Hypokalemia is defined as a serum potassium level below 3.5 mEq/L, requiring tests like spot urine potassium and the trans tubular potassium gradient (TTKG) for diagnosis. Causes can be differentiated into renal and non-renal categories, with treatment tailored accordingly; oral potassium is preferred unless severe cases necessitate IV administration under ECG monitoring. Patients with hypokalemia may present with symptoms such as muscle weakness and cardiac arrhythmias, and chronic cases can lead to interstitial renal disease or increased digoxin toxicity.

1. HYPOKALEMIA
Serum potassium less than 3.5
milliequivalent per litre

2. STEP 1
Take the following tests

3. 1. Spot urine potassium
2. TTKG

4. Spot urine potassium is
denoted by U[K+]
It maybe less than 20 or more than 20

5. TTKG means
Trans Tubular Potassium Gradient

6. Trans Tubular Potassium
Gradient
TTKG= U[K+] times serum osmolality /
serum K+ times urine osmolality

7. So, along with spot urine
potassium and TTKG,
Serum and urine osmolality should also be
measured

8. If U[K+] is less than 20mEq/L
TTKG will definitely be less than 4
AND
THINK “NON RENAL”

9. If U[K+] is more than 20mEq/L
TTKG will definitely be more than 4
AND
THINK “RENAL”

10. NON RENAL
Gastrointestinal losses or intracellular
shifting or poor intake

11. RENAL
After thinking renal,
THINK
Metabolic acidosis or alkalosis

12. If metabolic acidosis
RTA type 1,2 or diabetic ketoacidosis or ureterosigmoid diversion

13. If metabolic alkalosis
THINK
Hypertension or Normal BP

14. If hypertension
Primary hyperaldosteronism or congenital adrenal hyperplasia or Liddle
syndrome

15. If BP is normal
Diuretics or Bartter and Gitelman syndromes

16. CAUSES OF HYPOKALEMIA
DONE!!

17. Treatment

18. Oral correction of deficit is
preferable
Unable to take oral: IV correction with ECG
monitoring

19. Correct deficit in 24 hours
Not more, not less

20. In 24 hours, we have to give
4mEq/kg
By giving oral potassium chloride 4 times

21. In severe hypokalemia, i.e.
less than 2.5 mEq/L
Forget oral, Give IV potassium under ECG
monitoring

22. In arrythmic people
Forget oral, Give IV potassium under ECG
monitoring

23. Situation: RAPID
CORRECTION REQUIRED
Give 1 mEq/kg in 1 hour

24. A patient with severe hypokalemia presents
with
• Skeletal and smooth muscle weakness (neck flop, abdomen
distension, ileus)
• Cardiac muscle arrythmias
AND REMEMBER
• Chronic hypokalemia= think INTERSTITIAL RENAL DISEASE
• Chronic hypokalemia= think INCREASED DIGOXIN TOXICITY