Is 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 >>

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 >>

Severe Lactic Acidosis Reversed By Thiamine Within 24 Hours

Severe lactic acidosis reversed by thiamine within 24 hours 1Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, A-8036 Graz, Austria Karin Amrein: [email protected] ; Werner Ribitsch: [email protected] ; Ronald Otto: [email protected] ; Harald C Worm: [email protected] ; Rudolf E Stauber: [email protected] This article has been cited by other articles in PMC. Thiamine is a water-soluble vitamin that plays a pivotal role in carbohydrate metabolism. In acute deficiency, pyruvate accumulates and is metabolized to lactate, and chronic deficiency may cause polyneuropathy and Wernicke encephalopathy. Classic symptoms include mental status change, ophthalmoplegia, and ataxia but are present in only a few patients [ 1 ]. Critically ill patients are prone to thiamine deficiency because of preexistent malnutrition, increased consumption in high-carbohydrate nutrition, and accelerated clearance in renal replacement. In retrospective [ 2 ] and prospective [ 3 , 4 ] studies, a substantial prevalence of thiamine deficiency has been described in both adult (10% to 20%) and pediatric (28%) patients. Thiamine deficiency may become clinically evident in any type of malnutrition that outlasts thiamine body stores (2 to 3 weeks), including alcoholism, bariatric surgery, or hyperemesis gravidarum, and results in high morbidity and mortality if untreated [ 1 ]. We report the case of a 56-year-old man with profound lactic acidosis that resolved rapidly after thiamine infusion. He was admitted because of a decreased level of consciousness (Glasgow Coma Scale score of 6). Vital signs, including blood pressure, heart rate, and oxygen saturation, were normal. Besides reporting regular alcohol consumption, relatives reported recen Continue reading >>

Treatment Of Lactic Acidosis.

Severe lactic acidosis is often associated with poor prognosis. Recognition and correction of the underlying process is the major step in the treatment of this serious condition. Intravenous administration of sodium bicarbonate has been the mainstay in the treatment of lactic acidosis. Aggressive use of this therapeutic modality, however, can lead to serious complications and should therefore be considered with caution. Peritoneal dialysis and hemodialysis provide large amounts of alkali without causing the hypernatremia or hypervolemia commonly associated with bicarbonate infusion. Peritoneal dialysis with bicarbonate-based dialysate, in particular, appears to be an ideal means of delivering physiologic buffer. Administration of methylene blue was initially thought to increase lactate metabolism by altering the cellular oxidative state. Its subsequent clinical use, however, showed little efficacy. Sodium nitroprusside has been advocated for the treatment of some forms of lactic acidosis as a method of alleviating regional hypoperfusion. Insulin therapy has been found to be quite useful in the treatment of phenformin-associated lactic acidosis and is recommended in this setting. Since dichloroacetate activates pyruvate dehydrogenase and enhances lactate metabolism, it may be a useful adjunct in the treatment of lactic acidosis. Continue reading >>

What Is Lactic Acidosis?: Signs, Symptoms, Causes And Treatment

What is lactic acidosis? It is a condition where lactate builds up in the body which leads to extremely low pH levels in the blood. Normally, your blood is alkaline or slightly basic. Lactic acidosis occurs when your blood is much more acidic than usual. Changes in blood pH levels can adversely affect your body’s organs. Lactic acidosis is a form of metabolic acidosis characterized by excessive accumulation of acid as a result of the body failing to metabolize lactic acidosis. Metabolic acidosis is a medical state that occurs when there is reduced systemic pH because of a decrease in bicarbonate or an increase in hydrogen ion concentration. Accumulation of lactic acids happens when there is inadequate oxygen in the muscles that is required to break down the glycogen and glucose for energy. In a normal body, lactate will exit muscle cells and travel to the liver, where it will be oxidized to pyruvate, and later converted to glucose. Glucose refers to a form of sugar which is one of the main sources of energy for the body. When there is reduced oxygen in the tissue, there will be a build up of lactic acid. This medical condition usually starts in the kidneys. Lactic acidosis normally occurs when the kidneys fail to excrete excess acids from the body. As a result, lactic acid accumulates in the body faster than it is removed. This build up of lactic acid leads to a pH imbalance in the body. There are two forms of lactic acid, that is D-lactate and L-lactate. D-lactate is a form produced in bacterial metabolism and may build up in patients who have had a gastric bypass or have short gut syndrome. On the other hand, L-lactic is produced from human metabolism. Both L-lactic and D-lactic are produced from pyruvate and metabolized to pyruvate by an enzyme known as lactate deh Continue reading >>

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 >>

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 >>

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 >>

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 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 >>

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

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 >>

Lactic Acidosis

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Lactic Acidosis: What You Need To Know

Lactic acidosis is a form of metabolic acidosis that begins in the kidneys. People with lactic acidosis have kidneys that are unable to remove excess acid from their body. If lactic acid builds up in the body more quickly than it can be removed, acidity levels in bodily fluids — such as blood — spike. This buildup of acid causes an imbalance in the body’s pH level, which should always be slightly alkaline instead of acidic. There are a few different types of acidosis. Lactic acid buildup occurs when there’s not enough oxygen in the muscles to break down glucose and glycogen. This is called anaerobic metabolism. There are two types of lactic acid: L-lactate and D-lactate. Most forms of lactic acidosis are caused by too much L-lactate. Lactic acidosis has many causes and can often be treated. But if left untreated, it may be life-threatening. The symptoms of lactic acidosis are typical of many health issues. If you experience any of these symptoms, you should contact your doctor immediately. Your doctor can help determine the root cause. Several symptoms of lactic acidosis represent a medical emergency: fruity-smelling breath (a possible indication of a serious complication of diabetes, called ketoacidosis) confusion jaundice (yellowing of the skin or the whites of the eyes) trouble breathing or shallow, rapid breathing If you know or suspect that you have lactic acidosis and have any of these symptoms, call 911 or go to an emergency room right away. Other lactic acidosis symptoms include: exhaustion or extreme fatigue muscle cramps or pain body weakness overall feelings of physical discomfort abdominal pain or discomfort diarrhea decrease in appetite headache rapid heart rate Lactic acidosis has a wide range of underlying causes, including carbon monoxide poisoni Continue reading >>

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 >>