Flashcards in Sodium disorders Deck (65)
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1
Normal serum Na+?
135-145 Meq/L
2
Normal plasma/serum osmolality?
285-300 Meq/L
3
Eqn to estimate plama/serum osmolality?
Na x 2 + BUN/2.8 + Gluc/18
4
Main contributor to serum osmolality?
Na
5
Symptoms of hypo/hypernatremia are due to effects on which orhan?
Brain
6
Sodium abnormalities are usually caused by ____________ NOT ___________.
Water problems
NOT
Salt problems
7
Extracellular hyp-O-osmolality have what effent on neurons?
swelling
8
Sx if Na+
nausea
malaise
9
Sx if Na+ = 115-120:
headache
lethargy
10
Sx if Na+
obtundation
seizures
coma
11
More severe sx in fast or slow hyp-O-natremia?
Fast
brain has less time to adapt
12
Effect of hyp-ER-natremia on neurons?
cells shrink
13
Sx of hyp-ER-natremia?
lethargy
weakness
irritability
twitching
seizures
coma
death
14
Decreased brain volume due to hyp-ER-natremia can have what effect on vasculature?
rupture cerebral vessels
15
Clinically significant water shift occurs with 30-35 mosm/kg osmolar gradient between plasma and brain; what is the corresponding rise in serum Na+?
17 meq/L
16
Hormone responsible for maintenance of plasma osmolality:
ADH
(arginine vasopressin)
17
Where is ADH produced?
supraoptic and paraventricular nuclei of hypothalamus
18
Where is ADH stored and released?
secretory granules
posterior pituitary
19
Osmotic stumuli of ADH release:
INCREASED plasma osmolality
20
Non-osmotic stimuli of ADH release:
hypovolemia --> baroreceptors
pain
esophageal stimuli
medications
21
What receptor binds ADH to release aquaporin 2 to luminal membrane?
Where does this occur?
V2 (activates protein kinase)
collecting tubule
22
With high presence of ADH:
Urine osmolality = ?
Plasma osmolality = ?
urine- increased
serum- decreased
**water flows out of tubule back into blood
23
In low/absent ADH state:
Urine osmolality= ?
Blood osmolality= ?
urine- increased
blood- decreased
**water excreted in urine
24
Physiologic responses to HIGH plasma osmolality:
thirst
ADH release
water reabsorption
concentration of urine --> high urine osmolality
25
Physiologic response to LOW plasma osmolality:
No thirst
No ADH release
Loss of free water -- collecting tubules impermeable
Low urine osmolality -- dilute urine
26
Plasma osmolality maintained within __%.
1%
27
Indicator of the presence of ADH?
Urine osmolality
28
What generally tells you what the kidney THINKS about the body's volume status?
urine sodium
29
Range of urine osmolality in a normal kidney?
50-1400 mosm/L
30
