Differential Diagnosis

The patient's presentation of elevated late-night salivary cortisol levels, hypertension, and osteoporosis of the lumbar spine suggests an underlying endocrine disorder. Here is a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Cushing's Syndrome: The elevated late-night salivary cortisol levels are a strong indicator of Cushing's Syndrome, a condition caused by excess cortisol production. The patient's hypertension and osteoporosis are also consistent with this diagnosis. The slightly elevated adrenocorticotropic hormone (ACTH) level suggests that the excess cortisol production may be due to an ACTH-producing pituitary adenoma (Cushing's disease).

• Other Likely Diagnoses

  • Primary Aldosteronism: Although the primary issue appears to be cortisol-related, primary aldosteronism (Conn's syndrome) can also cause hypertension and could potentially contribute to osteoporosis. However, the direct link to elevated cortisol levels makes this less likely.
  • Pheochromocytoma: This rare tumor of the adrenal gland can cause episodic hypertension and could potentially affect cortisol levels indirectly, but it's less directly linked to the findings of elevated cortisol and osteoporosis.

• Do Not Miss Diagnoses

  • Adrenal Carcinoma: A rare but potentially deadly cause of Cushing's Syndrome, an adrenal carcinoma could explain the elevated cortisol levels. It's crucial to consider this diagnosis due to its severe prognosis and the need for prompt surgical intervention.
  • Familial Cushing's Syndrome: Although rare, familial forms of Cushing's Syndrome can present at a young age and may have a more aggressive course, making early diagnosis critical.

• Rare Diagnoses

  • Ectopic ACTH-producing Tumor: Tumors outside the pituitary gland can produce ACTH, leading to Cushing's Syndrome. This diagnosis is less likely given the patient's age and presentation but should be considered if other tests are inconclusive.
  • Familial Glucocorticoid Resistance: A rare genetic disorder characterized by resistance to glucocorticoids, leading to an increase in ACTH and cortisol production. This condition could explain the elevated cortisol levels but is extremely rare and would require specific genetic testing for diagnosis.