Differential Diagnosis for Elevated FSH, LH, and Testosterone Levels

The given hormone levels are FSH 10.5, LH 7.7, high total testosterone (40 nmol), high SHBG (90), but normal calculated free testosterone. These levels are being considered in the context of oligospermia versus non-obstructive azoospermia.

• Single Most Likely Diagnosis

  • Oligospermia: The presence of high FSH and LH levels with normal calculated free testosterone suggests that the testes are producing sperm, but the sperm count is low. This is more indicative of oligospermia, where there is a reduced sperm count but not a complete absence of sperm.

• Other Likely Diagnoses

  • Hypogonadism: Despite the normal calculated free testosterone, the high LH and FSH levels could indicate a form of hypogonadism where the testes are not responding adequately to gonadotropin stimulation, leading to low sperm production.
  • Testicular dysfunction: The elevated FSH and LH with high total testosterone but normal free testosterone could suggest testicular dysfunction, where the testes are producing testosterone but not functioning properly in terms of sperm production.

• Do Not Miss Diagnoses

  • Pituitary tumors: Although less likely, it's crucial not to miss the possibility of pituitary tumors, especially given the elevated LH and FSH levels. Pituitary tumors can disrupt normal pituitary-gonadal axis function, leading to abnormal hormone levels and potentially affecting sperm production.
  • Androgen resistance syndromes: Conditions like androgen insensitivity syndrome could present with high testosterone levels due to resistance at the receptor level, but this would typically be associated with more significant clinical manifestations and is less likely given the context.

• Rare Diagnoses

  • Congenital adrenal hyperplasia: This is a rare condition that could potentially affect hormone levels, including testosterone, but it would typically present with other significant clinical findings and is not directly indicated by the provided hormone levels.
  • Thyroid disorders: Thyroid dysfunction can affect reproductive hormone levels, but it's less directly related to the specific pattern of FSH, LH, and testosterone levels described, making it a less likely but not impossible consideration.