Renal Acid-Base Flashcards
What are the values of pH, [H+], and [HCO3-] in Metabolic Acidosis?
pH < 7.38
[H+] > 42 nM
HCO3- < 24
What is the compensatory response in Metabolic Acidosis? What about Respiratory Acidosis?
Metabolic Acidosis: Decrease CO2- (hyperventilate)
Respiratory Acidosis: Increase HCO3-
What is the compensatory response in Metabolic Alkalosis? What about Respiratory Alkalosis?
Metabolic Alkalosis: Increase CO2 (hypoventilate)
Respiratory Alkalosis: Decrease HCO3-
What are the 3 ways in which we classify Metabolic Acidosis
Bicarbonate Loss
Failure to Excrete Acid (or Regenerate Bicarbonate)
Bicarbonate Consumption
What is the anion gap (AG)?
Provide the associated equation.
AG = The difference between Na+ and the sum of Cl- and HCO3- that represents the other plasma anions.
AG = [Na+] - ([Cl-]+ [HCO3-])
Which of the following will increase the Anion Gap?[Anion Gap Metabolic Acidosis (AGMA)]?:
Bicarbonate Loss
Bicarbonate Consumption
Failure to excrete acid/ regenerate bicarbonate
Bicarbonate Consumption
Failure to excrete acid/regenerate bicarbonate
Which of the following will increase the anion gap (AG) and WHY?
Hydrochloric acid
Carbonic Acid
Lactic Acid
Lactic Acid will increase the anion gap because it does not have a chloride or bicarbonate anion. When it gives off a protein it will lower the concentration of Cl- or HCO3- which will increase the AG. (High AG = Acidosis)
When hydrochloric or carbonic acid dissociate, they replace the Cl- or HCO3- that picks up the H+.
What are the types of acids/situations that can lead to Metabolic Acidosis? (There’s a mnemonic…)
GOLDMARK
Glycols, Oxoproline, L-Lactate, D-Lactate, Methanol, Aspirin, Renal Failure, Keto-acids
Briefly describe the pathophysiology of lactic acidosis. Does this affect the anion gap? If so how?
Lactic Acidosis - Increase in lactic acid production leads to a lower concentration of bicarbonate –> Acidosis
The anion gap is increased. (Bicarbonate consumption)
Briefly describe the pathophysiology of Renal Failure. Which stage affects the AG? How?
Increase in phosphate and sulfate anions increases unmeasured anions which decreases Cl- & HCO3- concentration which leads to acidosis.
The anion gap is increased in the early stages (HCO3- consumption)
In later stages kidneys cannot excrete acid (H+) which leads to NAGMA (?)
What are the two treatment options for lactic acidosis?
IV Bicarbonate
Treat underlying problem (ie. hypoperfusion)
What is the treatment options for renal failure?
Oral sodium bicarbonate
Briefly describe the pathophysiology of Diabetic Ketoacidosis (DKA).
Does it affect the anion gap (AG)? If so how?
In DKA, the body is not responding to insulin, which means the cells cannot absorb much glucose. This makes the cells use lipids (lipolysis) for energy. This generates beta hydroxybutyric acid and acetoacetic acid. In excess these lower Cl- and HCO3- leading to acidosis.
AG increases due to consumption of HCO3-…and Cl- (?)
Briefly describe the pathophysiology of Salicylate (ASA) Intoxication?
Does it affect the anion gap (AG)?
ASA (aspirin) Intoxication leads to build up of salicylic acid which decreases HCO3- and Cl- leading to acidosis.
This increases the AG. (Low Cl- and HCO3-)
ASA intoxication can also cause respiratory alkalosis (patient will over hyperventilate in response to ASA)
How can ASA Intoxication be treated?
Gastric Lavage, Charcoal
Urine alkalinization (Bicarbonate)
Dialysis if severe