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Is Lactic Acidosis?

Lactic Acidosis

Lactic Acidosis

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Why Does Lactic Acid Build Up In Muscles? And Why Does It Cause Soreness?

Why Does Lactic Acid Build Up In Muscles? And Why Does It Cause Soreness?

As our bodies perform strenuous exercise, we begin to breathe faster as we attempt to shuttle more oxygen to our working muscles. The body prefers to generate most of its energy using aerobic methods, meaning with oxygen. Some circumstances, however—such as evading the historical saber tooth tiger or lifting heavy weights—require energy production faster than our bodies can adequately deliver oxygen. In those cases, the working muscles generate energy anaerobically. This energy comes from glucose through a process called glycolysis, in which glucose is broken down or metabolized into a substance called pyruvate through a series of steps. When the body has plenty of oxygen, pyruvate is shuttled to an aerobic pathway to be further broken down for more energy. But when oxygen is limited, the body temporarily converts pyruvate into a substance called lactate, which allows glucose breakdown—and thus energy production—to continue. The working muscle cells can continue this type of anaerobic energy production at high rates for one to three minutes, during which time lactate can accumulate to high levels. A side effect of high lactate levels is an increase in the acidity of the muscle cells, along with disruptions of other metabolites. The same metabolic pathways that permit the breakdown of glucose to energy perform poorly in this acidic environment. On the surface, it seems counterproductive that a working muscle would produce something that would slow its capacity for more work. In reality, this is a natural defense mechanism for the body; it prevents permanent damage during extreme exertion by slowing the key systems needed to maintain muscle contraction. Once the body slows down, oxygen becomes available and lactate reverts back to pyruvate, allowing continued aero Continue reading >>

Acute Lactic Acidosis

Acute Lactic Acidosis

Author: Bret A Nicks, MD, MHA; Chief Editor: Romesh Khardori, MD, PhD, FACP more... Metabolic acidosis is defined as a state of decreased systemic pH resulting from either a primary increase in hydrogen ion (H+) or a reduction in bicarbonate (HCO3-) concentrations. In the acute state, respiratory compensation of acidosis occurs by hyperventilation resulting in a relative reduction in PaCO2. Chronically, renal compensation occurs by means of reabsorption of HCO3. [ 1 , 2 ] Acidosis arises from an increased production of acids, a loss of alkali, or a decreased renal excretion of acids. The underlying etiology of metabolic acidosis is classically categorized into those that cause an elevated anion gap (AG) (see the Anion Gap calculator) and those that do not. Lactic acidosis, identified by a state of acidosis and an elevated plasma lactate concentration is one type of anion gap metabolic acidosis and may result from numerous conditions. [ 2 , 3 , 4 ] It remains the most common cause of metabolic acidosis in hospitalized patients. The normal blood lactate concentration in unstressed patients is0.5-1 mmol/L. Patients with critical illness can be considered to have normal lactate concentrations of less than 2 mmol/L. Hyperlactatemia is defined as a mild to moderate persistent increase in blood lactate concentration (2-4 mmol/L) without metabolic acidosis, whereas lactic acidosis is characterized by persistently increased blood lactate levels (usually >4-5 mmol/L) in association with metabolic acidosis. [ 1 , 5 ] Elevated lactate levels, while typically thought of as a marker of inadequate tissue perfusion with concurrent shift toward increased anaerobic metabolism, can be present in patients in whom systemic hypoperfusion is not present and therefore should be considered wit 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 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 >>

Metformin-induced Lactic Acidosis: No One Left Behind

Metformin-induced Lactic Acidosis: No One Left Behind

Abstract Metformin is a safe drug when correctly used in properly selected patients. In real life, however, associated lactic acidosis has been repeatedly, although rarely, reported. The term metformin-induced lactic acidosis refers to cases that cannot be explained by any major risk factor other than drug accumulation, usually due to renal failure. Treatment consists of vital function support and drug removal, mainly achieved by renal replacement therapy. Despite dramatic clinical presentation, the prognosis of metformin-induced lactic acidosis is usually surprisingly good. In the previous issue of Critical Care, Friesecke and colleagues demonstrate that the survival rate of patients with severe lactic acidosis due to metformin accumulation can be strikingly higher than expected based on the initial clinical evaluation [1]. Metformin is nowadays the first-line drug of choice for the treatment of adults with type 2 diabetes [2]. This drug is the sixth most frequently prescribed in the USA (> 50 million prescriptions in 2009) and is taken by almost 1.5% of the Italian population [3, 4]. Metformin is a safe drug when correctly used in properly selected patients. In particular, no cases of lactic acidosis (a relatively common side effect of other biguanide compounds) were reported in 347 trials with 70,490 patient-years of metformin use [5]. Real life can differ from research settings, however, and lactic acidosis has been repeatedly, although rarely, observed in patients treated with metformin. The number of inquiries to the Swedish Poison Information Centre for metformin intoxication has increased 10 times during the past decade, with 25 cases of severe lactic acidosis reported in 2007 and 2008 [6]. According to the American Association of Poison Control Centers, metform Continue reading >>

Lactic Acidosis In A Patient With Type 2 Diabetes Mellitus

Lactic Acidosis In A Patient With Type 2 Diabetes Mellitus

Go to: Introduction A 49-year-old man presented to the emergency department complaining of dyspnea for 2 days. He had a history of hypertension, type 2 diabetes mellitus, atrial fibrillation, and a severe dilated cardiomyopathy. He had been hospitalized several times in the previous year for decompensated congestive heart failure (most recently, 1 month earlier). The plasma creatinine concentration was 1.13 mg/dl on discharge. Outpatient medications included insulin, digoxin, warfarin, spironolactone, metoprolol succinate, furosemide (80 mg two times per day; increased from 40 mg daily 1 month earlier), metolazone (2.5 mg daily; added 1 month earlier), and metformin (2500 mg in three divided doses; increased from 1000 mg 1 month earlier). Physical examination revealed an obese man in moderate respiratory distress. The temperature was 36.8°C, BP was 119/83 mmHg, and heart rate was 96 per minute. Peripheral hemoglobin oxygen saturation was 97% on room air, with a respiratory rate of 26 per minute. The heart rhythm was irregularly irregular; there was no S3 or murmur. Jugular venous pressure was about 8 cm. There was 1+ edema at the ankles. A chest radiograph showed cardiomegaly and central venous prominence. The N-terminal pro-B-type natriuretic peptide level was 5137 pg/ml (reference range = 1–138 pg/ml). The peripheral hemoglobin concentration was 12.5 g/dl, the white blood cell count was 12,500/µl (76% granulocytes), and the platelet count was 332,000/µL. Initial plasma chemistries are shown in Table 1. The impression was decompensated congestive heart failure. After administration of furosemide (160 mg intravenously), the urine output increased to 320 ml over the next 1 hour. There was no improvement in the dyspnea. Within 2 hours, the patient’s BP fell to 100/ 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 >>

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 >>

Lactic Acidosis: Symptoms, Causes, And Treatment

Lactic Acidosis: Symptoms, Causes, And Treatment

Lactic acidosis occurs when the body produces too much lactic acid and cannot metabolize it quickly enough. The condition can be a medical emergency. The onset of lactic acidosis might be rapid and occur within minutes or hours, or gradual, happening over a period of days. The best way to treat lactic acidosis is to find out what has caused it. Untreated lactic acidosis can result in severe and life-threatening complications. In some instances, these can escalate rapidly. It is not necessarily a medical emergency when caused by over-exercising. The prognosis for lactic acidosis will depend on its underlying cause. A blood test is used to diagnose the condition. Lactic acidosis symptoms that may indicate a medical emergency include a rapid heart rate and disorientaiton. Typically, symptoms of lactic acidosis do not stand out as distinct on their own but can be indicative of a variety of health issues. However, some symptoms known to occur in lactic acidosis indicate a medical emergency. Lactic acidosis can occur in people whose kidneys are unable to get rid of excess acid. Even when not related to just a kidney condition, some people's bodies make too much lactic acid and are unable to balance it out. Diabetes increases the risk of developing lactic acidosis. Lactic acidosis may develop in people with type 1 and 2 diabetes mellitus , especially if their diabetes is not well controlled. There have been reports of lactic acidosis in people who take metformin, which is a standard non-insulin medication for treating type 2 diabetes mellitus. However, the incidence is low, with equal to or less than 10 cases per 100,000 patient-years of using the drug, according to a 2014 report in the journal Metabolism. The incidence of lactic acidosis is higher in people with diabetes who 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 >>

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 >>

Lactic Acidosis And Exercise

Lactic Acidosis And Exercise

Lactic acid builds up naturally in the muscles during vigorous activity. Sometimes if we've overdone it during a workout or run, the body can't clear lactic acid or lactate quickly enough, and lactic acid levels build up. Lactic acid can irritate muscles, causing discomfort and soreness. Sore muscles after exercising is called delayed onset muscle soreness or DOMS. Lactic acid is just one cause of DOMS. Because lactic acid is removed from muscles between a few hours to under a day after a workout, it can't be blamed for lasting soreness some days after working out. Cooling down or warming down after exercise can help remove the lactic acid as well as letting the heart rate slow down more gradually. Some severe medical conditions can also cause lactic acidosis, which can be dangerous. During exercise, muscles metabolise glucose (sugar) into energy. Muscles receive glucose continually through the blood, and also have their own stores of sugar (called glycogen). Every person has an upper limit of exercise ability, called the anaerobic threshold or lactate threshold. The lactate threshold is basically a measurement of how fit the heart and blood vessels are. With regular exercise training, a persons lactate threshold goes up. Exercising at an intensity level below the lactate threshold produces very little lactic acid and the body quickly clears what is produced. A person can exercise below the lactate threshold for a long time, even for hours. Once the intensity of exercise exceeds the lactate threshold, muscles begin to use glucose inefficiently, through alternative chemical reactions. Lactic acid is produced and can rapidly build up in the blood and muscles. When a person's exercise intensity crosses the lactate threshold the activity rapidly becomes much more difficult Continue reading >>

Lactic Acidosis

Lactic Acidosis

The buildup of lactic acid in the bloodstream. This medical emergency most commonly results from oxygen deprivation in the body’s tissues, impaired liver function, respiratory failure, or cardiovascular disease. It can also be caused by a class of oral diabetes drugs called biguanides, which includes metformin (brand name Glucophage). Another biguanide called phenformin was pulled from the market in the United States in 1977 because of an unacceptably high rate of lactic acidosis associated with its use. Concerns about lactic acidosis also delayed the introduction of metformin to the U.S. market until 1995, despite the fact that it had been widely used for years in other countries. There have been reports of lactic acidosis occurring in people taking metformin, and the U.S. Food and Drug Administration estimates that lactic acidosis occurs in 5 out of every 100,000 people who use metformin for any length of time. However, this risk is much lower than it was in people taking phenformin, and it is not clear whether the episodes of lactic acidosis associated with metformin have actually been due to metformin use. In fact, the lactic acidosis could have been explained by the person’s diabetes and related medical conditions. Nonetheless, diabetes experts recommend that metformin not be used in people with congestive heart failure, kidney disease, or liver disease. They also recommend that it be discontinued (at least temporarily) in people undergoing certain medical imaging tests called contrast studies. Symptoms of lactic acidosis include feeling very weak or tired or having unusual muscle pain or unusual stomach discomfort. 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 >>

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