Lactic acidosis is a condition characterized by excess lactic acid in the body, which may arise due to excess production or underutilization of lactate (or lactic acid). It is a type of metabolic acidosis that changes the blood’s pH from slightly alkaline/basic to acidic. The condition may develop transiently after hectic exercise (due to oxygen deprivation and a consequent shift to anaerobic metabolism). However, it may also occur due to serious circulatory issues. Generally, your liver and kidneys are responsible for metabolizing and removing lactic acid, respectively. Thus, disturbances in the liver and kidneys can lead to a buildup.

In a study of 2550 participants, the prevalence of the disorder was found to be 6%, and the mortality rate of high lactate (pH above 7.09) was 57%. Researchers also found that severe acidosis and shock are often comorbid and have a mortality rate of about 50%.¹ Therefore, unattended lactic acidosis can lead to organ failure and even death. Treatment involves immediate management with oxygen therapy (and IV fluids). In general, doctors figure out the underlying cause of the acidosis and treat it accordingly.

Types Of Lactic Acidosis

Type A:

Lactic acidosis arising due to oxygen deprivation is referred to as type A lactic acidosis. A lowered blood flow (hypoperfusion) in the tissues can cause acidosis. It can occur temporarily due to excessive exercise or may be attributed to a serious underlying illness. In most cases, disorders that affect the circulation of the blood cause the infirmity. Several disorders that can lead to acid buildup include:

Heart Failure

Inefficient pumping due to cardiac failure can induce lactic acidosis by lowering blood volume (hypovolemia). Acidosis due to hypovolemic shock can also be seen in patients with cardiac arrest. ²

Pulmonary Disorders

Issues like COPD and severe asthma can compromise the ventilation of the lungs, leading to respiratory failure. This failure can induce acidosis.

Sepsis

Sepsis is a serious medical condition in which an infection causes self-damage to the body. It is the body’s extreme reaction where the immune system starts fighting your healthy tissues instead of the pathogen. It can quickly turn into a life-threatening condition called septic shock, where the patient’s blood pressure drops too low.

Cardiogenic Shock

Patients suffering from a severe heart attack are prone to developing a life-threatening condition where the heart muscle can not maintain adequate blood flow to the organs. A cardiogenic shock can cause high lactate levels in the blood (hyperlactatemia) and acidosis. Lactic acidosis secondary to cardiogenic shock requires immediate medical attention.³

Carbon monoxide poisoning leads to oxygen deprivation of the tissues, a condition called tissue hypoxia. Clinicians have noted high levels of serum lactate in patients suffering from carbon monoxide poisoning.⁴

Type B:

Lactic acidosis without hypoxia (or hypoxemia) is categorized as type B lactic acidosis. Based on the underlying cause, type B acidosis is further classified into:

Type B1

This type arises when the body is unable to metabolize lactate. It is generally seen in conditions affecting the normal working of the liver and the kidneys. Lactic acidosis secondary to diabetic ketoacidosis (DKA) is a significant morbidity and falls under the B1 category.⁵ Alcohol abusers and individuals suffering from cancer, HIV/AIDS may also develop this type of acidosis. Convulsions and tonic-clonic seizures can also contribute to a rise in serum lactate levels by altering the electrical activity of the brain.

Lactic acidosis induced by metformin — Uncontrolled diabetes and drugs like metformin can induce type B lactic acidosis

Type B2

Lactic acidosis due to drug/toxin reaction falls under this category. Metformin is a commonly prescribed drug for diabetes that can potentially cause lactic acidosis. Metformin-associated lactic acidosis (MALA) and hyperlactatemia are rare but have high mortality rates. The medicine raises acid levels by affecting mitochondrial respiration and inducing kidney failure.⁶ Other drugs that can have similar adverse effects on lactate levels include propofol (an anesthetic), epinephrine (adrenaline), and linezolid (an antibiotic) etc. Poisoning with alcohol, carbon monoxide, and cyanide can lead to lactic acidosis without inducing hypoxia.

Type B3

This is the rarest of all types and occurs as a congenital condition. Patients with type B3 lactic acidosis lack the enzymes necessary for lactic acid metabolization. Glycogen storage disease is characterized by an inherited deficiency of enzymes needed for glycogen synthesis. Lactic acidosis is a feature of the condition.⁷ Moreover, individuals lacking pyruvate carboxylase, fructase-1,6-diphosphatase, and pyruvate dehydrogenase enzymes can also develop lactic acidosis. Methylmalonic aciduria is an inherited enzyme-deficiency disorder linked to neonatal lactic acidosis.⁸

A rare condition that can cause acidosis is mitochondrial encephalomyopathy with stroke-like episodes (MELAS) in infants. Patients usually present with vomiting, fever, and seizures.

L-Lactate & D-Lactate:

Your body contains two types of lactate, i.e., L-lactate and D-lactate. The above-mentioned types classify the accumulation of the L-type. On the other hand, D-lactate accumulation is rare and occurs when overgrown bacteria in the colon metabolize carbohydrates and deliver the by-product (D-lactate) in the bloodstream. Chronic D-lactic acidosis is frequently associated with short bowel (gut) syndrome.⁹

Lactic Acidosis Symptoms

The excess lactic acid circulating in your body can have multiple presentations, including:

Athelete with muscle pain in legs — An athlete suffers from muscle pain due to exercise-induced lactic acidosis

Muscle Cramps & Pain:

A build-up of lactic acid in the muscles causes pain and cramping. The muscle pain you get during strenuous exercise is because of the acid accumulating in your soft tissues. Muscle ache is an unavoidable feature of acidosis, for which sports athletes adopt strategies to improve performance.¹⁰

Fatigue:

Exhaustion and fatigue are salient features of the acid imbalance. Athletes experience significant fatigue following hard training sessions. Therefore, sportspeople take rest and sports massage to alleviate fatigue associated with raised lactate levels.¹¹

Deep Breathing:

In most cases, lactic acidosis sets in due to a lack of optimal oxygen delivery to the body. Therefore, the body increases the respiratory rate to compensate for the oxygen deficiency. You may unintentionally take deeper breaths. Athletes experience hyperventilation during exercise, which is attributed to hyperlactatemia.¹² A rapid heartbeat mostly accompanies breathing difficulties.
Nausea and vomiting may accompany symptoms like muscle pain, fatigue, and rapid breathing.

Neurological Symptoms:

When the acid levels rise, patients start experiencing neurological issues. You may notice any one (or a combination) of the following symptoms:

Ataxia & Muscle Weakness

An excessive buildup of lactic acid in the body can interfere with the normal coordination of the muscles, i.e., ataxia. You may feel a loss of balance and a generalized clumsiness in the movement of your hands. Speech may also be slurred. There have been cases of ataxia in patients with D-lactic acidosis.¹³ Several patients also report having muscle weakness paired with drowsiness.

Confusion

Most patients with raised serum lactate levels report feeling confused. Delirium and confusion can alter a patient’s state of mind and interfere with normal thinking. This is usually seen in conjunction with other symptoms like gait disturbance and slurred speech.¹⁴

Reduced Urine Output:

The excess of lactate in the body can also affect your urinary output. In a clinical case of fenaminosuf poisoning, the patient developed oliguria along with severe lactic acidosis.¹⁵

Jaundice:

Yellowing of the skin and eyes, i.e., jaundice, can be observed in cases where acidosis arises due to liver impairment. Studies show that impaired liver function due to hepatitis can contribute to the development of lactic acidosis.¹⁶ Liver masses can present with jaundice and lactic acidosis, and may lead to life-threatening consequences.¹⁷

Lactic Acidosis Causes

Lactic acidosis arises either due to overproduction or an underutilization of the acid. Hypoxia, hypoperfusion, enzyme deficiency, and drug abuse are the main underlying mechanisms by which lactate levels rise abruptly.

Your body utilizes oxygen for the production of energy in a process called aerobic metabolism. The body’s oxygen demand is met by perfusion, i.e., influx of oxygen into the blood through the lungs. When enough oxygen is not available to the muscles, the body shifts to anerobic metabolism, and a byproduct of this metabolism is lactic acid. A variety of disorders can deprive the muscles of oxygen. Moreover, your body is capable of getting rid of lactic acid in the body. So, disturbances that hinder the body from flushing out lactate also lead to acid accumulation. Clinicians identify the following conditions that cause lactic acidosis:

Congestive heart failure (and cardiac arrest)
HIV/AIDS
Cancer (especially lymphomas and leukemias)
Sepsis
Short bowel syndrome
Drug use/abuse (alcohol, metformin, acetaminophen)
Tonic-clonic seizures

Lactic Acidosis Diagnosis

After taking a history of your disease, your doctor will order a blood test (blood lactate test) to diagnose the condition. Acidosis is confirmed if blood lactate levels are higher than 4 millimoles per liter. Your blood pH levels are also indicative of the underlying acidic condition. A blood pH below 7.35 also confirms the diagnosis.
Other tests that can be helpful include:

Basic metabolic panel (BMP) or a Comprehensive metabolic panel (CMP): These blood test checks multiple substances (chemicals) in your body to analyze your kidney and liver performance.
Arterial blood gas test: It tests the oxygen saturation, pH, and electrolyte balance in the arterial blood. Another test that measures the pH and electrolyte balance is the anion gap blood test.

Differential Diagnosis:

Lactic Acidosis Vs Metabolic Acidosis

Metabolic acidosis is a wider term used to explain any condition that causes acid accumulation in the body (and a consequent drop in pH), while lactic acidosis specifically refers to a type of metabolic acidosis where lactic acid builds up in the body. Metabolic acidosis can also develop due to decreased bicarbonate levels, whereas lactic acidosis is purely due to excess lactate.

Lactic Acidosis Treatment

Transient, exercise-induced lactic acidosis does not require any special treatment. You can manage the convulsions and muscle cramps following strenuous exercise by taking rest and hydrating yourself. During rest, your body returns to normal aerobic metabolism and breaks down the lactate (in the liver and kidneys).

Patient getting oxygen therapy — Oxygen therapy is administered as an immediate maneuver to lactic acidosis patients with hypoxia

Immediate Management:

In the clinic, the first step in the management of a patient with excessive lactate is to increase the oxygen supply to the muscles. Medical professionals immediately start IV fluids with other resuscitation protocols like oxygen therapy. Sufficient oxygen in the body helps lower the lactate levels (in type A cases).

Long-Term Management:

After immediate treatment, doctors try to figure out the underlying cause of the problem. Usually, a team of healthcare providers investigates the reason. In cases where hypoxia is present, type A causes, i.e., respiratory failure, heart failure, and septic shock, are suspected. These conditions are treated on an emergency basis as they are life-threatening.

Lactic Acidosis Prevention

Diabetic patients taking metformin for disease control need to check their blood pH levels regularly. Moreover, patients suffering from HIV/AIDS or cancer should discuss their medications with the doctor. You should inform your doctor about the development of any new symptoms. As alcohol abuse can lead to acidosis, individuals prone to the disorder should avoid misuse.

Final Word

Lactic acidosis is a condition of excess lactate in the body, which is divided into two types. Type A arises when the body (especially muscles) is deprived of oxygen. This type can develop transiently as a result of strenuous activity or may be indicative of some serious underlying disorder like heart failure, respiratory failure, sepsis, or shock, etc. On the other hand, no hypoxia or hypoxemia is seen in type B, and this develops due to poor metabolization of lactate. Enzyme deficiency and drug poisoning are major contributors to type B lactic acidosis. Morbidities like cancer, HIV/AIDS, tonic-clonic seizures, and short bowel syndrome can cause acidosis.

Patients suffer from muscle pain, cramps, breathing difficulties, fatigue, and confusion. Clinicians diagnose it by checking lactate levels and the pH level of the blood (below 7.35). Immediate treatment involves IV fluids, oxygen therapy, and investigations to find out the underlying cause of acid excess. In long-term management, doctors treat serious issues like sepsis and cardiac/respiratory failure, etc., on an emergency basis.

Refrences

1
Foucher, C. D., & Tubben, R. E. (2023). Lactic acidosis. In StatPearls [Internet]. StatPearls Publishing.
2
Emmett, M., Szerlip, H., Sterns, R. H., & Forman, J. P. (2022). Causes of lactic acidosis. UpToDate. UpToDate.
3
Jentzer, J. C., Schrage, B., Patel, P. C., Kashani, K. B., Barsness, G. W., Holmes Jr, D. R., … & Westermann, D. (2022). Association between the acidemia, lactic acidosis, and shock severity with outcomes in patients with cardiogenic shock. Journal of the American Heart Association, 11(9), e024932.
4
Usul, E., Halıcı, A., & Hoke, M. (2021). The Relationship of Lactate Levels with Carboxyhemoglobin Levels and Clinical Findings in Patients Admitted with Acute Carbon Monoxide Poisoning. Duzce Medical Journal, 23(1), 41-46.
5
Bhat, J. A., Masoodi, S. R., Bhat, M. H., Bhat, H., Ahmad, P. O., & Sood, M. (2021). Lactic acidosis in diabetic ketoacidosis: a marker of severity or alternate substrate for metabolism. Indian Journal of Endocrinology and Metabolism, 25(1), 59-66.
6
Thammavaranucupt, K., Phonyangnok, B., Parapiboon, W., Wongluechai, L., Pichitporn, W., Sumrittivanicha, J., … & Jayanama, K. (2022). Metformin-associated lactic acidosis and factors associated with 30-day mortality. PLoS One, 17(8), e0273678.
7
Hannah, W. B., Derks, T. G., Drumm, M. L., Grünert, S. C., Kishnani, P. S., & Vissing, J. (2023). Glycogen storage diseases. Nature Reviews Disease Primers, 9(1), 46.
8
Sakamoto, O., Ohura, T., Murayama, K., Ohtake, A., Harashima, H., Abukawa, D., … & Kure, S. (2011). Neonatal lactic acidosis with methylmalonic aciduria due to novel mutations in the SUCLG1 gene. Pediatrics International, 53(6), 921-925.
9
Darnell, H., Brenner, A., & Flomenhoft, D. (2024). S4713 Short Bowel Syndrome Resulting in Chronic D-Lactic Acidosis. Official journal of the American College of Gastroenterology| ACG, 119(10S), S2982-S2983.
10
Welis, W., Darni, D., & Mario, D. T. (2023). Sports Massage: How Does It Affect Reducing Lactic Acid Levels in Athletes?. Int. J. Hum. Mov. Sport. Sci, 11(1), 20-26.
11
Ambarawati, N. E. D., Jawi, I. M., Muliarta, I., Linawati, N., Sawitri, A., & Dinata, I. M. K. (2021). The Effect Of Sport Massage Toward The Decrease Of Fatigue. Sport and Fitness Journal, 9(3), 155-160.
12
Meyer, T., Faude, O., Scharhag, J., Urhausen, A., & Kindermann, W. (2004). Is lactic acidosis a cause of exercise induced hyperventilation at the respiratory compensation point?. British journal of sports medicine, 38(5), 622-625.
13
James, P. D., Black, D., Kuper, A., & Saibil, F. (2010). D-lactic acidosis and ataxia in a man with Crohn disease. Cmaj, 182(3), 276-279.
14
Bianchetti, D. G., Amelio, G. S., Lava, S. A., Bianchetti, M. G., Simonetti, G. D., Agostoni, C., … & Milani, G. P. (2018). D-lactic acidosis in humans: systematic literature review. Pediatric Nephrology, 33, 673-681.
15
Wei, W., Lau, W. B., Chen, Y., Hu, X., & Nie, H. (2014). Severe lactic acidosis and acute hepatic and renal insufficiency due to fenaminosulf poisoning. Clinical Toxicology, 52(4), 446-447.
16
Lange, C. M., Bojunga, J., Hofmann, W. P., Wunder, K., Mihm, U., Zeuzem, S., & Sarrazin, C. (2009). Severe lactic acidosis during treatment of chronic hepatitis B with entecavir in patients with impaired liver function. Hepatology, 50(6), 2001-2006.
17
Abdalla, H., & Bernardo, J. F. (2018). The Case| Life-threatening lactic acidosis in a patient with jaundice and liver masses. Kidney International, 93(3), 763-764.

Lactic Acidosis: Diagnosis and Management

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