Biochemical Tests 1: Potassium (K+) Flashcards
What is the reference range of potassium? (1)
3.5-5.3mmol/L
What is the reference range for mild hyperkalaemia? (1)
5.5-5.9mmol/L
What is the reference range for moderate hyperkalaemia? (1)
6-6.4mmol/L
What is the reference range for severe hyperkalaemia? (1)
> = 6.5mmol/L
What are the s/s of hyperkalaemia? (13)
MURDER (Muscle Weakness, urine output = low (renal failure), Respiratory failure (due to muscle weakness), decreased cardiac contractility (weak pulse/low HR), Early: muscle twitches/cramps, Rhythm changes (tall peaked T waves, prolonged PR interval) +
Fatigue
Muscle weakness
Abnormal cardiac conduction (Chest pain/palpitations, ECG changes, cardiac arrest.)
What are the causes of hyperkalaemia? (9)
Medicines
Renal (AKI/CKD, Rhabdomyolysis, Hypoaldosteronism)
Advanced CF
Acidosis
DKA
Severe Tissue Damage
Hormonal Effects
Fragile Blood Cells
Diet
Explain the management of hyperkalaeamia. (5)
ABCDE
Identify + tx underlying cause e.g. withhold drugs/reduce K+ intake.
Exclude pseudohyperkalaemia.
Increase fluids
Determine severity - severe/ECG changes = A+E Referral.
W. Factors can cause pseudohyperkalaemia? (4)
Contamination of sample
Delay in sample
Drip Arm
Haemolysis of sample
Explain the management of hyperkalaemia in community. (4)
Mild (5.5-5.9):
1. Correct cause, repeat bloods.
2. Meds review + diet changes
Moderate (6-6.4):
1. Carry out ECG
2. Assess course of action and px review.
Explain the management of hyperkalaemia in hospitals. (5)
Protect the heart:
1. ECG (30ml 10% Calcium gluconate IV over 10 mins or 10ml 10% CaCl over 5 mins.)
Shift K+ into cells
2. Insulin-glucose infusion (10 units soluble insulin in 25g Glucose via large IV access over 15-30 mins.
3. If patient has glucose < 7mmo/L = 10% glucose over 5hrs 50ml/hr rate.
4. 10-20 mg salbutamol nebuliser.
Remove K+ from body:
5. K+ exchange polymers AER = Calcium resonium 15g TDS.
6. K+ binders = Patiromer Initially 8.4g OD, Max. 8.4g TDS (Titrate 8.4g at least 1 week.)
OR Lokelma 10g TDS up to 72 hrs, maintenance = 5g OD according to K+ levels, 5g-10g on alternative days to 10g OD.
Monitoring:
ECG, K+ Levels (2-4 hrs), BM,
Baseline, 15, 30,90,120 mins up to 6 hrs.
Dose changes/Initiation (1-2 weeks)
<4mmol/L = reduce binder dose
4-5.3mmol/L = continue at current dose
>5.3mmol/L = increase binder dose
Once stable on binder = check K+ monthly.
Dialysis
W. are the risk factors of hyperkalaemia? (7)
AKI
CKD (Stage 4/5)
Dialysis dependence
Medication
Diabetes (DKA/RAAS)
Crohn’s Disease (Hepato-renal failure; spironolactone)
Addison’s Disease
Give e.g. of drugs causing hyperkalaemia. (8)
ACEi/ARB
MRA
K+ supplements / sparing diuretics
Trimethoprim / co-trimoxazole
NSAIDs
W. exacerbating factors can increase risk of hyperkalaemia? (5)
Renal impairment
Elderly
Diabetes
>= 1 RAAS
Combination of common culprit drugs
Explain how K+ binders are introduced in therapy. (4)
Indication for CKD in 3b-5 and HF:
Confirmed HF w. LVEF =< 40%, K+ = 6 mmol/L (not taking / reduce dose RAASi) + x dialysis
Px criteria:
Acute episodes (6-6.4mmol/L)
Restart withheld RAASi at low dose
K+ on repeat test = 5.5-6.4 mmol/L.
What is the reference range of mild hypokalaemia? (1)
< 3.5mmol/L
What is the reference range of moderate hypokalaemia? (1)
2.5-3mmol/L
What is the reference range of severe hypokalaemia? (1)
< 2.5mmol/L
W. are the causes of hypokalaemia? (4)
Medication
Reduced K+ intake
Abnormal losses (D+V, Ileostomy.)
Acid-base disturbances
W. are the s/s of hypokalaemia? (13)
7L’s +
Hypotonia
Cardiac Arrhythmias
Muscle Weakness
Fatigue
Confusion
Paralytic Ileus
Give e.g. of drugs that cause hypokalaemia. (5)
High dose salbutamol
Loop/ Thiazide-like diuretics
Insulin
Steroids
Chronic Laxatives Abuse
Explain the management process of hypokalaemia. (8)
Assess severity type
Identify and treat underlying cause
K-sparing drugs
Oral/IV drugs
Mild/Moderate:
Oral Sando K 1-2 tablets TDS for 3 days or Kay-CEE-L = 10-20ml TDS. AVOID slow K+.
Severe: IV + continuous cardiac monitoring.
