Endocrine #3 (Parathyroid/Calcium Disorders) Flashcards
What does the parathyroid gland do?
Produces PTH in response to low serum Calcium
PTH increases serum Calcium.
Risk Factors for hyperparathyroidism
-Female Gender***
-Lithium Use
-Parathyroid Adenoma (MCC)
-Men I and IIa
What is a cause of secondary hyperparathyroidism (think of the hormones, etc.)
What is another one?
-Chronic renal failure: causes poor production of Vitamin D –> low Calcium –> stimulate production and release of PTH
Calcium deficiency (for obvious reasons)
Signs and symptoms of hyperparathyroidism
-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
Diagnostic lab triad for PRIMARY hyperparathyroidism
How about in SECONDARY?
-Hypercalcemia (>10)
-Increased intact PTH
-Decreased Phosphate
-Low serum Calcium
-Increased intact PTH
-Elevated Phosphate
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?
-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
Treatment for hyperparathyroidism
-Definitive
-Medical Therapy
-Parathyroidectomy is definitive
-Vitamin D and Calcium supplement post surgery to prevent hypocalcemia
-Cinacalcet inhibits PTH in non-surgical patients
-IVF for severe hypercalcemia
2 MCC of hypoparathyroidism
-Post neck surgery (thyroidectomy, parathyroidectomy)
-Autoimmune destruction of parathyroid gland
-Others: Radiation therapy, hypomagnesemia
Signs and symptoms of hypoparathyroidism
-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
Diagnostic triad for hypoparathyroidism
-Hypocalcemia (<8)
-Decreased intact PTH
-Increased phosphate
What does an ECG for hypocalcemia/hypoparathyoridism show?
Prolonged QT interval (increased risk of arrhythmias)
Explain what calcium does to heart contractility and relate this to the QT interval
-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
Treatment for hypoparathyroidism
Why do you give both?
-Calcium supplementation + activated Vitamin D (Calcitriol)
-Vitamin D is needed to absorb the Calcium
However, what do you use for acute symptomatic hypocalcemia?
IV Calcium gluconate
What is seen on XR’s in hypoparathyroidism and hypocalcemia?
-Excessively dense bones
-Cutaneous calcifications
-Etc.
What is one eye manifestation of hypocalcemia? It is the MC eye manifestation of hypocalcemia
Early cataract formation
Regarding hypercalcemia, what is the MCC?
What are other causes that you should remember?
-Primary hyperparathyroidism (MCC), Malignancy
-Thiazide diuretics
-Granulomas (Sarcoidosis)
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)
-Intact PTH
-PTH-related protein
Again, what does ECG for hypercalcemia show?
Shortened QT interval, prolonged PR interval, QRS widening
Management of mild hypercalcemia (<12)
-No immediate treatment needed. Increase water intake (promotes calcium excretion)
Management for severe hypercalcemia (12-14)
-IVF (initially)
-IV loop diuretics (Furosemide)
-Calcitonin and Bisphosphontes (in malignancy)
-Glucocorticoids if due to Sarcoidosis
On the other hand, what are some causes of hypocalcemia (you just reviewed a few of them)
-Hypoparathyroidism (during neck surgery)
-Chronic renal disease (if PTH increased in response to hypocalcemia)
-Vitamin D deficiency
-Hypomagnesemia
-Diuretics, Bisphosphonates
Treatment for hypocalcemia if:
Mild:
Severe:
Mild: oral Calcium + Vitamin D
Severe: IV Calcium gluconate or IV Calcium carbonate
Explain what happens to the hormones in hypercalcemia
-Hypercalcemia stimulates calcitonin secretion: this decreases blood calcium (decreases GI/kidney absorption and increases bone mineralization)
