Parathyroid (HYPOcalcemia) Flashcards
In response to LOW Ca+ levels the Parathryoid will increase release of PTH and acts on which body systems to increase Ca levels?
Bone: increase resorption
Intestine: increase absorption or Ca and PO4
KIdney: incrase 1,25 dihydroxycholecalciferol, Increase Ca+ reabsorption, decrease PO4resporption
• Neuromuscular irritability - paresthesias, muscle cramps, tetany •
Lowered seizure threshold
- Mental status changes
- Cardiac - prolonged QT, arrhythmias, CHF
- Basal ganglia calcification
- Cataracts
- Positive Chvostek’s and Trousseau’s signs
signs of HYPOcalcemia
Primary hypocalcemia is caused by:
H a deficiency in PTH secretion: Primary hypoparathyroidism (iatrogenic, idiopathic, or familial)
Secondary Hyperparathyroidism reults in _____of PTH secreation and LOW calcium
Increase
Causes of secondary hyperparathroidism
Secondary hyperparathyroidism (very common – renal failure [cannot produce adequate 1,25(OH)2D], malabsorption [e.g. sprue]) Vitamin D deficiency
Labs come back:
Low serum Ca++
elevated/normal serum PO4
Low PTH
Normal 25 (OH)D3
Hypoparathryoidism
Labs:
Low Ca+
Elevated/normal PO4
Elevated PTH
Normal 25,0H
Pseudohypoparathyrodism
Labs
Low Ca+
N or Low PO4
Elevated PTH
LOW 25, OH D3
What do we see on the xray, what caused it?
: Basal Ganglia Calcification from Hypoparathyroidism
A postive Chvostek or Troussuea are signs of
Hypocalcemia
Causes of Hypoparathryoidism
• Genetic disorders • Autoimmune • Infiltrative • Pseudohypoparathyroidism
Pseudohypoparathyroidism (PTH resistance) – Type 1a has_____ mutation and Albright’s Hereditary Osteodystrophy (AHO)
GNAS
Pt comes in with HYPOcalcemia, you order what test?
PTH!!!
You order PTH test on pt with Hypocalcemia, comes back LOW; what could cause this?
LOW Ca+
LOW PTH
–> HypoParathyroidism but rule out Mg deficiency
Pt with Hypoparathryroidism have ____ Ca+ and _____PTH
Low Ca
Low PTH
Pt has hypocalcemia with HIGH PTH, what should would look at to determine if this is 2nd hyperparathryoidism or renal insufficiency?
look at serum PHosphate levels
HIgh phosphate: think PTH resistanc or renal insufficiency
Low phosphate; more likley 2nd hyperparathryoidism
Pt with renal insufficiency has HYPOCa+, what do we expect their PTH and Phosphate lelvels to be?
HIgh PTH
High Phosphate
What labs suggest pt had 2nd Hyperparathyroidism
Ca
PTH
Phosp
Low Ca
HIgh PTH
Low Phosphate
You think your pt may have 2nd hyperparathryoidsm as they ahve low Ca, High PTH and Low Phosphate, what else do we need to consider?
A vit D deficiency or occult malabsopriton; measure teh 25 (OH) vit D levels and get a 24 hr urine calcium and creatinine
*look at BMD and screen for celiacs
Acute hypocalcemia is initially managed with
IV calcium gluconate
Chronic hypocalcemia due to hypoparathyroidism is treated with calcium supplements and either
vitamin D2 or D3 or calcitriol
Made by osteocytes, increases urinary phosphate excretion decreases renal production of 1,25(OH)2D
Fibroblast-growth factor 23 (FGF23)
Excess FGF23 causes_______ and impaired bone mineralization (genetic forms of rickets, tumor-induced osteomalacia)
hypophosphatemia
What is the result of low FGF23 action?
Decreased FGF23 action causes hyperphosphatemia and tumoral calcinosis
