Fluid and Electrolyte Disorders Part II Flashcards
What are the causes of Hypokalemia?
Intracellular shifting
Total body deficit
Hypomagnesemia
How does intracellular shifting cause hypokalemia?
Metabolic alkalosis
Drugs: albuterol, theophylline, insulin
What can cause total body deficit of hypokalemia?
Poor dietary intake of potassium
Excessive loss: extra-renal (D/V), renal (diuretics, ampho B)
What is the clinical presentation of hypokalemia?
Variable, dependent on degree of hypokalemia
Muscle cramping, impaired muscle contraction
EKG changes (severe): ST-segment depression or flattening, cardiac arrhythmias (heart block, ventricular fibrillation)
What are the classifications of hypokalemia?
Mild: 3.0 - 3.5
Moderate - Severe: < 3.0
What is the general treatment for hypokalemia?
Correct underlying cause
What is the treatment of mild hypokalemia?
Oral potassium supplement
-Potassium chloride (KCl) tablets, powders, capsules, liquid
-GI upset with high doses PO KCl
=Limit to 20 mEq per dose to decrease GI upset
What is the treatment of moderate - severe hypokalemia?
Correct hypomagnesemia FIRST Asymptomatic: oral potassium supplement Symptomatic: IV potassium replacements -Limited by rate of infusion -USE IV IF PATIENT HAS SEVERE N/V/D -Peripheral line = 10 mEq per hour max -Central line = 20 mEq per hour max
For every __ mEq of potassium (oral or IV) raises serum potassium ___ mEq/L
10
0.1
What are the causes of hyperkalemia?
Extracellular shifting
Increased intake
Decreased output
How does extracellular shifting cause hyperkalemia?
Metabolic acidosis
How does increased intake cause hyperkalemia?
Exogenous: potassium supplements, salt substitutes
Endogenous: hemolysis, burns, muscle crush injuries
How does decreased output cause hyperkalemia?
Renal failure (acute or chronic) Drugs: ACE/ARBs, NSAIDs, K-sparing diuretics, bactrim
What is the clinical presentation for hyperkalemia?
Frequently asymptomatic
Sx: palpitations, skipped heartbeats, weakness, bradycardia
Life threatening arrhythmias develop at > 6.0
What are the classifications of hyperkalemia?
Mild: 5.5 - 6.0
Moderate - Severe: > 6.0
What is the general treatment of hyperkalemia?
Correct underlying cause
What is the treatment of mild hyperkalemia?
Sodium polystyrene sulfonate
Furosemide IV
What is the treatment moderate - severe hyperkalemia?
Symptomatic
First - antagonize effects of hyperkalemia (give calcium gluconate IV)
Second - rapid correction of hyperkalemia (insulin, albuterol)
What are the causes of hypomagnesemia?
Diet: poor nutrition
GI sources: V/D, malabsorption syndromes
Renal sources: loops, acute tubular acidosis, amphotericin, AG
Others: hypoparathyroidism, hyperaldosteronism
What is the clinical presentation of hypomagnesemia?
Typically asymptomatic
Sx: twichting, tetany, generalized convulsions (neuromuscular) and heart palpitations
Signs: Tremor, cardiac arrhythmias (vfib, torsades); EKG changes: widened QRS complex ad peaked T waves (mild); prolonged PR interval
What is the treatment if a patient is asymptomatic and serum Mg is 1.0 - 1.4 (mild)?
Oral magnesium supplementation (mag oxide)
SE: diarrhea
50% of mg excreted in urine
What is the treatment if a patient is symptomatic or serum Mg < 1.0 (severe)?
IV supplementation
Check Mg Q12h until within normal range
What typically occurs with hypomagnesemia?
Hypokalemia
How do you treat hypomagnesemia and hypokalemia?
Start magnesium infusion FIRST to prevent redistribution of potassium and further worsening of hypokalemia
What are the classifications for hypomagnesemia?
Mild: 1 - 1.4
Moderate - severe: < 1.0
What are the causes of hypermagnesemia?
Diet: poor nutrition
Excess intake: magnesium supplements
Renal sources: acute/chronic kidney failure
Others: hypothyroidism, lithium, Addison’s disease
What is the clinical presentation of hypermagnesemia?
Usually asymptomatic until > 4.0
Cardiac abnormalities, hyporeflexia, somnolence, coma, respiratory depression
What is the treatment of hypermagnesemia?
Correct/remove underlying cause
Moderate - severe: Calcium gluconate and loops + fluids; hemodialysis if severe and poor kidney function
-If patient was not dialysis dependent before coming to hte hospital, will try higher dose of loops to try to kick start the kidneys
What are the classifications for hypermagnesemia?
Mild/asymptomatic: < 4.0
Moderate - severe (+ symptoms): > 4.0
What is normal calcium range?
8.5 - 10.8
What is normal phosphate range?
2.6 - 4.5
What are the causes of hyperphosphatemia?
CKD - secondary hyperparathyroidism
Rhabdomyolysis
What are the causes of hypocalcemia?
CKD - reduction in calcium absorption d/t decrease in active vitamin D production by kidney
Surgically induced hypoparathyroidism
Malnutrition
What are the clinical presentations for hyperphosphatemia?
Deposition of calcium-phosphorous crystals in joints, eyes, skin and vasculature
What are the clinical presentations for hypocalcemia?
Tetany Paresthesias Confusion Hypotension Bradycardia QT prolongation Long-term osteoporosis
What is the corrected calcium equation?
Measured Ca + 0.8[4-albumin]
What is the treatment of hypocalcemia when asymptomatic w/o CKD?
Oral calcium
What is the treatment of hypocalcemia when asymptomatic w/CKD?
May give ergocalciferol
What is the treatment of hypocalcemia when symptomatic?
IV calcium gluconate (Bolus or continuous)
How many milligrams of elemental calcium are in 1 gram of IV calcium gluconate?
90 mg
What is the treatment of hyperphosphatemia with normal renal function?
IV fluids + furosemide
What is the treatment of hyperphosphatemia with renal failure?
Dietary phosphorous restrictions
If Ca * PO4 < 55 = calcium salts, sevelamer, or lanthanum
If Ca * PO4 > 55 = Sevelamer or Lanthanum
Velphoro for dialysis patients only
What are DDIs with calcium carbonate and acetate?
Iron
Zinc
FQ
Which drugs are chewable for phosphatemia?
Sucroferric oxyhydroxide
Lanthanum
Which drugs can be used for phsophatemia when calcifications are present?
Sevelamer
What are the side effects of calcium carbonate and acetate?
Constipation
N/V/D
Increased Ca
What are the side effects of sevelamer?
Pruritus
N/V/D
What are the side effects of lanthanum?
N/V/D
What are the side effects of sucroferric oxyhydroxide?
Dark colored feces
N/D
What are the DDIs with sucroferric oxyhydroxide?
Vit D analogs and levothyroxine
How much elemental iron is in sucroferric oxyhydroxide?
500mg
What are the causes of hypercalcemia?
Malignancy: bone, breast, lung
Hyperparathyroidism
Excessive intake
Drugs: thiazide diuretics, lithium, tamoxifen
What are the causes of hypophosphatermia?
Phosphate binders
Refeeding syndrome
Alcoholism
What is the clinical presentation of hypercalcemia?
D/t malignancy: N/V, polyuria, polydipsia, Ca > 15 = acute renal failure, ventricular arrhythmias
D/t hyperparathyroidism: Calcification of organs/skin, chronic renal failure, shortening of the QT interval
What are the treatments for hypercalcemia with functioning kidneys?
NS Furosemide Pamidronate Ibandronate Zoledronic acid Prednisone
What are the treatments for hypercalcemia with non-functioning kidneys?
Hemodialysis
Calcitonin
Prednisone
What is the clinical presentation of hypophosphatemia?
CNS: weakness, numbness, paresthesias, confusion
Others: myalgias, bone pain, arrhythmia, acute respiratory failure
Chronic: osteopenia and osteomalacia
What is the treatment for a patient that is asymptomatic with a PO4 > 1
Neutra-phos
What is the treatment for a patient that is symptomatic with PO4 < 1
IV therapy
Phosphate salts
