12. Hypoparathyroidism and Pseudohypoparathyroidism Flashcards
how many parathyroid glands do we have ?
four parathyroid glands
what is the function of the parathyroid gland ?
releases in response to low calcium levels = which causes the bones to give out calcium
increase calcium absorption for GI tract
increase calcium absorption from kidney with phosphate please
activation of VITAMIND d in kidneys
1,25 - dehydroxyvitD3 = calcitriol = only produced in the presence of PTH
having a much stronger effect than PTH = causes resorption of calcium
cholecalciferol produced UV from the skin goes to the liver and then the kidneys to be transformed into calciitriol
antagonist is calcitonin from the thyroid gland = when there is a lot of calcium in the blood
how does the blood ph regulate the calcium levels ?
during alkalosis the plasma protein which bind to hydrogen ions are released
causing the free calcium to bind = HYPOCALCEMIA
it is the free calcium which is active
when there is acidosis - there is hypercalcemia
what is the cause of hypoparathyroidism ?
Thyroidectomy that also resulted in parathyroidectomy
after radiation therapy in the
neck region
autoimmune
Congenital:
Parathyroid aplasia or hypoplasia (DiGeorge syndrome)
non autoimmune destruction - hemochrombtosis
what are the clinical signs and symptoms of hypoparathyroidism ?
Acute manifestations hypocalcemia : tetany muscle cramp parathesia and tingling laryngospasm
Chvostek sign: hypocalcemia tapping the facial nerve on the cheek → contraction of facial muscles
Trousseau sign: occlusion of brachial artery for a few minutes → carpal spasm
Chronic manifestations
Extrapyramidal disorders : parkinsonism, dystonia,
seizures
Ocular disease: cataracts, keratoconjunctivitis
Skeletal: increased bone mineral density, osteosclerosis
Dental abnormalities: dental hypoplasia, failure of tooth eruption, defective root formation
dry, puffy, coarse skin
and oncholysis
cv = cardiac arrhythmia
what is the diagnosis of hypoparathyroidism ?
positive Chvostek sign: hitting N. facialis in front of the external ear canal causes
muscle contractions in fac
Trousseau sign: muscular contraction of the hand when inflating a blood pressure cuff on the arm above systolic blood pressure for 3 minutes
Central nervous system basal ganglia calcifications through ct or MRI scan
definite
combination of hypocalcemia + hyperphosphatemia + LOW
PTH
what is dd of hypoparathyroidism ?
hyperventilation = respiratory alkalosis
the total Ca2+ in blood is serum is
NORMAL, only the the free calcium is decreased
Hypomagnesemia: magnesium needs for pth to be produced we have low PTH! low Ca2+, high Phosphate aaaaaand l ow Mg
treatment of hypoparathyroidism ?
acute Hypocalcemia: I.V. calciumgluconate which will quickly increase calcium
levels and thus will relieve symptom
The goal of treatment is to maintain the blood calcium level near the low end of the normal range!
chronic hypothyroidism:
Calicum and activated Vitamin D - calciferol , calcitriol , alphacalcidol
recombinant PTH analogous
thiazides diuretics + low sodium diet = reduce calcium excretion
what is pseuohypoparathyroidism ?
resistance to the parathyroid hormone
what is the diagnosis of pseudohypoparathyroidism ?
have a low serum calcium and high phosphate, but the parathyroid hormone level (PTH) is appropriately hig
what are the signs and symptoms of pseudohypoparathyroidism ?
the end-organ resistance is accompanied by a specific patterncalle -Albright hereditary osteodystrophy:
short stature
brachydactyly of 4th and 5th metacarpal or metatarsal
obesity - round facies
ectopic soft tissue
dermal ossification
carpo-pedal muscular spasms,
IQ is typically mildly depressed
any every other hypocalcemia symptoms
