Fluid and Electrolytes Overview

Fluid and Electrolytes

• Homeostasis is the state of equilibrium in the body, naturally maintained by adaptive responses.
• Body fluids and electrolytes are kept within narrow limits.
• Fluid and electrolyte imbalances are directly caused by illness or disease (e.g., burns, heart failure) or by therapeutic measures (e.g., IV fluid replacement, diuretics).
• Water status affects red blood cells (RBCs).
• In a hypotonic solution, water moves into the cell.
• In an isotonic solution, there is no net movement of water.
• In a hypertonic solution, water moves out of a cell.
• Geriatric patients have structural changes in their kidneys, reduced thirst, and decreased fluid intake due impaired mobility.
• Extracellular fluid volume deficit (hypovolemia) involves abnormal fluid loss, inadequate intake, or fluid shifts.
• Symptoms include dry mucous membranes, thirst, poor skin turgor, low urine output, and low blood pressure.
• Treatment involves oral or intravenous rehydration with electrolyte solutions.
• Extracellular fluid volume excess (hypervolemia) results from excessive fluid intake or abnormal fluid retention.
• Symptoms include edema (swelling), weight gain, elevated jugular venous pressure, and high blood pressure.
• Treatment includes diuretics and fluid restriction.
• Nursing interventions include monitoring I&O (input and output), vital signs, neurologic status, and daily weights.

Electrolytes: Sodium (Hypernatremia)

• Hypernatremia is a serum sodium level greater than 145 mEq/L. Causes include excess sodium intake (parenteral fluids, tube feedings without adequate water, near drowning in saltwater), and inadequate water intake (unconscious or cognitively impaired persons). Other causes include excess water loss due to high fever, heatstroke, osmotic diuretic therapy, and diarrhea. Diseases associated with hypernatremia include Diabetes insipidus, Hyperaldosteronism, and Cushing’s syndrome.
• Expected findings include decreased extracellular fluid volume (hypovolemia) with postural hypotension, tachycardia, decreased intravascular volume, elevated temperature, and intense thirst.
• Treatment involves preventing further water loss and replacing fluids with intravenous hypotonic solutions (D5W, 0.45% NS) if unable to tolerate oral fluids. Restrict sodium intake and increase water intake.
• Discharge instructions include teaching the importance of adequate fluid intake and a low-sodium diet. Monitor for early signs of hypernatremia, like polyuria, nausea, vomiting, orthostatic hypotension, and changes in mental status. Notify the primary care provider if these symptoms occur.

Electrolytes: Sodium (Hyponatremia)

• Hyponatremia is a serum sodium level below 135 mEq/L. Causes include: excess sodium loss (GI losses, renal losses, skin losses), inadequate sodium intake (fasting, malabsorption), excess water gain (excess hypotonic fluids, primary polydipsia), and diseases (SIADH, heart failure, cirrhosis, primary hypoaldosteronism).
• Expected clinical findings associated with hyponatremia include decreased extracellular fluid (ECF) volume with postural hypotension, tachycardia, decreased intravascular volume, and elevated temperature, along with potential symptoms like confusion, dizziness, tremors, seizures, and coma.
• Treatment for mild hyponatremia typically involves fluid restriction. More severe cases necessitate intravenous solutions containing sodium chloride (NaCl) or 3% NaCl.
• During discharge, patients should be taught the importance of adequate fluid intake and normal sodium intake. If fluid restriction is indicated, patients should be advised of the potential benefits of using ice chips, iced pops, or lemon drops to reduce thirst. Education on the recurrence of hyponatremia is included in discharge instructions, emphasizing that vomiting or diarrhea can lead to the condition due to excessive sodium in the gastrointestinal tract.

Electrolytes: Potassium (Hyperkalemia)

• Hyperkalemia is a serum potassium level greater than 5.0 mEq/L. Causes include excess potassium intake, renal failure, increased potassium shifting out of cells due to acidosis, and massive cell injury (trauma, sepsis, tumor lysis syndrome).
• Clinical findings include slow irregular heart rate, hypotension, restless, irritability, weakness, ascending paralysis, and paresthesia. Other symptoms can include PVCs, ventricular fibrillation, peaked T waves, wide QRS, increased bowel sounds, diarrhea and oliguria.
• Treatment involves stopping potassium intake, promoting potassium excretion (loop diuretics, sodium polystyrene sulfonate, calcium gluconate), and dialysis if needed, while managing acidosis.
• Discharge counseling prioritizes patient education on the dietary relationship between potassium intake and hyperkalemia.

Electrolytes: Potassium (Hypokalemia)

• Hypokalemia is a serum potassium level below 3.5 mEq/L. Causes include losses via GI tract (vomiting, diarrhea, NGT suction), renal losses (diuretics), diaphoresis, and dialysis, along with decreased potassium intake. Other causes include increased shifting of potassium into the cells (increased insulin release, insulin therapy to treat DKA, alkalosis, and increased epinephrine stress response); and problems with absorption (malabsorption).
• Expected clinical findings include slow irregular heart rate, hypotension, anxiety, lethargy, weakness, and decreased reflexes. Further symptoms could include flattened T waves, ST segment depression, prolonged PR interval, hypoactive bowel sounds, vomiting, cramping, abdominal distension, and shallow breathing.
• Treatment for hypokalemia includes potassium supplementation (either oral or intravenous).
• Discharge instructions focus on dietary recommendations, increasing potassium intake, and the potential side effects of potassium supplements.

Electrolytes: Calcium (Hypercalcemia)

• Hypercalcemia is a serum calcium level greater than 10.5 mg/dL. Possible causes include hyperparathyroidism (accounts for 2/3 of cases), prolonged immobilization, excessive calcium intake, and thiazide diuretics. Further causes include Paget's disease, adrenal insufficiency, mycobacterium infection, cancer (hematologic and bone mets, 2nd common cause).
• Expected findings include increased blood pressure, lethargy, weakness, fatigue, decreased memory, confusion, psychosis. Further symptoms include decreased deep tendon reflexes, bone pain, fractures, shortened ST segment, shortened Q interval, ventricular dysrhythmias, anorexia, nausea, vomiting, polyuria, dehydration, renal calculi, kidney stones.
• Treatment involves restricting calcium intake, promoting calcium excretion, and medications (synthetic calcitonin, bisphosphonates).

Electrolytes: Calcium (Hypocalcemia)

• Hypocalcemia is a serum calcium level below 9.0 mg/dL. Potential causes include hypoparathyroidism (accounts for 2/3rd of cases), renal insufficiency, acute pancreatitis, high phosphate concentration, vitamin D deficiency, low magnesium, diuretics, diarrhea, and chronic alcohol use.
• Expected findings include decreased blood pressure, weakness, fatigue, confusion, depression, hyperreflexia, muscle cramps, numbness, tingling around mouth, Chvostek and Trousseau signs, prolonged QT intervals, ventricular tachycardia, hyperactive bowel sounds, diarrhea, abdominal cramps.
• Treatment involves treating the underlying cause, oral calcium and vitamin D supplementation, intravenous calcium gluconate in severe cases, rebreathing into a paper bag to retain CO2, and addressing pain and anxiety that may contribute to hyperventilation.

Electrolytes: Magnesium (Hypermagnesemia)

• Hypermagnesemia is a serum magnesium level greater than 2.5 mEq/L. Potential causes include renal failure, excessive magnesium administration (eclampsia), and medications.
• Clinical features include lethargy, drowsiness, central nervous system (CNS) depression, decreased deep tendon reflexes, muscle weakness, warm flushed skin, hypothermia, nausea, vomiting, and heart blocks.
• Treatment involves preventing further magnesium intake (diet control), emergent measures for symptoms, intravenous calcium chloride or calcium gluconate if symptomatic, and fluid and diuretic support.

Electrolytes: Magnesium (Hypomagnesemia)

• Hypomagnesemia is a serum magnesium level below 1.5 mEq/L. Potential causes include malabsorption, malnutrition, alcoholism, diarrhea, vomiting, starvation, fasting, diuretics, and hyperaldosteronism.
• Clinical characteristics include confusion, seizures, hyperreflexia, muscle cramps, and dysrhythmias.
• Management involves treating the underlying cause, oral magnesium supplements, and intravenous or intramuscular magnesium administration for severe cases.

Explore the crucial concepts of fluid and electrolyte balance in the human body. This quiz covers topics such as homeostasis, the effects of different types of solutions on cells, and the implications for geriatric patients. Test your understanding of fluid mechanisms and their clinical significance.