fluid/acid-base HYPER K Flashcards
UW table. medications.
ACEI mechanism?
Inhibit angiotensin II formation, leading to decreased aldosterone secretion
UW table. medications. ARB mechanism?
Inhibit AT 1 receptor, leading to decreased aldosterone secretion
UW table. medications. K sparing diuretics mechanism?
Inhibit ENaC or aldosterone receptor
UW table. medications. nonselective BAB mechanism?
Inhibit beta-2- mediated intracellular potassium uptake
UW table. medications. NSAIDS mechanism?
Inhibit local prostagland in synthesis, leading to decreased renin & aldosterone secretion
Decreases renal perfusion resulting in decreased K+delivery to the collecting ducts
UW table. medications. cardiac glycosides mechanism?
Inhibit the Na+/K+-ATPase pump (eg, digoxin)
UW table. medications. succinylcholine mechanism?
Causes extracellular leakage of potassium through acetylcholine receptors
UW table. medications. trimetoprim mechanism?
Inhibits ENaC
UW table. medications. cyclosporine mechanism?
Blocks aldosterone activity (IL-2 transcription inhibitor – psoriasis, RA)
UW table. medications. heparin mechanism?
Blocks aldosterone production
FA. causes. 4 groups?
spurious
cellular shift
decr. excretion
incr. intake
FA. causes.
1. spurious causes?
hemolysis of blood samples, fist clenching during blood draws, delays in sample analysis, extreme leukocytosis or thrombocytosis
FA. causes.
2. cellular shift/increased potassium release from cells?
Cell lysis, tissue injury (rhabdomyolysis), tumor lysis syndrome, insulin deficiency, uncontroled hyperglycemia, hyperosmolality,
acidosis, drugs (from table), exercise
FA. causes. uptd
2. cellular shift/increased potassium release from cells. insulin effect?
Insulin promotes potassium entry into the cell.
In normal conditions – ingestion of glucose –> release of insulin –> promoted potassium entry to the cell.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. Uncontroled DM mechanism?
The combination of insulin deficiency (either impaired secretion or insulin resistance) and hyperosmolality induced by hyperglycemia frequently leads to hyperkalemia even though there may be marked potassium depletion due to urinary losses caused by the osmotic diuresis.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. Uncontroled DM. 2 mechanisms of K movement?
- The loss of cell water raises the cell potassium concentration, thereby creating a favorable gradient for passive potassium exit through potassium channels in the cell membrane.
2.The friction forces between solvent (water) and solute can result in potassium being carried along with water through the water pores in the cell membrane. This phenomenon of solvent drag is independent of the electrochemical gradient for potassium diffusion.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. what other than DM can inc. osmol/decr insulin?
somatostatin –> decr. insulin
Fasting is associated with an appropriate reduction in insulin levels that can lead to an increase in plasma potassium. This may be a particular problem in patients on dialysis OR prior SURGERY.
how to avoid hyperK in preop fasting?
The risk of hyperkalemia during preoperative fasting can be minimized by the administration of insulin and glucose in patients with diabetes, or glucose alone in patients without diabetes.
FA. causes. uptd
2. cellular shift/increased potassium release from cells.
incr. tissue catabolism?
tissue trauma or tissue lysis syndrome –> breakdown –> intracellular K is released into the ECF.
Trauma (including noncrushing), rhabdomyolysis, the administration of cytotoxic or radiation therapy to patients with lymphoma or leukemia (the tumor lysis syndrome), and severe accidental hypothermia.
FA. causes. uptd
2. cellular shift/increased potassium release from cells.
BAB mechanism?
Increased beta-2-adrenergic activity drives potassium into the cells and lowers the serum K.
BAB –> decr. K uptake by cells.
FA. causes. uptd
2. cellular shift/increased potassium release from cells.
BAB what incr K?
Incr. with nonselective - propranolol, labetolol
Cardioselective has less effect
FA. causes. uptd
2. cellular shift/increased potassium release from cells.
Hypercalemic periodic paralysis – AD disorder, presents as weakness episodes.
.
FA. causes. uptd
2. cellular shift/increased potassium release from cells.
Exercise?
K is normally released from muscle cells during exercise. The increase in plasma potassium is rarely important clinically.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. Digitalis?
dose-dependent inhibition of the Na-K-ATPase pump.
structurally related digitalis glycosides may be due to ingestion of plants: oleander or yellow oleander.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. RBC tranfusion?
leakage of potassium out of the red cells during storage
FA. causes. uptd
2. cellular shift/increased potassium release from cells. acetylcholine?
Acetylcholine receptors are normally concentrated within the neuromuscular junction, and the efflux of intracellular potassium caused by depolarization of these receptors is confined to this space.
FA. causes. uptd
2. cellular shift/increased potassium release from cells. drug aminocaproic acid?
The entry of cationic arginine into the cells presumably obligates potassium exit to maintain electroneutrality. Same mechanism for aminocaproic, since it is structural analogs