What is the treatment for lactic acidosis (high lactic acid)?

Treatment of Lactic Acidosis

The primary treatment of lactic acidosis is identifying and aggressively treating the underlying cause—not administering sodium bicarbonate, which lacks evidence for improving outcomes and may cause harm. 1, 2, 3, 4

Immediate Management Priorities

1. Identify and Treat the Underlying Cause

This is the single most critical intervention that determines survival 2, 5, 4:

Type A (Tissue Hypoxia):

• Restore tissue perfusion with fluid resuscitation (15-20 mL/kg/h isotonic saline initially) if shock is present 1
• Optimize oxygen delivery through mechanical ventilation, transfusion for severe anemia, or inotropic support for cardiogenic shock 2, 6
• Treat sepsis aggressively with source control, antibiotics within 3 hours, and hemodynamic support 1, 2
• Address mesenteric ischemia emergently if suspected (surgical consultation) 6

Type B (Non-Hypoxic):

• Discontinue offending medications immediately 2, 7, 8:
  • Metformin (especially with eGFR <30 mL/min/1.73m²) 8
  • NRTIs (stavudine, didanosine) in HIV patients 1, 2, 7
• For metformin-associated lactic acidosis: Prompt hemodialysis is recommended (metformin is dialyzable with clearance up to 170 mL/min) 8
• For D-lactic acidosis (short bowel syndrome): Restrict mono/oligosaccharides, encourage polysaccharides (starch), give thiamine supplements, and administer broad-spectrum antibiotics 1, 2

2. Supportive Care Measures

• Ensure adequate ventilation to facilitate CO₂ elimination and reduce work of breathing 2, 4
• Correct electrolyte abnormalities, particularly hyperkalemia in rhabdomyolysis cases 2
• Consider thiamine supplementation (addresses pyruvate dehydrogenase dysfunction) 1, 2, 4
• Monitor lactate serially every 1-2 hours initially, then every 4-6 hours to assess response 2

The Bicarbonate Controversy: When NOT to Use It

Sodium bicarbonate should NOT be used routinely for lactic acidosis, even with severe acidemia (pH ≥7.15). 1, 3

The Surviving Sepsis Campaign explicitly recommends against using sodium bicarbonate to improve hemodynamics or reduce vasopressor requirements in hypoperfusion-induced lactic acidemia with pH ≥7.15 1. This is based on convincing evidence that bicarbonate:

• Does not improve hemodynamics or cardiovascular function 1, 3
• Increases lactate production paradoxically 3, 4
• Causes hypernatremia and volume overload 8, 9
• Generates CO₂, which can worsen intracellular acidosis 3, 4
• Has never been shown to improve survival 3, 5, 4

Limited Bicarbonate Indications

The FDA label indicates sodium bicarbonate for "severe primary lactic acidosis" 10, but this conflicts with high-quality guideline evidence. If bicarbonate is considered (pH <7.15 with life-threatening hemodynamic instability), use cautiously 10:

• Administer 2-5 mEq/kg over 4-8 hours (not rapid boluses) 10
• Monitor arterial blood gases, plasma osmolarity, and hemodynamics closely 10
• Do not attempt full correction in the first 24 hours—target total CO₂ of ~20 mEq/L to avoid rebound alkalosis 10

Monitoring Requirements

Proper lactate measurement technique is essential 2:

• Use prechilled fluoride-oxalate tubes 2
• Transport on ice and process within 4 hours 2
• Collect without tourniquet or fist-clenching 2

Interpret lactate levels in context 2, 7:

• 2-5 mmol/L: Elevated, warrants investigation 2

• 5 mmol/L: Abnormal, requires intervention 2, 8

• 10 mmol/L: Life-threatening, medical emergency 2

Special Clinical Scenarios

Metformin-associated lactic acidosis:

• Higher risk in elderly (>65 years), renal impairment (eGFR <30), liver disease, heart failure, or acute illness 2, 7, 8
• Hemodialysis is the definitive treatment and often reverses symptoms 8

NRTI-associated lactic acidosis (HIV patients):

• Presents with nonspecific GI symptoms, weakness, dyspnea, and hepatomegaly 1, 2
• Discontinue NRTIs immediately—mortality is high without intervention 1, 2
• Risk is highest with stavudine/didanosine combinations, especially in pregnant/postpartum women 1

D-lactic acidosis:

• Occurs only in short bowel syndrome with preserved colon 1, 2
• Presents with confusion and metabolic acidosis with large anion gap 1
• Standard lactate assays may miss D-lactate—requires specific testing 1

Common Pitfalls to Avoid

• Do not reflexively give bicarbonate for any elevated lactate or low pH—treat the cause first 1, 3
• Do not ignore lactate elevation even without hypotension—it indicates tissue hypoperfusion and predicts mortality 2
• Do not continue metformin in patients with eGFR <30 mL/min/1.73m² or acute kidney injury 8
• Do not delay hemodialysis in metformin-associated lactic acidosis—it is both diagnostic and therapeutic 8
• Do not overlook thiamine deficiency as a reversible cause 1, 2, 4