Hyperkalemia: Difference between revisions
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***Duration of effect: 4 - 6 hours | ***Duration of effect: 4 - 6 hours | ||
***Consider mixing in 10 cc NS syringe to ensure small volume of 10 units insulin fully administered via IV | ***Consider mixing in 10 cc NS syringe to ensure small volume of 10 units insulin fully administered via IV | ||
*** | ***Insulin cleared renally, be careful about inducing hypoglycemia (ESRD patients) | ||
*Nebulized albuterol 5 - 20mg | *Nebulized albuterol 5 - 20mg | ||
**Response is dose-dependent | **Response is dose-dependent |
Revision as of 20:58, 11 August 2016
Background
- Defined as >6.0 mEq/L
- Consider pseudohyperkalemia (e.g. from hemolysis)
- Potassium secretion is proportional to flow rate and sodium delivery through distal nephron
- Thus, loop & thiazide diuretics cause hypokalmia
Medication Causes
Alter transmembrane potassium movement
- β blockers
- Digoxin
- Potassium-containing drugs
- Potassium supplements
- Salt substitutes
- Hyperosmolar solutions (mannitol, glucose)
- Suxamethonium
- Intravenous cationic amino acids
- Stored red blood cells (haemolysis releases potassium)
- Herbal medicines (such as alfalfa, dandelion, horsetail, milkweed, and nettle)
Reduce aldosterone secretion
- ACE inhibitors; Angiotensin II receptor blockers
- NSAIDs
- Heparin
- Antifungals (ketoconazole, fluconazole, itraconazole)
- Ciclosporin
- Tacrolimus
Block aldosterone binding to mineralocorticoid receptors
- Spironolactone
- Eplerenone
- Drospirenone
- Potassium sparing diuretics (amiloride, triamterene)
- Trimethoprim
- Pentamidine
Clinical Features
Differential Diagnosis
- Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis
- Redistribution (shift from intracellular to extracellular space)
- Acidemia (see DKA)
- Cellular breakdown: see Rhabdomyolysis/Crush syndrome, hemolysis, see Tumor lysis syndrome
- Increased total body potassium
- Inadequate excretion: Acute/chronic renal failure, Addison's disease, type 4 RTA
- Drug-induced: potassium-sparing diuretic (spironolactone), angiotensin converting enzyme inhibitors (ACE-I), nonsteroidal anti-inflammatory drugs (NSAIDs)
- Excessive intake: diet, blood transfusion
- Other causes: succinylcholine, digitalis, beta-blockers
Peaked T-waves
- MI (hyperacute T waves)
- Hyperkalemia
- Benign Early Repolarization
- De Winter's T waves (acute LAD occlusion)
Evaluation
ECG
Changes NOT always predictable and sequential
- 6.5 - 7.5 mEq/L: peaked T waves, prolonged PR interval, shortened QT interval
- 7.5 - 8.0 mEq/L: widened QRS interval, flattened P waves
- 10 - 12 mEq/L: sine wave, ventricular fibrillation, heart block
Management
Stabilize cardiac membranes
Indicated if there are any ECG changes or evidence of arrhythmias. Consider if K >7 mEq/L
- Either one of the following:
- Calcium gluconate: Give 10ml of a 10% solution over 10 mins
- Only 1/3 the calcium compared to calcium chloride
- Can cause hypotension due to osmotic shift
- Calcium chloride 1 gram IV
- Give over 1 - 2 minutes
- Extravasation is bad: use a good IV
- Usually given in code situations
- Calcium gluconate: Give 10ml of a 10% solution over 10 mins
- Takes effect in 15-30 minutes[1]
- (If given for hyperkalemic cardiac arrest, need to continue resuscitation for at least 30 minutes)
- Duration of action: 30 - 60 minutes [2]
- Use caution in patients taking Digoxin although risk of Stone heart may be unsubstantiated [3]
- Do serial ECGs to track progress: may need to give multiple doses
Shift K+ intracellularly
- Intravenous insulin + dextrose
- Give 10 units regular insulin intravenously with 25 to 50 grams (1 - 2 50 mL ampules) of 50% dextrose (D50)
- May withhold dextrose if blood sugar >300mg/dl (>17 mmol/L)
- Duration of effect: 4 - 6 hours
- Consider mixing in 10 cc NS syringe to ensure small volume of 10 units insulin fully administered via IV
- Insulin cleared renally, be careful about inducing hypoglycemia (ESRD patients)
- Give 10 units regular insulin intravenously with 25 to 50 grams (1 - 2 50 mL ampules) of 50% dextrose (D50)
- Nebulized albuterol 5 - 20mg
- Response is dose-dependent
- Peak effect: 30 minutes
- Duration of effect: 2 hours
- Intravenous sodium bicarbonate 50ml of 8.4% solution (1 ampoule) given over 5 minutes
- Duration of effect: 1 - 2 hours
- Generally not required, unless pH <7.1
Remove K+ from body
- Intravenous furosemide (Lasix) 40 - 80mg
- Ensure adequate urine output first
- Sodium polystyrene sulfonate (Kayexylate): 30 gm oral or per rectum
- Very Controversial, High Risk of Bowel Perforation, see: EBQ: Use of Kayexylate in Hyperkalemia
- Intravenous normal saline solution for volume expansion if dehydrated, rhabdomyolysis, diabetic ketoacidosis or other acidosis
- Definitive treatment is hemodialysis
See Also
External Links
References
- ↑ http://lifeinthefastlane.com/hyperkalemia/. Accessed 02/22/2016
- ↑ The Effect of Calcium on Severe Hyperkalemia http://hqmeded-ecg.blogspot.com/2015/04/the-effect-of-calcium-on-severe.html
- ↑ Erickson CP, Olson KR. Case files of the medical toxicology fellowship of the California poison control system-San Francisco: calcium plus digoxin-more taboo than toxic? J Med Toxicol. 2008 Mar;4(1):33-9