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Sheehan syndrome, also known as Simmond syndrome, postpartum hypopituitarism or postpartum pituitary gland necrosis, is hypopituitarism (decreased functioning of the pituitary gland), caused by ischemic necrosis due to blood loss and hypovolemic shock during and after childbirth.〔First Aid for the Obstetrics and Gynecology Clerkship, p. 226, PITUITARY (HYPOESTROGENIC AMENORRHEA)〕 ==Signs and symptoms== The various signs and symptoms in Sheehan's syndrome are caused by damage to the pituitary, which causes a decrease in one or more hormones it normally secretes (see Pathophysiology section). In Sheehan's syndrome, one or more of these hormones cannot perform their jobs, so the following problems result. Most common initial symptoms of Sheehan's syndrome are agalactorrhea (absence of lactation) and/or difficulties with lactation.〔 Many women also report amenorrhea or oligomenorrhea after delivery.〔 In some cases, a woman with Sheehan syndrome might be relatively asymptomatic, and the diagnosis is not made until years later, with features of hypopituitarism.〔 Such features include secondary hypothyroidism with tiredness, intolerance to cold, constipation, weight gain, hair loss and slowed thinking, as well as a slowed heart rate and low blood pressure. Another such feature is secondary adrenal insufficiency, which, in the rather chronic case is similar to Addison's disease with symptoms including fatigue, weight loss, hypoglycemia (low blood sugar levels), anemia and hyponatremia (low sodium levels). Such a woman may, however, become acutely exacerbated when her body is stressed by, for example, a severe infection or surgery years after her delivery, a condition equivalent with an Addisonian crisis.〔 The symptoms of adrenal crisis should be treated immediately and can be life-threatening 〔http://www.mayoclinic.org/diseases-conditions/addisons-disease/basics/definition/con-20021340〕 Gonadotropin deficiency will often cause amenorrhea, oligomenorrhea, hot flushes, or decreased libido.〔 Growth hormone deficiency causes many vague symptoms including fatigue and decreased muscle mass. Uncommonly, Sheehan syndrome may also appear acutely after delivery, mainly by hyponatremia.〔 There are several possible mechanisms by which hypopituitarism can result in hyponatremia, including decreased free-water clearance by hypothyroidism, direct syndrome of inappropriate antidiuretic hormone (ADH) hypersecretion, decreased free-water clearance by glucocorticoid deficiency (independent of ADH).〔 The potassium level in these situations is normal, because adrenal production of aldosterone is not dependent on the pituitary.〔 There have also been cases with acute hypoglycemia, presumably from lack of cortisol. The order of frequency of hormone loss has generally been found to be growth hormone, gonadotropins (FSH, LH), adrenocorticotrophin (ACTH) and thyroid stimulating hormone (TSH).〔Rabkin MT & Frantz AG. Hypopituitarism: a study of growth hormone and other endocrine functions. Annals of Internal Medicine 1966 64 1197–1207.〕〔Kelestimur F, Jonsson P, Molvalilar S, Gomez JM, Auernhammer CJ, Colak R, Koltowska-Häggström M, Goth MI. Sheehan's syndrome: baseline characteristics and effect of 2 years of growth hormone replacement therapy in 91 patients in KIMS - Pfizer International Metabolic Database. Eur J Endocrinol. 2005 Apr;152(4):581-7.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sheehan's syndrome」の詳細全文を読む スポンサード リンク
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