What is the treatment for metabolic alkalosis?

Treatment of Metabolic Alkalosis

The first-line treatment for metabolic alkalosis is addressing the underlying cause, with administration of chloride-containing solutions (normal saline) for chloride-responsive cases and potassium chloride supplementation for cases with hypokalemia. 1

Classification and Initial Assessment

• Metabolic alkalosis is characterized by elevated arterial pH (>7.45) and increased serum bicarbonate, requiring assessment of the underlying mechanism for appropriate treatment 2
• Classify the alkalosis as either chloride-responsive (urinary chloride <20 mEq/L) or chloride-resistant (urinary chloride >20 mEq/L) to guide treatment approach 1, 3
• Common causes include:
  • Diuretic therapy (especially loop and thiazide diuretics) 1
  • Vomiting or nasogastric suction (loss of gastric acid) 3
  • Hypokalemia and hypochloremia 1
  • Mineralocorticoid excess 2

Treatment Algorithm

Step 1: Address the Underlying Cause

• Discontinue or reduce doses of diuretics if possible 1
• Stop nasogastric suction if applicable 3
• Treat underlying conditions such as Bartter syndrome or mineralocorticoid excess 1

Step 2: Chloride-Responsive Alkalosis (Urinary Cl <20 mEq/L)

• Administer isotonic saline (0.9% NaCl) to correct volume depletion and provide chloride 4
• This form of alkalosis typically responds well to saline administration 3

Step 3: Potassium Replacement

• Administer potassium chloride (KCl) when hypokalemia is present 1
• Doses of 20-60 mEq/day are frequently required to maintain serum potassium in the 4.5-5.0 mEq/L range 1
• Use potassium chloride specifically, not other potassium salts like potassium citrate which can worsen alkalosis 1

Step 4: For Refractory Cases

• For diuretic-induced alkalosis, consider:
  • Adding a potassium-sparing diuretic such as spironolactone (starting at 100 mg/day, up to 400 mg/day) 5, 1
  • Amiloride (2.5-5 mg daily) is particularly effective for metabolic alkalosis associated with diuresis 1
  • Acetazolamide for patients with adequate kidney function, especially in heart failure patients 1

Step 5: Severe, Life-Threatening Alkalosis

• For severe cases (pH >7.60) unresponsive to conservative measures:
  • Consider dilute hydrochloric acid (0.1-0.2 N) administration through a central venous catheter 6
  • Ammonium chloride infusion may be used in patients with normal hepatic function 6
  • Hemodialysis with low bicarbonate dialysate may be considered in patients with renal failure 2

Special Considerations

• In heart failure patients with metabolic alkalosis, consider adding spironolactone to the diuretic regimen 1
• For Bartter syndrome, treatment includes:
  • Sodium chloride supplementation (5-10 mmol/kg/day) 1
  • Potassium chloride supplementation 1
  • NSAIDs to reduce prostaglandin-mediated salt wasting (with gastric protection) 1

Monitoring and Follow-up

• Monitor serum electrolytes, acid-base status, and volume status regularly 1
• Adjust therapy based on clinical response and laboratory parameters 1
• Be vigilant for complications of treatment:
  • Hyperkalemia with potassium-sparing diuretics, especially when combined with ACE inhibitors 1
  • Volume overload with excessive saline administration 3
  • Overcorrection leading to metabolic acidosis 6

Common Pitfalls to Avoid

• Using potassium salts other than potassium chloride, which may worsen alkalosis 1
• Administering potassium-sparing diuretics in patients with significant renal dysfunction or existing hyperkalemia 1
• Overlooking Bartter syndrome in patients with unexplained metabolic alkalosis, especially with a history of polyhydramnios and premature birth 1
• Failing to correct the underlying cause while focusing only on symptomatic treatment 2