Differential Diagnosis for a 23-year-old with Fatigue, Nausea, Vomiting, and Excessive Hunger

• Single Most Likely Diagnosis
  • Diabetes Mellitus (Type 1 or 2): This condition is characterized by high blood sugar levels, which can cause symptoms such as excessive hunger (polyphagia), fatigue, nausea, and vomiting. The age and combination of symptoms make this a highly plausible diagnosis.
• Other Likely Diagnoses
  • Gastroenteritis: Inflammation of the stomach and intestines, often due to infection, can lead to nausea, vomiting, and fatigue. Excessive hunger might not be a primary symptom but could occur after periods of vomiting due to the body's need for replenishment.
  • Hypothyroidism: Although less common in young adults, hypothyroidism can cause fatigue, nausea, and changes in appetite, including increased hunger.
  • Anemia: Fatigue and nausea can be symptoms of anemia, and while excessive hunger is not a typical symptom, some forms of anemia (like iron deficiency anemia) might lead to cravings or increased appetite.
• Do Not Miss Diagnoses
  • Diabetic Ketoacidosis (DKA): A serious complication of diabetes that can present with nausea, vomiting, and fatigue. It's crucial to diagnose promptly as it can be life-threatening.
  • Addisonian Crisis: Acute adrenal insufficiency can cause nausea, vomiting, fatigue, and changes in appetite. It's a medical emergency that requires immediate attention.
  • Pregnancy-related Conditions: Morning sickness and increased appetite can be symptoms of pregnancy. Although less likely to cause severe fatigue, it's a critical diagnosis not to miss due to its implications for the patient's health and the pregnancy's outcome.
• Rare Diagnoses
  • Pheochromocytoma: A rare tumor of the adrenal gland that can cause a variety of symptoms, including nausea, vomiting, fatigue, and weight loss despite increased appetite in some cases.
  • Insulinoma: A rare tumor of the pancreas that produces excess insulin, leading to hypoglycemia, which can cause fatigue, nausea, and increased hunger.
  • Rare Metabolic Disorders: Certain genetic disorders affecting metabolism can present with a combination of these symptoms, though they are much less common and would typically be considered after ruling out more prevalent conditions.