A 24-year-old woman, gravida 1 para 1, comes to the office for postpartum follow-up 2 weeks after a term vaginal delivery. Her baby is doing well, but she is concerned because she has not yet lactated. The patient knew she would lose weight and be tired after the baby was born, but she feels excessive fatigue and has had significant weight loss. She also has nausea, loss of appetite, and postural dizziness. The patient has no headaches, visual problems, cold intolerance, constipation, or polyuria. On examination, she appears fatigued and has mild pallor. Laboratory tests are drawn the next morning at 8:00 AM, with the following results: Which of the following pathologic processes is most likely responsible for this patient's symptoms?

Question

A 24-year-old woman, gravida 1 para 1, comes to the office for postpartum follow-up 2 weeks after a term vaginal delivery.  Her baby is doing well, but she is concerned because she has not yet lactated.  The patient knew she would lose weight and be tired after the baby was born, but she feels excessive fatigue and has had significant weight loss.  She also has nausea, loss of appetite, and postural dizziness.  The patient has no headaches, visual problems, cold intolerance, constipation, or polyuria.  On examination, she appears fatigued and has mild pallor.  Laboratory tests are drawn the next morning at 8:00 AM, with the following results:  Which of the following pathologic processes is most likely responsible for this patient's symptoms?

Quizplus · Accepted Answer

11ec160b_3915_2142_9249_71ea53cec13d_MD0001_00 This patient has signs of panhypopituitarism with failure of lactation, central hypothyroidism, and adrenal insufficiency. In the setting of a recent delivery, this most likely represents ischemic necrosis of the pituitary gland (Sheehan syndrome). During pregnancy, the pituitary enlarges due to estrogen-induced hyperplasia of the lactotrophs. However, the blood supply to the pituitary does not increase proportionally. As a result, the enlarged pituitary is vulnerable to ischemia in case of systemic hypotension due to peripartum hemorrhage (which this patient likely experienced given her low hemoglobin). The most common manifestation of Sheehan syndrome is failure of lactation due to prolactin deficiency. It also commonly causes hypocortisolism and hypothyroidism. Manifestations of thyroid deficiency may take a few weeks to develop due to the long circulating half-life of thyroxine (5-7 days) and peripheral conversion of thyroxine (T4) to T3. Cortisol deficiency manifests rapidly, however, with nausea, postural hypotension, fatigue, and weight loss. (Choice A) Pituitary apoplexy is due to sudden hemorrhage into the pituitary, usually in the setting of a preexisting pituitary adenoma. It usually presents with acute severe headache, ophthalmoplegia, and altered sensorium. (Choice B) Lymphocytic hypophysitis is the most common inflammatory condition of the pituitary and typically occurs during late pregnancy or the early postpartum period. In contrast to Sheehan syndrome, the presentation is acute with severe headaches and visual field defects. (Choice D) Primary pituitary cancer is extremely rare, although the pituitary is prone to metastases due to its rich vascular supply. These patients typically present with tumor mass effects (eg, headache, bitemporal hemianopsia). (Choice E) Non-malignant infiltrative lesions such as sarcoidosis and histiocytosis X mainly involve the suprasellar region, where they compress the hypothalamus and pituitary stalk. This disrupts the normal hypothalamic dopaminergic suppression of prolactin secretion, leading to increased prolactin levels and possible galactorrhea. Central diabetes insipidus may also be seen with resulting hypernatremia. Educational objective: High estrogen levels during pregnancy cause enlargement of the pituitary gland without a proportional increase in blood supply. Peripartum hypotension can cause ischemic necrosis of the pituitary leading to panhypopituitarism (Sheehan syndrome). Patients commonly develop failure of lactation due to deficiency of prolactin. __________ References: Sheehan's syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/23245206)

A 24-Year-Old Woman, Gravida 1 Para 1, Comes to the Office