Metabolic alkalosis

Question 1

What is metabolic alkalosis ?

Answer 1

• blood ph>7,45 due to an increase in HCO3- concentration

Question 2

How does metabolic alkalosis occurs ?

Answer 2

• loss of H+

- gain of HCO3-

Question 3

Metabolic alkalosis due to loss of H+, state examples

Answer 3

• vomiting

- hyperaldosteronemia

Question 4

Metabolic alkalosis due to loss of H+: Vomiting

Answer 4

• during vomiting:
  . loss of H+ ions (gastric secretions are very acidic)
  .build up of HCO3- in the blood (from the pancreatic secretion, which usually neutralizes the H+)

Question 5

Metabolic alkalosis due to loss of H+: Hyperaldosteronemia

Answer 5

• because of adrenal tumor
  Aldosterone stimulates prox and distal conversation tubule to reabsorb HCO3- (which makes the blood more alkaline) + also secretes H+ into the urine (making urine more acidic)

Question 6

Metabolic alkalosis due to gain of HCO3-, state examples

Answer 6

• severe dehydration/ volume contraction, excessive loss of extracellular fluid (loop diuretics + thiazide diuretics)
• diarrhea / use of diuretics (kidneys)
• ingestion of large amounts of antacids (NaHCO3)

All result an increase in HCO3- , which increases blood PH. Often associated with hypokalemia.

Question 7

Metabolic alkalosis due to gain of HCO3-: Severe dehydration/volume contraction, excessive loss of extracellular fluid (loop diuretics + thiazide diuretics)

Answer 7

• causes a direct increase in reabsorption of HCO3- and Na+ from the kidneys, also called contraction alkalosis
• severe dehydration can be caused by prolonged vomiting

Question 8

Metabolic alkalosis due to gain of HCO3-: diarrhea / use of diuretics (kidneys)

Answer 8

• would cause hypokalemia (decrease K+), due to excessive loss -> the loss of K+ or volume -> stimulates renin-angiotensin aldosterone mechanism - and II + aldosterone increase -> kidneys retain water + HCO3- and secretes more H+ in urines

Question 9

Metabolic alkalosis due to gain of HCO3-: ingestion of large amounts of antacids (NaHCO3)

Answer 9

• antacids neutralize stomach acid + relieve indigestion -> causes an increase in HCO3- > H+ in the stomach -> which causes an excess HCO3- in the blood

Question 10

Mechanisms used to keep PH in balance then HCO3- concentration decreases

Answer 10

• K+/H+ ion transporters: K+ goes in the cells, H+ goes in the blood. Contributes to hypokalemia
• Resp system: sensed by chemoreceptors -> decrease resp rate and depth of breathing -> causes decrease in minute ventilation -> increase PCO2 -> increase PH
• Kidney system: retain more H+ and reabsorb less HCO3-