Match each patient's clinical presentation of secondary amenorrhea with the most likely un… — USMLE Step 2 CK

Match each patient's clinical presentation of secondary amenorrhea with the most likely underlying pathophysiological mechanism.

A $24$ -year-old competitive marathon runner with a BMI of $17.5 \text{ kg/m}^2$ presents with $7$ months of amenorrhea and a thin endometrial stripe on ultrasound.Suppression of hypothalamic gonadotropin-releasing hormone (GnRH) pulsatility
A $33$ -year-old woman presents with $9$ months of amenorrhea and cyclic lower abdominal pain; she had a sharp curettage for retained placental tissue $18$ months ago. FSH and LH are normal.Obliteration of the uterine cavity by fibrous adhesions
A $38$ -year-old woman with a history of pelvic radiation presents with $12$ months of amenorrhea, severe hot flashes, and dyspareunia. Her FSH is $65 \text{ mIU/mL}$ .Accelerated depletion of ovarian follicles leading to estrogen deficiency
A $29$ -year-old woman presents with $6$ months of amenorrhea and bilateral galactorrhea. She recently began taking risperidone for bipolar disorder.Loss of tuberoinfundibular dopaminergic inhibition on lactotrophs

Cevap

The marathon runner matches with GnRH suppression, the patient with prior curettage matches with fibrous adhesions, the patient with prior radiation matches with ovarian follicle depletion, and the patient taking risperidone matches with loss of dopaminergic inhibition.

Each clinical vignette provides classic pathognomonic features for a distinct etiology of secondary amenorrhea. The competitive athlete has functional hypothalamic amenorrhea due to GnRH suppression. The patient with prior D&C and normal hormones has structural outflow obstruction (intrauterine synechiae). The patient with prior radiation and high FSH has primary ovarian insufficiency (follicular depletion). The patient on an antipsychotic has hyperprolactinemia due to dopamine receptor antagonism.

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Analyze the clinical presentation of the competitive marathon runner.

Identify functional hypothalamic amenorrhea.

Low BMI and extreme exercise lead to an energy deficit, which suppresses the hypothalamic-pituitary-ovarian axis directly at the level of the hypothalamus (GnRH).

Analyze the clinical presentation of the woman with prior sharp curettage.

Identify Asherman syndrome.

A history of uterine instrumentation followed by amenorrhea, cyclic pain, and normal gonadotropins strongly suggests structural damage to the endometrium (synechiae).

Analyze the clinical presentation of the woman with a history of pelvic radiation.

Identify primary ovarian insufficiency.

Radiation exposure irreversibly damages ovarian follicles. Low estrogen causes menopausal symptoms, and the lack of negative feedback results in elevated FSH levels.

Analyze the clinical presentation of the woman taking risperidone.

Identify medication-induced hyperprolactinemia.

Antipsychotics block dopamine D2 receptors, thereby removing the tonic inhibitory effect of dopamine on lactotrophs, leading to elevated prolactin which suppresses GnRH.

Anahtar Kavram

Secondary amenorrhea can result from multiple distinct pathophysiological mechanisms, including structural abnormalities (Asherman syndrome), ovarian failure (primary ovarian insufficiency), hypothalamic suppression (functional hypothalamic amenorrhea), and pituitary disruption (hyperprolactinemia).

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