Electrolyte Abnormalities Flashcards
What is the most abundant intracellular cation?
K
Importance of potassium?
Cell metabolism, neuromuscular and cardiac electrical transmission
Etiology of K imbalances
Renal dysfunction
Dietary
Meds side effects (diuretics)
Causes of hypokalemia
- Loss: renal excretion via diuretics, vomiting, diarrhea, hyperaldosteronism, hypomag
- Shift: insulin, dobutamine, epi
S/s of hypokalemia
- Weakness, fatigue, constipation, palpitations
- EKG: flat T, ST depression, U waves
Tx of mild hypokalemia
PO KCl (K-Dur, K-Lor, K-Tab)
Tx of mod-severe hypokalemia
IV KCl at 10 mEq/hr
10 mEq of KCl raises serum K by:
0.1 mEq/L
Causes of hyperkalemia
- Absolute: renal insufficiency, meds (ACE, ARB, digoxin)
- Pseudo: DKA, hemolysis
S/s of hyperkalemia
- Weakness, cramping, paresthesias
- EKG: peaked T, wide QRS, loss of P, sine wave
Sine wave on EKG is a late sign of:
Hyperkalemia
What is a late sign of hyperkalemia?
Sine wave on EKG
Tx of hyperkalemia
- ALWAYS on cardiac monitor
- Ca gluconate (stabilize myocytes)
- Regular insulin
- Albuterol nebulizer
- Lasix
- Na polystyrene sulfonate (Kayexalate)
- Dialysis
Importance of Na in the body
Indirect measure of free water in serum
Define osmolarity
Concentration of solutes per L of solution
- HIGH = fluid depletion
- LOW = fluid retention
Etiology of Na imbalances
- Hormonal (SIADH)
- Free water excess or loss
Causes of hyponatremia
- Hypovolemic: diuretics, DM, adrenal insufficiency, sweat, burns, vomiting, diarrhea
- Hypervolemic: CHF, cirrhosis, nephrotic synrome, preg, excess IVF
- Euvolemic: SIADH, Ca, water intoxication
S/s of hyponatremia
HA, N/V, lethargy, confusion, seizure, coma
What are the symptoms of hyponatremia determined by?
Degree and rapidity of development
Causes of hypernatremia
- Hypovolemic: sweating, vomiting, diarrhea, DI
- Hypervolemic: excess IV hydration, hyperaldosteronism
Tx of mild (asymp) hyponatremia
Fluid restriction
Tx of mod-severe hyponatremia
- Acute/severe: 3% hypertonic saline 100 ml over 10 min
- Chronic: 0.5 ml/kg/hr or less
Why is correction of chronic hyponatremia slow?
Avoid central pontine myelinolysis (flaccid paralysis, seizures)
S/s of hypernatremia
AMS, seizures, hyperreflexia, spasticity, lethargy
Tx of hypernatremia
Gradual correction w/hypotonic or isotonic fluids (to avoid cerebral herniation)
Importance of Ca in body
- Blood coagulation
- Nerve conduction
- Osteoclast bone activity
- APs for muscle contractions
Etiologies of Ca imbalance
Regulated via PTH, calcitonin (thyroid), calcitriol (kidneys)
What Ca level is most accurate?
Ionized Ca level
Causes of hypocalcemia?
Hypothyroid
HypoPTH
Thyroidectomy
CKD
S/S of hypocalcemia
- Paresthesias, hyperreflexia, tetany, Chvostek/Trousseau
- EKG: QT prolonged leading to Torsades
Tx of hypocalcemia
- Asymp: oral Ca carbonate (or citrate)
- 10% Ca gluconate IV
- Replace Mg 1st if deficient
Causes of hypercalcemia
- HyperPTH
- Bone cancer
- Prolonged immobilization
S/s of hypercalcemia
- Stones, bones, moans, psychic groans and fatigue overtones
- EKG: short QT