metabolic alkalosis Flashcards
metabolic alkalosis
disorders which raise serum bicarbonate and pH
For every 1 mEq/L change in serum bicarbonate, a _______ mm Hg change in pCO2
0.6-0.75
mixed acid-base disorder including a metabolic alkalosis
HCO3 inappropriately elevated out of proportion to expected metabolic compensation (below) or neither HCO3 or pCO2 in direction consistent with compensation
generation of an alkali load (2)
- addition of an alkali load
2. loss of acid
loss of acid in metabolic alkalosis
- vomiting leading to a loss in HCl from stomach
- primary mineralocorticoid excess leading to renal H+ secretion
alkali load in metabolic alkalosis
- adm. of bicarb w/ fluids w/ kidney function impairement
- large vol. blood transfusion with products anticoagulated with citrate salts
Healthy kidneys initially excrete excess bicarbonate, HOWEVER…
1.
… may all conspire to enhance urinary acidification and maintain the alkalosis
- Increased mineralocorticoid activity (aldosterone)
- Chloride depletion
- Hypokalemia
which three cells of distal/collecting tubule maintain metabolic alkalosis
- principal cell: Na+ reab
- intercalated A: H+ secretion
- intercalated B: HCO3- secretion
reduced delivery of _____ to JG triggers renin releasse
NaCl
aldosterone leads to the activation of the
ENaC
ENAC activation leads to
- Na reabs
2. tubular lumen more negative
intercalated A-cell is:
a. influenced by
b. secretes
c. leads to
a. influenced by aldosterone
b. secretes H+ion
c. leads to hypokalemia and increased conservation of potassium
intercalated B-cell:
a. channel
b. limited by
a. Pendrin (chloride-bicarb) bicarb efflux
b. limited by low chloride delivery leading to a reduced bicarb efflux
pendred syndrome:
a. inheritance
b. issue
c. under condition of increased distal Cl- delivery
d. severe
e. other organs affected
a. Autosomal recessive
b. reduced pendrin activity
c. under condition of increased distal Cl- delivery (like in thiazide diuretic), failure to reabsorb cl- and secrete HCO3
d. severe hypovolemia and metabolic alkalosis
e. other organs affected like hypothyroidism nad sensorineural hearing loss
Three important mineralocorticoid actions to enhance distal tubule H+ secretion
- Increase activity of Na+/K+ ATPase
- Increase number of open epithelial sodium channels (ENaC)
- Stimulate H-ATPase pump
Reduced chloride delivery to the distal tubule sensed at the juxtaglomerular apparatus (JGA)
chloride-dependent metabolic alkalosis
aldosterone is secreted autonomously independent of chloride state
chloride independent metabolic alkalosis
what does a low urine chloride indicate
chloride dependent
what does a nl or elevated urine chloride
independent alkalosis
- Vomiting or nasogastric suction
- Massive diuresis
- Post hypercapnia
- Congenital chloride diarrhea
- Cystic fibrosis (sweat losses)
- Bartters and Gitelmans syndromes*
- Special circumstance – urine chloride high
examples of chloride dependent metabolic alkalosis
- Hyperaldosteronism
- Calcium-alkali syndrome
- Congenital and acquired hypermineralocorticoid states
examples of chloride independent metabolic alkalosis
treatment of chloride dependent metabolic alkalosis
which is the indirect treatment?
- sodium chloride
- potassium chloride
- ammonium chloride
- arginine chlroride
- hydrochloric acid
indirect- CA inhibition
chloride dependent alkalosis sees initial losses of __, ___ and ___ (volume), a raise in _____, a drop in plasma/urine ___ and stimulates ____ and ____
intial losses of H+, Cl- and Na+, raises plasma HCO3, drop in plasma/urine Cl-, and stimulate renin and aldosterone
elevated plasma HCO3 in chloride dependent alkalosis is maintained by
- tubular sodium/bicarbonate reabs in the PCT
- aldosterone accelerating H+ secretion in the CT
true or false:
in chloride independent alkalosis, Na+ and Cl- deficiency is responsible for enhanced HCO3 reabs. anad H+ secretion
nope it is not responsible
in chloride independent alkalosis, _______ is not related to volume depletion
mineralocorticoid excess
chloride independent alkalosis, ___ and ____ supplementation do not enhance HC)3-
Na+ and Cl-
do we see potassium depletion and hypokalemia play a major role in chloride independent alkalosis
yep
treatment of chloride independent metabolic alkalosis
- ______ repletion
- ______blockade
- other ________ diuretics
- discontinuation of _________ with _______effect
- potassium repletion
- mineralocorticoid blockade
- other potassium sparing diuretics
- discontinuation of exogenous agents with mineralocorticoid effect