Differential Diagnoses

The differential diagnoses for the 12-year-old male patient can be categorized as follows:

• Single Most Likely Diagnosis
  • Hypothyroidism (known, stable on treatment): This is the most likely diagnosis as the patient is already being followed by Stanford Endocrinology for hypothyroidism and is on levothyroxine. The patient's symptoms and lab results are consistent with well-controlled hypothyroidism.
• Other Likely Diagnoses
  • Dyslipidemia (possible; lipemic sample noted): The patient's previous lab draw appeared lipemic, which suggests possible dyslipidemia. Obtaining a lipid profile is a reasonable next step.
  • Seasonal allergic rhinitis: The patient has a history of seasonal allergies and is taking cetirizine as needed, which suggests that this condition is likely still present.
• Do Not Miss Diagnoses
  • Prediabetes or type 2 diabetes (screening due to elevated fasting glucose): Although the patient does not have symptoms of diabetes, screening for prediabetes or type 2 diabetes is important due to the elevated fasting glucose.
  • Anemia: Although the patient denies fatigue, anemia could be a contributor to fatigue or other symptoms and should be considered.
  • Thyroid storm or crisis: Although the patient's hypothyroidism is well-controlled, it is essential to consider the possibility of a thyroid storm or crisis, especially if the patient's symptoms worsen or if there are changes in his lab results.
• Rare Diagnoses
  • Other endocrine disorders (e.g., adrenal insufficiency, growth hormone deficiency): Although rare, other endocrine disorders could be considered if the patient's symptoms or lab results are not consistent with hypothyroidism or if he does not respond to treatment.
  • Lipid disorders (e.g., familial hypercholesterolemia): Although rare, lipid disorders could be considered if the patient's lipid profile is abnormal and he has a family history of lipid disorders.