Lactic acidosis

Background

• Most common cause of metabolic acidosis in hospitalized patients

Clinical Features

• Anorexia
• Nausea
• Vomiting
• Abdominal pain
• Lethargy
• Hyperventilation
• Hypotension

Differential Diagnosis

Lactic acidosis

By Type

• Type A (tissue hypoperfusion)
  • Hypovolemia
  • Cardiac failure
  • Sepsis
• Type B (decreased utilization)
  • Alcoholism
    • ↓ Lactate utilization secondary to hepatic dysfunction
    • ↓ NAD+/NADH ratio leads to ↑ conversion of pyruvate to lactate
  • Metformin
  • DKA
    • Mainly due to D-lactate production, though hypovolemia contributes
  • Liver disease (decreased clearance)
  • Adrenergic receptor agonism; viz., albuterol, epinephrine, etc
  • Malignancy
  • Carbon Monoxide poisoning
  • Cyanide poisoning
• Type D
  • episodes of encephalopathy and metabolic acidosis typically following high carbohydrate meals in patients with short bowel syndrome
  • metabolic acidosis and high serum anion gap, normal lactate level, short bowel syn or other forms of malabsorption, and characteristic neurologic findings
    • Type D lactate is not detected with standard lactate levels

Complete List

• Any shock state
• Seizure
• Dead gut
• Hepatic failure
• Malignancy
• Exercise
• Albuterol and other beta agonists
• Toxicologic Causes:
  • Cyanide
  • Carbon Monoxide
  • Metformin
  • Didanosine
  • Stavudine
  • Zidovudine
  • Linezolid
  • Strychnine
  • Emtriva
  • Rotenone (Fish Poison
  • NaAzide (Lab Workers)
  • APAP (if Liver Fx)
  • Phospine (rodenticide)
  • NaMonofluoroacetate (Coyote Poison‐ give Etoh as antidote)
  • Inh (if patient seizes)
  • Hemlock
  • Depakote
  • Hydrogen Sulfide
  • Nitroprusside (if cyanide toxic)
  • Ricin & Castor Beans
  • Propofol
  • Sympathomimetics (cocaine, methamphetamine)
  • Jequirty peas (Abrus precatorius)
  • Prunus Amygdalus plants
  • Crab tree apple seeds & cassava (yucca)

Evaluation

• Hyperlactatemia = Lactate >2 mEq/L
• Lactic Acidosis = Lactate >4 mEq/L

Lactate False Positives=

• Beta-agonists or beta stimulation
• Extreme exercise
• Seizures, immediate ictal period
• Hepatic failure
  • Lactate ringer's solution unlikely to cause false positive except in hepatic failure

Management

• Treat underlying cause

Disposition

• Depends on underlying cause

See Also

• EBQ:Lactate clearance vs central venous oxygen saturation

External Links

• Pediatric Emergency Playbook Podcast: Big Labs, Little People

References

Authors

Ross Donaldson