Differential Diagnosis for Amenorrhea in a 15-year-old Girl
Single Most Likely Diagnosis
- D. Anovulation: This is the most likely cause given her history of irregular menses, moderate to heavy flow, and a family history of PCOS. Anovulation is common in adolescents, especially in the first few years after menarche, and can be exacerbated by factors such as weight concerns, stress, and a family history of hormonal imbalances.
Other Likely Diagnoses
- C. Polycystic Ovaries: Given her mother's history of PCOS and her own irregular menstrual cycles, polycystic ovaries are a plausible diagnosis. PCOS is a common endocrine disorder among women of reproductive age and can lead to amenorrhea due to anovulation.
- B. Purging Behavior: Although not directly related to the physical findings, her concern about weight and appearance could suggest purging behavior or other eating disorders, which can lead to amenorrhea due to significant weight loss and hormonal imbalance.
- E. Drug-induced Hypogonadism: The use of risperidone, an antipsychotic medication, could potentially affect her menstrual cycle, although this is less common. Some antipsychotics can influence the hypothalamic-pituitary-gonadal axis, leading to hormonal imbalances.
Do Not Miss Diagnoses
- A. Uterine Fibroids: Although less likely in a teenager, uterine fibroids can cause heavy menstrual bleeding and potentially lead to amenorrhea if they significantly affect the uterine cavity. They are a "do not miss" diagnosis due to their potential impact on fertility and the need for surgical intervention.
- F. Primary Ovarian Insufficiency: This condition, formerly known as premature ovarian failure, is a rare but important diagnosis not to miss. It can present with amenorrhea and has significant implications for fertility and long-term health.
Rare Diagnoses
- Other rare causes of amenorrhea, such as congenital adrenal hyperplasia, androgen insensitivity syndrome, or pituitary tumors, are not listed due to the provided information not strongly suggesting these conditions. However, in a comprehensive differential diagnosis, these would be considered, especially if initial evaluations do not reveal a clear cause.