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:

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.

1. ​ 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.

1. ​ 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 Physicians

In 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? → Uremia

1. ​ 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).