Lecture 7 - Acid Base Balance 2

Question 1

What is pH homeostasis?

Answer 1

Is a balance between acid production and acid excretion

Question 2

What causes a low pH?

Answer 2

Metabolic acidosis (decrease in bicarbonate) and increase in respiratory acidosis (increase in PCO2)

Question 3

What causes a high pH?

Answer 3

Metabolic alkalosis (increase in bicarbonate) and respiratory alkalosis (decrease in PCO2)

Question 4

How do you compensate for metabolic acidosis?

Answer 4

Increased ventilation with a decrease pCO2 and H+

Question 5

How do you compensate for respiratory acidosis?

Answer 5

Increased H+ secretion and excretion, all filtered bicarbonate reabsorbed, increased ammonia excretion

Question 6

How do you compensate for metabolic alkalosis?

Answer 6

Decreased ventilation and increased PCO2

Question 7

How do you compensate for respiratory alkalosis?

Answer 7

decreased HCO3- and decreased H+ secretion

Question 8

What is compensation?

Answer 8

To try and correct the fault

Question 9

What causes respiratory acidosis?

Answer 9

Obstructive airway disease and drugs which depress respiration

Question 10

What is the primary defect for respiratory acidosis?

Answer 10

Increase in PCO2

Question 11

What causes respiratory alkalosis?

Answer 11

Hyperventilation e.g. panic attacks, asthma and mechanical ventilation (salicylate overdose)

Question 12

What is the primary defect for respiratory alkalosis?

Answer 12

Decrease in PCO2

Question 13

What is a salicylate overdose?

Answer 13

Aspirin overdose

Question 14

What is the primary defect for metabolic acidosis?

Answer 14

Decrease in bicarbonate

Question 15

What are the causes for metabolic acidosis?

Answer 15

Gain of nonvolatile acid e.g. lactic acid, ketoacidosis and solvent abuse, lose of bicarbonate and decreased renal secretion

Question 16

What is the primary defect for metabolic alkalosis?

Answer 16

Increase in bicarbonate

Question 17

What are the causes of metabolic alkalosis?

Answer 17

Increased GI loss of protons - vomiting, increased renal loss of protons, administration of bicarbonate IV and liquorice

Question 18

What can too much liquorice cause?

Answer 18

Pseudohyperaldosteronism

Question 19

Why do people need bicarbonate IVs?

Answer 19

People who get acid reflux

Question 20

What is the first line of defence of acid base disturbance?

Answer 20

To minimise the changes in pH - although it does not correct the underlying disorder

Question 21

What is the multi step process for recovery from an acid-base disturbance process?

Answer 21

Acid base disturbance, buffering, respiratory compensation, renal compensation and correction of defect

Question 22

What is the immediate response for acid base disturbance?

Answer 22

Immediate/minutes

Question 23

What is the several hours response in acid base disturbance?

Answer 23

Respiratory compensation

Question 24

What is the longer (hours-day) response for acid base disturbance?

Answer 24

Renal compensation

Question 25

What is Pendrin?

Answer 25

It is a chloride bicarbonate antiporter

Question 26

What are beta intercalacted cells also know as?

Answer 26

Bicarbonate intercalating cells

Question 27

How do protons go back into the blood stream? - in the beta-intercalated cells of the distal tubule

Answer 27

By the V-ATPase

Question 28

When is the activity of the bicarbonate intercalated cells increased?

Answer 28

It is increased during metabolic alkalosis

Question 29

What helps with Cl- exchange?

Answer 29

The chloride transporter

Question 30

What diagram is used for acid-base disturbances?

Answer 30

The davenport diagram (it is not used clinically)

Question 31

What mmHg of CO2 is acidosis?

Answer 31

60mmHg

Question 32

What mmHg of CO2 is alkalosis?

Answer 32

20mmHg

Question 33

What is considered the buffer line in the davenport diagram?

Answer 33

40mmHg - this is where all the equivalences join together

Question 34

What does high bicarbonate acidosis = (in the davenport diagram)

Answer 34

Respiratory acidosis

Question 35

What condition is it where you have a low bicarbonate acidosis?

Answer 35

A metabolic acidosis

Question 36

What condition is it called if there is a high Bicarboante alkalosis?

Answer 36

Metabolic alkalosis

Question 37

What condition is it if you compensate with low bicarbonate alkalosis?

Answer 37

Respiratory alkalosis

Question 38

Acidosis with decrease pCO2 =

Answer 38

Metabolic acidosis

Question 39

Acidosis with increased bicarbonate =

Answer 39

Respiratory acidosis

Question 40

Alkalosis with increased PCO2 =

Answer 40

respiratory alkalosis

Question 41

Alkalosis with decreased bicarbonate =

Answer 41

Respiratory alkalosis

Question 42

Example Q - what is the condition, 7.28pH 26mmHg of PCO2, 14mEq of bicarbonate?

Answer 42

Bicarbonate = disorder and there is a decreased PCO2 therefore it is metabolic acidosis

Question 43

What is renal tubular acidosis?

Answer 43

To results from impaired H+ excretion by the kidneys

Question 44

What is type 1 renal tubular acidosis?

Answer 44

Distant renal tubular acidosis

Question 45

What is type 2 renal tubular acidosis?

Answer 45

Proximal renal tubular acidosis

Question 46

What are examples of Type 1 renal tubular acidosis?

Answer 46

Distal nephron dysfunction, increased H+ permeability and Sjogen syndrome

Question 47

How can type 2 - proximal tubular (RTA) be caused?

Answer 47

Usually due to a general dysfunction rather than specific transporter defect

Question 48

What does impaired H+ secretion in PT lead to?

Answer 48

Decreased in bicarbonate reabsorption

Question 49

What is the anion gap?

Answer 49

It is the difference in concentration of major ECF cations and anions

Question 50

What is the normal value for the anion gap?

Answer 50

8-16mEq

Question 51

What happens to the anion gap when there is acidosis from acid loading?

Answer 51

It increased to 17 and bicarbonate is reduced

Question 52

What happens to the anion gap when acidosis results from Bicarboante loss?

Answer 52

It decreased to 10 - it is within the normal range

Question 53

What is the equation for the anion gap with Na+, bicarbonate and Cl?

Answer 53

([Na+] - ([Cl-] + [HCO3-])

Question 54

Increased acid retention =

Answer 54

Decreased pH and increased RAAS production

Question 55

What causes decreased acid retention

Answer 55

Increased acid excretion and increased ammonia

Question 56

What does angiotensin II contribute to?

Answer 56

It contributes to tubular injury and fibrosis in chronic kidney disease

Question 57

What does ammonia genesis in chronic kidney disease result in?

Answer 57

It activates complement and exacerbates tissue damage - leads to an alternative compliment cascade