Severe Hypokalaemia

Introduction

• Severe Hypokalaemia when K⁺ <2.5^H

Etiology

1. Diuretic therapy
• Thiazides
• Loop diuretics
2. GI loss

1.                  Vomiting

2.                  Nasogastric aspiration

3.                  Diarrhoea

4.                  Ileostomy or

5.                  Fistulae

6.                  iIleus/intestinal obstruction

3. Hyperaldosteronism

• Primary- Conn’s syndrome
• Secondary-
1. Liver failure
2. Heart failure
3. Nephrotic syndrome
4. Cushing’s syndrome
3. Corticosteroid therapy
4. Renal disease
• Renal tubular acidosis- Types 1 and 2
5. Redistribution into cells

0. Beta-agonists, e.g. salbutamol
1. Insulin treatment
2. Correction of megaloblastic anaemia
3. Alkalosis
4. Hypokalaemic periodic paralysis- may be precipitated by carbohydrate intake, also occurs in association with hyperthyroidism (thyrotoxic periodic paralysis)
6. Reduced intake of K+
0. Intravenous fluids without
1. K+ Dietary deficiency
7. Hypomagnesaemia
8. Rare causes
0. Bartter’s
1. Gitelman’s syndromes
2. Liddle’s syndrome

Clinical assessmen

At first to look for any serious features.

• Arrythmia
• Neuromuscular features-
• Flaccid Paralysis
• Paralytic Ileus

Urgent Investigations

• S. Electrolytes
• ECG- VT, VF

• But ECG can not predict dangerous arrhythmia.

Management

If any serious symptoms/ K⁺ <2.5

IV Potassium - but

Not > 10 mmol of potassium per hour

Not > 40 mmol/L (if a peripheral vein )  may be upto 60 mmol/L (in a central vein)

Caution:

• Higher concentrations can cause localized pain from chemical phlebitis, irritation, and sclerosis.
• Continuous ECG monitoring is indicated, and the serum potassium level should be checked every 3–6 hours.^C

Occasionally, total deficit should be measured by the following formula-

Total Deficit= (4- Patient’s K+ level) x 5 x Wt. in Kg^C.

= (4-2) x 5 x 60 in a patient of 60 kg whom K⁺ level is 2 mmol/L

= 600 mmol/L

Or, roughly-

loss of 400 to 800 mmol of total-body K⁺ results in a reduction in serum K⁺ of approximately 2.0 mM^H.

• Magnesium deficiency should be corrected, particularly in refractory hypokalemia.

• Avoid glucose-containing fluid (DA) to prevent further shifts of potassium into the cells.