Differential Diagnosis for Infertility
The patient's presentation suggests a complex interplay of hormonal, reproductive, and possibly metabolic factors contributing to her infertility. The following differential diagnoses are organized into categories based on their likelihood and potential impact on the patient's health.
Single Most Likely Diagnosis
- Polycystic Ovary Syndrome (PCOS): This diagnosis is strongly suggested by the patient's history of irregular menses, difficulty conceiving, recurrent vaginal candidiasis, and the physical finding of thick, dark, velvety plaques under her axillae (likely acanthosis nigricans), which is associated with insulin resistance. The presence of bilaterally enlarged ovaries on pelvic examination further supports this diagnosis.
Other Likely Diagnoses
- Hyperandrogenism: Given the patient's symptoms of irregular periods and signs of hyperandrogenism (which could be part of PCOS or another condition), evaluating and addressing hyperandrogenism is crucial.
- Insulin Resistance: Often associated with PCOS, insulin resistance can contribute to infertility and is suggested by the presence of acanthosis nigricans.
- Ovulatory Dysfunction: This is a broad category that could encompass several specific issues, including those related to PCOS, but it's a key factor in the patient's difficulty conceiving.
Do Not Miss Diagnoses
- Thyroid Dysfunction: Although the TSH level is normal and the thyroid is not enlarged, thyroid dysfunction can sometimes present subtly and is a critical factor in fertility. It's essential to ensure that thyroid function is thoroughly evaluated.
- Pituitary Tumors: Despite normal prolactin levels, any form of pituitary dysfunction could impact fertility. A pituitary tumor could potentially cause hormonal imbalances leading to infertility.
- Endometriosis: Although there's no specific indication of endometriosis (e.g., cervical motion tenderness is absent), it's a common cause of infertility and pelvic pain in women of reproductive age and should be considered.
Rare Diagnoses
- Congenital Adrenal Hyperplasia (CAH): A rare genetic disorder that can cause hyperandrogenism and infertility. It's less likely given the patient's age and presentation but could be considered if other diagnoses are ruled out.
- Cushing's Syndrome: This rare endocrine disorder can cause hyperandrogenism, irregular periods, and infertility, among other symptoms. The presence of acanthosis nigricans might suggest insulin resistance, but Cushing's could also be a differential, albeit less likely.
- Genetic Disorders Affecting Fertility: Various genetic conditions can impact fertility, though they are less common. Given the patient's history of multiple sexual partners and never becoming pregnant, a genetic evaluation might be considered if initial diagnoses are ruled out.