What is the initial step in managing a patient with secondary amenorrhea (absence of menstruation)?

Initial Management of Secondary Amenorrhea

The initial step in managing a patient with secondary amenorrhea should be a pregnancy test followed by measurement of serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, and thyroid-stimulating hormone (TSH) to identify the underlying cause. 1

Diagnostic Algorithm

1. Pregnancy Test - Must be performed first in all cases of secondary amenorrhea

2. Initial Laboratory Panel:

   • LH and FSH levels
   • Prolactin level
   • TSH level

3. Interpretation of Results:

   • High FSH/LH: Suggests primary ovarian insufficiency
   • Low/normal FSH/LH with normal prolactin: Suggests functional hypothalamic amenorrhea (FHA)
   • Elevated prolactin: Suggests hyperprolactinemia
   • Abnormal TSH: Suggests thyroid dysfunction
   • Normal FSH/LH with signs of hyperandrogenism: Suggests polycystic ovary syndrome (PCOS)

Key Etiologies to Consider

• Functional Hypothalamic Amenorrhea (FHA): Accounts for approximately 20-35% of secondary amenorrhea cases 2

  • Associated with stress, excessive exercise, weight loss, and psychological disorders
  • Characterized by reduced GnRH pulsatility leading to decreased LH and FSH

• Polycystic Ovary Syndrome (PCOS): Common cause of secondary amenorrhea

  • Characterized by hyperandrogenism and polycystic ovarian morphology
  • Requires exclusion of other diagnoses

• Hyperprolactinemia: Important to rule out pituitary adenomas

  • Evaluate for galactorrhea and visual field defects

• Primary Ovarian Insufficiency: Characterized by elevated gonadotropins (FSH/LH)

Important Clinical Assessment Points

• Detailed History:

  • Menstrual pattern before cessation
  • Weight changes (loss of ≥10% body weight in 1 month is high-risk) 2
  • Exercise habits (excessive exercise is a risk factor for FHA)
  • Stress levels and psychological factors
  • Medication use (including contraceptives)
  • Eating behaviors (disordered eating is common in FHA) 2

• Physical Examination:

  • BMI calculation (BMI ≤17.5 kg/m² is high-risk) 2
  • Signs of hyperandrogenism (hirsutism, acne)
  • Galactorrhea
  • Thyroid examination
  • Signs of estrogen deficiency

Specific Investigations Based on Initial Results

• For suspected FHA:

  • Bone mineral density testing if amenorrhea persists >6 months 2
  • Nutritional assessment by a registered sports dietitian if exercise or weight loss-related 2

• For suspected PCOS:

  • Androgen levels (testosterone, DHEAS)
  • Pelvic ultrasound to assess for polycystic ovarian morphology

• For elevated prolactin:

  • Brain imaging to rule out pituitary adenoma

• For abnormal TSH:

  • Complete thyroid function tests (free T4, T3)

Common Pitfalls to Avoid

• Failure to rule out pregnancy - Always the first step regardless of sexual history
• Missing eating disorders - FHA is commonly associated with disordered eating and requires careful assessment
• Overlooking anatomical causes - Outflow tract abnormalities should be considered, especially if there's a history of pelvic surgery
• Premature diagnosis of PCOS - Requires exclusion of other causes of hyperandrogenism and amenorrhea
• Neglecting bone health - Prolonged hypoestrogenism in FHA increases risk of osteoporosis

By following this systematic approach to secondary amenorrhea, clinicians can efficiently identify the underlying cause and initiate appropriate management to prevent long-term complications such as bone loss, endometrial hyperplasia, and infertility.