Hyperkalaemia

Question 1

What is hyperkalaemia

Answer 1

• Serum potassium >5.5 
• Mild 5.5-5.9 mmol/L 
• Moderate 6.0-6.4  mmol/L
• Severe >6.5mmol/L
First assess the patient—do they look unwell, is there an obvious cause? If not, could it be an artefactual result?

Question 2

What are the causes of hyperkalaemia

Answer 2

Reduced renal excretion
○ Renal failure- AKI, CKD, Renal tubular acidosis
○ Reduced tubular loss (potassium sparing diuretics, anti inflammatory, ACEIs ,ARBS, suxamethonium, ciclosporin, heparin mineralocorticoid deficiency- adidons’s)

 K+ leaving cells
	○ Metabolic acidosis
	○ Beta blockers
	○ Digoxin
	○ Hyperkalaemia periodic paralysis -condition that causes episodes of extreme muscle weakness usually beginning in infancy or early childhood. Most often, these episodes involve a temporary inability to move muscles in the arms and legs

Increased potassium in the circulation
○ Increased intake
○ Usually parenteral- as it is very difficult to overdose on K+
○ Foods high in them: salt substitutes (contain K+ NOT Na), bananas, oranges, kiwi, avocado, spinach, tomatoes
○ Cell damage (rhabdomyolysis, burns, trauma, haemolysis, massive transfusion, crush injury)
○ Tumour lysis syndrome

Or artefactual results - if the patient
○ Poor venepuncture technique
○ Not using vacutainers
○ Narrow needles
○ Injecting blood through narrow needles into vacutainers
○ Not taking them in the right order- take blood cultures first - reduces contamination, Citrate for clotting, Then biochemistry serum or heparine tube, Then do FBC and glucose. If you were to take FBC tube first it will contaminate with EDTA- which contains K+ this puts K+ up, drops calcium therefore know can do it

Question 3

What drugs cause hyperkalaemia

Answer 3

BB, ACEI, ARBS, spironolactone, Digoxin, BB, suxamethonium, ciclosporin, NSAIDS

Question 4

What are the sympatoms of hyperkalaemia

Answer 4

Likely with acidosis
Symptoms: fatigue, weakness, muscle pain, SOB, stiffness
Signs : bradycardia, flaccid paralysis, absent reflexes

Worrying signs Include a fast irregular pulse, chest pain, weakness, palpitations, and light-headedness.

Question 5

What are the signs on the ECG

Answer 5

Earliest: T tented T waves 
P waves flattened 
Prolonged PR until P waves absent 
QTS bizzare morphology and Heartblock 
Ensure hyperkalaemia + ECG- monitor on CARDIAC MONITOR

Note reverse tick with digoxin!

Question 6

How do you investigate hyperkalaemia

Answer 6

Bloods: repeat the potassium whilst obtaining an ECG with a venous blood gas
Additionally, consider
U&Es, FBCs, LFTs, blood sugar
VBG to review for acidosis
Digoxin levels if applicable to rule out toxicity
Serum cortisol/aldosterone if mineralocorticoid insufficiency is suspected

Question 7

How do you manage hyperkalaemia

Answer 7

Following an ABCDE, consider whether the patient has a hyperkalaemic emergency or hyperkalaemia without an emergency. This depends on local guidelines but put simply those who are symptomatic, have ECG changes, have severe hyperkalaemia with ongoing reasons for the hyperkalaemia to worsen are some examples of an emergency.

> 6.5 mmol or 6 with ECG CHANGES

Question 8

How do you manage non urgent hyperkalaemia

Answer 8

Treat the cause (remove courses including drugs/foods)
Give 0.9% NACL if tolerate
Dicuss with seniors: GI binders (e.g. calcium resonium or patiromer depending on local guidelines) or dialysis (if appropriate).
You may need to refer to the renal registrar or ITU team for emergency dialysis.
They may take several hours to days to work
Note there is some evidence of GI toxicity in resonium with ulceration & perforation, hence you must discuss this with seniors!

Ensure you monitor for rebound hyperkalaemia & recurrence (which will occur if you don’t find & treat an underlying cause or excrete the potassium out).

Question 9

How do you manage emergency hyperkalaemia

Answer 9

PUT ON CARDIAC MONITOR and serial ECGs

• If ECG changes- Calcium gluconate (large vein or central catheter) give 10ml of 10% (slowly max rate 2ml/min) repeat if needed max dose 40ml. Works within minutes & last around 30-60 minutes
• Insulin & Dextrose over 15 mins- glucose 25g in 50mls (50% glucose) with 10 units of soluble human Insulin (Dextrose/Insulin infusion). In addition, give 10% glucose by infusion @50mls/hour for 5 hours for patients with pre-treatment blood glucose < 7.0mmol/L to avoid risk of hypoglycaemia. Check BM every 30mins for 2 hrs then hourly- required up to 12 hours. Lasts about 4-6 hrs

-Sodium bicarbonate to manage acidosis
Mild to moderate acidosis (pH 7.1-7.3): If patient is not fluid overloaded, use 500 mL 1.4% NaHCO3 over 2-3 hours then recheck bicarbonate
 Severe acidosis (arterial pH  <7.1) :Use 500mL 1.4% NaHCO3 in 1 hour; (volume overload or cardiac arrest, use 50mL 8.4% NaHCO3 slowly via a large vein.
Do not give NAHCO3 in T2RF or hypocalcaemia

• 10-20mg neb salbutamol (Caution in patients with tachycardia or ischaemic heart disease. )
• An oral potassium binder, Sodium Zirconium Cyclosilicate (Lokelma) 10g three times a day for up to 72 hours may be useful. Chronic use needs specailist
• Treat the cause! - Remember to stop all potassium-retaining/containing drugs if possible, ensure dietary review of dietary potassium
• Haemofilitration ITU
• Check K+ x2 daily initially then once daily when <6mmol/L give dietary advice where appropriate

Question 10

What does dread stand for?

Answer 10

DREAD- DKA, renal failure, endocrine (addisons), artefact, Drugs (K+ sparing/ACEi)