Hypopituitarism resulting from an infarct of the pituitary gland following postpartum shock, hemorrhage, or trauma. Damage to the anterior portion of the pituitary gland causes partial or complete loss of thyroid, adrenocorticoid, and gonadal functions.
Reye-Sheehan Syndrome; Postpartum Panhypopituitarism Syndrome; Postpartum Hypophyseogenic Myxedema.
Described by Harold Leeming Sheehan, English pathologist, in 1937.
Incidence is estimated up to 5/100,000 births.
Sheehan reported a series of cases of hypopituitarism following intrapartum hypotension. Typically, the patient suffered from massive peripartum hemorrhage and the ensuing hypotension led to ischemia and infarction of the highly vascular pituitary gland in the pregnant patient. In many of the reported cases, postmortem examination demonstrated anterior pituitary necrosis. A case of posterior pituitary damage with clinical evidence of diabetes insipidus has also been reported.
Clinical features. Laboratory evidence of abnormal adrenal (low urinary steroids and low plasma cortisol), thyroid (low plasma T3 and T4) or ovarian (low follicle-stimulating hormone, luteinizing hormone, plasma estrogen, progesterone) function. Also, low growth hormone and low prolactin levels, with growth hormone secretion usually being the first one to fail. Further confirmation by provocative tests including insulin tolerance test, metyrapone, thyrotropin-releasing hormone, or luteinizing hormone-releasing hormone. Other laboratory values include hyponatremia, anemia, and hypoglycemia.
The cardinal characteristics for diagnosis are amenorrhea or oligomenorrhea, hot flashes, and/or decreased sex drive. Symptoms of hypothyroidism such as fatigue, bradycardia, hypotension, weight gain, and constipation may occur months later along with the loss of axillary and pubic hair. The skin is dry, the eyebrows thin. The thyroid may be impalpable. There is a characteristic facial expression, described as waxy white and sallow, as a result of a lack of melatonin. Untreated patients may have a low pulse rate with an often low and labile blood pressure. Atypical patient may have maintained menstruation and with subsequent pregnancies, may have much improved symptoms because of the adrenocortical hormones secreted by the placenta. Treatment is by hormone replacement including hydrocortisone and thyroxine, and ovulation may be induced with follicle-stimulating hormone and luteinizing hormone therapy.
Precautions before anesthesia
An anesthesiology consultation is highly recommended before elective surgical procedures. Establish diagnosis by history, clinical examination, and laboratory evidence. Assess fluid and electrolyte status and correct if required. Intravenous hydrocortisone should be available and used if suspected in untreated hypopituitarism before anesthesia commence.
Hydrocortisone cover should be continued throughout the perioperative period because of the inadequate stress response by the pituitary remnants. Adequate fluid hydration should be given and care should be taken to avoid further stressors such ...