May 3, 2016 - SG12 - Abnormal Hydrogen

Question 1

Approach to Acid-Base Problems

Answer 1

1. Is it acidemia or alkalemia
2. Look at bicarbonate and HCO3 to determine if respiratory is at play
3. Calculate AG and determine if abnormal
4. Compare dAG and dHCO3

Question 2

High Anion Gap DDx

Answer 2

MUDPILES

Methanol

Urea

DKA

Propylene glycol

Infection

Lactic acidosis

Ethylene glycol

Salicylicates

Question 3

Sepsis and Lactic Acidosis

Answer 3

Sepsis can cause lactic acidosis by not providing adequate blood and oxygen to the tissues, causing cells to undergo anaerobic respiration where pyrvuvate is used to produce lactic acid.

Question 4

Metformin and Lactic Acidosis

Answer 4

Although metformin is relatively safe, it CAN sometimes be a cause of lactic acidosis. If this occurs, it should be stopped (at least temporarily).

Question 5

Calcium Oxylate Crystals

Answer 5

A sign of ethylene glycol poisoning.

Found in the urine.

Question 6

Decreased LOC and Acidosis

Answer 6

Decreased LOC can cause a respiratory acidosis because you aren’t capable of blowing off the excess CO2 that you should be.

Question 7

Vomitting and Alkalosis

Answer 7

When you vomit you lose HCl molecules. These are pumped across the parietal cells, but in order to pump them across you need to exchange for a bicarbonate molecule which will go into the blood, resulting in alkalosis.

Question 8

Treatment for Toxic Alcohol Poisoning

Answer 8

Administer ethanol via IV. Ethanol has a greater affinity for alcohol dehydrogenase and will compete for the active site over the more toxic alcohol compounds. The patient needs to go on hemodialysis to remove the toxic compounds.

Probably a psychiatric consultation as well…

Question 9

Mechanisms for Metabolic Alkalosis

Answer 9

Decreased EABV and Hypokalemia

Decreased EABV activates the RAAS system which enhances the exchange of NHE3 which brings more sodium into the cell and hydrogen out. When we uptake sodium, we also uptake bicarbonate.

Hypokalemia in the proximal tubule can also lead to alkalosis. As K+ ions leave, the cell retains H+ ions which makes it acidotic inside the cell. Glutaminase sees the acidotic environment and increases bicarbonate production.