Review the following clinical presentations and arterial blood gas results. Which primary acid-base disorder best matches each clinical vignette?
- A 22-year-old woman with type 1 diabetes presents with rapid breathing. Arterial blood gas shows pH 7.28, pCO2 28 mmHg, and HCO3 12 mEq/L.High anion gap metabolic acidosis
- A 68-year-old man with severe COPD presents with worsened dyspnea. Arterial blood gas shows pH 7.26, pCO2 65 mmHg, and HCO3 28 mEq/L.Acute respiratory acidosis
- A 19-year-old woman presents with carpopedal spasm during a panic attack. Arterial blood gas shows pH 7.52, pCO2 22 mmHg, and HCO3 20 mEq/L.Acute respiratory alkalosis
- A 55-year-old man with peptic ulcer disease presents with 3 days of intractable vomiting. Arterial blood gas shows pH 7.54, pCO2 48 mmHg, and HCO3 40 mEq/L.Metabolic alkalosis
- A 45-year-old woman presents with 4 days of severe watery diarrhea. Arterial blood gas shows pH 7.31, pCO2 32 mmHg, and HCO3 16 mEq/L. Serum sodium is 140 mEq/L, and chloride is 114 mEq/L.Normal anion gap metabolic acidosis
Answer
The correct matches pair each clinical scenario with its hallmark primary acid-base disturbance: DKA with High anion gap metabolic acidosis; COPD exacerbation with Acute respiratory acidosis; panic attack with Acute respiratory alkalosis; vomiting with Metabolic alkalosis; and diarrhea with Normal anion gap metabolic acidosis.
Each vignette represents a classic primary acid-base disorder. Diabetic ketoacidosis causes a high anion gap metabolic acidosis. Acute COPD exacerbation causes CO2 retention and acute respiratory acidosis. Panic attacks cause hyperventilation and acute respiratory alkalosis. Intractable vomiting causes loss of gastric acid, resulting in metabolic alkalosis. Severe diarrhea causes direct loss of bicarbonate, resulting in a normal anion gap metabolic acidosis.
Step-by-Step Solution
Key Concept
Interpretation of primary acid-base disorders based on arterial blood gas and clinical context.