Metabolic Acidosis Anion Gap Interpretation

Treat a low bicarbonate as metabolic acidosis only after checking pH and PCO2. Acidemia with reduced bicarbonate supports a primary metabolic acidosis; low pH with elevated PCO2 instead indicates respiratory acidosis. A simultaneous low bicarbonate and an abnormal PCO2 can represent a mixed disorder rather than compensation alone. PubMedPubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - PubMed

Calculate the serum anion gap from the chemistry panel: AG = Na − (Cl + HCO3). The usual potassium-excluded reference interval is 8-12 mEq/L; if potassium is included, the typical interval is 12-16 mEq/L. Use the laboratory's own interval when available, because an isolated value near 12 mEq/L may be normal in one assay and abnormal in another. PubMed+1PubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - PubMedpublications aap82: Ingestions: Diagnosis and Management - AAP Publications

Interpret the gap as a screen for unmeasured anions, not as a substitute for direct measurement of lactate or ketones. Albumin is a major normal unmeasured anion, and albumin-corrected AG has different performance than uncorrected AG for detecting hyperlactatemia in critically ill patients; obtain a concurrent albumin when an apparently normal AG conflicts with the clinical picture. PubMed+1PubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - PubMedPubMedAnion gap, anion gap corrected for albumin, base deficit and unmeasured anions in critically ill patients: implications on the assessment of metabolic acidosis and the diagnosis of hyperlactatemia - PubMed

In high-anion-gap metabolic acidosis, the common actionable branches are lactic acidosis, ketoacidosis, kidney failure, and toxin or drug exposure. Lactate, acetoacetate and beta-hydroxybutyrate, formate, and glycolate are examples of unmeasured anions that widen the gap. BMJ+2BMJOverview of acid-base and electrolyte disorders - Summary of relevant conditions | BMJ Best Practice USScienceDirect8Drug and chemical-induced metabolic acidosis - ScienceDirectPubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - PubMed

Measure lactate promptly when shock, trauma, critical illness, tissue hypoxia, seizures, carbon monoxide or cyanide exposure, biguanide exposure, or impaired oxygen utilization is possible. Severe hyperlactatemia has been defined as lactate greater than 4.0 mmol/L in critically ill cohorts; a lactate above 5 mmol/L with acidemia and increased AG is characteristic of lactic acidosis described in metformin labeling. ScienceDirect+2ScienceDirect8Drug and chemical-induced metabolic acidosis - ScienceDirectendocrinenews endocrine[PDF] Hormone Therapy - Endocrine NewsPubMedAnion gap, anion gap corrected for albumin, base deficit and unmeasured anions in critically ill patients: implications on the assessment of metabolic acidosis and the diagnosis of hyperlactatemia - PubMed

Measure serum or urine ketones in every unexplained high-gap acidosis, including patients without marked hyperglycemia. SGLT2 inhibitor-associated euglycemic DKA is characterized by glucose below 250 mg/dL, pH below 7.3, bicarbonate below 18 mmol/L, and ketosis; fasting, infection, insulin discontinuation, alcohol use, and dehydration are reported triggers. Wolters KluwerWolters KluwerCombined lactic acidosis and ketoacidosis in a... : Cardiovascular Endocrinology & Metabolism In suspected euglycemic DKA, discontinue oral diabetic agents and initiate a DKA protocol with intravenous fluids, potassium replacement, intravenous insulin infusion, and hourly glucose monitoring. Wolters KluwerWolters KluwerSevere euglycemic diabetic ketoacidosis secondary... : Annals of Medicine & Surgery

Attribute a high gap to kidney failure only after measuring lactate and ketones and reviewing exposures. Renal failure is a standard high-gap branch, but concurrent sepsis, ketoacidosis, metformin accumulation, or ingestion may contribute a second process. BMJ+2BMJOverview of acid-base and electrolyte disorders - Summary of relevant conditions | BMJ Best Practice USScienceDirectMetabolic Acidosis - an overview | ScienceDirect TopicsPubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - StatPearls - NCBI

Normal-anion-gap metabolic acidosis is usually hyperchloremic because chloride replaces lost bicarbonate on an approximately equimolar basis. The practical branches are extrarenal bicarbonate loss, renal tubular acidosis, hypoaldosteronism, and exogenous acid or chloride-containing loads. BMJ+2BMJOverview of acid-base and electrolyte disorders - Summary of relevant conditions | BMJ Best Practice USScienceDirectMetabolic Acidosis - an overview | ScienceDirect TopicsScienceDirectSevere Non-Anion Gap Metabolic Acidosis Induced by Topiramate: A Case Report

Start with history and serum potassium. Diarrhea, intestinal fistula, ureterosigmoidostomy, and other gastrointestinal losses favor extrarenal bicarbonate loss. Renal causes include distal, proximal, and type 4 renal tubular acidosis; type 4 RTA and hypoaldosteronism are particularly relevant when hyperkalemia accompanies the acidosis. ScienceDirectScienceDirectMetabolic Acidosis - an overview | ScienceDirect Topics

Review drugs before pursuing rare renal disorders. Topiramate can induce clinically significant hyperchloremic non-gap acidosis; medication-associated acidosis should be suspected when low bicarbonate develops after exposure without a competing gastrointestinal loss or high-gap process. ScienceDirectScienceDirectSevere Non-Anion Gap Metabolic Acidosis Induced by Topiramate: A Case Report

Suspect a mixed disorder when the clinical setting predicts more than one acid load, when lactate and ketones are both elevated, or when respiratory findings are disproportionate to the metabolic process. Systematic assessment of pH, bicarbonate, PCO2, and AG is particularly important in mixed acid-base disorders. PubMedPubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - PubMed

A high AG may coexist with hyperchloremic acidosis, especially after gastrointestinal bicarbonate loss or chloride-rich exposures. Conversely, an elevated osmolar gap can coexist with alcoholic ketoacidosis or lactic acidosis and should not bypass direct testing for lactate and ketones. ScienceDirect+1ScienceDirectMetabolic Acidosis - an overview | ScienceDirect Topicsjournal chestnetA CASE OF KETOACIDOSIS AND LACTIC ACIDOSIS WITH OSMOLAR GAP DUE TO ALCOHOL USE AND STARVATION KETOSIS - CHEST

Trend the same measures used to establish the diagnosis: chemistry-panel bicarbonate and AG, blood gas pH and PCO2 when acidemia is severe or ventilation is unstable, serum lactate when elevated, ketones in ketoacidosis, creatinine in renal dysfunction, and measured osmolality or toxin concentrations when toxic alcohol ingestion is suspected. Toxic-alcohol management uses ongoing metabolic monitoring to guide antidote and extracorporeal treatment duration. Nature+1NatureToxic Alcohol Poisoning and Metabolic Acidosis | Toxicology | Pharmacology and Pharmaceutical Sciences | Health sciences | Topics | Nature IndexPubMedAnion Gap and Non-Anion Gap Metabolic Acidosis - StatPearls - NCBI