Differential Diagnosis

The patient presents with a complex set of symptoms including seizures, hyperglycemia (blood sugar 593), diplopia, polyphagia, polydipsia, diaphoresis, and a history of recent strokes in the frontal lobe. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Diabetic Ketoacidosis (DKA): The combination of hyperglycemia (blood sugar 593), polyphagia, polydipsia, and diaphoresis strongly suggests DKA, especially in the context of seizures which could be precipitated by the severe metabolic derangement. The recent strokes could be related to the hyperglycemic state or other underlying vascular risk factors.

• Other Likely Diagnoses

  • Hyperosmolar Hyperglycemic State (HHS): Similar to DKA but without significant ketosis, HHS can present with severe hyperglycemia, altered mental status, and seizures. The absence of ketosis does not rule out this diagnosis, and it's particularly concerning in the context of recent strokes.
  • Stroke (with seizures as a complication): Given the patient's history of recent frontal lobe strokes, seizures could be a direct complication of the stroke. The hyperglycemia could be stress-induced or related to the stroke itself.
  • Hypoglycemia (with rebound hyperglycemia): Although the blood sugar is high, if the patient has been experiencing significant swings in blood glucose, hypoglycemic episodes could precipitate seizures and other symptoms, followed by rebound hyperglycemia.

• Do Not Miss Diagnoses

  • Meningitis or Encephalitis: Infections of the central nervous system can present with seizures, altered mental status, and could potentially cause or be exacerbated by hyperglycemia. Given the severity of the presentation, missing this diagnosis could be fatal.
  • Septic Shock: Sepsis can cause hyperglycemia, seizures (through various mechanisms including hypoglycemic episodes, direct cerebral effects, or as part of septic encephalopathy), and could be precipitated by the recent strokes if they led to aspiration or other infections.
  • Cerebral Vasculitis: Although less common, cerebral vasculitis could explain the strokes, seizures, and potentially the hyperglycemia if there's associated systemic inflammation.

• Rare Diagnoses

  • Insulinoma: A rare tumor of the pancreas that produces excess insulin, potentially causing hypoglycemic episodes that could lead to seizures. However, the presentation with hyperglycemia makes this less likely unless there's a complex endocrine disorder.
  • Pituitary Apoplexy: A condition where the pituitary gland suddenly hemorrhages, potentially leading to acute hormonal imbalances, including diabetes insipidus (which could explain polydipsia) and adrenal insufficiency. However, the direct connection to hyperglycemia and seizures is less clear without additional symptoms like acute headache or visual field defects.