Differential Diagnosis

The patient's presentation with altered level of consciousness, likely non-convulsive status epilepticus, diabetic with increased anion gap metabolic acidosis, and a history of hypertension, diabetes, and alcohol use disorder, along with an osmolar gap of 20, suggests a complex clinical picture. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Diabetic Ketoacidosis (DKA) with possible alcohol-related complications: The patient's diabetes, increased anion gap metabolic acidosis, and altered mental status are highly suggestive of DKA. The history of alcohol use disorder could complicate the picture with potential for alcohol withdrawal, intoxication, or other alcohol-related metabolic derangements. The osmolar gap of 20 could be consistent with the presence of ketones or other osmotically active substances.

• Other Likely Diagnoses

  • Alcoholic Ketoacidosis: Given the patient's history of alcohol use disorder, alcoholic ketoacidosis is a strong consideration, especially if the patient has recently reduced or stopped alcohol intake. This condition can also present with an increased anion gap metabolic acidosis and altered mental status.
  • Ethylene Glycol or Methanol Poisoning: Although less common, the presence of an increased anion gap metabolic acidosis and an osmolar gap could suggest ingestion of ethylene glycol or methanol, both of which can cause severe metabolic derangements and altered mental status.
  • Lactic Acidosis: This could be secondary to sepsis, shock, or other causes of tissue hypoperfusion, and is a consideration given the patient's altered level of consciousness and metabolic acidosis.

• Do Not Miss Diagnoses

  • Sepsis: A life-threatening condition that can cause altered mental status, metabolic acidosis, and can be a precipitant for DKA or other metabolic derangements. Sepsis must be considered and ruled out promptly.
  • Intracranial Hemorrhage or Stroke: Given the patient's history of hypertension, these are critical diagnoses not to miss, as they can cause altered mental status and have significant implications for management.
  • Infection (e.g., Meningitis, Encephalitis): Infections of the central nervous system can present with altered mental status and require urgent diagnosis and treatment.

• Rare Diagnoses

  • Ketone Body Production from Other Sources (e.g., starvation ketoacidosis): Though less likely given the patient's diabetes, starvation ketoacidosis could be a consideration if the patient has had significantly reduced oral intake.
  • Other Toxins or Poisonings: Depending on the clinical context and availability of specific tests, other toxins or poisonings could be considered, though they are less likely given the information provided.
  • Mitochondrial Disorders: Rare genetic disorders affecting mitochondrial function could potentially present with episodes of lactic acidosis and altered mental status, but these would be much less common and typically have other distinguishing features.