Midterm 2: Acid Base/Electrolytes/Renal/Minerals/Glucose/Lipids/Thyroid/Pituitary/Adrenal Flashcards
What is the most important osmotic solute in the ECF
Na
What are 2 mechanisms that cause hypernatremic hypertonic dehydration
water loss due to water intake
- pure water loss due to panting/hyperventilation/diabetes insipidus
increases in total body Na
- iatrogenic from IV Na
- increased intake
What is a common cause of hypernatremic hypertonic dehydration from an increase in total salt
playdough toxicity
What are 3 causes of hyponatremic dehydration
increased Na loss with continued water intake
- GI/renal loss
- sweat (horses)
- 3rd space
excess water
- edematous disorder
- liver dz
- nephrotic syndrome
- CHF
shifting water
- hyperglycemia created an osmotic gradient that moves fluid from ICF to ECF
What are 3 main causes of hyperchloremia
dehydration/water loss
hyperchloremic metabolic acidosis
pseudohyperchloremia (associated with KBr - Cl and K are measured as the same by accident)
What is the electrolyte imbalance that defines hypochloremic metabolic acidosis?
a disproportionate decrease in Cl
(disproportionate to Na)
What is the main source of K?
diet
means that anorexia can cause hypokalemia
Where is most K found in the body? What causes it to move?
intracellularly mainly
its movement is regulated by aldosterone (stimulates excretion)
moves extracellularly…
- due to insulin or catecholamines
- acidosis
moves intracellularly…
- due to alkalosis
Give 2 common causes of pseudohyperkalemia
blood sample left sitting for too long
- platelets have high K naturally (thrombocytosis or degradation can increase levels)
Japanese dog breeds/horses/cows
- higher K in RBC (will release into sample if they are left sitting)
What is the most common cause of pathalogic hyperkalemia?
reduced renal excretion (low GFR)
- from addisons/urinary obstruction/renal failure
also
- iatrogenic
- shifting of K out of cells due to necrosis
What are the common causes of hypokalemia
anorexia (cows especially)
renal excretion
GI loss
skin loss (horses/sweating)
List the primary respiratory and metabolic acids
respiratory = pCO2
metabolic = LUKE
- lactic
- uremic
- ketones
- exogenous
Describe how the lungs parameters change for acid base disturbances
alkalosis = low pCO2
- fast ventilation
acidosis = high pCO2
- slow ventilation
can change quickly in response to changes
Describe how the kidneys adapt to acid base disturbances
excrete H+
- directly or via other compounds
conserve/make bicarb
Describe the acid base changes you would see with a primary respiratory acidosis? What are 4 potential causes?
There would be an elevated pCO2.
There would be compensation via metabolic alkalosis in which you would pee out acid and increase bicarb
due to hypoventilation
- pulmonary disease
- drugs
- asthma
- anesthesia
Describe the acid base changes you would see with a primary respiratory alkalosis? What are 3 potential causes?
There would be a decreased pCO2
There would be compensatory metabolic acidosis where bicarb is excreted and H+ is retained
due to hyperventilation
- stress
- pain
- overheating
Describe the acid base changes you would see with a primary metabolic acidosis?
You would see a low bicarb
- due to excess acid (LUKE)
- due to reduced bicard (d+/renal)
there would be a compensatory respiratory alkalosis and thus a low pCO2
How is anion gap used to evaluate a metabolic acidosis
Differentiates whether the low bicarb is due to a loss of bicarb or a gain of acids
If the anion gap is increased = due to a gain of acids because there is an increased number of unmeasured cations
What is the formula to calculate the anion gap
AG = (Na+K) - (Cl+bicarb)
it measured the gap between unmeasured anions and cations (uA- - uC+)
Using the anion gap, how do you explain the acid base abnormalities of hypochloremic metabolic acidosis?
There is a normal anion gap because hypochloremic metabolic acidosis is caused by loss of bicarb
- GI loss (cattle)
- renal loss
To maintain electroneutrality, there is an increase in Cl to compensate for the loss of bicarb
= disproportionate increase in Cl
Describe the acid base changes you would see with a primary metabolic alkalosis?
There will be in increased bicarb
- due to decreased acid (v+/obstruction/torsion/mass)
- increased bicarb (less common)
There will be a compensatory respiratory acidosis resulting in increased pCO2
Describe the normal cycle and relationship of Cl and bicarb
Stomach requires HCl
carbonic anhydrase reaction: in the parietal cell
- turn water and CO2 into H+ and bicarb
- Cl leaves the cell and forms HCl in the stomach lumen
- bicarb is traded for Cl from the bloodstream
HCl travels to the duodenum
- bicarb is taken up by pancreas and secreted in duodenum
- neutralization of HCl = recycled to Cl in the bloodstream
Describe how an obstruction or a torsion can cause a disproportionate hypochloremic metabolic alkalosis
causes complete occulsion of the pylorus
HCl is continuously produced which generates a Cl demand
- carbonic acid is broken up to make more bicarb
- bicarb accumulates
How to identify which is the primary acid base disturbance
SAME
- ‘arrows’/change in the same direction = MEtabolic
ex. pH increase and bicarb increase
REVERSE
- ‘arrows’/change in opposite directions = Resp
ex. pH increase and pCO2 decrease
