Usmle 1 Parathyroid Hormone

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Parathyroid Hormone
• Phosphate Trashing Hormone (PTH)
- • Be sure to check Phosphorus
- • If Ca2+ and P are going in different direction
- • Think PTH
- • If Ca2+ and P are going in same direction
- • Think Vitamin D
• 2nd messenger for PTH = cAMP
- • Calcitonin comes from c-cells of Thyroid
- • Inhibit osteoclastic activity
Parathyroid
• Four small, pea-sized glands behind the thyroid gland
- • Most common cancer:
- • Adenocarcinoma
• Men Syndromes
Actions of PTH
- • Stimulus: low calcium; high phosphorus
- • Inhibition: high calcium; low phosphorus
- • Stimulates OSTEOCLASTIC ACTIVITY
- • Cofactors
- • Vitamin A
- • Vitamin Mg
- • ↑ Vitamin A
- • Hypercalcemia
- • Moans, Groans → pancreatitis
- • Bones
- • Stones
- • Acts on the PCT of the kidney
- • Waste Phosphorus (secrete it out)
- • Vitamin D Action
- • Activates 1-alpha hydroxylase
- • Syn of the active form of vitamin D 1,25
- • Ca2+ ATPase in the Late DCT
- • ↑ GI absorption (jejunum) of Ca
- • ↑ kidney reabsorption of Ca
- • Ca2+ ATPase in the Late DCT
Hypercalcemia
- • MCC of Isolated Hypercalcemia
- • Parathyroid Adenoma
- • Associated with MEN I and II
Hyperparathyroidism
- • Primary: due to parathyroid adenoma
- • MCC of isolated hypercalcemia in adults
- • Secondary: due to renal failure
- • Renal Osteodystrophy
- • Osteitis Fibrosa Cystica- fibrous tissue
- • Osteopenia- low density
- • Osteomalacia- nutrition (soft bones)
- • Osteosclerosis- trauma
Hypoparathyroidism
- • Tetany
- • involuntary contraction of muscles from ↓ calcium in blood
- • MCC = Thyroidectomy
- • ↓ PTH
- • ↓ Serum Calcium
- • ↑ Serum P
Pseudohypoparathyroidism
- • ↑↑↑ PTH
- • ↓ Serum Calcium
- • ↑ Serum P
• Problem is with the receptors not working

• Kidney Problem
Pseudo pseudo

• Hypoparathyroidism

• only difference is that calcium is normal

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docbrito

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Usmle 1 Parathyroid Hormone

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Usmle 1 Parathyroid Hormone

Updated

2024-07-06T19:33:08Z