HyperKalemia - Potassium increase - Causes, level, diagnosis and Rx:
Hyperkalemia - increase in the level of potassium
Causes, level, diagnosis and Rx:
s-K> 5.5mmol/l
requires emergency management:
Symptoms
Nausea, Muscle weakness, fatigue, anesthesia, palpitation, cardiac arrhythmia, areflexia, asending weakness, and hypoventilation
Renal metabolic acidosis - impaired amonia genesis
Causes, level, diagnosis and Rx:
s-K> 5.5mmol/l
requires emergency management:
- ECG, repeat bloods,
- stop exogenous potassium and potassium retaining medications
- Assess potential causes of transcellular shift
- estimate the GFR
- Drugs: ACE inhibitors, Potassium sparing drugs, digitalis toxicity (blocks the Na/K ATPase, Succinylcholine, B-Blockers
- Potassium Supliments - Potassium Chloride suppliments or KCl IVI
- PEN G - antibioltics
- Breakup of cells: Rhabdomyolysis, tumour lysis syndrome, Hemolysis - the intracellular K leaks out to the extracellular space - increasing potassium in the blood
- Metabolic Acidosis (except for keto and lactic acidosis) and Insulin deficiency - DKA - both acidosis and insulin deficiency
- Potassium can not be excreated
- decreased GFR
- renal failure
- decreased effective circulating volume
- NSAID in renal insufficiency
- HYPOALDOSTERONISM
- Causes of Hyerkalemia with Normal GFR
- Low renin and low aldosterone
- associated with DM2, NSAID, Chronic interstitial nephritis, HIV
- Normal renin and low aldosterone
- Adrenal insufficiency - Addisons disease, AIDS, metastatic Ca
- ACE inhibitors
- Angiotensin II receptor blockers
- heparin
- Congenital adrenal hyperplasia with 21-hydroxylase deficiency
- Aldosterone resistance
- K-sparing diuretics: spironolactone, amiloride, trimeterne
- Drugs that mimic K-sparing diuretics: pantamide, trimetoprim, cyclosporin, tracrolimus
- Psudohypoaldosteronism
So what do you do?
Symptoms
Nausea, Muscle weakness, fatigue, anesthesia, palpitation, cardiac arrhythmia, areflexia, asending weakness, and hypoventilation
Renal metabolic acidosis - impaired amonia genesis
- EKG - deepening T waves - peaked and narrow T waves.
- low amplitude p waves or loss of P waves
- Prolonged PR interval
- QRS wave complex widening
- Ventricluar fibrillation, asystole
- Death
- EKG is not sensitive enough to measure progress in management
Goal of treatment to protect the heart with calcium gluconate, shift K into cells and enhance K removal from the Body
- Protect the heart:
- Give calcium - antagonises the effects of potassium on the heart (but has no effect on the K levels)
Use calcium gluconate, 1 to 2 Amps (10ml of 10% solution) IVI except if there is digitalis toxicity.
- stabilize the membrane potential - Shift K into the cells - Send the potassium in the cell
- Use Insulin - 10 to 20 units IV- also give dextrose 50% - D50W - 1 to 2 amps to prevent hypoglycemia
- Review s-glucose q1h
- Infusion at a rate of 1 unit per hour
- NaHCO3 1-3 amps (given as 3 amps NaHCO3 in 1L D5W)
- drives K intracellular in exchange for H+
- Use salbutamol inhalations
- B2 Agonist (Ventolin) in nabulised form (2cc or 10mg inhaled) or 0.5mcg IV
- stimulates NaK ATPase, may result in tachycardia - use with caution
Increase the excretion of potassium
- via the urine
- furosimide (>40mg IV) with IV fluids to prevent dehydration
- fludrocortisone (symthetic miralocorticoid) if suspect aldosterone deficiency
- via gut
- using Kayexelate - 20 to 50 mg
- cation resins - Kayexelate plus Sorbitol po to avoid constipation
- Kayexelate enemas with TAP WATER (not sorbitol)
- dialysis - renal failure, life threatening, hyperkalemia unresponsive to Rx
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