Metabolic
Electrolytes and trace elements are crucial for life, and abnormal levels can indicate underlying disease. This section provides a summary of each major electrolyte and their metabolic function and properties
Biochemical Theory and Pathways
- Electrolytes: Crucial for fluid balance, nerve/muscle function
- Trace Elements: Essential for enzymes, hormones, and immunity
- Key Electrolytes: Sodium, potassium, chloride, bicarbonate
- Other Important ions: Calcium, magnesium, phosphorus, iron, Trace elements
- Regulation
- Hormones: Aldosterone, ADH, PTH, Vitamin D, FGF23
- Organs: Kidneys, lungs, parathyroid glands
- Transport Mechanisms
- Ion channels
- Pumps (e.g., \(Na^+\)/\(K^+\) ATPase)
- Binding proteins (e.g., transferrin)
Normal States
- Normal Electrolyte Concentrations
- \(Na^+\): 136-145 mmol/L
- \(K^+\): 3.5-5.1 mmol/L
- \(Cl^-\): 98-107 mmol/L
- \(HCO_3^-\): 23-29 mmol/L
- \(Ca^{2+}\): 8.6-10.2 mg/dL
- \(Mg^{2+}\): 1.7-2.2 mg/dL
- \(P\): 2.5-4.5 mg/dL
- \(Fe\): 60-170 μg/dL
- TIBC: 240-450 μg/dL
- Balanced Distribution: Between ICF and ECF
- Functional Regulation: By hormones and kidneys
Abnormal States
- Sodium Imbalances: Hyponatremia, hypernatremia
- Potassium Imbalances: Hypokalemia, hyperkalemia
- Chloride Imbalances: Hypochloremia, hyperchloremia
- Calcium Imbalances: Hypocalcemia, hypercalcemia
- Magnesium Imbalances: Hypomagnesemia, hypermagnesemia
- Phosphate Imbalances: Hypophosphatemia, hyperphosphatemia
- Iron Imbalances: Iron deficiency anemia, hemochromatosis
Functions and Imbalances
- Sodium (\(Na^+\))
- Function: Fluid balance, nerve/muscle function
- Hyponatremia: Fluid overload, sodium loss
- Hypernatremia: Dehydration, sodium gain
- Potassium (\(K^+\))
- Function: Membrane potential, nerve/muscle function
- Hypokalemia: Loss (diuretics), cellular shift
- Hyperkalemia: Renal failure, cellular release
- Chloride (\(Cl^-\))
- Function: Fluid balance, nerve transmission
- Hypochloremia: Loss (vomiting), increased bicarbonate
- Hyperchloremia: Excess infusion, dehydration
- Calcium (\(Ca^{2+}\))
- Function: Bone structure, muscle contraction, clotting
- Hypocalcemia: Hypoparathyroidism, vitamin D deficiency
- Hypercalcemia: Hyperparathyroidism, malignancy
- Magnesium (\(Mg^{2+}\))
- Function: Enzyme activity, muscle function
- Hypomagnesemia: Poor intake, impaired absorption
- Hypermagnesemia: Renal failure, excess intake
- Phosphorus (\(P\))
- Function: Bone structure, energy production
- Hypophosphatemia: Poor intake, cellular shift
- Hyperphosphatemia: Renal failure, hypoparathyroidism
- Iron (\(Fe\))
- Function: Oxygen transport (hemoglobin)
- Iron Deficiency: Anemia
- Iron overload: Hemochromatosis
- Trace Elements
- Function: Varies by element (e.g., enzyme cofactors, hormone synthesis)
- Imbalances: Deficiency or toxicity