Parathyroid Function: Calc reg (start for exam 2) Flashcards
Describe Calcium jobs
m
o
m
b
n
i
maintained in narrow range
optical nerve impulse
muscle contractions
blood coag
normal secretions
initial adhesion
What is calcium regulated by
hormonal control
Describe PTH
secreted from…
what receptors
prim targets?
secreted from glands adjacent to thyroid
calcium sensing receptors
primary targets bone and kidney
Describe bone and calcium
mobilizes….
increases..
releases…
mobilizes calcium from bone which increases bone reabsorbtion and releases minerals into blood stream
Describe Kidney 3 effects
inc reab
inc phos
enhance a
increased reabsorb of renal tube calcium
increased phosph excretion
enhanced alpha-hydrox of 25 hydrox Vit D
Describe calcitriol
active met of….induces active re …
active met of Vit. D induces active absorption of calcium in small intestine
Describe low blood calcium
sensed by parathroid CSR - secretes PTH - activates cascade to restore normal blood ca
Describe Vit D hormone
steriod hormone from cholesterol
Describe Vit D3
rare in nature, liver/seafood, fortified milk, more potent then D2
Describe Vit D2
edible mushrooms
Describe endogenous VIT D
synth of
what is a natural ligand for…
treats 2nd….due to
synth of Vit D from sunshine
1,25 (OH) 2D - natural ligand for VIT D steriod receptor
(treats 2nd hyperparathy due to chronic renal failure)
Activated Vit D
causes active…
how much absorbed passively
absence of?
causes active adsorbtion of calcium in small intestine
5-10% absorb passively
absence of phosphate (higher passive absorb)
Describe hypocalcemia
decreased plasma [] calcium
lack of Vit D
Describe Bones, what stimulates maturation
active Vit D stimulates osteoclast maturation
Describe the steps ca+2 falling
stimulates
increases
decreased
increases 1
stimulates PTH, increases bone reabs, decreases urinary loss, Increases 1,25(OH)sD production
Describe PTH
maintains…
P/V
3 organs
maintains optimal calcium levels: PTH/Vit D work w/ 3 organs
3 organs: GI/Kidney/Bone
Describe GI regulation of PTH
norm..
altered function causes?
normal func required/opt absorbtion
altered intestinal funct: gastric bypass
bowel fistula
short bowel syndrome
Role of kidneys in PTH
metabolism
renal failure…
..incr
state?
calcium metabolism
renal failure = dist in calcium/phosph metabolism
PTH inc renal tube aborb of calcium reducing renal loss
Hypercalcemia
Bone physiology
how much calcium
storge of?
1kg of calcium
stoarge of calcium/magn./phosph
Describe bone turnover (remodeling)
reg/coupled process, breakdown/creation
if “uncoupling” occurs mismatched form/reabs
inc fracture
What are bone turn over markers used for?
to monitor therapy/predict bone fract risk
Bone turnover marker for formation
alk phos total and specific bone ALP
Describe the two types of bone
Cortical bone: shaft of bones, strong,light weight exremities
Trabecular bone: axial skeleton, cross hairs/honeycomb - trabeculae strenght for weight
Describe parathyroid disorders
hypercalemia
mod elevation
chronic mild
hypercalcemia elev in calcium above expected normal
lethargy/coma
Mod elev: personality changes, kidney stones
chronic mild: sympt free
What is the most common cause of hypercalcemia
PHPT outpt setting
Describe PHPT (primary hyperparathyroidism)
causes?
key feature autonom prod of?
gender association?
inc due to multicha?
Hypercalc
key feature: autonomas overprod of PTH by single gland
woman 3x more
inc due to multichannel analyzers
Diagnosis of PHPT
elevation of serum..
biochem findings
inc excretion of
inc al
dec 25
inc 1
elev serum calcium/improp norm or elev PTH
biochem findings: hypercalc/hypophosph
inc urine calc excretion
inc alk phosph
dec 25-OH-D
inc 1,25 (OH) 2D
Management of PHPT
what surgery?
inoperative….half life
insid
kid
bone loss?
parathyroidectomy
intraoperative PTH half life 5 min drops rapidly
insidious onset
kidney stones 20-30%
bone loss cortical > trabular bone
Secondary Hyperparathyroid
causes? low
complete rise in?
low c/p
inc al
hypo
deficiency?
hypercalcemia - low blood calcium
complete rise in PTH
low calc/phosph
inc alk phos
hypocalc/phoph
VIT D deficiency
2nd/3rd HPT in renal failure
what has a central role?
what causes what changes….?
failure to excrete..
proportional to?
kidney central roll CKD causes bone/skeletal changes
kidney fails to excrete phosph (impaired Vit D)
bone changes proportional to severity
What differentiates 2nd/3rd HPT in renal failure
sustained?
trans…
CKD reduces
increases
PTH?
sustained hypercalcemia
some pts delevope transient hypercal
CKD reduced urine phosph excret
inc blood phosph
PTH increased
FHH familial hypocalcemia/hypercalcemia
benign mutation to
..production and elevated….are?
results in?
benign germline mutation CSR - upsets
PTH production and calcium elevated not prognostic
results in stable/mild hypercalcemia since birth
Clinical features: of FHH familial hypocalcemia/hypercalcemia
increased c
inc m
inc pt
whats <100mg
mutant
end orgn…
surgery?
Inc serum calcium
inc serum magnesium
inc PTH
urine calc <100mg
mutant CSR
end org dysfunction not common
NO SURGERY
Describe Hyperthyrodism
inc b/h
PTH levels?
disease state?
what can cause hyperparathyroidism?
hyper…?
inc bone reabsorbtion/hypercalcemia
PTH dec
addisons disease - low PTH steroid replacement
HCTZ/lithium cause hyperthyroidism
hypervitaminosis
Describe PTH rp (parathryoid related protein)
secreted by?
similar to?
receptors?
healthy humans?
lactation?
substance secreted by cancer
struct similar to PTH/funct features
same receptors
healthy human levels should be low/none
normal lactation can cause PTH rp
Hypercalcemia due to PTHrp is not due to what root cause?
secretion not reg by?
PTHrp cant facilitate?
cancer
secreation not regulated by very high BP
PTH rp cant facilitate renal hydroxylation of 25 VIT D
Hypoparathyroidism
inad…
common causes?
inadequate parathyroid gland function
common causes:
neck surgery - thyroidectomy
accidental gland removal
damage to glands in surgert
Auto immune destruction in hypothyroidism
Type 1 diabetes
hashimotos
addisons
malignant deficiencies
Pseudohypoparathyroidism
inherit …lack of
intestinal..
inherited disorder lack of PTH response
intenstinal disorders result in malabsorb of calc/VIT D
Rickets
before epith plate closure in children
Osteomalacia
minerilization in adults
Osteoporosis
what type of bones?
prevelence?
malform/reab ratio?
risk of?
diseases?
porous bones in adults
most prevelent bone disease in adults
bone malformation/excessive reab 4:1 F:M
hip fractures
cushings disease
