Related Subjects:
|Metabolic acidosis
|Aspirin or Salicylates toxicity
|Ethylene glycol toxicity
|Renal Tubular Acidosis
|Lactic acidosis
|Metabolic alkalosis
|Arterial Blood gas analysis
Any patient with sepsis and a lactate >4 mmol/L should be treated as for septic shock, even if normotensive. This requires immediate IV fluid resuscitation, antibiotics, and inotropes according to the sepsis resuscitation bundle.
About Lactate and Lactic Acidosis
- Normal lactate: < 1 mmol/L
- Raised lactate: >2 mmol/L
- Lactic acidosis: Lactate >4 mmol/L with reduced serum pH < 7.35
🧬 Aetiology
- Increased lactate production: Due to tissue hypoxia, intense exercise, or metabolic disruptions
- Reduced lactate clearance: Often due to liver dysfunction or impaired lactate metabolism
Classification of Lactic Acidosis
- Type A (Hypoxia-driven): Due to tissue hypoxia
- Causes include shock, anaemia, hypoxia, bowel ischaemia
- Severe exercise, seizures, cholera
- Phaeochromocytoma, tumour lysis syndrome
- Type B (Non-hypoxia related): Excess lactate production or impaired clearance
- Severe liver disease, diabetic ketoacidosis (DKA), chronic ethanol abuse
- Drug-induced: Metformin, methanol, ethanol, ethylene glycol, salicylates, cyanide
🩺 Clinical Features
- Shock symptoms: hypotension, peri-arrest, or moribund appearance
- Respiratory: Kussmaul respirations, tachypnoea
- Organ failure signs: Possible cardiac, liver, or renal failure
🔎 Investigations
- Blood tests: FBC, U&E, LFT, glucose, troponin
- Lactate levels: >5 mmol/L is consistent with lactic acidosis
- Bicarbonate (HCO3): Often reduced in metabolic acidosis
- Other tests: CXR, urinalysis, blood cultures, and ABG to assess anion gap and confirm metabolic acidosis
💊 Management
- Immediate stabilization: Support ABCs with high-flow oxygen, identify and treat underlying cause
- Sepsis treatment: IV crystalloid fluids and broad-spectrum antibiotics; consider surgical debridement or drainage as needed
- Specific interventions: Haemoperfusion or haemodialysis for ethylene glycol or methanol poisoning
