Clinical Implications - Evaluating Hypokalemia and Hyperkalemia in the patient Flashcards
What are the 3 sites that the body can lose K+?
- Kidneys
- GI tract
- Skin
What are the 2 diuretics that cause K+ loss from the kidney?
- Furosemide
2. Thiazides
At what sites do diuretics act on to induce K+ loss?
The distal-K+ secretory system
What does the distal K+ secretory system consist of? (3)
- ICT (initial collecting tubule)
- CCT (cortical collecting tubule)
- Proximal portion of MCD (medullary collecting tubule)
What is another way K+ can be lost from the kidney aside from diuretics?
Individuals with renal tubule disorders or alterations in the renin-angiotensin-aldosterone system
How can you lose K+ from the GI system? (2)
- Diarrhea
2. Vomiting
How can you lose K+ from the skin? (2)
- Dehydration and perspiration from exercise
2. Lost fluid from severe burns
What are some miscellaneous ways that the body can lose K+ aside from the kidney, GI tract, and the skin? (3)
- Alkalosis
- Catecholamine surge
- Excessive insulin administration
What is pica? What is a consequence of this?
A behavior where one consumes clay. The clay binds to the K+ and prevents it from reabsorption in the GI tract.
What is pseudohyperkalemia?
False lab results that indicate hyperkalemia, but is actually from traumatic hemolysis of red blood cells during blood drawing.
Why do hemolyzed red blood cells cause elevated plasma K+ levels?
Because their intracellular fluids have now been released into the blood (duh). Not specific to RBCs. Any other cell that releases its contents will cause this too.
Would patients with myeloproliferative disorders (excessive generation of platelets and WBCs) exhibit a high or low plasma K+ concentration? Why?
High, because K+ is released during clot formation.
If you have healthy kidneys, will excessive intake of K+ cause hyperkalemia?
Naww mayne
The use of Digitalis (a Na/K pump blocker) would cause hyper- or hypo-kalemia?
HYPERkalemia
What is the main cause of hyperkalemia?
Renal failure
How do you temporarily treat severe hyperkalemia (conc. > 8mM) that causes changes in an ECG?
Administer the following:
- Calcium gluconate
- NaHCO3
- Glucose
- Insulin
How does calcium gluconate treat severe hyperkalemia?
Ca2+ raises the threshold for action potentials and lessens membrane excitability.
How does administration of NaHCO3, glucose, and insulin lower K+ concentration?
By moving them to intracellular fluid (fromt the ECF) inside cells
In addition to temporary medications in treating hyperkalemia, how does one get rid of excess K+?
Administer a non-absorbable cation exchange resin
What does a non-absorbable cation exchanger resin do?
Binds to K+ and because it is non-absorbable, carries it out of the GI tract (out of the body).
Why do doctors use the temporary medications instead of just solely using resins?
Because resin takes a long take to take effect.
For patients with end-stage renal failure, how do physicians get rid of excess K+?
Dialysis
