Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
53 Cards in this Set
- Front
- Back
|
What are causes of spurious hyperkalemia?
|
Hemolysis (most common cause...ischemia, etc.)
Thrombocytosis>1,000,000 Leukocytosis>200,000 Abnormal erythrocytes Ischemic blood drawing |
|
|
How can you tell if hyperkalemia is spurious?
|
A normal EKG with a hyperkalemic blood reading
|
|
|
What is the mechanism of acidosis and hyperkalemia?
|
1. Decreased gradient for Na/H exchange
2. Decreased Na moving into cells..not as much Na/K exchange 3. Decreased movement of K into cells 4. HYPERKALEMIA |
|
|
What is the mechanism for hyperkalemia and acidosis?
|
1. Inhibition of the Na/K atpase-->increase of Na in cells
2. Decreased influx of Na via Na/H exchange-->less H efflux 3. Increased intracellular H+, decreased ammonia production-->acidosis |
|
|
What are some causes of hyperkalemia due to redistribution?
|
Exercise
Diabetes --> lack of insulin Hyperosmolar states (hyperglycemia, mannitol) Acidosis Cytolysis Catabloic states Drugs |
|
|
What types of drugs can induce hyperkalemia?
|
Beta blockers
Digitalis Potassium sparing diuretics |
|
|
In what conditions can cause hyperkalemia due to excess consumption?
|
When people aren't able to excrete it by some other cause
|
|
|
What are some causes of true hyperkalemia?
|
Damage to the collecting tubules
Drug-induced inhibition of principal cell transport mechanisms Lack of functional nephrons for any reason Reduced solute delivery to collecting tubule sites Impaired aldosterone |
|
|
What are some of the ways that collecting tubules can be damaged in hyperkalemia?
|
Obstruction
Interstitial nephritis |
|
|
What are some Na channel blockers (in principal cells) that can cause hyperkalemia?
|
Amiloride
Triamterene Pentamidine Trimethoprim |
|
|
How is it that NSAIDs cause problems with K excretion?
|
Prostaglandins produced by the kidney are regulators of blood flow. You alter the prostaglandins-->slowing of flow-->hyperkalemia
|
|
|
What are some of the drugs that effect aldosterone, possibly causing hyperkalemia?
|
ACEIs
A2 receptor blockers Heparin (via hypoaldosteronism) Spironolactone |
|
|
What are some of the manifestations of hyperkalemia?
|
Cardiac arrhythmias
Decreased renal ammonia production-->metabolic acidosis Decreased plasma renin, increased aldosterone Increased insulin, glucagon, catecholamines Antihypertensive effect |
|
|
What is the treatment of hyperkalemia?
|
IMMEDIATELY:
Restore excitability Redistribute K back within the cells ASAP Effect net removal of K CHRONICALLY Limit intake Promote excretion |
|
|
What are ways that you can restore excitability to cells in hyperkalemia?
|
Parenteral calcium gluconate; you can repeat this ONCE
This makes the membrane more stable..correcting the EKG problems |
|
|
What are ways that you can redistribute K back within the cells during hyperkalemia?
|
Sodium bicarb (lowering the pH-->higher K in cells)
Insulin+glucose (stimulate the ATPase) B2 agonists (stimulate the ATPase) |
|
|
What are ways that you can effect net removal of K in hyperkalemia?
|
Sodium polystyrene sulfonate orally-->remove K from GI tract
Forced diuresis: Dialysis |
|
|
Chronically, what are some ways to treat hyperkalemia?
|
DIET!
Increased Na intake+diuretics Mineralocorticoids Sodium polystyrene sulfonate: bind K to increase excretion Limit problematic drugs: -ACEI/ARBs -Aldo blockers -NSAIDs |
|
|
What are some causes of spurious hypokalemia?
|
Leukocytosis >100,000
Erythrocyte uptake when blood is drawn shortly after insulin administration Not very common. |
|
|
What are some causes of hypokalemia?
|
Alkalosis
Hyperadrenergic states Insulin excess Drugs: beta agonists, cAMP phosphodiesterase inhibitors, CCBs |
|
|
Why would a person in a hospital be hypokalemic?
|
They're not taking it in and someone didn't remember to include K inside their fluids
|
|
|
What are some causes of excess losses leading to hypokalemia?
|
Renally: aldosterone driven
Extrarenal: GI disorders |
|
|
Why do excess mineralocorticoid states lead to hypokalemia?
|
Mineralocorticoids stimulate aldosterone-->K loss
Also, they increase flow-->potassium loss that way |
|
|
Why do diuretics induce hypokalemia?
|
Increase flow-->K loss
Induce RAA-->K loss Diuretics themselves cause hypokalemia |
|
|
In what patients should you be especially concerned with diuretic induced hypokalemia?
|
Patients with:
-Cardiac glycoside meds -Acute MI -Chronic heart disease |
|
|
What are characteristic lab findings in hyperaldosteronism?
|
HTN
|
|
|
What does licorice do to the kidneys?
|
Allows cortisol to act as a mineralocorticoid-->hypokalemia
|
|
|
In what situation are you acidotic and hypokalemic? Why?
|
Type I renal tubular acidosis
There's an H/K antiporter on the apical side of the cells that doesn't work (H into lumen, K into tubule) It doesn't work...hypokalemia and acidemia |
|
|
What tubule function abnormalities can cause hypokalemia?
|
Hypomagnesemia
Type I renal tubular acidosis |
|
|
What are some extrarenal causes of hypokalemia?
|
Upper GI fluid losses (vomiting, gastric drainage)
Lower GI losses (diarrhea) Hormones causing shifts away from the ECF: insulin, epinephrine, other beta agonists |
|
|
What is the mechanism of hypokalemia in upper GI fluid loss?
|
You lose acid from the GI tract by vomiting or drainage
Then, you have: compensatory hypokalemia from the kidney volume depletion causing aldosterone release-->hypokalemia |
|
|
What is the relationship in the PC's and IC's in hypokalemia and alkalosis?
|
|
|
|
What is the effect of large volume diarrhea, fistulas, and enterostomies on potassium status? Acid/base status?
|
Hypokalemia (losing K)
Acidotic (you're losing bicarbonate) |
|
|
In what conditions are you alkaline and hypokalemic?
|
Upper Gi causes
Diuretics |
|
|
In what conditions are you acidotic and hypokalemic?
|
Lower GI (losing bicarb with potassium)
Type 1 renal tubular acidosis (channel problems) |
|
|
In what situations are you hypertensive and hypokalemic?
|
Primary mineralocorticoid
|
|
|
What is the relationship between Cl/Bicarbonate and alkalosis?
How do you treat these alkaloses? |
Rule 1: you can't have both high Cl and HCO3 - they're both anions...your body doesn't want to have abnormally high anion levels, so one has to go
Rule 2: There's a Bicarb/Cl exchanger in ICs of the CD In metabolic alkalosis, you've got high HCO3-->low Cl Treat this by giving Cl ions...which drives HCO3 out of the body! |
|
|
Why is Na not a reliable marker of volume status during metabolic alkalosis? What's a better use?
|
Because there's so much bicarbonate around...it uses Na to neutralize the charge-->artificially high Na levels
You measure urine chloride |
|
|
What are causes of volume depletion/low urine cloride alkalosis?
|
Upper GI loss (not losing bicarb)
Previous use of diuretics |
|
|
What are causes of high urine chloride/chloride insensitive alkalosis? What are other findings in this case?
|
Primary excess mineralocorticoids
HTN |
|
|
What are the effects of hypokalemia?
|
Arrhythmias
Decreased insulin release-->glucose intolerance (K is a stimulus for insulin release) Muscle weakness Renal dysfunction |
|
|
What is the treatment of hypokalemia?
|
Give people oral K..not just K for the extracellular, but also for the intracellular space
|
|
|
What are different K-sparing agents you can give to replace K?
|
Amiloride
Triamterene Spironolactone |
|
|
How should you go about correcting hypokalemia? Why?
|
Give oral K
You can easily push someone to hyperkalemia with IV infusions |
|
|
What are causes of hypomagnesmia?
|
Inadequate supply
Decreased absorption: (diarrhea, fistulas, small bowel resection) Renal losses (DIURETICS, toxins) |
|
|
What are some causes of renal loss of magnesium?
|
Diuretics!
Toxins: aminoglycosides, cis-platinum, Amphotericin B, cyclosporine |
|
|
What are some causes of hypermagnesemia?
|
Decreased renal excretion
|
|
|
What other condition is associated with hypomagnesemia?
|
HYPOKALEMIA
|
|
|
If you're hypokalemic, what should you order a lab for?
|
Magnesium
Hypokalemia occurs with hypomagnesemia 40-60% percent of the time |
|
|
Other than hypokalemia, what other electrolyte imbalance occurs with hypomagnesemia? How?
|
Hypocalcemia
Hypomagnesemia suppresses PTH secretion Hypomagnesemia promotes resistance of bone to Ca2+ mobilizing effects of PTH |
|
|
What is the treatment of hypomagnesemia?
|
Oral/parenteral:
Mg K Ca |
|
|
What are some symptoms of hypomagnesemia?
|
Hypomagnesemia think SUPER EXCITED!
Arrhythmias Seizures Tetany, fasiculations Positive chvostek's, trosseau's signs Weakness, anorexia Hypokalemia, hypocalcemia |
|
|
What are some symptoms of hypermagnesemia?
|
Bradycardia
Hypotension Muscle weakness, respiratory paralysis Decreased/absent deep tendon reflexes Sedation |
