The patient described above displays symptoms consistent with Sheehan's syndrome. Sheehan's syndrome typically results when blood supply to the enlarged anterior pituitary of pregnancy is compromised, resulting in ischemic necrosis which can be caused by obstetric hemorrage, shock, or other triggers leading to decreased perfusion of the anterior pituitary.
In pregnancy, the anterior pituitary grows in size, sometimes reaching more than double its original size. This growth is not accompanied by an increase in vascular perfusion; therefore, events that compromise blood flow to the anterior pituitary (pituitary enlargement compresses blood supply to the gland) have a large impact on the gland, resulting in decreases in FSH, LH, ACTH, TSH, Prolactin, and GH. Hormonal imbalances can lead to the symptoms observed (agalactia, hypotension, weight loss, amenorrhea).
Kelestimur states that Sheehan's syndrome typically occurs due to ischemia of the anterior pituitary as a result of severe postpartum hemorrhage. Both failure of lactation after birth and failure to resume menses after delivery are the most common presenting symptoms.
Anderson and Etches state that postpartum hemorrhage, defined as the loss of more than 500 mL of blood after delivery, occurs in up to 18% of births. Reduction of postpartum hemorrhage is the most important step in preventing the ill effects associated with Sheehan syndrome.
Illustration A contains a flowchart depicting the numerous pathways in which ischemic necrosis of the pituitary can occur.
Answer 2: A prolactinoma would be more consistent with galactorrhea, not agalactia.
Answer 3: In pregnancy, there is an increase in anterior pituitary size.
Answer 4: In primary sella syndrome there is compression of the pituitary. This syndrome would be more consistent with hyperprolactinemia since it may cause the release of the anterior pituitary from hypothalamic inhibition.
Answer 5: In pregnancy, there is an increase in anterior pituitary size without an increase in anterior pituitary bloodflow.
Kelestimur F. Sheehan's syndrome. Pituitary. 2003;6(4)
PMID:15237929 (Link to Abstract)
Anderson JM, Etches D. Prevention and management of postpartum hemorrhage. Am Fam Physician. 2007 Mar 15;75(6)
PMID:17390600 (Link to Abstract)