Potassium Imbalances Quiz

Potassium Imbalances

• Potassium is the primary intracellular fluid (ICF) cation, with 98% found inside cells.
• Concentration levels: ICF potassium ~140 mmol/L; extracellular fluid (ECF) potassium ranges from 3.5 to 5.1 mmol/L.
• Sodium-potassium pump maintains concentration differences, essential for nerve impulse transmission and muscle contraction.
• Potassium regulates intracellular osmolality, promotes cellular growth, and aids glucose storage in the liver and muscle.
• Dietary intake primarily includes fruits, vegetables, and salt substitutes; daily intake ranges from 50 to 100 mmol.
• Kidneys excrete about 90% of ingested potassium; impairment leads to toxic accumulation.
• Factors causing potassium shifts: insulin, alkalosis, β-adrenergic stimulation (stress), cell building (rapid RBC production).
• Potassium moves from ICF to ECF due to acidosis, trauma, and exercise.
• Hyperkalemia (high potassium levels) can result from excessive intake, renal failure, or cellular destruction.
• Common hyperkalemia causes: renal failure, massive cell destruction (e.g., burns, crush injury), metabolic acidosis, adrenal insufficiency, and certain diuretics.
• Hyperkalemia manifestations: muscle weakness, leg cramps, cardiac disturbances (e.g., tall T waves, loss of P waves, prolonged P–R interval).
• Hypokalemia (low potassium levels) often caused by GI losses (vomiting, diarrhea) or renal losses (diuretics, adrenal issues).
• Hypokalemia manifestations: fatigue, muscle weakness, cramps, cardiac dysrhythmias, and altered ECG readings (flattened T waves, presence of U waves).
• Treatment for hyperkalemia includes dietary potassium restriction, dialysis, and medications to drive potassium back into cells (e.g., insulin, calcium gluconate).
• Hypokalemia treatment involves potassium chloride (KCl) supplementation, either orally or intravenously, ensuring proper urine output.

Calcium Imbalances

• Calcium is primarily obtained through dietary intake, with only 30% absorption in the GI tract.
• Over 99% of calcium is stored in bones, which regulate serum calcium levels.
• Calcium has an inverse relationship with phosphorus; when one increases, the other decreases.
• Functions of calcium: nerve impulse transmission, myocardial contraction, blood clotting, muscle contraction, and bone health.
• Serum calcium exists in three forms: ionized (active), bound to proteins, and complexed with other ions.
• Ionized calcium levels can be influenced by pH changes; acidosis increases while alkalosis decreases ionized calcium.
• Calcium homeostasis is regulated by parathyroid hormone (PTH), calcitonin, and vitamin D.
• Symptoms of hypocalcemia (low calcium levels): fatigue, muscle cramps, tingling, tetany, and potentially life-threatening dysrhythmias.
• Common causes of hypocalcemia include chronic renal failure, vitamin D deficiency, and hypothyroidism.
• Hypercalcemia causes: hyperparathyroidism, malignancies, vitamin D overdose, and prolonged immobilization.
• Hypercalcemia symptoms include confusion, fatigue, muscle weakness, constipation, and dysrhythmias.
• Treatment for hypercalcemia focuses on promoting calcium excretion through diuretics and hydration.### IV Saline Therapy and Calcium Balance
• Careful monitoring is crucial during IV saline therapy to prevent fluid overload, especially in patients with impaired renal function.
• Synthetic calcitonin can lower serum calcium levels; a low-calcium diet may also be recommended.
• Weight-bearing activities are encouraged to improve bone mineralization.
• In hypercalcemia related to malignancy, biophosphonates like zoledronic acid are effective as they inhibit osteoclast activity without cytotoxic side effects.

Hypocalcemia

• Decreased production of parathyroid hormone (PTH) can lead to hypocalcemia, particularly after damage to the parathyroid glands during neck surgery.
• Acute pancreatitis can cause hypocalcemia due to fatty acid binding with calcium.
• Blood transfusions can cause hypocalcemia due to citrate binding with calcium.
• Symptoms of hypocalcemia may include tetany, Trousseau's sign (carpal spasms from BP cuff inflation), and Chvostek's sign (facial muscle contraction upon nerve tapping).
• Severe hypocalcemia treatment often requires IV calcium gluconate, while mild cases are treated with dietary supplementation.

Phosphate Imbalances

• Phosphorus is vital for muscle, RBC, and nerve functions, as well as energy production and bone formation.
• Hypophosphatemia can stem from malabsorption, alcohol withdrawal, or excessive use of phosphate-binding antacids.
• Clinical manifestations include CNS dysfunction, rhabdomyolysis, and cardiac dysrhythmias.
• Hyperphosphatemia primarily occurs due to renal failure or dietary excess; it can lead to soft tissue calcification and neuromuscular irritability.
• Management focuses on treating underlying causes, dietary modifications, and ensuring adequate hydration.

Magnesium Imbalances

• Magnesium is significant for enzyme function, ATP production, and muscle contraction.
• Hypermagnesemia is generally associated with renal insufficiency and excessive intake, resulting in hypotension and sedation.
• Hypomagnesemia can arise from poor dietary intake, gastrointestinal loss, or diuretics, displaying symptoms similar to hypocalcemia.
• Treatment for magnesium deficiency includes dietary supplementation and, in severe cases, IV magnesium administration.

Protein Imbalances

• Proteins, mainly albumin, regulate plasma volume and oncotic pressure; hypoproteinemia can cause fluid retention and edema.
• Causes of hypoproteinemia include malnutrition, liver disease, and nephrotic syndrome.
• Clinical manifestations involve slow healing, fatigue, and muscle loss.
• Management strategies may require high-protein diets or enteral/parenteral nutrition in severe cases.