Parathyroid Pathology - Krafts Flashcards
Where are the upper and lower parathyroids from embryologically?
Upper pair from fourth pharyngeal pouch, descends with the thyroid
Lower pair from third pharyngeal pouch, descends with the thymus
What are the three cells of the parathyroid?
Chief cells
Oxyphil cells (look important, but they aren’t)
Fat cells
What controls PTH release?
Free calcium!
↓ serum calcium => ↑ PTH synthesis and release
↑ serum calcium => ↓ PTH synthesis and release
MD PIMPS ME
Malignancy Diuretics Parathyroid (hyperparathyroidism) Idiopathic Megadose of vitamin D Paget disease Sarcoidosis Milk-alkali syndrome Endocrine (thyrotoxicosis)
What is the most common cause of symptomatic and asymptomatic hypercalcemia?
Most common cause of symptomatic hypercalcemia:
Malignancy
Most common cause of asymptomatic hypercalcemia:
Hyperparathyroidism
What are the causes of Primary, Secondary, and Tertiary Hyperparathyroidism?
Primary =>parathyroid problem (adenoma)
Secondary => chronic hypocalcemia (renal failure)
Tertiary => autonomous parathyroids
Pseudohyperparathyroidism => PTH-related protein (lung cancer)
What are the three causes of Primary Hyperparathyroidism?
Parathyroid adenoma
Parathyroid hyperplasia
Parathyroid carcinoma
What are the signs and symptoms in Primary Hyperparathyroidism?
Often asymptomatic!
Stone: kidney stones, other stones
Bone: pain, brown tumors, worse
Groan: gastrointestinal problems
Moan: mental changes
What are the Laboratory findings in Primary Hyperparathyroidism?
↑ serum PTH
↑ serum calcium
↓ serum phosphate
What are the bone changes is Primary Hyperparathyroidism?
Osteoclast activation
Osteoblast activation
Brown tumors (cystic bleeding in bone)
Osteitis fibrosa cystica (long-standing bony changes)
What is the most common cause of Primary Hyperparathyroidism?
Parathyroid Adenoma (Usually solitary)
What are the potential genetic defects in Parathyroid Adenoma?
PRAD 1 overexpression
MEN 1 loss or mutation
What are the three potential causes of Secondary Hyperparathyroidism?
Renal failure (most cases)
Diet poor in calcium
Vitamin D deficiency
What are the causes of Hypoparathyroidism?
Iatrogenic
Hereditary => DiGeorge syndrome, Agenesis (X-linked)
Idiopathic atrophy
What are the signs and symptoms of Hypoparathyroidism?
Neuromuscular irritability: Perioral numbness, Muscle weakness, cramps, tetany
Chvostek sign => tap Facial Nerve and get twitching
Trousseau sign => carpal spasm with BP cuff pressure
Heart arrhythmias
Dental abnormalities (enamel hypoplasia)
