pathophysiology, clinical manifestations, management and findings-elecabg

Pathophysiology of hyponatremia

Water imbalance > sodium imbalance; excess water dilutes sodium in ECF

Pathophysiology of dilutional hyponatremia

Excess water in ECF without edema

Pathophysiology of hyponatremia with low urine sodium

Nephrons retain sodium to compensate for nonrenal fluid loss

Pathophysiology of hyponatremia with high urine sodium

Renal salt wasting due to renal dysfunction or diuretic use

Neurologic manifestations of hyponatremia

Altered mental status, seizures, coma, cerebral edema

GI manifestations of hyponatremia

Anorexia, nausea, vomiting, abdominal cramping

CV manifestations of hyponatremia

Orthostatic hypotension, tachycardia

Severe sodium <115 mEq/L signs

Lethargy, confusion, twitching, focal weakness, papilledema, seizures, death

Diagnostic findings in hyponatremia

Decreased serum sodium, low serum osmolality, low urine sodium, low specific gravity

Urine findings in SIADH hyponatremia

Urine sodium >20 mEq/L, specific gravity >1.012

Medical management of hyponatremia

Sodium replacement (oral, NGT, IV), hypertonic saline if severe, fluid restriction

Max correction rate of serum sodium

≤12 mEq/L per 24 hours

Drug therapy for SIADH hyponatremia

ADH receptor antagonists (conivaptan, tolvaptan), lithium

Nursing management of hyponatremia

Monitor I&O, weight, labs, assess neuro status, restrict fluids, provide sodium-rich diet

Pathophysiology of hypernatremia

Water loss > sodium loss or sodium gain > water gain, cells shrink from water shift

Causes of hypernatremia

Fluid deprivation, DI, hypertonic enteral feeding without water, watery diarrhea, burns, hyperventilation

Neurologic manifestations of hypernatremia

Restlessness, irritability, hallucinations, lethargy, seizures, coma

GI manifestations of hypernatremia

Nausea, vomiting, anorexia

Other signs of hypernatremia

Thirst, elevated temp, dry tongue, sticky mucosa, pulmonary edema, twitching, hyperreflexia

Diagnostic findings in hypernatremia

Increased serum sodium, increased osmolality, decreased urine sodium, decreased CVP

Medical management of hypernatremia

Gradual lowering with hypotonic (0.45% NaCl) or D5W, avoid rapid correction

Drug therapy for hypernatremia

Desmopressin acetate if DI, diuretics if sodium overload

Nursing management of hypernatremia

Monitor fluids, provide oral fluids, assess thirst, temp, behavior changes

Pathophysiology of hypokalemia

ECF K loss increases gradient; excitable tissues less responsive to normal stimuli

Causes of hypokalemia

GI loss, diuretics, hyperaldosteronism, alkalosis, insulin therapy, poor intake

Neuromuscular signs of hypokalemia

Weakness, cramps, paresthesias, paralysis

GI manifestations of hypokalemia

Anorexia, nausea, vomiting, constipation, ileus

Respiratory signs of hypokalemia

Shallow respirations, SOB

Cardiac signs of hypokalemia

Dysrhythmias, postural hypotension, flattened T waves, U waves

Renal signs of hypokalemia

Polyuria, nocturia, dilute urine

Diagnostic findings in hypokalemia

Low K+, ECG with flattened T waves and U waves, elevated pH, low Mg

Medical management of hypokalemia

Oral or IV K replacement, stop K-wasting drugs, give K-sparing diuretics if needed

IV potassium administration rules

Never IV push/IM, dilute, max 10–20 mEq/hr, give via pump

Nursing management of hypokalemia

Monitor ECG, labs, respiratory status, encourage K-rich diet, prevent falls

Pathophysiology of hyperkalemia

High serum K+ decreases ICF-ECF gradient → excitable tissues overly responsive → arrhythmias

Causes of hyperkalemia

Decreased renal excretion, rapid K+ intake, cell damage, acidosis, K-sparing drugs, Addison’s disease

Neuromuscular signs of hyperkalemia

Twitching, paresthesia, progressing to weakness, flaccid paralysis

GI manifestations of hyperkalemia

Diarrhea, hyperactive bowel sounds

Cardiac signs of hyperkalemia

Bradycardia, hypotension, tall peaked T waves, widened QRS, VFib, asystole

Diagnostic findings in hyperkalemia

Serum K+ >5.0, ECG with peaked T waves, prolonged PR, ABG: metabolic acidosis

Medical management of mild hyperkalemia

Dietary restriction, stop K drugs

Drug therapy for severe hyperkalemia

Kayexalate, insulin + glucose, NaHCO3, calcium gluconate, beta-agonists

Emergency management of hyperkalemia

Hemodialysis

Nursing management of hyperkalemia

Monitor ECG, neuro status, labs, prepare for dialysis, implement fall precautions

Pathophysiology of hypocalcemia

Low Ca increases sodium movement across membranes → increased excitability

Causes of hypocalcemia

Hypoparathyroidism, renal failure, Vit D deficiency, pancreatitis, hypomagnesemia, alkalosis

Neuromuscular signs of hypocalcemia

Tetany, paresthesias, seizures, Chvostek’s sign, Trousseau’s sign

Cardiac signs of hypocalcemia

Prolonged ST interval, prolonged QT, hypotension

GI signs of hypocalcemia

Abdominal cramps, diarrhea

Skeletal effects of chronic hypocalcemia

Osteoporosis, bone fractures

Diagnostic findings in hypocalcemia

Serum Ca <8.8, ionized Ca <4.5, prolonged QT/ST, alkalosis, low albumin

Medical management of acute hypocalcemia

IV calcium gluconate or chloride, Vit D, Mg supplements, high-protein diet

Nursing management of hypocalcemia

Seizure precautions, airway equipment ready, monitor Ca/Mg, encourage Ca-rich diet

Pathophysiology of hypercalcemia

Excess Ca → excitable tissues less responsive → decreased neuromuscular activity

Causes of hypercalcemia

Hyperparathyroidism, malignancy, thiazide use, immobility, dehydration

CV signs of hypercalcemia

Shortened QT, dysrhythmias, increased BP early then bradycardia later

Neuro signs of hypercalcemia

Weakness, confusion, lethargy, coma

GI signs of hypercalcemia

Constipation, anorexia, abdominal pain, hypoactive bowel sounds

Renal signs of hypercalcemia

Polyuria, kidney stones, dehydration

Diagnostic findings in hypercalcemia

Serum Ca >10.5, shortened QT, bone changes, renal calculi

Medical management of hypercalcemia

Hydration with NS, loop diuretics, bisphosphonates, calcitonin, corticosteroids

Emergency treatment for severe hypercalcemia

Dialysis

Nursing management of hypercalcemia

Encourage fluids, monitor ECG, strain urine for stones, ambulation, avoid LR

Pathophysiology of hypomagnesemia

Low Mg increases neural excitability → tetany, seizures

Causes of hypomagnesemia

Alcoholism, diarrhea, diuretics, malnutrition

Neuromuscular signs of hypomagnesemia

Tremors, tetany, seizures, positive Chvostek’s and Trousseau’s signs

Cardiac signs of hypomagnesemia

Prolonged QT, torsades de pointes

Diagnostic findings in hypomagnesemia

Mg <1.3, ECG with prolonged QT, often with hypocalcemia

Medical management of hypomagnesemia

Oral/IV Mg replacement, Mg sulfate IV

Nursing management of hypomagnesemia

Monitor ECG, neuro status, seizure precautions, encourage Mg diet

Pathophysiology of hypermagnesemia

Excess Mg depresses neuromuscular activity

Causes of hypermagnesemia

Renal failure, excessive Mg intake (antacids, laxatives)

Neuromuscular signs of hypermagnesemia

Decreased reflexes, weakness, lethargy

Cardiac signs of hypermagnesemia

Bradycardia, hypotension, cardiac arrest

Diagnostic findings in hypermagnesemia

Mg >2.1, ECG with widened QRS

Medical management of hypermagnesemia

IV calcium gluconate, stop Mg intake, dialysis

Nursing management of hypermagnesemia

Monitor ECG, assess reflexes, respiratory support if severe

ABG normal values

pH 7.35–7.45, PaCO2 35–45, HCO3 22–26, PaO2 80–100

Pathophysiology of respiratory acidosis

Hypoventilation → CO2 retention → low pH

Causes of respiratory acidosis

COPD, respiratory depression, airway obstruction

Clinical manifestations of respiratory acidosis

Confusion, headache, drowsiness, increased ICP

Diagnostic findings of respiratory acidosis

Low pH, high PaCO2, HCO3 normal or high if compensated

Management of respiratory acidosis

Improve ventilation, bronchodilators, O2, treat underlying cause

Pathophysiology of respiratory alkalosis

Hyperventilation → CO2 loss → high pH

Causes of respiratory alkalosis

Anxiety, fever, hypoxemia

Clinical manifestations of respiratory alkalosis

Lightheadedness, numbness, tetany, palpitations

Diagnostic findings of respiratory alkalosis

High pH, low PaCO2, HCO3 normal or low if compensated

Management of respiratory alkalosis

Correct cause, rebreathing techniques, sedatives

Pathophysiology of metabolic acidosis

Excess acid or loss of HCO3 → low pH

Causes of metabolic acidosis

Diabetic ketoacidosis, diarrhea, renal failure

Clinical manifestations of metabolic acidosis

Headache, confusion, Kussmaul respirations

Diagnostic findings of metabolic acidosis

Low pH, low HCO3, PaCO2 normal or low if compensated

Management of metabolic acidosis

IV bicarbonate if severe, correct underlying cause

Pathophysiology of metabolic alkalosis

Excess HCO3 or loss of acid → high pH

Causes of metabolic alkalosis

Vomiting, diuretic use, antacid abuse

Clinical manifestations of metabolic alkalosis

Dizziness, tingling, muscle cramps

Diagnostic findings of metabolic alkalosis

High pH, high HCO3, PaCO2 normal or high if compensated

Management of metabolic alkalosis

Restore fluid/electrolytes, stop causative drugs, give KCl if hypokalemia

Nursing role in ABG analysis

Assess pH first, then PaCO2, then HCO3; determine compensation

Compensated ABG finding

Normal pH with abnormal CO2 and HCO3