GOLD MARK (better than MUDPILES): Anion Gap Metabolic Acidosis Mnemonic

The GOLD MARK causes are divided into three major pathophysiologic groups based on the source of the acid production:1. 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.2. 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.3. Metabolic Causes → Endogenous Acid Production • L-lactate → Type A (ischemia), Type B (mitochondrial dysfunction) • D-lactate → Short gut syndrome, bacterial overgrowth • Renal Failure → Uremia, organic acids • Ketones → Starvation, alcohol, diabetic ketoacidosis (DKA) • 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:1. 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? → Uremia2. 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).

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