Electrolytes From Dr Watson’s PPT Flashcards
What is the sodium level that defines hyponatremia?
Na⁺ < 135 mEq/L
Hyponatremia is characterized by low sodium levels in the blood.
What primarily causes hyponatremia?
Primarily reflects water retention relative to sodium loss
This condition can be classified by total body sodium content.
List the classifications of hyponatremia based on total body sodium content.
- Hypovolemic (e.g., diuretics, GI losses)
- Euvolemic (e.g., SIADH, hypothyroidism)
- Hypervolemic (e.g., CHF, cirrhosis)
These classifications help in understanding the underlying causes of hyponatremia.
What are common neurological symptoms of hyponatremia?
- Mild nausea
- Seizures
- Coma
- Death (especially when [Na⁺] < 120 mEq/L)
The severity of symptoms depends on the speed of onset and the degree of sodium deficiency.
What is a critical consideration in diagnosing hyponatremia?
Evaluate osmolality to rule out pseudohyponatremia
This helps differentiate true hyponatremia from conditions that may falsely lower sodium readings.
What is the treatment for hypovolemic hyponatremia?
Isotonic saline
Treatment should be tailored to the patient’s volume status and symptom severity.
What should be avoided during the correction of hyponatremia?
Rapid correction to prevent osmotic demyelination
Slow correction is crucial to avoid complications.
What defines hypernatremia?
Na⁺ > 145 mEq/L
Hypernatremia indicates high sodium levels in the blood.
What typically causes hypernatremia?
Results from water loss exceeding sodium loss or sodium gain
Causes can vary based on volume status.
List the classifications of hypernatremia based on volume status.
- Hypovolemic (e.g., GI or renal losses)
- Euvolemic (e.g., diabetes insipidus)
- Hypervolemic (e.g., hypertonic saline administration)
Understanding these classifications aids in diagnosis and treatment.
What are common neurological symptoms of hypernatremia?
- Restlessness
- Lethargy
- Seizures
- Coma
Symptoms are due to cellular dehydration.
What is a key diagnostic consideration for hypernatremia?
Assess volume status, urine osmolality, and history of water access
This helps in distinguishing between different causes.
What is the treatment for hypovolemic hypernatremia?
Restore intravascular volume first, then administer hypotonic fluids (e.g., D5W)
Gradual correction is essential to prevent cerebral edema.
What sodium level indicates hypokalemia?
K⁺ < 3.5 mEq/L
Hypokalemia is characterized by low potassium levels in the blood.
What are common causes of hypokalemia?
- Intercompartmental shifts (e.g., alkalosis)
- Increased losses (e.g., diuretics, vomiting)
- Inadequate intake
Plasma [K⁺] may underestimate the total body deficit.
What are clinical manifestations of hypokalemia?
- Muscle weakness
- Hyporeflexia
- Ileus
- ECG changes (flattened T waves, U waves)
- Arrhythmias
Severe hypokalemia can lead to serious complications.
What is the treatment for symptomatic or severe hypokalemia?
IV K⁺ with central line use and ECG monitoring if >10 mEq/h
Oral K⁺ is safest for mild/moderate cases.
What defines hyperkalemia?
K⁺ > 5.5 mEq/L
Hyperkalemia indicates high potassium levels in the blood.
What are the causes of hyperkalemia?
- Intercompartmental shifts (e.g., acidosis)
- Decreased renal excretion (e.g., renal failure)
- Excessive intake
Pseudohyperkalemia must be ruled out.
What are clinical manifestations of hyperkalemia?
- Neuromuscular weakness
- Life-threatening cardiac arrhythmias
ECG changes can progress significantly, leading to severe complications.
What is the first step in treating hyperkalemia?
Stabilize myocardium with IV calcium
This is critical to prevent cardiac complications.
What defines hypocalcemia?
Ionized Ca²⁺ < 4.0 mg/dL or Total Ca²⁺ < 8.5 mg/dL
Hypocalcemia indicates low calcium levels in the blood.
What are common causes of hypocalcemia?
- Hypoparathyroidism
- Vitamin D deficiency
- Hyperphosphatemia (CKD)
- Calcium chelation
Ionized calcium is the physiologically relevant form for diagnosis.
What are clinical manifestations of hypocalcemia?
- Paresthesia
- Tetany (Chvostek & Trousseau signs)
- Seizures
- Laryngospasm
- Bronchospasm
Cardiovascular effects can also be significant.
What is the treatment for acute symptomatic hypocalcemia?
IV calcium (chloride or gluconate), ideally via central line
Monitoring ionized calcium closely is essential.
What defines hypercalcemia?
Ionized Ca²⁺ > 5.3 mg/dL or Total Ca²⁺ > 10.5 mg/dL
Hypercalcemia indicates high calcium levels in the blood.
What are common causes of hypercalcemia?
- Hyperparathyroidism
- Malignancy (PTHrP, bone metastases)
- Granulomatous disease
Ionized calcium reflects true severity and should be used for assessment.
What are clinical manifestations of hypercalcemia?
- Nausea
- Vomiting
- Weakness
- Polyuria
- Confusion
Cardiac signs can also be significant.
What is the first step in treating hypercalcemia?
IV saline hydration followed by loop diuretics
This promotes calciuresis and helps manage levels.
What is a key anesthetic consideration for significant hyperkalemia?
Delay elective surgery
Close monitoring of ECG and neuromuscular function is essential.
What is a key anesthetic consideration for significant hypercalcemia?
Defer elective surgery
Monitoring ionized calcium and volume status is crucial.
