Differential Diagnosis for Irregular Periods

The patient's presentation of irregular periods, recent weight gain, and negative pregnancy test can be approached by considering the following categories:

• Single Most Likely Diagnosis

  • Polycystic Ovary Syndrome (PCOS): This is a common endocrine disorder in women of reproductive age, characterized by irregular menstrual cycles, often associated with weight gain, and can be linked to hormonal imbalances. The patient's recent weight gain and irregular periods without other symptoms like heavy bleeding make PCOS a plausible diagnosis.

• Other Likely Diagnoses

  • Thyroid Dysfunction: Both hypothyroidism and hyperthyroidism can cause menstrual irregularities. Weight gain is more commonly associated with hypothyroidism, which could align with the patient's symptoms.
  • Hyperprolactinemia: Elevated prolactin levels can disrupt the normal menstrual cycle, leading to irregular periods. Weight gain can also occur, though it's not a primary symptom.
  • Stress or Lifestyle Changes: Significant stress or changes in lifestyle, including weight gain, can affect the hypothalamic-pituitary-adrenal axis, leading to irregular menstrual cycles.

• Do Not Miss Diagnoses

  • Pituitary Tumor: Although rare, a pituitary tumor (such as a prolactinoma) can cause hyperprolactinemia, leading to menstrual irregularities. It's crucial to consider this diagnosis due to its potential impact on health if left untreated.
  • Premature Ovarian Failure (POF): Now more commonly referred to as Premature Ovarian Insufficiency (POI), this condition involves the loss of function of the ovaries before age 40. It can present with irregular periods and is important to diagnose due to its implications for fertility and long-term health.

• Rare Diagnoses

  • Congenital Adrenal Hyperplasia (CAH): A group of inherited disorders that affect the adrenal glands, CAH can lead to hormonal imbalances that might cause irregular menstrual periods. However, it is less common and typically diagnosed earlier in life.
  • Androgen-Secreting Tumors: Rare tumors that can produce androgens, leading to hormonal imbalances and potentially causing irregular periods. These are uncommon and usually present with additional symptoms such as hirsutism or virilization.