Sepsis: What is one common and serious disorder illness in which lactic acid is elevated?

October 1, 2025 •

5 min read

Approximately 1.7 million adults in the U.S. develop sepsis each year, a severe condition where the body's immune response to an infection damages its own tissues and organs. This widespread dysfunction often leads to elevated lactic acid, making sepsis one common and serious disorder illness in which lactic acid is elevated. This buildup, known as lactic acidosis, serves as a crucial biomarker for assessing the severity of the illness.

Quick Summary

Sepsis, a life-threatening organ dysfunction from infection, often results in a dangerous buildup of lactic acid, a condition known as lactic acidosis. This elevated lactate level indicates significant metabolic stress and tissue hypoperfusion. Effective treatment relies on addressing the underlying infection and normalizing lactate levels to improve patient outcomes.

Key Points

Sepsis is a serious disorder causing high lactic acid: Sepsis is the most common cause of Type A lactic acidosis in critically ill patients, where a severe infection leads to widespread organ dysfunction.
High lactic acid indicates tissue stress: Elevated lactate levels signal metabolic stress and reduced oxygen delivery (hypoxia) to the body's tissues, which is a key indicator of severe illness like septic shock.
Treatment targets the underlying cause: The primary treatment for lactic acidosis is to correct the medical problem causing it, which in sepsis involves administering antibiotics, intravenous fluids, and vasopressors.
Monitoring lactate is crucial for prognosis: In critical care, serial monitoring of lactate levels and lactate clearance is essential. A reduction in lactate levels correlates with a better patient outcome.
Lactic acidosis has diverse causes: Besides sepsis, other conditions like cardiogenic shock, severe liver disease, certain medications (e.g., metformin), and poisoning can also cause dangerously high lactic acid.
Symptoms include rapid breathing and confusion: Watch for common symptoms such as nausea, rapid breathing, fatigue, and confusion, especially in patients with a known infection, as they may indicate lactic acidosis.

Understanding Lactic Acid and Acidosis

In a healthy body, lactic acid, or lactate, is a normal byproduct of metabolism, particularly from muscle and red blood cells. It is cleared from the bloodstream primarily by the liver and kidneys. However, under conditions of intense cellular stress or limited oxygen supply (hypoxia), the body's metabolic processes shift to anaerobic glycolysis, leading to an overproduction of lactate. This, combined with impaired organ function that hinders clearance, causes lactic acid to accumulate in the bloodstream.

When this buildup becomes significant enough to lower the body's pH balance, the condition is known as lactic acidosis. This metabolic imbalance can profoundly affect the function of vital organs, potentially leading to organ failure and death if not managed swiftly. For clinicians, the measurement of lactate levels serves as a vital tool for risk assessment and prognosis in critical illness.

The Strong Link Between Sepsis and High Lactate

Sepsis is the most common cause of lactic acidosis in hospitalized and critically ill patients, a condition classified as Type A lactic acidosis because it is linked to tissue hypoperfusion. A severe infection triggers the body's immune system to release inflammatory mediators that disrupt blood flow and cellular function throughout the body. This leads to systemic shock, where blood pressure drops, and oxygen delivery to tissues becomes dangerously low.

The physiological response to sepsis and septic shock involves:

Tissue Hypoxia: Inadequate blood flow deprives tissues of oxygen, forcing cells to produce energy through inefficient anaerobic pathways, which generates excess lactate.
Decreased Lactate Clearance: The liver, which is responsible for clearing most of the body's lactate, is also affected by the widespread inflammation and poor perfusion. This further exacerbates the lactate buildup.
Catecholamine Stimulation: The body's stress response releases high levels of epinephrine (adrenaline), which can stimulate aerobic glycolysis in muscles, further contributing to lactate production even when oxygen is present.

The Sepsis-3 definition for septic shock includes a lactate level of more than 2 mmol/L that persists despite adequate fluid resuscitation. This highlights that elevated lactate is a key marker of a severe, life-threatening progression of sepsis.

Key Symptoms and Diagnostic Process

Symptoms of lactic acidosis are often intertwined with the underlying condition causing it. In a patient with sepsis, the presence of elevated lactate may correspond with signs of organ dysfunction. The clinical presentation varies depending on the severity of the acidosis, but symptoms to watch for include:

Fatigue and Weakness: Persistent exhaustion is a common and early sign.
Rapid Breathing: The body's natural response to acidosis is to try to expel carbon dioxide, which increases the breathing rate.
Gastrointestinal Distress: Nausea, vomiting, and abdominal pain are frequently reported.
Confusion or Altered Mental Status: As the body's pH balance shifts, neurological function can be impaired.
Cardiovascular Changes: A rapid heart rate (tachycardia) and low blood pressure may be present.
Hypothermia: A low body temperature can be a sign of septic shock.
Signs of Shock: Cool or mottled skin and decreased urine output are critical signs of poor tissue perfusion.

Diagnosis involves a blood test to measure the lactate level, often in conjunction with other tests like arterial blood gas analysis to check the blood's pH. In critical care settings like the emergency room or ICU, serial lactate measurements are taken to monitor the patient's response to treatment.

Other Notable Causes of Lactic Acidosis

While sepsis is the most prevalent and serious cause, elevated lactic acid can also result from other conditions, categorized as Type B lactic acidosis, which is not necessarily caused by systemic hypoperfusion.


Feature	Type A Lactic Acidosis (e.g., Sepsis)	Type B Lactic Acidosis (Misc. Causes)
Primary Mechanism	Inadequate tissue oxygenation (hypoxia) due to poor blood flow.	Disruption of cellular metabolism without widespread oxygen deficit.
Associated Conditions	Septic shock, cardiogenic shock, hypovolemic shock, severe trauma, cardiac arrest.	Liver disease, malignancies, metformin use (especially with kidney dysfunction), toxin ingestion (e.g., cyanide, methanol), severe exercise, seizures.
Clinical Context	Critically ill patients, often in a state of shock.	Can occur in chronically ill patients, with certain drug exposures, or transiently.
Initial Treatment	Restoration of oxygen delivery (e.g., fluids, vasopressors, oxygen therapy).	Addressing the specific underlying cause, such as stopping an offending medication.

The Critical Importance of Treatment and Monitoring

Effective treatment for lactic acidosis requires a swift and aggressive approach to resolve the underlying cause. In the context of sepsis, this involves a bundle of care interventions designed to stabilize the patient and fight the infection:

Immediate Antibiotics: Broad-spectrum antibiotics are administered as soon as possible to combat the infection.
Intravenous Fluids: Fluid resuscitation is critical to improve blood volume and pressure, which enhances oxygen delivery to tissues.
Vasopressors: If fluids alone do not restore blood pressure, medications like norepinephrine may be used to constrict blood vessels and raise blood pressure.
Lactate Monitoring: Serial blood lactate measurements are performed to track the patient's metabolic response to treatment. A high lactate clearance (a rapid decrease in lactate levels) is associated with a better prognosis.

Monitoring lactate levels is a critical component of assessing treatment efficacy. The faster a patient's lactate levels can be normalized, the better their chances of survival. However, it's important to note that lactate trends, not just a single value, provide the most useful information for patient management.

Conclusion

While many conditions can cause a temporary rise in lactic acid, the severe and prolonged elevation seen in lactic acidosis is a hallmark of serious systemic illnesses. In the critical care setting, sepsis is the most common and dangerous cause of elevated lactate, signaling widespread tissue hypoperfusion and metabolic distress. The measurement of lactic acid levels is a fundamental component of diagnosing and managing critically ill patients, with prompt and targeted treatment of the underlying infection being the key to reversing lactic acidosis and improving patient outcomes. Understanding the link between sepsis and elevated lactic acid is crucial for both healthcare providers and the general public, as early recognition and aggressive intervention can be lifesaving. More information on sepsis management can be found at the Sepsis Alliance.

Frequently Asked Questions

Lactic acidosis is a condition characterized by an excessive buildup of lactic acid in the bloodstream, which causes the blood to become more acidic than normal. This can occur from overproduction of lactate, decreased clearance by the liver and kidneys, or both.

Sepsis, particularly septic shock, is the most common and serious disorder in which lactic acid is elevated. It is a life-threatening condition caused by a severe immune response to an infection.

In sepsis, high lactic acid is caused by poor tissue perfusion, a condition where inadequate blood flow leads to insufficient oxygen supply to cells. The cells then switch to anaerobic metabolism, producing excess lactate that the impaired liver cannot clear efficiently.

Symptoms can include rapid breathing, fatigue, confusion, nausea, and abdominal pain. In advanced stages, signs of shock such as low blood pressure, rapid heart rate, and cool, mottled extremities may be present.

Lactic acidosis is diagnosed with a blood test that measures the level of lactate and often an arterial blood gas test to check the blood's pH balance. Elevated lactate levels and decreased pH confirm the diagnosis.

Treatment involves a bundle of interventions, including rapid administration of broad-spectrum antibiotics, intravenous fluids to raise blood pressure, and sometimes vasopressors. The underlying infection must be controlled to resolve the lactic acidosis.

Metformin can cause lactic acidosis, but it is rare and primarily occurs in patients with pre-existing conditions like kidney or liver failure. In these patients, the drug can impair lactate clearance, leading to accumulation.