Differential Diagnosis for Alkalosis in a Patient with Fever, Hypotension, and Alcohol Withdrawal

• Single Most Likely Diagnosis
  • Respiratory alkalosis due to hyperventilation from fever and alcohol withdrawal: This is the most likely cause, as fever and alcohol withdrawal can both lead to hyperventilation, resulting in a respiratory alkalosis.
• Other Likely Diagnoses
  • Metabolic alkalosis due to vomiting or nasogastric suction: Patients with alcohol withdrawal may experience vomiting, which can lead to loss of hydrogen ions and a consequent metabolic alkalosis.
  • Metabolic alkalosis due to volume contraction: Hypotension can lead to volume contraction, which can cause a metabolic alkalosis due to increased bicarbonate reabsorption in the kidneys.
• Do Not Miss Diagnoses
  • Meningitis or sepsis causing respiratory alkalosis: Although less likely, these conditions can cause hyperventilation and must be considered due to their high mortality rate if left untreated.
  • Adrenal insufficiency: This condition can cause hypotension and metabolic alkalosis, and is critical to diagnose as it requires prompt treatment with corticosteroids.
• Rare Diagnoses
  • Salicylate toxicity: This can cause a mixed respiratory and metabolic alkalosis, but is less common and typically associated with other symptoms such as tinnitus and altered mental status.
  • Hyperthyroidism: Although rare, hyperthyroidism can cause hyperventilation and a respiratory alkalosis, and should be considered in patients with unexplained fever and tachycardia.