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What Are The Causes Of Metabolic Acidosis And Alkalosis?

Metabolic Alkalosis

Metabolic Alkalosis

Practice Essentials Metabolic alkalosis is a primary increase in serum bicarbonate (HCO3-) concentration. This occurs as a consequence of a loss of H+ from the body or a gain in HCO3-. In its pure form, it manifests as alkalemia (pH >7.40). As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension (PaCO2), which diminishes the change in pH that would otherwise occur. Normally, arterial PaCO2 increases by 0.5-0.7 mm Hg for every 1 mEq/L increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in PaCO2 is not within this range, then a mixed acid-base disturbance occurs. For example, if the increase in PaCO2 is more than 0.7 times the increase in bicarbonate, then metabolic alkalosis coexists with primary respiratory acidosis. Likewise, if the increase in PaCO2 is less than the expected change, then a primary respiratory alkalosis is also present. The first clue to metabolic alkalosis is often an elevated bicarbonate concentration that is observed when serum electrolyte measurements are obtained. Remember that an elevated serum bicarbonate concentration may also be observed as a compensatory response to primary respiratory acidosis. However, a bicarbonate concentration greater than 35 mEq/L is almost always caused by metabolic alkalosis. Metabolic alkalosis is diagnosed by measuring serum electrolytes and arterial blood gases. If the etiology of metabolic alkalosis is not clear from the clinical history and physical examination, including drug use and the presence of hypertension, then a urine chloride ion concentration can be obtained. Calculation of the serum anion gap may also help to differentiate between primary metabolic alkalosis and metabolic compe Continue reading >>

Metabolic Acidosis And Alkalosis

Metabolic Acidosis And Alkalosis

Page Index Metabolic Acidosis. Metabolic Alkalosis Emergency Therapy Treating Metabolic Acidosis Calculating the Dose Use Half the Calculated Dose Reasons to Limit the Bicarbonate Dose: Injected into Plasma Volume Fizzes with Acid Causes Respiratory Acidosis Raises Intracellular PCO2 Subsequent Residual Changes Metabolic Acidosis. The following is a brief summary. For additional information visit: E-Medicine (Christie Thomas) or Wikepedia Etiology: There are many causes of primary metabolic acidosis and they are commonly classified by the anion gap: Metabolic Acidosis with a Normal Anion Gap: Longstanding diarrhea (bicarbonate loss) Uretero-sigmoidostomy Pancreatic fistula Renal Tubular Acidosis Intoxication, e.g., ammonium chloride, acetazolamide, bile acid sequestrants Renal failure Metabolic Acidosis with an Elevated Anion Gap: lactic acidosis ketoacidosis chronic renal failure (accumulation of sulfates, phosphates, uric acid) intoxication, e.g., salicylates, ethanol, methanol, formaldehyde, ethylene glycol, paraldehyde, INH, toluene, sulfates, metformin. rhabdomyolysis For further details visit: E-Medicine (Christie Thomas). Treating Severe Metabolic Acidosis. The ideal treatment for metabolic acidosis is correction of the underlying cause. When urgency dictates more rapid correction, treatment is based on clinical considerations, supported by laboratory evidence. The best measure of the level of metabolic acidosis is the Standard Base Excess (SBE) because it is independent of PCO2. If it is decided to administer bicarbonate, the SBE and the size of the treatable space are used to calculate the dose required: Metabolic Alkalosis Etiology: Primary Metabolic alkalosis may occur from various causes including: Loss of acid via the urine, stools, or vomiting Transfer of Continue reading >>

Metabolic Acidosis

Metabolic Acidosis

Metabolic acidosis is primary reduction in bicarbonate (HCO3−), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly subnormal. Metabolic acidoses are categorized as high or normal anion gap based on the presence or absence of unmeasured anions in serum. Causes include accumulation of ketones and lactic acid, renal failure, and drug or toxin ingestion (high anion gap) and GI or renal HCO3− loss (normal anion gap). Symptoms and signs in severe cases include nausea and vomiting, lethargy, and hyperpnea. Diagnosis is clinical and with ABG and serum electrolyte measurement. The cause is treated; IV sodium bicarbonate may be indicated when pH is very low. Acidemia (arterial pH < 7.35) results when acid load overwhelms respiratory compensation. Causes are classified by their effect on the anion gap (see The Anion Gap and see Table: Causes of Metabolic Acidosis). High anion gap acidosis Ketoacidosis is a common complication of type 1 diabetes mellitus (see diabetic ketoacidosis), but it also occurs with chronic alcoholism (see alcoholic ketoacidosis), undernutrition, and, to a lesser degree, fasting. In these conditions, the body converts from glucose to free fatty acid (FFA) metabolism; FFAs are converted by the liver into ketoacids, acetoacetic acid, and beta-hydroxybutyrate (all unmeasured anions). Ketoacidosis is also a rare manifestation of congenital isovaleric and methylmalonic acidemia. Lactic acidosis is the most common cause of metabolic acidosis in hospitalized patients. Lactate accumulation results from a combination of excess formation and decreased utilization of lactate. Excess lactate production occurs during states of anaerobic metabolism. The most serious form occurs during the various types o Continue reading >>

Extreme Metabolic Alkalosis In Intensive Care

Extreme Metabolic Alkalosis In Intensive Care

Go to: Case Reports A 60-year-old man presented to the emergency department with the complaints of weakness, difficulty in breathing, decreased appetite and absolute constipation for ten days. He was restless and disoriented. Hemodynamic parameters were normal. Investigations and systemic examination revealed severe metabolic alkalosis (pH 7.66) with dyselectrolytemia and volume depletion [Tables 1 and 2]. His respiratory and neurologic systems were unremarkable. The abdomen was distended and multiple fluid and air levels seen on an abdominal radiogram, confirmed sub acute intestinal obstruction. Despite denials of use of any diuretics or laxatives, when his regular medicines were checked, loop diuretics and combinations with potassium sparing diuretics were recovered-confirming long term diuretic abuse. All diuretics were removed from patient's bedside and patient was hydrated to achieve a central venous pressure (CVP) of at least 10 cm water (opening CVP 1 cm water) and a urine output of more than 1 ml/kg/hour. Obstipation was relieved by manual evacuation of hard dried up faeces - the cause of sub acute intestinal obstruction. Supplementation of potassium, chloride, sodium and magnesium led to improvement of serum electrolytes and resolution of alkalemia over 36 hours [Table 2]. The patient's respiratory distress, weakness and lassitude resolved. Patient was discharged after four days without any complains. Arterial Blood Gas values Continue reading >>

Alkalosis

Alkalosis

Your blood is made up of acids and bases. The amount of acids and bases in your blood can be measured on a pH scale. It’s important to maintain the correct balance between acids and bases. Even a slight change can cause health problems. Normally, your blood should have a slightly higher amount of bases than acids. Alkalosis occurs when your body has too many bases. It can occur due to decreased blood levels of carbon dioxide, which is an acid. It can also occur due to increased blood levels of bicarbonate, which is a base. This condition may also be related to other underlying health issues such as low potassium, or hypokalemia. The earlier it’s detected and treated, the better the outcome is. Acid-base balance » There are five main types of alkalosis. Respiratory alkalosis Respiratory alkalosis occurs when there isn’t enough carbon dioxide in your bloodstream. It’s often caused by: hyperventilation, which commonly occurs with anxiety high fever lack of oxygen salicylate poisoning being in high altitudes Metabolic alkalosis Metabolic alkalosis develops when your body loses too much acid or gains too much base. This can be attributed to: excess vomiting, which causes electrolyte loss overuse of diuretics a large loss of potassium or sodium in a short amount of time antacids accidental ingestion of bicarbonate, which can be found in baking soda laxatives alcohol abuse Hypochloremic alkalosis Hypochloremic alkalosis occurs when there’s a significant decline of chloride in your body. This can be due to prolonged vomiting or sweating. Chloride is an important chemical needed to maintain balance in bodily fluids, and it’s an essential part of your body’s digestive fluids. Hypokalemic alkalosis Hypokalemic alkalosis occurs when your body lacks the normal amount Continue reading >>

Causes Of Metabolic Alkalosis

Causes Of Metabolic Alkalosis

INTRODUCTION Metabolic alkalosis, a disorder that elevates the serum bicarbonate, can result from several mechanisms: intracellular shift of hydrogen ions; gastrointestinal loss of hydrogen ions; excessive renal hydrogen ion loss; administration and retention of bicarbonate ions; or volume contraction around a constant amount of extracellular bicarbonate (contraction alkalosis) (table 1) [1-4]. Hydrogen ions are derived from the dissociation of water into hydrogen and hydroxyl ions; therefore, when hydrogen ions are removed from the extracellular fluid, the remaining hydroxyl ion combines with carbon dioxide to form bicarbonate. Gastrointestinal and renal hydrogen loss is usually accompanied by the loss of chloride and potassium, resulting in hypochloremia and hypokalemia. Patients with preserved renal function will most often rapidly excrete excess bicarbonate in the urine. Thus, metabolic alkalosis can only persist if the ability to excrete excess bicarbonate in the urine is impaired due to one of the following causes: hypovolemia; reduced effective arterial blood volume (due, for example, to heart failure or cirrhosis); chloride depletion; hypokalemia; reduced glomerular filtration rate; hyperaldosteronism; or combinations of these factors [3,5,6]. The causes of metabolic alkalosis will be reviewed here. The pathogenesis, evaluation, and treatment of this disorder are discussed separately. (See "Pathogenesis of metabolic alkalosis" and "Clinical manifestations and evaluation of metabolic alkalosis" and "Treatment of metabolic alkalosis".) INTRACELLULAR SHIFT OF HYDROGEN Metabolic alkalosis can be generated by a shift of hydrogen ions into the cells. This most often occurs in patients with potassium deficits and hypokalemia. This may be an important pathophysiologic m Continue reading >>

Chapter 47. Acidosis And Alkalosis

Chapter 47. Acidosis And Alkalosis

Systemic arterial pH is maintained between 7.35 and 7.45 by extracellular and intracellular chemical buffering together with respiratory and renal regulatory mechanisms. The control of arterial CO2 tension (Paco2) by the central nervous system (CNS) and respiratory systems and the control of the plasma bicarbonate by the kidneys stabilize the arterial pH by excretion or retention of acid or alkali. The metabolic and respiratory components that regulate systemic pH are described by the Henderson-Hasselbalch equation: Under most circumstances, CO2 production and excretion are matched, and the usual steady-state Paco2 is maintained at 40 mmHg. Underexcretion of CO2 produces hypercapnia, and overexcretion causes hypocapnia. Nevertheless, production and excretion are again matched at a new steady-state Paco2. Therefore, the Paco2 is regulated primarily by neural respiratory factors and is not subject to regulation by the rate of CO2 production. Hypercapnia is usually the result of hypoventilation rather than of increased CO2 production. Increases or decreases in Paco2 represent derangements of neural respiratory control or are due to compensatory changes in response to a primary alteration in the plasma [HCO3−]. The kidneys regulate plasma [HCO3−] through three main processes: (1) “reabsorption” of filtered HCO3−, (2) formation of titratable acid, and (3) excretion of NH4+ in the urine. The kidney filters ∼4000 mmol of HCO3− per day. To reabsorb the filtered load of HCO3−, the renal tubules must therefore secrete 4000 mmol of hydrogen ions. Between 80 and 90% of HCO3− is reabsorbed in the proximal tubule. The distal nephron reabsorbs the remainder and secretes H+ to defend systemic pH. While this quantity of protons, 40–60 mmol/d, is small, it must be sec Continue reading >>

Metabolic Acidosis Nclex Review Notes

Metabolic Acidosis Nclex Review Notes

Are you studying metabolic acidosis and need to know a mnemonic on how to remember the causes? This article will give you a clever mnemonic and simplify the signs and symptoms and nursing interventions on how to remember metabolic acidosis for nursing lecture exams and NCLEX. In addition, you will learn how to differentiate metabolic acidosis from metabolic alkalosis. Don’t forget to take the metabolic acidosis and metabolic alkalosis quiz. This article will cover: Metabolic acidosis simplified Lab values expected with metabolic acidosis Causes of metabolic acidosis Signs and symptoms of metabolic acidosis Nursing interventions for metabolic acidosis Lecture on Metabolic Acidosis Metabolic Acidosis Metabolic Acidosis in Simple Terms: a metabolic problem due to the buildup of acid in the body fluids which affects the bicarbonate (HCO3 levels) either from: increased acid production (ex: DKA where ketones (acids) increase in the body which decreases bicarbonate) decreased acid excretion (ex: renal failure where there is high amount of waste left in the body which causes the acids to increase and bicarb can’t control imbalance) loss of too much bicarb (diarrhea) When this acidic phenomena is taking place in the body other systems will try to compensate to increase the bicarb back to normal. One system that tries to compensate is the respiratory system. In order to compensate, the respiratory system will cause the body to hyperventilate by increasing breathing through Kussmaul’s respirations. Kussmaul respirations are deep, rapid breathes. The body hopes this will help expel CO2 (an acid) which will “hopefully” increase the pH back to normal. Lab values expected in Metabolic Acidosis: HCO3: decreased <22 Blood pH: decreased <7.35 CO2: <35 or normal (may be normal b Continue reading >>

Alkalosis

Alkalosis

The kidneys and lungs maintain the proper balance (proper pH level) of chemicals called acids and bases in the body. Decreased carbon dioxide (an acid) level or increased bicarbonate (a base) level makes the body too alkaline, a condition called alkalosis. There are different types of alkalosis. These are described below. Respiratory alkalosis is caused by a low carbon dioxide level in the blood. This can be due to: Fever Being at a high altitude Lack of oxygen Liver disease Metabolic alkalosis is caused by too much bicarbonate in the blood. It can also occur due to certain kidney diseases. Hypochloremic alkalosis is caused by an extreme lack or loss of chloride, such as from prolonged vomiting. Hypokalemic alkalosis is caused by the kidneys' response to an extreme lack or loss of potassium. This can occur from taking certain water pills (diuretics). Compensated alkalosis occurs when the body returns the acid-base balance to normal in cases of alkalosis, but bicarbonate and carbon dioxide levels remain abnormal. Continue reading >>

Acid-base Balance

Acid-base Balance

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 the Arterial Blood Gases article more useful, or one of our other health articles. Disorders of acid-base balance can lead to severe complications in many disease states.[1]Arterial blood pH is normally closely regulated to between 7.35 and 7.45. Maintaining the pH within these limits is achieved by bicarbonate, other buffers, the lungs and the kidneys. Primary changes in bicarbonate are metabolic and primary changes in carbon dioxide are respiratory. In the absence of any significant respiratory disease or hyperventilation, the primary cause is much more likely to be metabolic. However, central hypoventilation (eg, caused by CNS disturbance such as stroke, head injury or brain tumour) causes respiratory acidosis. In general, the kidneys compensate for respiratory causes and the lungs compensate for metabolic causes. Therefore, hyperventilation may be a cause of respiratory alkalosis or a compensatory mechanism for metabolic acidosis. Deep sighing respiration (Kussmaul breathing) is a common feature of acidosis (hyperventilation in an attempt to remove carbon dioxide) but may take some hours to appear. Investigations Analysis of arterial blood gases provides: pH: determines whether there is an overall acidosis or alkalosis. Venous pH is in practice as reliable as arterial pH. Carbon dioxide partial pressure (PaCO2): if raised with acidosis then the acidosis is respiratory. If decreased with alkalosis then the alkalosis is respiratory. Otherwise any change is compensatory. Standard bicarbonate (SBCe): analysis of blood gases provides a bicarbonate level whic Continue reading >>

What Is Metabolic Acidosis?

What Is Metabolic Acidosis?

Metabolic acidosis happens when the chemical balance of acids and bases in your blood gets thrown off. Your body: Is making too much acid Isn't getting rid of enough acid Doesn't have enough base to offset a normal amount of acid When any of these happen, chemical reactions and processes in your body don't work right. Although severe episodes can be life-threatening, sometimes metabolic acidosis is a mild condition. You can treat it, but how depends on what's causing it. Causes of Metabolic Acidosis Different things can set up an acid-base imbalance in your blood. Ketoacidosis. When you have diabetes and don't get enough insulin and get dehydrated, your body burns fat instead of carbs as fuel, and that makes ketones. Lots of ketones in your blood turn it acidic. People who drink a lot of alcohol for a long time and don't eat enough also build up ketones. It can happen when you aren't eating at all, too. Lactic acidosis. The cells in your body make lactic acid when they don't have a lot of oxygen to use. This acid can build up, too. It might happen when you're exercising intensely. Big drops in blood pressure, heart failure, cardiac arrest, and an overwhelming infection can also cause it. Renal tubular acidosis. Healthy kidneys take acids out of your blood and get rid of them in your pee. Kidney diseases as well as some immune system and genetic disorders can damage kidneys so they leave too much acid in your blood. Hyperchloremic acidosis. Severe diarrhea, laxative abuse, and kidney problems can cause lower levels of bicarbonate, the base that helps neutralize acids in blood. Respiratory acidosis also results in blood that's too acidic. But it starts in a different way, when your body has too much carbon dioxide because of a problem with your lungs. Continue reading >>

Metabolic Alkalosis

Metabolic Alkalosis

Metabolic alkalosis is primary increase in bicarbonate (HCO3−) with or without compensatory increase in carbon dioxide partial pressure (Pco2); pH may be high or nearly normal. Common causes include prolonged vomiting, hypovolemia, diuretic use, and hypokalemia. Renal impairment of HCO3− excretion must be present to sustain alkalosis. Symptoms and signs in severe cases include headache, lethargy, and tetany. Diagnosis is clinical and with ABG and serum electrolyte measurement. The underlying condition is treated; oral or IV acetazolamide or hydrochloric acid is sometimes indicated. Metabolic alkalosis is bicarbonate HCO3− accumulation due to Regardless of initial cause, persistence of metabolic alkalosis indicates that the kidneys have increased their HCO3− reabsorption, because HCO3− is normally freely filtered by the kidneys and hence excreted. Volume depletion and hypokalemia are the most common stimuli for increased HCO3− reabsorption, but any condition that elevates aldosterone or mineralocorticoids (which enhance sodium [Na] reabsorption and potassium [K] and H+ excretion) can elevate HCO3−. Thus, hypokalemia is both a cause and a frequent consequence of metabolic alkalosis. Causes are listed; the most common are volume depletion (particularly when involving loss of gastric acid and chloride [Cl] due to recurrent vomiting or nasogastric suction) and diuretic use (see Table: Causes of Metabolic Alkalosis). Causes of Metabolic Alkalosis Cause Comments GI acid loss* Gastric acid loss due to vomiting or nasogastric suction Loss of HCl and acid coupled with contraction alkalosis due to release of aldosterone and subsequent resorption of HCO3 Congenital chloridorrhea Fecal Cl loss and HCO3 retention Villous adenoma Probably secondary to K depletion Renal a Continue reading >>

Acidosis

Acidosis

When your body fluids contain too much acid, it’s known as acidosis. Acidosis occurs when your kidneys and lungs can’t keep your body’s pH in balance. Many of the body’s processes produce acid. Your lungs and kidneys can usually compensate for slight pH imbalances, but problems with these organs can lead to excess acid accumulating in your body. The acidity of your blood is measured by determining its pH. A lower pH means that your blood is more acidic, while a higher pH means that your blood is more basic. The pH of your blood should be around 7.4. According to the American Association for Clinical Chemistry (AACC), acidosis is characterized by a pH of 7.35 or lower. Alkalosis is characterized by a pH level of 7.45 or higher. While seemingly slight, these numerical differences can be serious. Acidosis can lead to numerous health issues, and it can even be life-threatening. There are two types of acidosis, each with various causes. The type of acidosis is categorized as either respiratory acidosis or metabolic acidosis, depending on the primary cause of your acidosis. Respiratory acidosis Respiratory acidosis occurs when too much CO2 builds up in the body. Normally, the lungs remove CO2 while you breathe. However, sometimes your body can’t get rid of enough CO2. This may happen due to: chronic airway conditions, like asthma injury to the chest obesity, which can make breathing difficult sedative misuse deformed chest structure Metabolic acidosis Metabolic acidosis starts in the kidneys instead of the lungs. It occurs when they can’t eliminate enough acid or when they get rid of too much base. There are three major forms of metabolic acidosis: Diabetic acidosis occurs in people with diabetes that’s poorly controlled. If your body lacks enough insulin, keton Continue reading >>

Metabolic Acidosis: Causes, Symptoms, And Treatment

Metabolic Acidosis: Causes, Symptoms, And Treatment

The Terrible Effects of Acid Acid corrosion is a well-known fact. Acid rain can peel the paint off of a car. Acidifying ocean water bleaches and destroys coral reefs. Acid can burn a giant hole through metal. It can also burn holes, called cavities, into your teeth. I think I've made my point. Acid, regardless of where it's at, is going to hurt. And when your body is full of acid, then it's going to destroy your fragile, soft, internal organs even more quickly than it can destroy your bony teeth and chunks of thick metal. What Is Metabolic Acidosis? The condition that fills your body with proportionately too much acid is known as metabolic acidosis. Metabolic acidosis refers to a physiological state characterized by an increase in the amount of acid produced or ingested by the body, the decreased renal excretion of acid, or bicarbonate loss from the body. Metabolism is a word that refers to a set of biochemical processes within your body that produce energy and sustain life. If these processes go haywire, due to disease, then they can cause an excess production of hydrogen (H+) ions. These ions are acidic, and therefore the level of acidity in your body increases, leading to acidemia, an abnormally low pH of the blood, <7.35. The pH of the blood mimics the overall physiological state in the body. In short, a metabolic process is like a power plant producing energy. If a nuclear power plant goes haywire for any reason, then we know what the consequences will be: uncontrolled and excessive nuclear energetic reactions leading to the leakage of large amounts of radioactive material out into the environment. In our body, this radioactive material is acid (or hydrogen ions). Acidemia can also occur if the kidneys are sick and they do not excrete enough hydrogen ions out of th Continue reading >>

Disorders Of Acid-base Balance

Disorders Of Acid-base Balance

Learning Objectives By the end of this section, you will be able to: Identify the three blood variables considered when making a diagnosis of acidosis or alkalosis Identify the source of compensation for blood pH problems of a respiratory origin Identify the source of compensation for blood pH problems of a metabolic/renal origin Normal arterial blood pH is restricted to a very narrow range of 7.35 to 7.45. A person who has a blood pH below 7.35 is considered to be in acidosis (actually, “physiological acidosis,” because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal. Acidosis has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued. A person who has a blood pH above 7.45 is considered to be in alkalosis, and a pH above 7.8 is fatal. Some symptoms of alkalosis include cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting. Both acidosis and alkalosis can be caused by either metabolic or respiratory disorders. As discussed earlier in this chapter, the concentration of carbonic acid in the blood is dependent on the level of CO2 in the body and the amount of CO2 gas exhaled through the lungs. Thus, the respiratory contribution to acid-base balance is usually discussed in terms of CO2 (rather than of carbonic acid). Remember that a molecule of carbonic acid is lost for every molecule of CO2 exhaled, and a molecule of carbonic acid is formed for every molecule of CO2 retained. Metabolic Acidosis: Primary Bicarbonate Deficiency Metabolic acidosis occurs when the blood is too acidic (pH below 7.35) due to too little bicarbonate, a condition called primary bicar Continue reading >>

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