Hyperkalemia

1
Hyperkalemia
2
Daily Requirements

• 1 meq/kg/day
• 1 meq of K per inch of banana
• If the average person weighs 70 kg then to
  fulfill your necessary daily requirements you
  need to eat a 6 foot banana

3
Definition

• Normal serum potassium 3.5-5.5 mEq/L
• Hyperkalemia is a serum potassium greater than
  5.5 mEq/L

4
What to Do??

• Is the value accurate??
• Are there EKG changes??
• Is there evidence of Hemolysis on lab specimen??
• Recheck blood

5
EKG ChangesPeaked T Waves
6
EKG ChangesWidening of QRS Complex
7
EKG ChangesVentricular Tach/Torsades
8
Treatment

• 1- Stabilize myocardial membrane
• 2- Drive extracellular potassium into the cells
• 3- Removal of Potassium from the body

9
TreatmentStabilize the Myocardial Membrane

• Elevations in the extracellular potassium
  concentration will result in a decrease in
  membrane excitability that may be manifested
  clinically by impaired cardiac conduction and/or
  muscle weakness or paralysis
• Calcium antagonizes the cellular effects of
  Hyperkalemia

10
TreatmentStabilize the Myocardial Membrane

• Types of Calcium
• Calcium Gluconate ? can be given central or
  peripherally
• Calcium Chloride ? can only be given via central
  line
• Has higher concentration of calcium and if given
  peripherally will cause local sclerosis and
  gangrene

11
TreatmentDrive Extracellular Potassium Into the
Cells

• 1- ?2 Agonists (albuterol)
• Drives K2 intracellular by increasing Na-K
  ATPase in skeletal muscle
• Usual dose for asthma 0.5 cc/3cc NSS
• Dose for hyperkalemia 5cc over 10 min
• 10X more potent
• Effects occur in 20-30 min
• ADR-palpitations/arrhythmia

12
TreatmentDrive Extracellular Potassium Into the
Cells

• 2- Insulin and Glucose
• Drives K2 intracellular by increasing Na-K
  ATPase in skeletal muscle
• 1 amp D50 with 5-10 units of regular insulin IV
• Effects seen in 30 min with peak in 60 min
• Duration several hours
• ADRs hypoglycemia

13
TreatmentDrive Extracellular Potassium Into the
Cells

• 3- Sodium Bicarbonate (NaHCO3)
• Causes an alkalosis leading to potassium wasting
• Only works if hyperkalemia 2o to ongoing severe
  metabolic acidosis
• Onset few minutes but effects are not long lasting

14
Treatment Removal of Potassium From the Body

• 1- Loop Diuretic
• Leads to loss of K in urine by inhibiting
  NA-K-2CL transporter in Loop of Henle
• Need renal function and volume to get filtrate to
  Loop of Henle

15
Treatment Removal of Potassium From the Body

• 2- Sodium Polystyrene Sulfonate (Kayexalate)
• Exchanges Na for K and binds it in gut,
  primarily in large intestine, decreasing total
  body potassium
• K removed from body 8-12 hours after
  administration in stool
• Given PO/PR
• ADRs intestinal necrosis/gangrene
• DO NOT GIVE INDISCRIMINATLY

16
Treatment Removal of Potassium From the Body

• Hemodialysis

• Peritoneal Dialysis

17
Causes

• Pseudohypokalemia
• Transcellular shift
• Endogenous
• Medications
• Excessive intake

18
CausesPseudohypokalemia

• Prolonged use of tourniquet
• Hemolysis (in vitro)
• Delay in processing of blood
• Severe leukocytosis
• Severe thrombocytosis

19
CausesEndogenous

• Rhabdomyolysis
• Hemolysis
• Tumor lysis syndrome
• Severe exercise

20
CausesTranscellular Shift

• ? Blockers, Digoxin
• Insulin deficient states
• Hyperglycemia/hypertonic-severe
• Metabolic acidosis
• Ischemic gut
• NSAID!!!

• Sepsis- inc catecholamine states
• Adrenal insufficiency
• Hyporenin/Hypoaldo states
• Type 4 RTA, sickle cell, intestinal nephritis,
  obstructive uropathy

21
CausesTranscellular Shift (cont)

• Renal failure
• With dec. renal perfusion from hypovolemia there
  may not be adequate distal flow to allow distal
  principle cell Na and K exchange
• If ATN with tubule damage the also no NA K
  exchange
• Azotemia may cause metabolic acidosis

22
CausesMedications

• ? Blockers
• Bactrim
• K sparing diuretics
• Digoxin
• Succinycholine
• NSAIDS
• Dec GFR

• Inhibit Aldosterone
• Ace I/ARBS
• Spironolactone
• Heparin/Lovenox
• NSAIDs