Differentiating Sheehan Syndrome and Asherman Syndrome Based on Withdrawal Bleeding
Sheehan syndrome can have a withdrawal bleed while Asherman syndrome typically cannot due to the fundamental difference in their pathophysiology - Sheehan's affects hormonal production while Asherman's involves physical scarring of the endometrium.
Pathophysiological Differences
Sheehan Syndrome
- Definition: Postpartum pituitary necrosis resulting from severe hemorrhage during childbirth 1
- Mechanism: Ischemic damage to the pituitary gland causing variable degrees of hypopituitarism 2
- Hormonal Effects:
- Most commonly affects growth hormone and prolactin secretion
- Can also affect gonadotropins (FSH/LH), TSH, and ACTH 1
- Hormonal deficiencies may be partial, allowing for fluctuating estrogen levels
Asherman Syndrome
- Definition: Intrauterine adhesions/scarring resulting from uterine instrumentation, typically after pregnancy 3
- Mechanism: Physical scarring of the endometrium causing mechanical obstruction 4
- Structural Effects:
- Destruction of the endometrial lining
- Formation of intrauterine adhesions preventing normal endometrial growth
- Physical barrier to menstrual flow 4
Withdrawal Bleeding Patterns
Sheehan Syndrome
- Can have withdrawal bleeding because:
- The pituitary damage may be partial, allowing for fluctuating estrogen levels
- When given exogenous progesterone, the endometrium that has been primed by residual estrogen can respond with withdrawal bleeding 5
- The progestin challenge test may be positive in up to 60% of women with functional hypothalamic amenorrhea, which shares similarities with Sheehan's 5
Asherman Syndrome
- Cannot typically have withdrawal bleeding because:
- The endometrium is physically scarred or absent in affected areas
- Even with hormonal stimulation, there is no functional endometrium to respond 4
- Physical adhesions prevent the shedding of any endometrial tissue that might grow 3
- Up to 25% of women may have normal menses if adhesions are partial, but withdrawal bleeding is typically absent in moderate to severe cases 4
Diagnostic Implications
Progestin Challenge Test
- Sheehan Syndrome: May show withdrawal bleeding if partial pituitary function remains 5
- Asherman Syndrome: Typically negative regardless of hormonal status due to physical barriers 5
Imaging Findings
- Sheehan Syndrome: MRI shows empty sella or pituitary atrophy 6
- Asherman Syndrome: Hysteroscopy is the gold standard, showing intrauterine adhesions 3
- Hysterosalpingography shows filling defects but is only 16.7% accurate in characterizing intrauterine adhesions 5
Clinical Pearls and Pitfalls
- Important caveat: The absence of withdrawal bleeding is not diagnostic of Asherman syndrome, as severe cases of Sheehan syndrome with complete pituitary failure will also not have withdrawal bleeding
- Diagnostic pitfall: Relying solely on withdrawal bleeding patterns without appropriate imaging can lead to misdiagnosis
- Treatment implications: Hormone replacement therapy is appropriate for Sheehan syndrome 2, while Asherman syndrome requires surgical adhesiolysis 3
Conclusion
The key distinction is that Sheehan syndrome affects hormone production at the pituitary level while potentially preserving the endometrial tissue, allowing for possible withdrawal bleeding with hormone supplementation. In contrast, Asherman syndrome involves physical destruction of the endometrium, preventing withdrawal bleeding regardless of hormonal status.