11.4: Acid / Alka

Question 1

What is metabolic acidosis?

Answer 1

• Decrease in bicarb [] in plasma
• Increases [H] plasma
• Accompanied by decrease in PCO2 to maintain PH
• Known as respiratory alkalosis

Question 2

What is respiratory alkalosis?

Answer 2

• Decrease in PCO2 to normalize PH increase in metabolic acidosis

Question 3

What is total CO2 / CO2 content?

Answer 3

What the chemistry lab calls bicarb when they measure it

Question 4

What is the henderson Equation?

Answer 4

H+ = 24 PCO2 / HCO3-

***Want to keep hydrogen ion constant

Question 5

Various [H] and PHs

Answer 5

7. 1 = 80
8. 2 = 63
9. 3 = 51
10. 4 = 40
11. 5 = 32
12. 6 = 25
13. 7 = 20

Question 6

Equation of acid base homeostasis?

Answer 6

H + HCO3- -> H2CO3 -> H20 + PCO2 (excreted by lungs)

Question 7

What are the abnormalities with respiratory alk/acidosis in?

Answer 7

• PCO2

- Compensatory movement in bicarb

Question 8

Predicted volume of compensation in alka / acid?

Answer 8

1.2 decrease bicarb = decrease in PCO2

.7 increase bicarb = increase in PCO2

Question 9

What is electroneutrality?

Answer 9

• Anions in body must match volume of cations
• Na + UC = HCO3 + Cl + UA
• UC/A: unmeasured cations and anions

Question 10

What is the anion gap?

Answer 10

• Na+, Cl-, and HCO3- are most prevalent ions
• DIfference between Na+ and Cl- + HCO3- is “anion gap”
• Anions must equal cations so no “real” gap
• ***Usually is 10 - 12

Question 11

What does increased anion gap acidosis point to?

Answer 11

• Overproduction of an organic acid with retention of organic anion
• Organic acids are anions
• The acid is titrating the bicarb dropping its volume

Question 12

2 causes and subclasses of increased anion gap acidosis?

Answer 12

Increase organic acid production
1. Ketoacidosis 
2. Lactic acidosis
3. Toxin ingestion 
Failure to excrete organic ions:
1. Renal failure

Question 13

What is hyperchloremic acidosis?

Answer 13

• Bicarb is low, Cl- may increase to keep neutrality

Question 14

Causes of Hyperchloremic acidosis?

Answer 14

1. GI loss of bicarb: diarrhea
2. Renal loss of bicarb: Renal tubular acidosis (RTA)
3. Failure to excrete acid: renal failure
4. Acid administration: TPN
5. High doses of saline

Question 15

What is type II RTA?

Answer 15

“Renal Tubular acidosis” proximal tubule

• Impairment in HCO 3 reabsorption in proximal
• Bicarb begins to be spilled in urine at earlier level
• Causes acidosis in body with increased Cl- resorption with Na to neutralize HCO3 that was dumped
• Patient will have low serum bicarb and high Cl

Question 16

What is Type I RTA?

Answer 16

• Inability to excrete H in distal tubule
• H ATPase normally pumps H out to combine with bicard
• This is impaired in RTA II

Question 17

2 most common causes of hyperchloremic acidosis?

Answer 17

1. Diarrhea

2. Kidney disease

Question 18

How treat metabolic acidosis?

Answer 18

Normal anion gap: bicarb

• Na or K / bicarb can be given as well
• Bicarb formers can be given as well

Question 19

What is metabolic alkalosis?

Answer 19

• Increase in plasma bicarb

- Accompanied by increased PCO2 to maintain PH

Question 20

Generation of metabolic alkalosis?

Answer 20

1. Net loss of H from ECF
2. Increased Bicarb to ECF
3. Loss of chloride in excess of bicarb

Question 21

How can H be lost?

Answer 21

1. GI tract: vomit
2. Renal: in urine
3. Shift into cells

Question 22

What happens to H in stomach?

Answer 22

• Titrate by pancreatic bicarb

- If H is lost in vomiting, net increase in bicarb

Question 23

How is H lost in urine?

Answer 23

1. Excess mineralocorticoids: ADH (tumor)

Question 24

What is mineralocorticoid in humans?

Answer 24

Aldosterone

Question 25

Why does H shift into cells?

Answer 25

- K moves out of cells in sever HYPOkalemia | - H moves in to replace charge

Question 26

What can cause bicard gain?

Answer 26

1. Exogenous: bicarb, lactate, citrate, acetate | 2. Chloride rich fluid loss: more bicarb resorbed

Question 27

How is Cl lost in GI?

Answer 27

1. Villous adenoma: Cl secreting tumor into school | 2. Failure of gut to resorb

Question 28

Causes of renal chloride loss?

Answer 28

1. Diuretics: impair resorption 2. Bartter's syndrome: defect of K2Cl in loop 3. Gitelman's syndrome: defect in NACL cotransporter in distal

Question 29

How is Cl lost in skin?

Answer 29

CF loss of Cl in excess of bicarb in sweat

Question 30

How does kidney handle bicard?

Answer 30

- Freely filtered - Reabsorbed in proximal nephron - That consumed by acid is regenerated in distal

Question 31

Reason for maintenance of metabolic alkalosis?

Answer 31

- Chloride depletion - If you give solely Cl- back it corrects - Usually given as NaCl

Question 32

Why does chloride correct metabolic alkalosis?

Answer 32

- In type B intercalated cell, Cl moves into cell allowing bicarb to be dumped in urine to correct alkalosis

Question 33

Signs of metabolic alkalosis?

Answer 33

1. Hypoventilation 2. Vomiting 3. Diuretics 4. Cramps 5. Htn.

Question 34

What is low Cl in urine indicative of?

Answer 34

- Cl depletion

Question 35

DD for metabolic alkalosis?

Answer 35

1. Chloride responsive: low Cl in urine 2. Chloride resistant: high Cl seen in urine: ADH excess state - Extra Cl- will just be dumped in urine

Question 36

How is metabolic alkalosis treated?

Answer 36

* Potassium administration * Acetazolamide * Volume repletion * Intravenous HCl or NH4Cl

Question 37

What is normal PCO2?

Answer 37

40

Question 38

What is normal anion gap?

Answer 38

- 10 - 12 - If less than this when you calculate its normal anion gap - If higher, high anion gap