Sheehan's Syndrome (Postpartum pituitary gland necrosis).
- High estrogen levels during pregnancy stimulate the growth of the pituitary, causing it to enlarge and become more vascular.
- If significant hypotension occurs while the pituitary is still enlarged (the most common cause is postpartum hemorrhage), ischemic necrosis of the pituitary occurs.
- A deficiency of multiple pituitary hormones (panhypopituitarism) follows this ischemia. Prolactin deficiency is one sequel of the necrosis, which has important symptomatic and diagnostic significance. As prolactin is responsible for milk secretion from the breast, its deficiency leads to a failure to lactate which can be emotionally devastating to women planning on breastfeeding.
- Patients suffering from Sheehan syndrome also commonly have hypothyroidism and hypocortisolism.
Pituitary apoplexy.
- Osmosis
- Pituitary apoplexy refers to acute hemorrhage into the pituitary gland. This condition often occurs in patients with preexisting pituitary adenomas. Typically, chronic symptoms such as headaches and decreased libido, related to the pituitary tumor, are present for months prior to the actual hemorrhage event.
- The bleeding often manifests acutely with severe headache and visual disturbances. Signs of meningeal irritation may also be observed and can mimic subarachnoid hemorrhage. However, subarachnoid hemorrhage can be differentiated from a sellar mass with suprasellar extension by the presence of bitemporal hemianopsia, which only occurs in the latter.
- Patients with pituitary apoplexy can experience cardiovascular collapse due to ACTH deficiency and subsequent adrenocortical insufficiency. Pituitary apoplexy is a medical emergency that necessitates urgent neurosurgical consultation and treatment with glucocorticoid.
Note:
Empty sella syndrome is a condition where the pituitary gland shrinks or becomes flattened, creating a void in the sella turcica, its residing place. When the pituitary gland shrinks or becomes flattened, it cannot be seen on an MRI scan, making the pituitary gland appear as an "empty sella". This condition is often idiopathic and common in obese women.