What is the acid-base disorder diagnosis based on the given electrolyte panel?

Metabolic Acidosis with Elevated Anion Gap

The patient has a metabolic acidosis with an elevated anion gap of 15, indicating an anion gap metabolic acidosis that requires identification of the underlying cause and appropriate treatment.

Acid-Base Analysis

1. Calculate the anion gap:

   • Anion gap = Na⁺ - (Cl⁻ + HCO₃⁻)
   • Anion gap = 139 - (107 + 17) = 15 mEq/L
   • Normal anion gap range: 8-12 mEq/L 1

2. Identify the primary disorder:

   • Low bicarbonate (CO₂) of 17 mEq/L (normal range 22-29 mEq/L)
   • Elevated anion gap of 15 mEq/L
   • These findings confirm a primary metabolic acidosis with elevated anion gap

3. Assess for compensation:

   • Without arterial blood gas data, we cannot fully assess respiratory compensation
   • Expected respiratory compensation would be hyperventilation with decreased PaCO₂

Differential Diagnosis

The elevated anion gap metabolic acidosis can be remembered using the mnemonic MUDPILES:

• M: Methanol intoxication
• U: Uremia (renal failure)
• D: Diabetic ketoacidosis (DKA)
• P: Paraldehyde, Propylene glycol
• I: Isoniazid, Iron
• L: Lactic acidosis
• E: Ethylene glycol
• S: Salicylates, Starvation ketosis

Clinical Approach

1. Initial laboratory assessment should include:

   • Arterial blood gases to confirm pH and assess respiratory compensation
   • Serum ketones and glucose to evaluate for DKA or starvation ketosis
   • Serum lactate to assess for lactic acidosis
   • BUN/creatinine to evaluate renal function
   • Toxicology screen if toxic ingestion suspected
   • Serum osmolality to calculate osmolar gap (for toxic alcohol ingestions) 1

2. Treatment approach:

   • Address the underlying cause of the anion gap metabolic acidosis
   • Fluid resuscitation with isotonic saline at 15-20 mL/kg/hr initially for most causes 1
   • Consider bicarbonate therapy only for severe acidosis (pH <7.2) at 1-2 mEq/kg over 1 hour 1
   • Monitor electrolytes, especially potassium, as treatment of acidosis may cause hypokalemia 2

Special Considerations

• If DKA is suspected (based on hyperglycemia and ketones), insulin therapy and fluid resuscitation are the mainstays of treatment 3
• For toxic alcohol ingestions, consider fomepizole or ethanol and possible hemodialysis 1
• In patients with renal failure, hemodialysis may be necessary to correct the acidosis 1
• Serial monitoring of acid-base status is crucial to assess response to treatment 1

Pitfalls to Avoid

1. Don't administer bicarbonate therapy routinely for metabolic acidosis unless pH is <7.2, as it may cause paradoxical CNS acidosis and other complications 1

2. Don't rely solely on urine ketone testing if DKA is suspected, as it only measures acetoacetic acid and acetone, not β-hydroxybutyrate (the predominant ketone body) 1

3. Don't forget to monitor serum potassium closely during treatment, as correction of acidosis can lead to hypokalemia 2

4. Don't miss mixed acid-base disorders, which are common and may complicate diagnosis and treatment 4

The key to successful management is identifying and treating the underlying cause while supporting the patient through the acute phase of illness.