What are the management strategies for lactic acidosis?

Management Strategies for Lactic Acidosis

The management of lactic acidosis must focus on identifying and treating the underlying cause while providing supportive care, with immediate discontinuation of contributing medications and prompt initiation of hemodialysis in severe cases. 1, 2

Identification and Classification

Lactic acidosis is characterized by:

• Elevated blood lactate concentrations (>5 mmol/L)
• Anion gap acidosis (Na - [Cl+CO2] >16)
• Increased lactate:pyruvate ratio 1

Clinical Presentation

• Early symptoms: malaise, myalgias, abdominal pain, respiratory distress, somnolence
• Advanced symptoms: tachypnea, dyspnea, hypotension, resistant bradyarrhythmias
• Laboratory findings: elevated aminotransferases, creatine phosphokinase, lactic dehydrogenase, lipase, amylase 1

Common Causes

1. Type A (tissue hypoxia/oxygen deficit)

   • Circulatory failure (shock, severe heart failure)
   • Respiratory failure
   • Severe anemia

2. Type B (metabolic dysfunction)

   • Medication-induced (metformin, NRTIs)
   • Liver failure
   • Renal failure
   • Malignancy
   • Sepsis

Management Algorithm

Step 1: Immediate Interventions

• Discontinue contributing medications
  • Metformin
  • NRTIs
  • SGLT2 inhibitors 1, 2
• Establish hemodynamic stability
  • IV fluid resuscitation
  • Vasopressors if needed for shock

Step 2: Treat Underlying Cause

• For metformin-associated lactic acidosis:
  • Immediately discontinue metformin
  • Initiate prompt hemodialysis 2, 3
• For tissue hypoxia:
  • Optimize oxygen delivery
  • Treat shock or heart failure
• For sepsis:
  • Appropriate antibiotics
  • Source control

Step 3: Supportive Measures

• Renal replacement therapy
  • Continuous venovenous hemodiafiltration (CVVHDF) is preferred for hemodynamically unstable patients
  • Conventional hemodialysis for stable patients 3
  • Hemodialysis corrects acidosis and removes accumulated metformin (clearance up to 170 mL/min under good hemodynamic conditions) 2
• Adjunctive therapies
  • Thiamine and riboflavin administration may be considered based on pathophysiologic rationale, though clinical validation is limited 1

Special Considerations for Common Causes

Metformin-Associated Lactic Acidosis (MALA)

• Risk factors:
  • eGFR <45 mL/min/1.73m²
  • Acute kidney injury
  • Liver disease
  • Heart failure
  • Hypoxic states
  • Excessive alcohol intake 2
• Prevention:
  • Avoid metformin in patients with eGFR <30 mL/min/1.73m²
  • Reduce dose in patients with eGFR 30-45 mL/min/1.73m²
  • Temporarily discontinue during acute illness, iodinated contrast procedures, or major surgery 4, 2
• Treatment:
  • Prompt hemodialysis is recommended for correction of acidosis and removal of accumulated metformin 2

SGLT2 Inhibitor-Associated Euglycemic Diabetic Ketoacidosis

• Discontinue SGLT2 inhibitors in patients with severe COVID-19 or other acute illness 1
• Provide insulin and glucose to suppress ketogenesis

HIV Treatment-Related Lactic Acidosis

• Discontinue NRTIs if clinical and laboratory manifestations of lactic acidosis occur
• Consider bicarbonate infusions and hemodialysis 1

Common Pitfalls and Caveats

1. Delayed recognition: Lactic acidosis often presents with nonspecific symptoms; maintain high suspicion in at-risk patients.

2. Inappropriate use of sodium bicarbonate: NaHCO₃ may increase lactate production and is generally of little value in treating type A lactic acidosis 5.

3. Failure to discontinue contributing medications: Metformin should be immediately discontinued in patients with suspected lactic acidosis 2.

4. Inadequate monitoring: Lactate testing requires standardized sample handling (prechilled fluoride-oxalate tubes, immediate transport on ice, processing within 4 hours) 1.

5. Overlooking the need for dialysis: Hemodialysis should be systematically performed in severe forms of lactic acidosis, as it provides both symptomatic and etiological treatment 6.

By promptly identifying and addressing the underlying cause while providing appropriate supportive care, the management of lactic acidosis can significantly improve patient outcomes and reduce mortality.