Electrolyte Abnormalities Flashcards
1
Q
Clinical features of HYPERnatremia
A
- AMS - lethargy, confusion, irritability
- Advanced neurologic deficit - coma, seizure
- Expanded intravascular volume
- Pleural effusion, Ascities, Peripheral edema, HF
- C/o thirst or polyuria
- N/V
- Neuromuscular irritability - myoclonus, tremor/rigidity, hyperactive reflexes, weakness
2
Q
DDx of HYPERnatremia: Uosm 700-800 mosmol/L
A
- Unreplaced insensible losses
- GI losses
- Na overload
- Deficit in thirst (rare)
3
Q
DDx of HYPERnatremia: Uosm < 300 mosm/L
A
Diabetes insipidus
4
Q
Tx of HYPERnatremia
A
- Determine volume status of patient
a. Hypernatremia w/ Hypervolemia: Diuretics + HD - Free H2O deficit = {(plasma Na/140) - 1} x kg x 0.6
a. Goal Na less than or equal to 145
b. Replace half free water deficit in 1st 24 hrs and remaineder in following 2-3 days
c. Use 5% dextrose in water or 0.45% NaCl to correct deficit
d. Monitor serum Na every 1-2 hrs
* *rate of Na correction should NOT exceed 0.5 mEq/L per hour or 10-12 mEq/L per day
5
Q
Tx of Central Diabetes Insipidus
A
- DDAVP
- Low Na diet
- Low-dose thiazide diuretic
- Carbamezapine (enhances vasopressin secretion
- NSAIDs
- Impairs renal prostaglandin synthesis
- Potentiates ADH action
6
Q
Tx of Nephrogenic Diabetes Insipidus
A
- Tx underlying cause (eliminate effecting drug (lithium))
- Treat symptomatic polyuria
- Low Na diet
- Thiazide diuretic
- Vasopressin and analog has no role in tx
7
Q
What is the exact rate of correction (of HYPOnatremia) with hypertonic saline?
A
- 10 mEq/L in first 24 hours
- 20 mEq/L in first 48 hours
- In dire situations where serum Na is less than 105 mEq/L - correction is 1-2 mEq/L in first few hours using 3% hypertonic saline
8
Q
S/s of HYPERkalemia
A
- Weakness, tingling, parasthesias
- Flaccid paralysis (primarily LE)
- Hypoventilation
- Metabolic Acidosis
- Cardiac toxicity
a. usually precedes neurologic toxicity
b. EKG changes
9
Q
EKG changes for HYPERkalemia
A
- Increased T-wave amplitude (6-7 mEq/L)
- Flattened P wave, prolonged PR interval, widened QRS complex
- AV conduction delay
- Loss of P wave
- V Fib and Asystole (10-12 mEq/L)
10
Q
Tx of HYPERkalemia
A
- Protect myocardium - CaCl
- Sodium Bicarb 50 mEq IV
- Insulin + D50 IV
- Albuterol
- Loop/Thiazide Diuretics
- Promote GI loss w/ cation exchange resins
- Hyperventilate (if intubated)
11
Q
S/s of HYPOkalemia
A
K < 3 mEq/L
- Fatigue
- Myalgia
- Muscle weakness in proximal LE
- Constipation and intestinal ileum
- Glucose intolerance
- EKG: flattened/inverted T-waves, Prominent U wave, ST depression, Prolonged QT
K < 2 mEq/L
- Progressive weakness
- Hypoventilation
- Complete paralysis
- Increased risk of rhabdomyolysis
- EKG: Prolonged PR, Decreased voltage, Widening QRS, Increased risk of Ventricular arrhythmia
12
Q
Causes of HYPOcalcemia
A
- PTH deficiency (gland removed, severe hypomagnesemia, burns, sepsis, pancreatitis)
- Vit D deficiency
- Hyperphosphatemia (renal failure, tumor lysis, rhabdo)
- Renal failure
- Citrate toxicity
- Acute alkalemia
- Post-cardiopulmonary bypass
- Acute pancreatitis
13
Q
S/s of HYPOcalcemia
A
- CV
- ECG changes: QT prolongation, heart block
- Heart Failure
- Hypotension
- Digitalis insensitivity
- Impaired beta agonist action
- Tetany (Chvostek/Trousseau’s sign)
- Muscle spasm
- Pappilledema
- Seizures
- Irritability/Mental Status changes
- Apnea
- Laryngeal spasm (stridor after thyroidectomy)
- Bronchospasm
14
Q
Indications for Mg Therapy
A
- Premature labor: Tocolysis
- Pre-eclampsia and eclampsia
- Tetanus and pheochromocytoma
- Cardiology
- Improves myocardial oxygen demand
- Reduces incidence of dysrhythmias in post-MI and CHF
- Tx for Torsades de Pointes
- Respiratory
- Asthma management - smooth muscle relaxation in bronchioles
15
Q
S/s Mg Toxicity: Mg level 5-7 mg/dL
A
- Lethargy
- Drowsiness
- Flushing
- Nausea
- Vomiting
- Diminished deep tendon reflexes
