Symptoms of High Lactic Acid (Hyperlactatemia)
Initial Presentation
The early symptoms of elevated lactic acid are often nonspecific gastrointestinal complaints including nausea, vomiting, abdominal pain, abdominal distention, and diarrhea, which can progress to more severe manifestations if untreated. 1
Gastrointestinal Symptoms
The initial clinical presentation typically includes:
- Nausea and vomiting that persists for 1-6 weeks 1
- Abdominal pain and distention that is otherwise unexplained 1
- Anorexia (loss of appetite) 1
- Diarrhea 1
- Hepatomegaly (enlarged liver) 1
These gastrointestinal symptoms often occur without substantial elevation of hepatic enzymes initially, making early recognition challenging. 1
Respiratory Symptoms
As lactic acidosis progresses, respiratory compensation occurs:
- Dyspnea (shortness of breath) 1
- Tachypnea (rapid breathing) in severe cases 1
- Respiratory failure requiring mechanical ventilation in fulminant cases 1
Neuromuscular Symptoms
Neurologic and muscular manifestations include:
- Generalized weakness 1
- Ascending neuromuscular weakness 1
- Myalgias (muscle pain) 1
- Paresthesias (numbness and tingling) 1
Systemic Symptoms
Critical Clinical Context
Lactate levels between 2-5 mmol/L are considered elevated and must be correlated with symptoms; levels >5 mmol/L are abnormal, and levels >10 mmol/L indicate serious and potentially life-threatening situations. 1, 2
Important Caveats
- Symptoms can be variable and nonspecific, making diagnosis challenging without a high index of suspicion 1
- The syndrome can present with a prodrome lasting 1-6 weeks before severe decompensation occurs 1
- Pregnant women and those on certain medications (particularly NRTIs like stavudine and didanosine) are at higher risk and may present late in gestation 1
- Not all elevated lactate indicates tissue hypoxia—consider medication effects (epinephrine, albuterol), exercise, or metabolic causes before attributing to sepsis 2, 3
When to Be Most Concerned
Elevated lactate accompanied by abdominal pain should prompt immediate consideration of mesenteric ischemia, even in clinically stable-appearing patients (hazard ratio for irreversible intestinal ischemia: 4.1). 2 This represents a surgical emergency that can be missed if symptoms are attributed solely to lactic acidosis itself.