From the Guidelines
Hyperlactatemia presents with non-specific symptoms such as unexplained fatigue, muscle weakness, abdominal discomfort, and shortness of breath, which can progress to severe complications like confusion, altered mental status, and hypotension if left untreated. The signs and symptoms of hyperlactatemia can vary based on the severity and underlying cause of the condition. Early signs may include:
- Unexplained fatigue
- Muscle weakness
- Abdominal discomfort
- Shortness of breath during normal activities As lactate levels rise further, patients may experience:
- Nausea
- Vomiting
- Rapid breathing (tachypnea)
- Increased heart rate (tachycardia) as the body attempts to compensate for metabolic acidosis In severe cases, confusion, altered mental status, and hypotension may develop, potentially progressing to shock. Physical examination might reveal cool, clammy skin and decreased urine output. Laboratory findings typically show lactate levels above 2 mmol/L, with values exceeding 4 mmol/L indicating severe hyperlactatemia 1. These symptoms occur because elevated lactate reflects tissue hypoxia or metabolic dysfunction, where cells switch to anaerobic metabolism, producing lactic acid as a byproduct. This metabolic shift happens when oxygen delivery is insufficient (as in shock, severe anemia, or cardiac failure) or when cells cannot properly utilize available oxygen (as in sepsis, certain medications, or mitochondrial disorders) 1. Prompt recognition of these symptoms is crucial as hyperlactatemia often indicates serious underlying pathology requiring immediate medical attention.
From the Research
Signs and Symptoms of Hyperlactatemia
The signs and symptoms of hyperlactatemia (elevated lactate levels) can be associated with significant morbidity and mortality, particularly in patients with severe sepsis or septic shock 2. Some of the key signs and symptoms include:
- Increased blood lactate concentration
- Lactic acidosis (hyperlactatemia and serum pH < 7.35)
- Tissue hypoxia and anaerobic glycolysis
- Organ dysfunction
- Sepsis
Clinical Implications
The clinical implications of serum lactate measurement in diagnosis, monitoring, and prognostication in acute and intensive care settings are significant 2, 3. Some of the key points to consider include:
- Elevated lactate levels can be a marker of significant physiologic derangements
- Lactic acidosis can occur due to various etiologies, including hypoperfusion, medications, organ dysfunction, and sepsis
- Acidemia can cause deleterious effects in almost every organ system, but can also have positive effects, such as increasing localized blood flow and oxygen delivery
Prognostic Factors
Prognostic factors for mortality in severe sepsis patients with lactic acidosis include:
- Lactate clearance: a decrement in lactate clearance of at least 10% for the first 6 hours, 24 hours, and 48 hours of treatment was more dominant among survivors than non-survivors 4
- Vasopressor use: vasopressor use was significantly associated with mortality after adjusting for confounding variables 4
- Initial lactate level: initial lactate level was associated with hospital mortality 4
Treatment
The treatment of lactic acidosis is aimed at reversing the underlying cause, rather than simply correcting the acidemia 5, 6. Some of the key points to consider include: