High Anion Gap Metabolic Acidosis
When acidosis is present on blood tests, the first step in determining the cause is determining the anion gap. If the anion gap is high (>12 mEq/L), there are several potential causes. High anion gap metabolic acidosis is a form of metabolic acidosis characterized by a high anion gap (a medical value based on the concentrations of ions in a patient's serum). An anion gap is usually considered to be high if it is over 12 mEq/L. High anion gap metabolic acidosis is caused generally by acid produced by the body,. More rarely, high anion gap metabolic acidosis may be caused by ingesting methanol or overdosing on aspirin. The Delta Ratio is a formula that can be used to assess elevated anion gap metabolic acidosis and to evaluate whether mixed acid base disorder (metabolic acidosis) is present. The list of agents that cause high anion gap metabolic acidosis is similar to but broader than the list of agents that cause a serum osmolal gap. Causes Causes include: The newest mnemonic was proposed in The Lancet reflecting current causes of anion gap metabolic acidosis: G — glycols (ethylene glycol & propylene glycol) O — oxoproline, a metabolite of paracetamol L — L-lactate, the chemical responsible for lactic acidosis D — D-lactate M — methanol A — aspirin R — renal failure K — ketoacidosis, ketones generated from starvation, alcohol, and diabetic ketoacidosis The mnemonic MUDPILES is commonly used to remember the causes of increased anion gap metabolic acidosis. M — Methanol U — Uremia (chronic kidney failure) D — Diabetic ketoacidosis P — Paracetamol, Propylene glycol (used as an inactive stabilizer in many medications; historically, the "P" also stood for Paraldehyde, though this substance is not commonly used today) I — Infectio Continue reading >>
Gold Mark: An Anion Gap Mnemonic For The 21st Century
A Lancet Editorial1 in 1977, referring to an article entitled “Clinical use of the anion gap”2 opined: “In an age when all too often plasma-electrolyte measurements are ordered without any deliberate judgment being made as to the likely usefulness of the result, it is refreshing to have a reminder of the subtleties involved in the interpretation of this commonest set of clinical-chemistry tests”. We have discovered some new twists over the past 30 years and would like to share an easily remembered mnemonic aid. The metabolic acidoses are generally separated into two categories on the basis of an anion gap calculation (Na+[Cl−HCO3−]): the high-anion-gap metabolic acidoses, and the normal-anion-gap, or hyperchloraemic, metabolic acidoses. Two popular mnemonics are often used to remember the major causes of the high-gap metabolic acidoses. The first is KUSMALE (a useful misspelling of Adolph Kussmaul's name), which represents Ketoacidosis, Uraemia, Salicylate poisoning, Methanol, Aldehyde (paraldehyde), Lactate, and Ethylene glycol. The second is MUD PILES, representing Methanol, Uraemia, Diabetes, Paraldehyde, Iron (and Isoniazid), Lactate, Ethylene glycol, and Salicylate. Metabolic acidosis due to excessive paraldehyde use has become exceedingly rare. Iron and isoniazid are just two of many drugs and toxins that cause hypotension and lactic acidosis (isoniazid can also generate a component of ketoacidosis). Three “new” organic anion-gap-generating acids and acid precursors have been recognised in recent years. They are D-lactic acid, which can occur in some patients with short bowel syndromes; 5-oxoproline (or pyroglutamic acid) associated with chronic paracetamol use, often by malnourished women; and the anion-gap acidosis generated by high-dose propylen Continue reading >>
Medical Mnemonics: Causes Of Anion Gap Metabolic Acidosis – “gold Mark”
The classic mnemonic often used to remember the causes of anion gap metabolic acidosis is “MUDPILES” M – Methanol U – Uremia D – Diabetic ketoacidosis P – Propylene Glycol I – Isoniazid L – Lactic Acidosis E – Ethylene Glycol S – Salicylates More recently a new mnemonic has been suggested to update new our understanding of anion-gap generating acids. The updated mnemonic “GOLD MARK” was proposed in a 2008 article in The Lancet. G – Glycols (ethylene glycol and propylene glycol) O – Oxoproline L – L-Lactate D – D-Lactate M – Methanol A – Aspirin R – Renal Failure K – Ketoacidosis As medicine evolves, so do our Mnemonics. This is the fifth medical mnemonic in our series of Monday Mnemonics. Continue reading >>
OVERVIEW Anion Gap = Na+ – (Cl- + HCO3-) The Anion Gap (AG) is a derived variable primarily used for the evaluation of metabolic acidosis to determine the presence of unmeasured anions The normal anion gap depends on serum phosphate and serum albumin concentrations An elevated anion gap strongly suggests the presence of a metabolic acidosis The normal anion gap varies with different assays, but is typically 4 to 12mmol/L (if measured by ion selective electrode; 8 to 16 if measured by older technique of flame photometry) If AG > 30 mmol/L then metabolic acidosis invariably present If AG 20-29mmol/L then 1/3 will not have a metabolic acidosis K can be added to Na+, but in practice offers little advantage ALBUMIN AND PHOSPHATE the normal anion gap depends on serum phosphate and serum albumin the normal AG = 0.2 x [albumin] (g/L) + 1.5 x [phosphate] (mmol/L) albumin is the major unmeasured anion and contributes almost the whole of the value of the anion gap. every 1g/L decrease in albumin will decrease anion gap by 0.25 mmoles a normally high anion gap acidosis in a patient with hypoalbuminaemia may appear as a normal anion gap acidosis. this is particularly relevant in ICU patients where lower albumin levels are common HIGH ANION GAP METABOLIC ACIDOSIS (HAGMA) HAGMA results from accumulation of organic acids or impaired H+ excretion Causes (LTKR) Lactate Toxins Ketones Renal Causes (CATMUDPILES) CO, CN Alcoholic ketoacidosis and starvation ketoacidosis Toluene Metformin, Methanol Uremia DKA Pyroglutamic acidosis, paracetamol, phenformin, propylene glycol, paraladehyde Iron, Isoniazid Lactic acidosis Ethylene glycol Salicylates Effects of albumin Anion gap may be underesitmated in hypoalbuminaemia, because if albumin decreased by 1g/L then the anion gap decreases by 0.25 Continue reading >>
High Anion Gap Metabolic Acidosis
Abstract In the previous chapter, we presented various causes of high anion gap (AG) metabolic acidosis. For discussion purpose, these causes can be conveniently divided into the following categories: 3. 5-Oxoproline (pyroglutamic acid) Continue reading >>
Clinical Aspects Of The Anion Gap
The anion gap (AG) is a calculated parameter derived from measured serum/plasma electrolyte concentrations. The clinical value of this calculated parameter is the main focus of this article. Both increased and reduced anion gap have clinical significance, but the deviation from normal that has most clinical significance is increased anion gap associated with metabolic acidosis. This reflects the main clinical utility of the anion gap, which is to help in elucidating disturbances of acid-base balance. The article begins with a discussion of the concept of the anion gap, how it is calculated and issues surrounding the anion gap reference interval. CONCEPT OF THE ANION GAP - ITS DEFINITION AND CALCULATION Blood plasma is an aqueous (water) solution containing a plethora of chemical species including some that have a net electrical charge, the result of dissociation of salts and acids in the aqueous medium. Those that have a net positive charge are called cations and those with a net negative charge are called anions; collectively these electrically charged species are called ions. The law of electrochemical neutrality demands that, in common with all solutions, blood serum/plasma is electrochemically neutral so that the sum of the concentration of cations always equals the sum of the concentration of anions . This immutable law is reflected in FIGURE 1, a graphic display of the concentration of the major ions normally present in plasma/serum. It is clear from this that quantitatively the most significant cation in plasma is sodium (Na+), and the most significant anions are chloride (Cl-) and bicarbonate HCO3-. The concentration of these three plasma constituents (sodium, chloride and bicarbonate) along with the cation potassium (K+) are routinely measured in the clinica Continue reading >>
Acid-base And Electrolyte Teaching Case Non–anion Gap Metabolic Acidosis: A Clinical Approach To Evaluation
Acid-base disturbances can result from kidney or nonkidney disorders. We present a case of high-volume ileostomy output causing large bicarbonate losses and resulting in a non–anion gap metabolic acidosis. Non–anion gap metabolic acidosis can present as a form of either acute or chronic metabolic acidosis. A complete clinical history and physical examination are critical initial steps to begin the evaluation process, followed by measuring serum electrolytes with a focus on potassium level, blood gas, urine pH, and either direct or indirect urine ammonium concentration. The present case was selected to highlight the differential diagnosis of a non–anion gap metabolic acidosis and illustrate a systematic approach to this problem. Continue reading >>
Metabolic Acidosis With An Elevated Anion Gap.
Abstract Determining the cause of metabolic acidosis with a high anion gap may present a diagnostic challenge. Possible causes include ketoacidosis, certain toxic ingestions, renal failure and lactic acidosis. Many of these entities present with nausea, vomiting and changes in mental status; however, there are specific hallmarks in the signs, symptoms and laboratory findings that help to differentiate among them. Continue reading >>
Serum Anion Gap In The Differential Diagnosis Of Metabolic Acidosis In Critically Ill Newborns.
Abstract OBJECTIVES: To determine in critically ill newborn infants (1) the range of the serum anion gap without metabolic acidosis and (2) whether the serum anion gap can be used to distinguish newborns with lactic acidosis from those with hyperchloremic metabolic acidosis. STUDY DESIGN: Umbilical arterial blood gases and serum electrolyte and lactate concentrations were measured simultaneously in 210 samples from 63 infants over the first week of life. Metabolic acidosis was defined as a blood base deficit (BD) >4 mmol/L. The anion gap was calculated as [Na(+)] - [C1(-)] - [TCO (2)]. Lactic acidosis was defined as a serum lactate concentration >2 SD above the mean serum lactate concentration in samples without metabolic acidosis. RESULTS: In 89 blood samples with BD <4 mmol/L, serum lactate concentration decreased with postnatal age (r = 0.51). The upper limit of serum lactate concentration was 3.8 mmol/L at less than 48 hours, 2.4 mmol/L between 48 and 96 hours, and 1.5 mmol/L for infants greater than 96 hours of age. The mean serum anion gap +/- 2 SD in 174 samples without lactic acidosis was 8 +/- 4 mmol/L; in 36 samples with lactic acidosis it was 16 +/- 9 mmol/L (P <.0001). Serum anion gap and lactate concentration were poorly correlated for samples without lactic acidosis (r = 0.04) but highly correlated in those with lactic acidosis (r = 0.81, P <.0001). None of the 85 samples with metabolic acidosis but without lactic acidosis had an anion gap >16 mmol/L; only 4 of 36 samples with lactic acidosis had an anion gap <8 meq/L. However, 25 of 36 samples with lactic acidosis had serum anion gaps of 8 to 16 mmol/L. CONCLUSION: In the presence of metabolic acidosis, a serum anion gap >16 mmol/L is highly predictive of lactic acidosis; a serum anion gap <8 is highly pr Continue reading >>
The anion gap is the difference between primary measured cations (sodium Na+ and potassium K+) and the primary measured anions (chloride Cl- and bicarbonate HCO3-) in serum. This test is most commonly performed in patients who present with altered mental status, unknown exposures, acute renal failure, and acute illnesses.  See the Anion Gap calculator. The reference range of the anion gap is 3-11 mEq/L The normal value for the serum anion gap is 8-16 mEq/L. However, there are always unmeasurable anions, so an anion gap of less than 11 mEq/L using any of the equations listed in Description is considered normal. For the urine anion gap, the most prominently unmeasured anion is ammonia. Healthy subjects typically have a gap of 0 to slightly normal (< 10 mEq/L). A urine anion gap of more than 20 mEq/L is seen in metabolic acidosis when the kidneys are unable to excrete ammonia (such as in renal tubular acidosis). If the urine anion gap is zero or negative but the serum AG is positive, the source is most likely gastrointestinal (diarrhea or vomiting).  Continue reading >>
Metabolic Acidosis (increased Anion Gap)
metabolic acidosis (increased anion gap) FREE subscriptions for doctors and students... click here You have 3 open access pages. Increased anion gap: diabetic ketoacidosis starvation ketoacidosis lactic acidosis (types A and B) acidosis of renal failure salicylate poisoning methanol poisoning ammonium chloride Links: diabetic ketoacidosis lactic acidosis acute renal failure (ARF) salicylate poisoning This site is intended for the use of healthcare professionals only. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions. Copyright 2016 Oxbridge Solutions Ltd®. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions Ltd® receives funding from advertising but maintains editorial independence more... GPnotebook stores small data files on your computer called cookies so that we can recognise you and provide you with the best service. If you do not want to receive cookies please do not use GPnotebook. Continue reading >>
High Anion Gap Metabolic Acidosis
Go to: Introduction High anion gap metabolic acidosis (HAGMA) is a subcategory of acidosis of metabolic (i.e., non-respiratory) etiology. Differentiation of acidosis into a particular subtype, whether high anion gap metabolic acidosis or non-anion gap metabolic acidosis (NAGMA), aids in the determination of the etiology and hence appropriate treatment. Go to: Etiology Although there have been many broadly inclusive mnemonic devices for high anion gap metabolic acidosis, the use of "GOLD MARK" has gained popularity for its focus on causes common to the 21st century. Glycols (ethylene glycol, propylene glycol) Oxoproline (pyroglutamic acid, the toxic metabolite of excessive acetaminophen or paracetamol) L-Lactate (standard lactic acid seen in lactic acidosis) D-Lactate (exogenous lactic acid produced by gut bacteria) Methanol (this is inclusive of alcohols in general) Aspirin (salicylic acid) Ketones (diabetic, alcoholic and starvation ketosis) Of note, metformin has been omitted from this list due to a lack of evidence for metformin-induced lactic acidosis. In fact, a Cochrane review found substantial evidence that metformin was not a cause of lactic acidosis. The same could not be said of the older biguanide, phenformin, which does increase the incidence of lactic acidosis by approximately tenfold. Furthermore, the addition of massive rhabdomyolysis would be appropriate given the potentially large amounts of hydrogen ions released by muscle breakdown. Go to: Epidemiology High anion gap metabolic acidosis is one of the most common metabolic derangements seen in critical care patients. Exact numbers are not readily available. Go to: Pathophysiology The most common method of evaluation of metabolic acidosis involves the Henderson-Hasselbalch equation and the Lewis model in Continue reading >>
Recurrent Severe Anion Gap Metabolic Acidosis Secondary To Episodic Ethylene Glycol Intoxication.
Abstract Acute ethylene glycol toxicity and its attendant metabolic derangement is a well described clinical entity. Recurrent severe anion gap metabolic acidosis consequent to episodic ingestion of ethylene glycol has not been previously reported. We present a patient who developed severe anion gap metabolic acidosis with no osmolar gap and hypokalemia, consequent to episodic ethylene glycol ingestion. Modest artifactual elevation of the serum lactic acid level and rapid response to intravenous bicarbonate infusion may serve as diagnostic clues. Consideration of these aberrant features should be included in the clinical assessment of severe anion gap metabolic acidosis. Continue reading >>
Best Case Ever 56 Anion Gap Metabolic Acidosis
In this month’s Best Case Ever on EM Cases Dr. Ross Claybo and Dr. Keerat Grewal tell the story of a patient with a complicated anion gap metabolic acidosis. We discuss how to sort through the differential diagnosis with a better mnemonic than MUDPILES, the controversy around administering sodium bicarbonate for metabolic acidosis, the indications for fomepizole and the value of taking time to to build a therapeutic relationship with your ED patients. Podcast production and sound design by Anton Helman. Show notes by Anton Helman, March 2017 The MUDPILES mnemonic for anion gap metabolic acidosis is out of date Why? Metabolic acidosis due to paraldehyde overdose is exceedingly rare Iron and isoniazid are just two of many drugs and toxins that cause hypotension and lactic acidosis (isoniazid can also generate a component of ketoacidosis). Three “newer” anion-gap-generating acids have been recognised recently: D-lactic acid, which can occur in some patients with short bowel syndromes. 5-oxoproline (or pyroglutamic acid) associated with chronic acetaminophen use. Propylene glycol infusions – solvent used for several IV medications including lorazepam and phenobarbital. The GOLDMARK mnemonic for anion gap metabolic acidosis is more useful GOLDMARK mnemonic for anion gap metabolic acidosis Glycols (ethylene glycol & propylene glycol) Oxoproline (metabolite of acetaminophen) L-lactate D-lactate (acetaminophen, short bowel syndrome, propylene glycol infusions for lorazepam and phenobarbital) Methanol ASA Renal Failure Ketoacidosis (starvation, alcohol and DKA) Osmolar Gap common differential diagnosis Ketoacids (DKA, AKA, starvation ketosis) Alcohols Sepsis Ischemia Sodium bicarbonate for metabolic acidosis: Still controversial The indcations for sodium bicarb for metab Continue reading >>
High Anion Gap Metabolic Acidosis Induced By Cumulation Of Ketones, L- And D-lactate, 5-oxoproline And Acute Renal Failure.
Abstract INTRODUCTION: Frequent causes of high anion gap metabolic acidosis (HAGMA) are lactic acidosis, ketoacidosis and impaired renal function. In this case report, a HAGMA caused by ketones, L- and D-lactate, acute renal failure as well as 5-oxoproline is discussed. CASE PRESENTATION: A 69-year-old woman was admitted to the emergency department with lowered consciousness, hyperventilation, diarrhoea and vomiting. The patient had suffered uncontrolled type 2 diabetes mellitus, underwent gastric bypass surgery in the past and was chronically treated with high doses of paracetamol and fosfomycin. Urosepsis was diagnosed, whilst laboratory analysis of serum bicarbonate concentration and calculation of the anion gap indicated a HAGMA. L-lactate, D-lactate, β-hydroxybutyric acid, acetone and 5-oxoproline serum levels were markedly elevated and renal function was impaired. DISCUSSION: We concluded that this case of HAGMA was induced by a variety of underlying conditions: sepsis, hyperglycaemia, prior gastric bypass surgery, decreased renal perfusion and paracetamol intake. Risk factors for 5-oxoproline intoxication present in this case are female gender, sepsis, impaired renal function and uncontrolled type 2 diabetes mellitus. Furthermore, chronic antibiotic treatment with fosfomycin might have played a role in the increased production of 5-oxoproline. CONCLUSION: Paracetamol-induced 5-oxoproline intoxication should be considered as a cause of HAGMA in patients with female gender, sepsis, impaired renal function or uncontrolled type 2 diabetes mellitus, even when other more obvious causes of HAGMA such as lactate, ketones or renal failure can be identified. Continue reading >>