GOLD MARK (better than MUDPILES): Anion Gap Metabolic Acidosis Mnemonic (7,440.12 MRRM)

The GOLD MARK causes are divided into three major pathophysiologic groups based on the source of the acid production:​ Alcohols (Toxic Ingestions) → Emergency Toxins​ Glycols → Ethylene glycol (antifreeze) and propylene glycol​ Methanol → Windshield washer fluid, homemade alcohol substitutes​ Why grouped together?​ Common in suicide attempts, accidental ingestions, or chronic alcoholics.​ Key labs: Serum osmolality, anion gap, osmolar gap.​ Imaging: Calcium oxalate crystals on urine microscopy (ethylene glycol).​ Treatment: Fomepizole or ethanol (blocks alcohol dehydrogenase), hemodialysis in severe cases.​ OTCs & Medication-Related Causes → Common but Easily Missed​ Oxoproline → Chronic acetaminophen (Tylenol) use, often in malnourished patients​ Aspirin → Salicylates, including bismuth subsalicylate (Pepto-Bismol)​ Why grouped together?​ Often overlooked in chronic users or the elderly.​ Key signs: Tachypnea (respiratory alkalosis), tinnitus (aspirin), altered mental status.​ Key labs: Salicylate level, ABG (mixed acid-base disorder).​ Treatment: Alkalinization (sodium bicarb drip), dialysis for severe cases.​ Metabolic Causes → Endogenous Acid Production​ L-lactate → Type A (ischemia), Type B (mitochondrial dysfunction)…L for Loser anaerobic (super winded loser in the race: anaerobic)​ D-lactate → Short gut syndrome, bacterial overgrowth …GI can think “diet for D”​ Renal Failure → Uremia, organic acids​ Ketones → Starvation, alcohol, diabetic ketoacidosis (DKA) think… Keytones are SAD ​ Why grouped together?​ These involve internal production of acids due to organ dysfunction.​ Key labs:​ Lactate level (for sepsis, ischemia).​ BHB (beta-hydroxybutyrate) for DKA.​ BUN/Cr for renal failure.​ Urinalysis (ketones, glucose, uremia markers).​ Treatment:​ Fluids, treat underlying cause (DKA → insulin drip, renal failure → dialysis).Clinically Important Considerations for EM PhysiciansIn the ED, when a patient has metabolic acidosis with an elevated anion gap, think:​ What is the patient’s history?​ Suicide attempt or confusion? → Alcohols, aspirin​ Chronic Tylenol use or malnourished? → Oxoproline​ Sepsis, shock, ischemia? → L-lactate​ Short gut, diarrhea, recent antibiotics? → D-lactate​ Known diabetes, alcoholism, or fasting? → Ketones​ Chronic kidney disease? → Uremia​ What tests should I order immediately?​ ABG/VBG → Confirms metabolic acidosis.​ Anion gap calculation → Determines if the acidosis is anion gap or non-anion gap.​ Serum osmolality & osmolar gap → Alcohol toxicity (ethylene glycol, methanol).​ Lactate level → Sepsis, ischemia, mitochondrial dysfunction.​ BHB (Beta-hydroxybutyrate) → DKA vs. alcoholic/starvation ketosis.​ Salicylate level & acetaminophen level → Toxic ingestion screening.​ CMP (BUN/Cr, glucose, liver enzymes, electrolytes) → Renal failure, DKA, liver dysfunction.Takeaway: What’s an Emergency?​ Dialysis Emergencies → Methanol, ethylene glycol, severe aspirin toxicity, uremia.​ Toxin Emergencies → Alcohols (treat with fomepizole), salicylates (alkalinization & dialysis).​ Septic Shock / Tissue Hypoxia → Elevated L-lactate = immediate resuscitation with fluids & source control!​ DKA → Fluids, insulin drip, and monitor for electrolyte shifts (esp. potassium).