Hypokalaemia Flashcards Preview

Electrolytes and Acid-base disorders > Hypokalaemia > Flashcards

Flashcards in Hypokalaemia Deck (9)
Loading flashcards...
1
Q

Hypokalaemia >>> acid-base disorder

A

Metabolic alkalosis OR metabolic acidosis (both are possible)

2
Q

Hypokalaemia + metabolic alkalosis >>> causes

A
  • Vomiting
    • ​​Peptic ulcer >>> pyloric stenosis
    • Any cause of vomiting
  • ​Aspiration
    • ​Nasogastric suction, gastric aspiration etc.
  • ​Extra intake of >
    • ​Diuretics
    • ​Liquorice
    • Carbenoxolone
  • Diseases >
    • ​Hypokalaemia (due to any cause)
    • Primary hyperaldosteronism (Or Conn’s syndrome)
    • Cushing’s syndrome
    • Congenital or inherited >
      • CAH (Congenital Adrenal Hyperplasia) (AR)
      • Bartter’s syndrome (AR)

(All the causes of metabolic alkalosis are included here; As all the causes have associated hypokalaemia)

3
Q

Hypokalaemia + metabolic acidosis >>> causes

A
  • Diarrhoea (> hyperchloraemia, normal anion gap)
  • RTA (Renal tubular acidosis) type 1,2,3 (> hyperchloraemia, normal anion gap)
  • Acetozolamide (> hyperchloraemia, normal anion gap)
  • Partially treated DKA (DKA has a raised anion gap)

Except these 4, rest of the common causes of metabolic acidosis are related to hyperkalaemia

Type 4 RTA has hyperkalaemia + metabolic acidosis, normal anion gap

4
Q

Hypokalaemia >>> ECG features

A
  • PR >>> Prolonged PR interval
  • QT >>> Long QT
  • ST >>> ST depression
  • T >>> Small or absent T wave (occasionally inversion)
  • Extra >>> U wave

Mnemonnic: U have no Pot (ST), no T; but a long PR and long QT

5
Q

At which K level, do ECG features of hypokalaemia develop?

A

<2.7mmol/L

6
Q

ECG features: Hypokalaemia vs Hypomagnesaemia

A

​Hypokalaemia has >>>

  • PR >>> Prolonged PR interval
  • QT >>> Long QT
  • ST >>> ST depression
  • T >>> Small or absent T wave (occasionally inversion)
  • U wave

​Hypomagnesaemia has all the same features as above; but NO U wave

7
Q

U wave in ECG >>> Diagnosis

OR U wave is only present in- ?

A

Hypokalaemia

8
Q

Which electrolyte deficiency can cause hypokalaemia?

A
  • Mg (Magnesium) deficiency (hypomagnesaemia)
  • In such cases, try to normalise the Mg level first;
    • ​​because, normalising K level may be difficult until the Mg deficiency has been corrected
9
Q

Approx. a drop of 1mmol in serum K is equivalent to >>> ?body loss

A

A total body loss of 200mmol of K