A retrospective study in Turkey found that the prevalence of Sheehan’s syndrome was directly proportional to the amount of at-home deliveries each decade. This may be due to previously limited obstetric techniques present in a home environment. For example, an area of improvement in preventing the condition could be an increase in the efficacy of treatment to hypovolemic shock through blood transfusion.Pituitary necrosis may directly result from a lack of blood flow in the hypophyseal artery as a result of pituitary gland enlargement during pregnancy. One cause of pituitary growth associated with the risk of Sheehan’s syndrome is the hyperplasia of lactotrophs (responsible for prolactin production). Ischemia may occur as a result of vasospasm, thrombosis, or vascular compression sometimes as a result of an increase in the amount of lactotroph cells throughout gestation (contributing to the enlargement of the pituitary gland). Necrosis may occur as a result of severe hypotension or shock due to excessive uterine bleeding following childbirth. Sheehan’s syndrome may occur as a result of the arterial constriction and abnormal hypotension in conjunction with an insufficiency to meet the increased demand in blood supply of the pituitary gland seen during pregnancy. This increased blood-flow and metabolic demand is associated with the previously mentioned hyperplasia of lactotrophs.Some possible predisposing factors to Sheehan’s syndrome may include: inherited or acquired disseminated blood coagulation (DIC), restriction pituitary blood supply, small sella size, vasospasm, or thrombosis.
Post-Partum Hemorrhaging (PPH) is believed to be a predictor of Sheehan’s syndrome, so the symptoms of anaemia, obesity, and advanced maternal age may increase the risk of Sheehan Syndrome. Atony of the uterus may be related to PPH that could induce Sheehan’s syndrome. This results in the abnormally prolonged flow of blood to the placenta after delivery. Pathophysiology
Sheehans syndrome is caused by damage to the pituitary, thereby causing a decrease in one or more of the hormones it normally secretes. The anterior pituitary is supplied by a low pressure portal venous system. A 1995 study found that 56.2% of patients with diagnosed Sheehan’s syndrome experienced a loss of all pituitary hormones (with the remaining 43.8% having selective pituitary insufficiency). Since the growth hormone-secreting cells are located at the periphery of the pituitary (and are therefore most likely to be affected by ischemia), all of the patients experienced growth hormone deficiency. Diagnosis
Hormonal assays are conducted to determine a patient has low levels of T4, TSH, estrogen, gonadotropin, cortisol, and ACTH depending on the extent of necrosis. It might be difficult to detect damage to these hormone pathways if hormone levels are at the borderline of the abnormal range. In this case, stimulation tests will be done to determine if the pituitary is responsive to hypothalamic hormones. For example, to determine deficiencies in cortisol release, synthetic ACTH might be administered, and hormonal assays will be conducted to determine the strength of the response. Additionally, MRI of the pituitary and hypothalamus: this helps to exclude tumor or other pathologies.