calcium

PTH increases serum Calcium.

Question 2

Risk Factors for hyperparathyroidism

Answer 2

-Female Gender***
-Lithium Use
-Parathyroid Adenoma (MCC)
-Men I and IIa

Question 3

What is a cause of secondary hyperparathyroidism (think of the hormones, etc.)

What is another one?

Answer 3

-Chronic renal failure: causes poor production of Vitamin D –> low Calcium –> stimulate production and release of PTH

Calcium deficiency (for obvious reasons)

Question 4

Signs and symptoms of hyperparathyroidism

Answer 4

-Most are asymptomatic (incidental finding)

-Hypercalcemia (moans, bones, stones, groans, thrones): Bone pain, kidney and gallstones, abdominal pain, constipation/n/v, confusion/malaise/depression/psychosis
-Decreased DTR’s
-Increased risk of pathologic fractures

Question 5

Diagnostic lab triad for PRIMARY hyperparathyroidism

How about in SECONDARY?

Answer 5

-Hypercalcemia (>10)
-Increased intact PTH
-Decreased Phosphate

-Low serum Calcium
-Increased intact PTH
-Elevated Phosphate

Question 6

What is another diagnostic study that can be done for hyperparathyroidism (think about what is happening to the Calcium)

What are some findings on XR’s for hyperparathyroidism/hypercalcemia?

Answer 6

-Increased 24-hour urinary calcium excretion

-Bone scan: osteopenia

-XR: Demineralization of bones, subperiosteol bone resorption (especially in the fingers), cysts in the jaw bone, salt and pepper skull

Question 7

Treatment for hyperparathyroidism
-Definitive
-Medical Therapy

Answer 7

-Parathyroidectomy is definitive

-Vitamin D and Calcium supplement post surgery to prevent hypocalcemia
-Cinacalcet inhibits PTH in non-surgical patients
-IVF for severe hypercalcemia

Question 8

2 MCC of hypoparathyroidism

Answer 8

-Post neck surgery (thyroidectomy, parathyroidectomy)
-Autoimmune destruction of parathyroid gland

-Others: Radiation therapy, hypomagnesemia

Question 9

Signs and symptoms of hypoparathyroidism

Answer 9

-Signs of hypocalcemia: increased muscle contraction, carpopedal spasm, tetany, cramping, convulsions

-Trousseau Sign: carpopedal spasms when the BP cuff if inflated

-Chvostek Sign: tapping of cheek causes facial spasm

-Decreased eyebrow hair, blurry vision, brittle nails, teeth defects, hyperreflexia

Question 10

Diagnostic triad for hypoparathyroidism

Answer 10

-Hypocalcemia (<8)
-Decreased intact PTH
-Increased phosphate

Question 11

What does an ECG for hypocalcemia/hypoparathyoridism show?

Answer 11

Prolonged QT interval (increased risk of arrhythmias)

Question 12

Explain what calcium does to heart contractility and relate this to the QT interval

Answer 12

-Calcium increases muscle contractility and, therefore, hypocalcemia leads to impaired myocardial contractility (prolonged QT interval)

-Hypercalcemia leads to SHORTENED QT interval because contractility has increased

Question 13

Treatment for hypoparathyroidism

Why do you give both?

Answer 13

-Calcium supplementation + activated Vitamin D (Calcitriol)

-Vitamin D is needed to absorb the Calcium

Question 14

However, what do you use for acute symptomatic hypocalcemia?

Answer 14

IV Calcium gluconate

Question 15

What is seen on XR’s in hypoparathyroidism and hypocalcemia?

Answer 15

-Excessively dense bones
-Cutaneous calcifications
-Etc.

Question 16

What is one eye manifestation of hypocalcemia? It is the MC eye manifestation of hypocalcemia

Answer 16

Early cataract formation

Question 17

Regarding hypercalcemia, what is the MCC?

What are other causes that you should remember?

Answer 17

-Primary hyperparathyroidism (MCC), Malignancy
-Thiazide diuretics
-Granulomas (Sarcoidosis)

Question 18

Labs for hypercalcemia:

-Once hypercalcemia is confirmed, what lab should be ordered (to rule out primary hyperparathyroidism)

-What is often ordered if intact PTH is normal or low (to rule out malignancy)

Answer 18

-Intact PTH

-PTH-related protein

Question 19

Again, what does ECG for hypercalcemia show?

Answer 19

Shortened QT interval, prolonged PR interval, QRS widening

Question 20

Management of mild hypercalcemia (<12)

Answer 20

-No immediate treatment needed. Increase water intake (promotes calcium excretion)

Question 21

Management for severe hypercalcemia (12-14)

Answer 21

-IVF (initially)
-IV loop diuretics (Furosemide)
-Calcitonin and Bisphosphontes (in malignancy)
-Glucocorticoids if due to Sarcoidosis

Question 22

On the other hand, what are some causes of hypocalcemia (you just reviewed a few of them)

Answer 22

-Hypoparathyroidism (during neck surgery)
-Chronic renal disease (if PTH increased in response to hypocalcemia)
-Vitamin D deficiency
-Hypomagnesemia
-Diuretics, Bisphosphonates

Question 23

Treatment for hypocalcemia if:

Mild:
Severe:

Answer 23

Mild: oral Calcium + Vitamin D

Severe: IV Calcium gluconate or IV Calcium carbonate

Question 24

Explain what happens to the hormones in hypercalcemia

Answer 24

-Hypercalcemia stimulates calcitonin secretion: this decreases blood calcium (decreases GI/kidney absorption and increases bone mineralization)