| Sheehan syndrome | |
|---|---|
| Classification and external resources | |
| ICD-10 | E23.0 |
| ICD-9 | 253.2 |
| DiseasesDB | 11998 |
| MedlinePlus | 001175 |
| eMedicine | med/1914 |
| MeSH | D007018 |
Sheehan syndrome, also known as Simmonds' syndrome or postpartum hypopituitarism or postpartum pituitary necrosis, is hypopituitarism (decreased functioning of the pituitary gland), caused by necrosis due to blood loss and hypovolemic shock during and after childbirth. Pituitary damage unrelated to pregnancy is called Simmonds' disease.[1]
Contents |
It is a rare complication of pregnancy, usually occurring after excessive blood loss. The presence of disseminated intravascular coagulation (i.e., in amniotic fluid embolism or HELLP syndrome) also appears to be a factor in its development.
Most common initial symptoms of Sheehan's syndrome are agalactorrhea (absence of lactation) and/or difficulties with lactation.[2] Many women also report amenorrhea or oligomenorrhea after delivery.[2] 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.[2] 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.[2] Gonadotropin deficiency will often cause amenorrhea, oligomenorrhea, hot flushes, or decreased libido.[2] Growth hormone deficiency causes many vague symptoms including fatigue and decreased muscle mass.[2]
Uncommonly, Sheehan syndrome may also appear acutely after delivery, mainly by hyponatremia.[2] 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).[2] The potassium level in these situations is normal, because adrenal production of aldosterone is not dependent on the pituitary.[2] There have also been cases with acute hypoglycemia.[3]
Hypertrophy and hyperplasia of lactotrophs during pregnancy results in the enlargement of the anterior pituitary, without a corresponding increase in blood supply.
Secondly, the anterior pituitary is supplied by a low pressure portal venous system.[4]
These vulnerabilities, when affected by major hemorrhage or hypotension during the peripartum period, can result in ischaemia of the affected pituitary regions leading to necrosis.
The posterior pituitary is usually not affected due to its direct arterial supply.
The specific association with postpartum shock or haemorrhage was described in 1937 by the British pathologist Harold Leeming Sheehan (1900-1988),[5] whereas Simmond's syndrome occurs in either sex due to causes unrelated to pregnancy.[6]
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||