Differential Diagnosis for PCOS, Cushing's, and Adrenal Disorders
The following differential diagnosis is based on laboratory findings and clinical presentation.
- Single most likely diagnosis:
- Polycystic Ovary Syndrome (PCOS): This is often the most likely diagnosis in women of reproductive age presenting with irregular menstrual cycles, hyperandrogenism, and polycystic ovaries on ultrasound. Key lab findings include elevated androgen levels (testosterone, androstenedione), LH/FSH ratio > 2, and insulin resistance.
- Other Likely diagnoses:
- Cushing's Syndrome: Characterized by excess cortisol production, leading to weight gain, hypertension, and hyperglycemia. Lab findings include elevated 24-hour urine free cortisol, midnight cortisol levels, and a failed dexamethasone suppression test.
- Congenital Adrenal Hyperplasia (CAH): A group of autosomal recessive disorders affecting adrenal steroidogenesis. Lab findings include elevated 17-hydroxyprogesterone, androgen levels, and sometimes cortisol deficiency.
- Do Not Miss diagnoses:
- Adrenal Cushing's: Due to an adrenal tumor (adenoma or carcinoma) producing excess cortisol. Lab findings are similar to Cushing's syndrome, but imaging studies (CT or MRI) are crucial for diagnosis.
- Pheochromocytoma: A rare, usually benign tumor of the adrenal medulla, secreting catecholamines. Lab findings include elevated plasma or urine metanephrines, and imaging studies (CT or MRI) are essential for diagnosis.
- Rare diagnoses:
- Adrenal incidentaloma: A non-functioning adrenal tumor discovered incidentally on imaging studies. Most are benign, but some can be malignant. Lab findings are usually normal, but further evaluation is necessary to rule out functioning tumors.
- 11-Beta Hydroxylase Deficiency: A rare form of CAH, leading to excess androgen production and hypertension due to 11-deoxycorticosterone accumulation. Lab findings include elevated 11-deoxycortisol and 11-deoxycorticosterone.