Ren 6 - Acid-Base Disorders

Question 1

What are some causes of Metabolic acidosis?

Answer 1

Adding acid to the blood (causes High anion gap)
[MUD PPIILE]
Methanol. Uremia. Diabetic ketoacidosis.
Propylene glycol. Paraldehyde. Iron tablets. Isoniazid. Lactic acid. Ethylene glycol (antifreeze)
Salicylates.
Losing excessive HCO3- (causes normal anion gap).

Question 2

What is the cause of normal anion gap acidosis?

Answer 2

Not adding acid, but losing bicarb.

Diarrhea. Renal tubular acidosis. Spironolactone. Acetazolamide.

Question 3

What are the causes of repiratory alkalosis?

Answer 3

Hyperventilating. Psychogenic (panic, anxiety attack). High altitude. Acute hypoxemia (PE). Aspirin toxicity (causes metabolic acidosis later: ASA will directly stimulate the respiratory center in the brain and cause hyperventilation).

Question 4

What are the causes of respiratory acidosis?

Answer 4

Hypoventilating. Airway obstruction. Air trapping. Lung disease. Weak respiratory muscles. Opioids.

Question 5

What are the causes of metabolic alkalosis?

Answer 5

Losing hydrogen someway: Excessive vomiting. Diuretics. Hyperaldosteronism.

Question 6

What is Type 1 RTA and what does it cause?

Answer 6

It is Renal tubular acidosis; it is also know as distal RTA; acidosis in the distal nephron aka the collecting tubule. The alpha-intercalated cells in the collecting tubule are not able to secrete hydrogen as they usually do. Causes urine pH greater than 5.5. Causes Hypokalemia.

Question 7

What is type 4 RTA and what does it cause?

Answer 7

It is renal tubular acidosis: it is due to hypoaldosteronism.

• Causes hyperkalemia since the low aldosterone is not putting enoght potassium into the urine.
• Causes the prevention of collecting tubules from generating amonium (NH4+).
• Causes urine pH less than 5.5.

Question 8

What is type 2 RTA and what does it cause?

Answer 8

It is renal tubular acidosis: caused by proximal tubule defect of HCO3- reabsorption. Causes hypokalemia. Causes hypophosphatemia.

Question 9

What is a simplified Henderson-Hasselbalch equation?

Answer 9

It is pH is related to HCO3-/ pCO2 (bicarb over partial pressure of CO2).

Question 10

What does high bicarbonate in ABG say?

Answer 10

Metabolic alkalosis.

Question 11

What does low PCO2 in ABG say?

Answer 11

Respiratory alkalosis.

Question 12

What can compensatory mechanism against primary acid/base inbalance never achieve?

Answer 12

A compensatory mechanism should never bring the pH all the way back into normal range.

Question 13

What would a normal pH but bicarb and pCO2 are out of normal range mean?

Answer 13

That it is a mixed; both primary metabolic acidosis and primary respiratory alkalosis.

Question 14

What is the Winter formula?

Answer 14

It is PCO2 = (1.5 x HCO3-) + 8 +/- 2.

• It is used to estimate what the PCO2 should be in cases of metabolic acidosis based on respiratory compensation.
• ONLY use in settings of metabolic acidosis.
• If the measured PCO2 is higher than the calculated value, there is also a primary respiratory acidosis.
• If the measured PCO2 is lower than the calculated value, there is also a primary respiratory alkalosis.

Question 15

What should PO2 should be compared to PCO2?

Answer 15

Double the value of PCO2.

Question 16

What should HCO3- be compared to pCO2?

Answer 16

It should be half.

Question 17

Determine the Acid-Base Disorder:
pH: 7.4
HCO3-: 23
PCO2: 40

Answer 17

Normal; no disorder here.

Question 18

Determine the Acid-Base Disorder:
pH: 7.5
HCO3-: 35
PCO2: 42

Answer 18

Metabolic alkalosis.

Question 19

Determine the Acid-Base Disorder:
pH: 7.33
HCO3-: 13
PCO2: 28

Answer 19

Metabolic acidosis w/ resp compensation.

Question 20

Determine the Acid-Base Disorder:
pH: 7.42
HCO3-: 32
PCO2: 64

Answer 20

Metabolic alkalosis and respiratory acidosis.

Question 21

Determine the Acid-Base Disorder:
pH: 7.2
HCO3-: 18
PCO2: 40

Answer 21

Metabolic acidosis.

Question 22

Determine the Acid-Base Disorder:
pH: 7.2
HCO3-: 24
PCO2: 54

Answer 22

Respiratory acidosis.

Question 23

Determine the Acid-Base Disorder:
pH: 7.52
HCO3-: 22
PCO2: 22

Answer 23

Respiratory alkalosis.

Question 24

Determine the Acid-Base Disorder:
pH: 7.66
HCO3-: 36
PCO2: 30

Answer 24

Combined metabolic and respiratory alkalosis.

Question 25

Determine the Acid-Base Disorder:
pH: 7.47
HCO3-: 14
PCO2: 22

Answer 25

Respiratory alkalosis with metabolic compensation.

Question 26

Determine the Acid-Base Disorder:
pH: 7.46
HCO3-: 35
PCO2: 53

Answer 26

Metabolic alkalosis with respiratory compensation.

Question 27

Determine the Acid-Base Disorder:
pH: 7.39
HCO3-: 12
PCO2: 22

Answer 27

Metabolic acidosis and respiratory alkalosis.

Question 28

Determine the Acid-Base Disorder:
pH: 7.34
HCO3-: 31
PCO2: 62

Answer 28

Respiratory acidosis with metabolic compensation.

Question 29

Determine the Acid-Base Disorder:
pH: 7.1
HCO3-: 15
PCO2: 50

Answer 29

Combined metabolic and respiratory acidosis.

Question 30

Determine the Acid-Base Disorder:
pH: 7.24
HCO3-: 24
PCO2: 53

Answer 30

Respiratory acidosis.

Question 31

Determine the Acid-Base Disorder:
pH: 7.58
HCO3-: 34
PCO2: 28

Answer 31

Metabolic alkalosis, respiratory alkalosis.

Question 32

Determine the Acid-Base Disorder:
pH: 7.23
HCO3-: 19
PCO2: 38

Answer 32

Metabolic acidosis.

Question 33

Determine the Acid-Base Disorder:
pH: 7.33
HCO3-: 30
PCO2: 58

Answer 33

Respiratory acidosis with metabolic compensation.

Question 34

A patient with a history of kidney stones presents with hypokalemia and metabolic acidosis. The anion gap is normal. Urine pH is 5.7. What is the underlying defect?

Answer 34

Renal tubular acidosis type I. Only type I RTA has high urine pH.