Parathyroid Disorders

Question 1

Parathyroid glands are responsible for

Answer 1

Regulating calcium levels in the blood through a negative feedback system involving the gut, kidneys, and bones

Question 2

Risk factors for primary hyperparathyroidism (most common type)

Answer 2

Neck radiation, age >50, female sex (2:1), multi glandular hyperplasia, or family history of MEN-1 and MEN-2a (both uncommon)

Question 3

Secondary hyperparathyroidism occurs due to

Answer 3

Decreased levels of 1,25-dihydroxyvitamin, hyperphosphatemia, and hypocalcemia in presence of CKD or
Vitamin D deficiency due to poor diet, lack of sun, malabsorption, liver disease, or other chronic illnesses

Question 4

Tertiary hyperparathyroidism is the progression of parathyroid hyperplasia due to

Answer 4

Autonomous over production of PtH causing hypercalcemia

Question 5

Symptoms of hyperparathyroidism

Answer 5

“Bones, stones, groans, and psychiatric overtones”
- osteoporosis, bone pain
- kidney stones; excessive urination
- ulcers, constipation, abdominal pain
- fatigue, depression, forgetfulness, weakness

Question 6

Diagnostics of hyperparathyroidism

Answer 6

-hypercalcemia on more than 1 serum measurement
-check ionized calcium, albumin, PTH, creatinine, and 25-hydroxyvitamin D
-24-hr urine calcium and creatinine to distinguish from familial hypocalciuric hypercalcemia (FHH)
-BMD (DEXA scan)

Question 7

Findings in primary hyperparathyroidism

Answer 7

-elevated immunoreactive PTH (intact PTH)
-persistent hypercalcemia (if severe, consider parathyroid cancer)
-may need outpatient nuclear scanning (Sestamibi scan)

Question 8

Risk factors for benign adenomas

Answer 8

Genetic disorders, lithium, CKD, women >60, radiation to head/neck

Question 9

Parathyroid cancer should be considered if

Answer 9

Hypercalcemia is >14, serum PTH >2x normal, a cervical mass is palpated in a hypercalcemic patient, there is unilateral vocal cord paralysis, or renal and skeletal disease are noted in a patient with a markedly elevated PTH

Question 10

Normal serum calcium and PTH levels

Answer 10

Serum calcium 8.5-10.4
PTH 10-65

Question 11

Chronic renal failure is associated with hypo-vitamin D, hyperphosphatemia, and hyperparathyroidism. What should be monitored?

Answer 11

-calcium
-creatinine
-UA
-PTH
(every 3 months)

Question 12

Medical treatment for high risk patients with hyperparathyroidism

Answer 12

Calcium salts (which also bind phosphorous) and vitamin D

Question 13

In mild hyperparathyroid disease, what should be monitored?

Answer 13

-calcium
-creatinine
-UA
-PTH
(every 6-12 months)
-bone density (every 12 months)

Question 14

The goal of oral calcium should be

Answer 14

1g/day or less

Question 15

What are factors that aggravate hypercalcemia, that should be avoided?

Answer 15

Thiazide diuretics, lithium, prolonged bed rest or inactivity

Question 16

Preventive measures of hyperparathyroidism

Answer 16

-physical activity to minimize bone resorption
-drink 8 glasses water/day to minimize risk of nephrolithiasis
-maintain moderate calcium intake (1000mg/day) as a low calcium diet may lead to further increases in PTH secretion and could aggravate bone disease
-maintain moderate vit D intake (400-600 IU daily)

Question 17

If serum calcitriol levels are high, then restrict to

Answer 17

<800mg/day

Question 18

Vitamin D deficiency stimulates

Answer 18

PTH secretion and bone resorption

Question 19

Causes of hypocalcemia/hypoparathyroidism

Answer 19

-parathyroidectomy (inadequate PTH secretion)
-hypoalbuminemia
-vitamin D deficiency
-abnormal magnesium metabolism
-extravascular deposition of calcium
-medications
-genetic causes
-autoimmune conditions

Question 20

Symptoms of hypocalcemia/hypoparathyroidism

Answer 20

-peripheral nervous system: numbness, paresthesias, muscle stiffness, and cramps, fasciculations, and tetany
-cardiovascular system: decreased contractility, QT-prolongation, vasodilation that can result in CHF, dysrhythmia, rarely - hypotension

Question 21

Medications/compounds that suppress the release of PTH

Answer 21

Aluminum, asparaginase, doxorubicin, cytosine arabinoside, cimetidine, alcohol, aminoglycosides, cisplatin, pentamidine, digoxin, amphotericin B

Question 22

Diagnostic work-up for hypoparathyroidism

Answer 22

-repeat calcium measurement for confirmation and measure serum albumin concentration (calcium is bound to albumin)
-if abnormal, check an ionized (free) calcium level for accuracy
-serum magnesium and phosphate levels

Question 23

Treatment for hypoparathyroidism

Answer 23

-IV calcium for symptomatic patients and those with serum corrected calcium of <7.5
-PO calcium for mild disease (1500-2000mg of Carbonate or Citrate) in divided doses
-vitamin D deficiency - calcium supplementation with addition of vit D2 or D3 (50,000 IU weekly for 6-8 weeks)
-hypomagnesemia - IV mag sulfate until level is >0.8