Calcium and Parathyroid Flashcards
What do calcium sensing receptors do?
Sense low calcium and then stimulate production of PTH
On which organs does PTH act?
Bone: Stimulates Ca resorption
Kidney: Stimulates Ca reabsorption
Gut: Via raising 1,25 (OH)VitD, stimulates Ca absorption
What is main result of hyperparathyroidism?
Hypercalcemia
What are leading causes of primary hypercalcemia?
Solitary adenoma: 85%
Diffuse hyperplasia: 15%
Parathyroid carcinoma:
What is net result of PTH on phosphate?
Lowers phosphate– although it raises phosphate resorption from bone, this is “trumped” by increased phosphate excretion in kidney
What are signs of hyperparathyroidism in following areas:
GI (3)
CVS (1)
Bone (2)
Brain (2)
GI: pancreatitis, stomach ulcers, kidney stones
CVS: High BP
Bone: osteitis fibrosa cystica, low BMD in cortical bone
Brain: Depression/psychosis
What criteria constitute a “symptomatic patient” for hyperparathyroidism? (2) What is treatment mainstay?
Symptomatic patient displays kidney stones or a fracture
Treatment would be surgical
What are criteria for asymptomatic hyperparathyroid patient that requires surgery? (4)
Age 1 above upper limit of lab value
Low creatinine levels
Osteoporosis
Describe histologic appearance of parathyroid adenoma
Lots of normal-looking parathyroid cells in well-encapsulated adenoma
Describe secondary hyperparathyroidism. What are underlying causes? (3)
In secondary hyper functioning parathyroid glands compensate for hypoglycemia
Treatment is to address underlying cause:
Renal insufficiency (no 1,25(OH)VitD)
Calcium malabsorption
Vitamin D Deficiency
What is tertiary hyperparathyroidism? What is the treatment?
Hyperfunctioning parathyroid gland and hyper secretion due to prolonged secondary hyperparathyroidism.
Treat with surgery if severe.
What is familial hypocalciuric hypercalcemia?
What are the lab findings?
Autosomal dominant mutation in Calcium-Sensing receptor leading to shift in parathyroid set point for calcium.
Lab findings: Elevated serum Ca with low urine calcium and normal PTH
What is treatment for familial hypocalciuric hypercalcemia?
Nah it’s benign
What are three categories of hypoparathyroidism causes?
Name an example of each.
Post-surgical (thyroidectomy)
Infiltrative disease: hemochromatosis, wilson’s disease
Congenital: DiGeorge syndrome, autosomal polyglandular syndrome type 1
What are symptoms of hypoparathyroidism?
What are big signs?
Cardiac arrhythmia
Neuromuscular irritability: perioral, tingling of fingers/toes, tetany
Signs: Chvostek’s sign (ipsilateral lip twitch on tapping), Trousseau’s sign (carpal spasm)
What is treatment for hypoparathyroidism? What do you monitor?
Rx: Oral calcium and 1,25 (OH)VitD
Monitor: Serum/urine calcium levels
What is goal serum calcium level for hypoparathyroidism? Why?
Low normal– if too much calcium most will be excreted by kidneys, but this runs risk of kidney stone
Vitamin D intoxication: What are symptoms (4)and lab sign?
VitaminD intoxification requires large doses– it results in nausea, vomiting, weakness and altered mental status.
It results in prolonged hypercalcemia
What is the treatment for Vitamin D intoxication? (2)
Hydration, no dietary calcium
What is the etiology of vitamin D deficiency? (3)
What does it lead to?
Lack of solar irradiation
Decreased intake or impaired absorption
Metabolic defects in VitD hormone system– inadequate activation in liver/kidney, abnormalities of VitD-receptor
Leads to secondary hyperparathyroidism
How is vitamin D deficiency treated?
Vitamin D intake
Vitamin D enriched foods– milk, cheese, fish, eggs
What are metabolic bone diseases associated with vitamin D deficiency? (2) In which populations are they most common
Rickets in children
Osteomalacia in adults
What is the main result of rickets in relation to bone? What are some signs? (2)
Lack of mineralization of bones.
Bowing of legs and metaphyseal cupping/fraying
What is the clinical presentation of osteomalacia?
Usually asymptomatic
Symptoms: diffuse pain and tenderness, proximal muscle weakness
What is treatment for vitamin D deficiency?
Treat underlying disorder
Correct hypoglycemia and vitamin D deficiency
