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Lactic Acidosis Causes

Review Metformin-associated Lactic Acidosis: Current Perspectives On Causes And Risk

Review Metformin-associated Lactic Acidosis: Current Perspectives On Causes And Risk

Abstract Although metformin has become a drug of choice for the treatment of type 2 diabetes mellitus, some patients may not receive it owing to the risk of lactic acidosis. Metformin, along with other drugs in the biguanide class, increases plasma lactate levels in a plasma concentration-dependent manner by inhibiting mitochondrial respiration predominantly in the liver. Elevated plasma metformin concentrations (as occur in individuals with renal impairment) and a secondary event or condition that further disrupts lactate production or clearance (e.g., cirrhosis, sepsis, or hypoperfusion), are typically necessary to cause metformin-associated lactic acidosis (MALA). As these secondary events may be unpredictable and the mortality rate for MALA approaches 50%, metformin has been contraindicated in moderate and severe renal impairment since its FDA approval in patients with normal renal function or mild renal insufficiency to minimize the potential for toxic metformin levels and MALA. However, the reported incidence of lactic acidosis in clinical practice has proved to be very low (< 10 cases per 100,000 patient-years). Several groups have suggested that current renal function cutoffs for metformin are too conservative, thus depriving a substantial number of type 2 diabetes patients from the potential benefit of metformin therapy. On the other hand, the success of metformin as the first-line diabetes therapy may be a direct consequence of conservative labeling, the absence of which could have led to excess patient risk and eventual withdrawal from the market, as happened with earlier biguanide therapies. An investigational delayed-release metformin currently under development could potentially provide a treatment option for patients with renal impairment pending the resu Continue reading >>

Causes Of Lactic Acidosis

Causes Of Lactic Acidosis

INTRODUCTION AND DEFINITION Lactate levels greater than 2 mmol/L represent hyperlactatemia, whereas lactic acidosis is generally defined as a serum lactate concentration above 4 mmol/L. Lactic acidosis is the most common cause of metabolic acidosis in hospitalized patients. Although the acidosis is usually associated with an elevated anion gap, moderately increased lactate levels can be observed with a normal anion gap (especially if hypoalbuminemia exists and the anion gap is not appropriately corrected). When lactic acidosis exists as an isolated acid-base disturbance, the arterial pH is reduced. However, other coexisting disorders can raise the pH into the normal range or even generate an elevated pH. (See "Approach to the adult with metabolic acidosis", section on 'Assessment of the serum anion gap' and "Simple and mixed acid-base disorders".) Lactic acidosis occurs when lactic acid production exceeds lactic acid clearance. The increase in lactate production is usually caused by impaired tissue oxygenation, either from decreased oxygen delivery or a defect in mitochondrial oxygen utilization. (See "Approach to the adult with metabolic acidosis".) The pathophysiology and causes of lactic acidosis will be reviewed here. The possible role of bicarbonate therapy in such patients is discussed separately. (See "Bicarbonate therapy in lactic acidosis".) PATHOPHYSIOLOGY A review of the biochemistry of lactate generation and metabolism is important in understanding the pathogenesis of lactic acidosis [1]. Both overproduction and reduced metabolism of lactate appear to be operative in most patients. Cellular lactate generation is influenced by the "redox state" of the cell. The redox state in the cellular cytoplasm is reflected by the ratio of oxidized and reduced nicotine ad Continue reading >>

Lactic Acid | Michigan Medicine

Lactic Acid | Michigan Medicine

A lactic acid test is a blood test that measures the level of lactic acid made in the body. Most of it is made by muscle tissue and red blood cells . When the oxygen level in the body is normal, carbohydrate breaks down into water and carbon dioxide. When the oxygen level is low, carbohydrate breaks down for energy and makes lactic acid. Lactic acid levels get higher when strenuous exercise or other conditionssuch as heart failure , a severe infection ( sepsis ), or shock lower the flow of blood and oxygen throughout the body. Lactic acid levels can also get higher when the liver is severely damaged or diseased, because the liver normally breaks down lactic acid. Very high levels of lactic acid cause a serious, sometimes life-threatening condition called lactic acidosis. Lactic acidosis can also occur in a person who takes metformin (Glucophage) to control diabetes when heart or kidney failure or a severe infection is also present. A lactic acid test is generally done on a blood sample taken from a vein in the arm but it may also be done on a sample of blood taken from an artery ( arterial blood gas ). Check for lactic acidosis. Symptoms of lactic acidosis include rapid breathing, excessive sweating, cool and clammy skin, sweet-smelling breath, belly pain, nausea or vomiting, confusion, and coma. See whether the right amount of oxygen is reaching the body's tissues. Find the cause for a high amount of acid (low pH ) in the blood. Do not eat or drink anything other than water for 8 to 10 hours before the test. Do not exercise for several hours before the test. Do not clench your fist while having your blood drawn for a lactic acid test. These activities may change the results. The health professional drawing blood will: Wrap an elastic band around your upper arm to stop Continue reading >>

Lactic Acidosis: Background, Etiology, Epidemiology

Lactic Acidosis: Background, Etiology, Epidemiology

Author: Kyle J Gunnerson, MD; Chief Editor: Michael R Pinsky, MD, CM, Dr(HC), FCCP, MCCM more... In basic terms, lactic acid is the normal endpoint of the anaerobic breakdown of glucose in the tissues. The lactate exits the cells and is transported to the liver, where it is oxidized back to pyruvate and ultimately converted to glucose via the Cori cycle. In the setting of decreased tissue oxygenation, lactic acid is produced as the anaerobic cycle is utilized for energy production. With a persistent oxygen debt and overwhelming of the body's buffering abilities (whether from chronic dysfunction or excessive production), lactic acidosis ensues. [ 1 , 2 ] (See Etiology.) Lactic acid exists in 2 optical isomeric forms, L-lactate and D-lactate. L-lactate is the most commonly measured level, as it is the only form produced in human metabolism. Its excess represents increased anaerobic metabolism due to tissue hypoperfusion. (See Workup.) D-lactate is a byproduct of bacterial metabolism and may accumulate in patients with short-gut syndrome or in those with a history of gastric bypass or small-bowel resection. [ 3 ] By the turn of the 20th century, many physicians recognized that patients who are critically ill could exhibit metabolic acidosis unaccompanied by elevation of ketones or other measurable anions. In 1925, Clausen identified the accumulation of lactic acid in blood as a cause of acid-base disorder. Several decades later, Huckabee's seminal work firmly established that lactic acidosis frequently accompanies severe illnesses and that tissue hypoperfusion underlies the pathogenesis. In their classic 1976 monograph, Cohen and Woods classified the causes of lactic acidosis according to the presence or absence of adequate tissue oxygenation. (See Presentationand Differe Continue reading >>

Lactic Acidosis

Lactic Acidosis

Patient professional reference Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use. You may find one of our health articles more useful. Description Lactic acidosis is a form of metabolic acidosis due to the inadequate clearance of lactic acid from the blood. Lactate is a byproduct of anaerobic respiration and is normally cleared from the blood by the liver, kidney and skeletal muscle. Lactic acidosis occurs when the body's buffering systems are overloaded and tends to cause a pH of ≤7.25 with plasma lactate ≥5 mmol/L. It is usually caused by a state of tissue hypoperfusion and/or hypoxia. This causes pyruvic acid to be preferentially converted to lactate during anaerobic respiration. Hyperlactataemia is defined as plasma lactate >2 mmol/L. Classification Cohen and Woods devised the following system in 1976 and it is still widely used:[1] Type A: lactic acidosis occurs with clinical evidence of tissue hypoperfusion or hypoxia. Type B: lactic acidosis occurs without clinical evidence of tissue hypoperfusion or hypoxia. It is further subdivided into: Type B1: due to underlying disease. Type B2: due to effects of drugs or toxins. Type B3: due to inborn or acquired errors of metabolism. Epidemiology The prevalence is very difficult to estimate, as it occurs in critically ill patients, who are not often suitable subjects for research. It is certainly a common occurrence in patients in high-dependency areas of hospitals.[2] The incidence of symptomatic hyperlactataemia appears to be rising as a consequence of the use of antiretroviral therapy to treat HIV infection. It appears to increase in those taking stavudine (d4T) regimens.[3] Causes of lactic acid Continue reading >>

Congenital Lactic Acidosis

Congenital Lactic Acidosis

Causes Most cases of congenital lactic acidosis are caused by one or more inherited mutations of genes within the DNA located within the nucleus (nDNA) or within the mitochondria (mtDNA) of cells. Genes carry the genetic instructions for cells. A mutation is a change in a gene located in nuclear or mitochondrial DNA that may cause disease. Mutations of nDNA, which occur in cellular chromosomes, can be inherited through different forms of transmission of the mutation, including autosomal recessive, autosomal dominant or X-linked recessive inheritance. Mutations affecting the genes for mitochondria (mtDNA) are inherited from the mother. MtDNA that is found in sperm cells is typically lost during fertilization. As a result, all human mtDNA comes from the mother. An affected mother will pass on the mutation to all her children, but only her daughters will pass on the mutation to their children. Mitochondria, which are found by the hundreds or thousands in the cells of the body, particularly in muscle and nerve tissue, carry the blueprints for regulating energy production. As cells divide, the number of normal mtDNA and mutated mtDNA are distributed in an unpredictable fashion among different tissues. Consequently, mutated mtDNA accumulates at different rates among different tissues in the same individual. Thus, family members who have the identical mutation in mtDNA may exhibit a variety of different symptoms and signs at different times and to varying degrees of severity. Pyruvate dehydrogenase complex (PDC) deficiency is a genetic mitochondrial disease of carbohydrate metabolism that is due to a mutation in nDNA. It is generally considered to be the most common cause of biochemically proven cases of congenital lactic acidosis. PDC deficiency can be inherited as an autosom Continue reading >>

Lactic Acidosis

Lactic Acidosis

hyperlactaemia: a level from 2 to 5 mmol/L normal production is 20 mmols/kg/day, enters the circulation and undergoes hepatic and renal metabolism (Cori cycle) all tissues can produce lactate under anaerobic conditions lactic acid has a pK value of about 4 so it is fully dissociated into lactate and H+ at body pH (i.e. it is a strong ion) during heavy exercise, the skeletal muscles contribute most of the much increased circulating lactate during pregnancy, the placenta is an important producer of lactate (can pass to fetus as well) major source in sepsis and ARDS is the lung lactate is metabolised predominantly in the liver (60%) and kidney (30%) the heart can also use lactate for ATP production 50% is converted into glucose (gluconeogenesis) and 50% into CO2 and water (citric acid cycle) this results in no net acid accumulation but requires aerobic metabolism the small amount of lactate that is renally filtered (180mmol/day) is fully reabsorbed (ii) impaired hepatic metabolism of lactate (large capacity to clear) clinically there is often a combination of the above to produce a persistent lactic acidosis anaerobic muscular activity (sprinting, generalised convulsions) tissue hypoperfusion (shock, cardiac arrest, regional hypoperfusion -> mesenteric ischaemia) reduced tissue oxygen delivery (hypoxaemia, anaemia) or utilisation (CO poisoning) Type B No Evidence of Inadequate Tissue Oxygen Delivery once documented the cause must be found and treated appropriately D lactate is isomer of lactate produced by intestinal bacterial and not by humans it is not detected on standard lactate assays a bed side test may be able to be developed to help with diagnosis of mesenteric ischaemia venous samples are equivalent to arterial in clinical practice do not need to take off tourniq Continue reading >>

Lactate And Lactic Acidosis

Lactate And Lactic Acidosis

The integrity and function of all cells depend on an adequate supply of oxygen. Severe acute illness is frequently associated with inadequate tissue perfusion and/or reduced amount of oxygen in blood (hypoxemia) leading to tissue hypoxia. If not reversed, tissue hypoxia can rapidly progress to multiorgan failure and death. For this reason a major imperative of critical care is to monitor tissue oxygenation so that timely intervention directed at restoring an adequate supply of oxygen can be implemented. Measurement of blood lactate concentration has traditionally been used to monitor tissue oxygenation, a utility based on the wisdom gleaned over 50 years ago that cells deprived of adequate oxygen produce excessive quantities of lactate. The real-time monitoring of blood lactate concentration necessary in a critical care setting was only made possible by the development of electrode-based lactate biosensors around a decade ago. These biosensors are now incorporated into modern blood gas analyzers and other point-of-care analytical instruments, allowing lactate measurement by non-laboratory staff on a drop (100 L) of blood within a minute or two. Whilst blood lactate concentration is invariably raised in those with significant tissue hypoxia, it can also be raised in a number of conditions not associated with tissue hypoxia. Very often patients with raised blood lactate concentration (hyperlactatemia) also have a reduced blood pH (acidosis). The combination of hyperlactatemia and acidosis is called lactic acidosis. This is the most common cause of metabolic acidosis. The focus of this article is the causes and clinical significance of hyperlactatemia and lactic acidosis. The article begins with a brief overview of normal lactate metabolism. Normal lactate production and Continue reading >>

Glyburide And Metformin (oral Route)

Glyburide And Metformin (oral Route)

Precautions Drug information provided by: Micromedex It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood tests may be needed to check for unwanted effects. Under certain conditions, too much metformin can cause lactic acidosis. The symptoms of lactic acidosis are severe and quick to appear. They usually occur when other health problems not related to the medicine are present and very severe, such as a heart attack or kidney failure. The symptoms of lactic acidosis include abdominal or stomach discomfort; decreased appetite; diarrhea; fast, shallow breathing; a general feeling of discomfort; muscle pain or cramping; and unusual sleepiness, tiredness, or weakness. If you have any symptoms of lactic acidosis, get emergency medical help right away. It is very important to carefully follow any instructions from your health care team about: Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your health care team. Other medicines—Do not take other medicines unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems. Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about diabetes medicine dosing changes that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy may be needed because of the problems that can occur in patients with diabetes during pregnancy. Travel—Keep your recent prescription and your medical history with yo Continue reading >>

Lactic Acidosis And Exercise: What You Need To Know

Lactic Acidosis And Exercise: What You Need To Know

Muscle ache, burning, rapid breathing, nausea, stomach pain: If you've experienced the unpleasant feeling of lactic acidosis, you likely remember it. It's temporary. It happens when too much acid builds up in your bloodstream. The most common reason it happens is intense exercise. Symptoms The symptoms may include a burning feeling in your muscles, cramps, nausea, weakness, and feeling exhausted. It's your body's way to tell you to stop what you're doing The symptoms happen in the moment. The soreness you sometimes feel in your muscles a day or two after an intense workout isn't from lactic acidosis. It's your muscles recovering from the workout you gave them. Intense Exercise. When you exercise, your body uses oxygen to break down glucose for energy. During intense exercise, there may not be enough oxygen available to complete the process, so a substance called lactate is made. Your body can convert this lactate to energy without using oxygen. But this lactate or lactic acid can build up in your bloodstream faster than you can burn it off. The point when lactic acid starts to build up is called the "lactate threshold." Some medical conditions can also bring on lactic acidosis, including: Vitamin B deficiency Shock Some drugs, including metformin, a drug used to treat diabetes, and all nucleoside reverse transcriptase inhibitor (NRTI) drugs used to treat HIV/AIDS can cause lactic acidosis. If you are on any of these medications and have any symptoms of lactic acidosis, get medical help immediately. Preventing Lactic Acidosis Begin any exercise routine gradually. Pace yourself. Don't go from being a couch potato to trying to run a marathon in a week. Start with an aerobic exercise like running or fast walking. You can build up your pace and distance slowly. Increase the Continue reading >>

Lactic Acidosis

Lactic Acidosis

Lactic acidosis is a medical condition characterized by the buildup of lactate (especially L-lactate) in the body, which results in an excessively low pH in the bloodstream. It is a form of metabolic acidosis, in which excessive acid accumulates due to a problem with the body's metabolism of lactic acid. Lactic acidosis is typically the result of an underlying acute or chronic medical condition, medication, or poisoning. The symptoms are generally attributable to these underlying causes, but may include nausea, vomiting, rapid deep breathing, and generalised weakness. The diagnosis is made on biochemical analysis of blood (often initially on arterial blood gas samples), and once confirmed, generally prompts an investigation to establish the underlying cause to treat the acidosis. In some situations, hemofiltration (purification of the blood) is temporarily required. In rare chronic forms of lactic acidosis caused by mitochondrial disease, a specific diet or dichloroacetate may be used. The prognosis of lactic acidosis depends largely on the underlying cause; in some situations (such as severe infections), it indicates an increased risk of death. Classification[edit] The Cohen-Woods classification categorizes causes of lactic acidosis as:[1] Type A: Decreased tissue oxygenation (e.g., from decreased blood flow) Type B B1: Underlying diseases (sometimes causing type A) B2: Medication or intoxication B3: Inborn error of metabolism Signs and symptoms[edit] Lactic acidosis is commonly found in people who are unwell, such as those with severe heart and/or lung disease, a severe infection with sepsis, the systemic inflammatory response syndrome due to another cause, severe physical trauma, or severe depletion of body fluids.[2] Symptoms in humans include all those of typical m Continue reading >>

What Is A Lactic Acid Blood Test?

What Is A Lactic Acid Blood Test?

It’s a test that measures the amount of lactic acid (also called “lactate”) in your blood. This acid is made in muscle cells and red blood cells. It forms when your body turns food into energy. Your body relies on this energy when its oxygen levels are low. Oxygen levels might drop during an intense workout or when you have an infection or disease. Once you finish your workout or recover from the illness, your lactic acid level tends to go back to normal. But sometimes, it doesn't. Higher-than-normal lactic acid levels can lead to a condition called lactic acidosis. If it’s severe enough, it can upset your body’s pH balance, which indicates the level of acid in your blood. Lactic acidosis can lead to these symptoms: It’s a simple blood test. Your doctor will draw blood from a vein or artery using a needle. In rare cases, he may take a sample of cerebrospinal fluid from your spinal column during a procedure called a spinal tap. Normally, you don’t have to adjust your routine to prepare for the test. If your lactic acid level is normal, you don’t have lactic acidosis. Your cells are making enough oxygen. It also tells your doctor that something other than lactic acidosis is causing your symptoms. He’ll likely order other tests to find out what it is. If your lactic acid level is high, it could be caused by a number of things. Most often, it’s because you have a condition that makes it hard for you to breathe in enough oxygen. Some of these conditions could include: Severe lung disease or respiratory failure Fluid build-up in your lungs Very low red blood cell count (severe anemia) A higher-than-normal lactic acid level in your blood can also be a sign of problems with your metabolism. And, your body might need more oxygen than normal because you have o Continue reading >>

Metformin And Fatal Lactic Acidosis

Metformin And Fatal Lactic Acidosis

Publications Published: July 1998 Information on this subject has been updated. Read the most recent information. Dr P Pillans,former Medical Assessor, Centre for Adverse Reactions Monitoring (CARM), Dunedin Metformin is a useful anti-hyperglycaemic agent but significant mortality is associated with drug-induced lactic acidosis. Significant renal and hepatic disease, alcoholism and conditions associated with hypoxia (eg. cardiac and pulmonary disease, surgery) are contraindications to the use of metformin. Other risk factors for metformin-induced lactic acidosis are sepsis, dehydration, high dosages and increasing age. Metformin remains a major reported cause of drug-associated mortality in New Zealand. Of the 12 cases of lactic acidosis associated with metformin reported to CARM since 1977, 2 occurred in the last year and 8 cases had a fatal outcome. Metformin useful but small risk of potentially fatal lactic acidosis Metformin is a useful therapeutic agent for obese non-insulin dependent diabetics and those whose glycaemia cannot be controlled by sulphonylurea monotherapy. Lactic acidosis is an uncommon but potentially fatal adverse effect. The reported frequency of lactic acidosis is 0.06 per 1000 patient-years, mostly in patients with predisposing factors.1 Examples of metformin-induced lactic acidosis cases reported to CARM include: A 69-year-old man, with renal and cardiac disease, was prescribed metformin due to failing glycaemic control on glibenclamide monotherapy. He was well for six weeks, then developed lactic acidosis and died within 3 days. Post-surgical lactic acidosis caused the death of a 70-year-old man whose metformin was not withdrawn at the time of surgery. A 56-year-old woman, with no predisposing disease, died from lactic acidosis following major Continue reading >>

Lactic Acidosis

Lactic Acidosis

Background In basic terms, lactic acid is the normal endpoint of the anaerobic breakdown of glucose in the tissues. The lactate exits the cells and is transported to the liver, where it is oxidized back to pyruvate and ultimately converted to glucose via the Cori cycle. In the setting of decreased tissue oxygenation, lactic acid is produced as the anaerobic cycle is utilized for energy production. With a persistent oxygen debt and overwhelming of the body's buffering abilities (whether from chronic dysfunction or excessive production), lactic acidosis ensues. [1, 2] (See Etiology.) Lactic acid exists in 2 optical isomeric forms, L-lactate and D-lactate. L-lactate is the most commonly measured level, as it is the only form produced in human metabolism. Its excess represents increased anaerobic metabolism due to tissue hypoperfusion. (See Workup.) D-lactate is a byproduct of bacterial metabolism and may accumulate in patients with short-gut syndrome or in those with a history of gastric bypass or small-bowel resection. [3] By the turn of the 20th century, many physicians recognized that patients who are critically ill could exhibit metabolic acidosis unaccompanied by elevation of ketones or other measurable anions. In 1925, Clausen identified the accumulation of lactic acid in blood as a cause of acid-base disorder. Several decades later, Huckabee's seminal work firmly established that lactic acidosis frequently accompanies severe illnesses and that tissue hypoperfusion underlies the pathogenesis. In their classic 1976 monograph, Cohen and Woods classified the causes of lactic acidosis according to the presence or absence of adequate tissue oxygenation. (See Presentation and Differentials.) The causes of lactic acidosis are listed in the chart below. Go to Acute Lactic Ac Continue reading >>

Chronic Lactic Acidosis In An Adult: A New Syndrome Associated With An Altered Redox State Of Certain Nad/nadh Coupled Reactions - Sciencedirect

Chronic Lactic Acidosis In An Adult: A New Syndrome Associated With An Altered Redox State Of Certain Nad/nadh Coupled Reactions - Sciencedirect

Volume 48, Issue 1 , January 1970, Pages 104-112 Chronic lactic acidosis in an adult: A new syndrome associated with an altered redox state of certain NAD/NADH coupled reactions Author links open overlay panel Karl E.SussmanM.D. Get rights and content Chronically elevated blood lactic acid, pyruvic acid and increased L:P ratios have been found in a twenty-eight year old woman with episodic acidosis. The patient has no other associated disease. Alcohol ingestion increases the hyperlacticacidemia and exacerbates the patient's symptoms of weakness and easy fatiguability. Moderate exercise increases blood lactic acid levels from 3,1 to 10.2 M per ml and lowers arterial blood pH from 7.4 to 7.26. Hyperuricemia is present due to depressed uric acid clearance. Certain NAD/NADH coupled metabolic reactions are clearly shifted towards the reduced state (lactate/pyruvate, -glycerophosphate dihydroxyacetone phosphate and galactose-glucose interconversion). Skeletal muscle and liver demonstrate normal total NAD/NADH content and partition of these pyridine nucleotides. Four members of the patient's maternal family have an abnormal lactate response to the combination of alcohol ingestion and exercise, suggesting that this defect may be an inherited disorder. Continue reading >>

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