Electrolytes/Trace Elements Lab

electrolytes

-are markers for total body composition

-are most frequently checked as serum levels

where do we get the majority of our electrolytes from?

our diet

extracellular ions

Na, Cl

intracellular ions

K, Mg, PO4

what electrolytes and trace elements are found in a BMP?

Na, K, Cl, HCO3, Ca

sodium (Na)

• reference range is 135-145 mEf/L

• main phys role: regulating bodily fluid and water balance

• it affects electrical potential for neuromuscular function and maintains blood pressure

  • is regulated by the kidneys

hyponatremia

• Na < LLN

• severe when < 120 mEq/L

meds that can cause hyponatremia

• *diuretics (loop and thiazide), antiepileptics

• ACE, NSAIDs, antidepressants

what disease states may manifest from hyponatremia

• dehydration

  • occurs when Na depletion > total body water loss —- makes sense because hyponatremia is insufficient Na so the depletion of it is greater than the loss of water

  • diarrhea and vomiting is what causes this hypotonic dehydration

• fluid overload (dilutional)

  • dilution creates Na imbalance

  • examples- kidney failure, adrenal changes, polydipsia, etc

hypernatremia

• Na > ULN

• mild cases are asymptomatic or experience restlessness

• severe when Na > 160 mEq/L

meds that may cause hypernatremia

• steroids, PO contraceptive, laxatives

• licorice

what disease states may manifest from hypernatremia

• inadequate water intake

• uncontrollable water loss (via sweat, fever, kidney (polyuria), GI (vomit, etc))

chloride (Cl)

• reference range = 95-105 mEq/L

• main phys role = acid-base balance

• affects fluid distribution

  • kidney regulates this ion and either retains or secretes it in exchange for bicarb

hypochloremia

• Cl < LLN

meds that may cause hypochloremia

• *diuretics

• drugs with bicarb (if you exchange the two, then it means their concentrations/levels must be opposite, therefore increased bicarb means decreased Cl)

• chronic use of laxatives or high doses of H2RA or PPI for acid reflux

hypochloremia may manifest as

• *diseases that change fluid balance (ex- congestive HF, burns, SIADH)

• acid/base disturbances

• loss of gastric acid (ex-vomit)

hyperchloremia

• Cl > ULN

meds that may cause hyperchloremia

• saline IVs, NSAIDs, corticosteroids, androgens and estrogens

• acetazolamide

hyperchloremia may manifest as

• acid/base disturbances

• excessive intake of Na (via saline infusions)

• dehydration (Cl levels help the kidneys decide how much water to retain or excrete; excess Cl makes kidneys think there is too much fluid and therefore causes water loss)

• Gi fluid loss

• mineralocorticoid deficiency

potassium (K)

• reference range = 3.5-5 mEq/L

• main phys role = muscle and nerve excitability via its effect on action potential (think muscle contraction, issues may cause cardiac dysfunction for example)

• has many other roles such as affecting intracellular volume, protein synthesis, carb metabolism, etc

• kidneys are in charge of its regulation

hypokalemia

• mild symptoms- muscle cramps, weakness

• severe cases when K < 3 mEq/L (inability to concentrate urine, loss of muscle reflexes, heart arrhythmias)

meds that may cause hypokalemia

• *diuretics, high dose penicillin

• laxatives or K binders that increase defecation

• insulins and beta 2 agonists