Hypo and hyperkalaemia

Question 1

What are causes of hyperkalaemia?

Answer 1

Increased K intake and decreased renal excretion: e.g. K sparing diuretics, NSAIDs, trimethoprim, ACEi, heparin, ciclosporin

Decreased cellular K entry or increased cellular K exit: e.g. metabolic acidosis, hyperosmolality (hyperglycaemia), insulin deficiency, beta blockers

Pseudohyperkalaemia

Massive blood transfusion
Rhabdomyolysis
Burns
Addisons

Question 2

What are Sx of hyperkalaemia

Answer 2

Fast irregular pulse
chest pain
weakness
palpitations
light headed

Question 3

What Ix in hyperkalaemia?

Answer 3

Metabolic panel (K, glucose, HCO3, urea, Cr)
FBC
ECG

Other Ix will depend on suspected cause:

ABG: metabolic acidosis
urine dip: CK in rhabdomyolysis
cortisol/aldosterone: Addison’s
urine pH: renal tubular acidosis

Question 4

What are ECG findinds in hyperkalaemia

Answer 4

Tall tented T waves
Prolonged PR
Flattened P wave
Widened QRS
VF and asystole can occur

Question 5

What are DDx for hyperkalaemia

Answer 5

Different causes

CKD, DKA or HHS, drugs, AKI

Question 6

What is Rx of hyperkalaemia

Answer 6

Find and remove cause

1. Cardiac protection e.g. Ca Cl or Ca gluconate, repeat after 5 mins as effect is short lives
2. Nebulised salbutamol, IV insulin: lower serum K

calcium resonium

3. RRT may be needed

Continuous cardiac monitoring until serum K is in safe range

Question 7

What are complications of hyperkalaemia?

Answer 7

VF or cardiac arrest

Question 8

What are Sx of hypokalaemia?

Answer 8

Muscle weakness
hypotonia
hyporeflexia
cramps
tetany
paliptations
light headedness
constipation

Question 9

what are causes of hypokalaemia

Answer 9

Diuretics
vomiting and diarrhoea (metabolic alkalosis)
pyloric stenosis
Cushing's and use of steroids 
Conn's syndrome 
Alkalosis

Question 10

What Ix in hypokalaemia?

Answer 10

Metabolic panel (K, glucose, HCO3, urea, Cr)
FBC
ECG

Other Ix will depend on suspected cause:

Urine K and Cl are useful to differentiate renal and non-renal causes
ABG
Other electrolytes, good if alcoholism is suspected

Question 11

What ECG changes in hyopkalaemia?

Answer 11

ST depression
Decreased T wave amplitude
U waves

Sinus brady, AV bloc, VT and VT can all occur

Question 12

What is Rx of hypokalaemai

Answer 12

If >2.5, oral K

If <2.5, IV K, no more than 20mmol/hour.

Question 13

What are causes of hypokalaemia with acidosis?

Answer 13

diarrhoea
renal tubular acidosis
acetazolamide
partially treated diabetic ketoacidosis

Question 14

What are causes of hypokalaemia with alkalosis?

Answer 14

vomiting
thiazide and loop diuretics
Cushing’s syndrome
Conn’s syndrome (primary hyperaldosteronism)