Hypokalemia

Normal range 3.5-5

Hypokalemia <3.5

The symptoms usually occur at level 2.5 mmol/L. Might be sooner if rapid depletion and might be at much lower level if chronic depletion.

Investigation

Depend on the causes. Not all cases need to do the similar investigation.

Depend on hospital. Certain have limited resource and need to out source and take some time.

Some of the investigation

a. Serum aldosterone and renin

b. Arterial blood gas

c. Urine potassium

d. Serum and urine osmolarity

e. FBC-hyperleucocytosis can cause pseudohypokalaemia.

Treatment

Asymptomatic, no ECG changes

>2.5mmol/L : oral potassium replacement. Discharge.

<2.5mmol/L : Fast correction.

Symptomatic

Fast correct. Similar as above.

How much to correct

Formula for correction:

Deficit (mmol) = (4 current potassium level) X weight X 0.4

mmol/13.3= gram

Administration: 1g in 100cc NS over 1 hour.

In most cases, hypokalemic patients are also hypomagnesemic. So Mg2+ may be added to the infusion both to optimize tubular reuptake of potassium and to contrast proarrhythmic effect of hypokalemia.

Disposition:

depend on the cause. Certain case might need admission and proper follow up.

Local setting (special circumstance)

Have lower treshold to correct hypokalemia since we are working in rural area, patient might leave few kilometers away and have transport problem to reach hospital.

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