Parathyroid Flashcards
Where are the superior parathyroid glands located?
4th branchial pouch
Constant location
Where are the inferior parathyroid glands located?
3rd branchial pouch
Variable location: can be in heart or even sinuses
Blood supply to parathyroid glands?
Superior thyroid artery
What does parathyroid hormone do?
Stimulates osteoclasts
Increases calcium concentration through renal and GI absorption (synthesis of D3)
Phosphate excretion
What role in calcium regulation does Vitamin D play?
Stimulates intestinal absorption of calcium
Deficiency causes increase in PTH (secondary cause of hyperparathyroidism)
What hormone inhibits parathyroid hormone?
Calcitonin (C cells of the thyroid)
What causes most hypercalcemia in a hospital setting?
Cancer
What causes most hypercalcemia in an outpatient setting?
Hyperparathyroidism
What are some triggers for hypercalcemia?
Family history, MEN syndrome HTN PUD Vitamin D deficiency Early osteoporosis
Symptoms of hyperparathyroidism?
Stones Renal failure Bone pain, osteoporosis Polyuria, constipation Depression
Is hyperparathyroidism more common in men or women?
3:1 women to men
Near menopause
What are symptoms of hypercalcemic crisis?
Anorexia, weakness, vomiting
Acute pancreatitis
Dehydration (along with polyuria, polydipsia)
Mental status changes
Treatment for hypercalcemic crisis?
IV fluids
Loop diuretic (gets rid of calcium)
Bisphosphonates
-Calcitonin, Mithramycin?
Lab findings in hyperparathyroidism?
Calcium high
Phosphorous low
PTH
Causes of hyperparathyroidism?
Single gland-85%
Diffuse hyperplasia-10-12%
Double adenoma-1-2%
Carcinoma-<1%
How do we treat familial hypocalciuric hypercalcemia (FHH)?
No need to operate
Normal in family
Single best test for locating abnormal parathyroid glands?
Sestamibi scintigraphy
Initial imaging for parathyroid glands?
US
What imaging is useful for locating parathyroid glands in the mediastinum or transesophageal groove?
4D CT scan
What expensive imaging very sensitive when it comes to finding parathyroid glands?
MRI
-Use if all others fail
What are indications for parathyroid surgery in asymptomatic patients?
Serum calcium level over 11.5 Creatinine clearance less then 30% of normal 24 hr urine calcium >400 Bone mass < 2 SDs from normal Young patients who request surgery
What PTH level is abnormal?
> 65
What is gold standard treatment for primary hyperparathyroidism?
Central neck exploration/Parathyroidectomy
-Do a rapid parathyroid test during procedure (over 65?)
Treatment for parathyroid hyperplasia?
Less successful
3.5 gland parathyroidectomy
4 gland parathyroidectomy w/ autograft to forearm (patient is without PTH for 6 months until graft kicks in)
