Sheehan Syndrome

Hypopituitarism resulting from an infarct of the pituitary gland following postpartum shock or hemorrhage. Damage to the anterior portion of the pituitary gland causes partial or complete loss of thyroid, adrenocorticoid, and gonadal functions. Very rarely pituitary infarction occurs with diabetic vasculitis, sickle cell anemia, and idiopathic disease (most often called in these conditions as the Simmonds syndrome).

Reye-Sheehan Syndrome; Postpartum Panhypopituitarism Syndrome; Postpartum Hypophyseogenic Myxedema.

Described by Harold Leeming Sheehan, English pathologist, in 1937.

Incidence is estimated incidence at 1 to 2:10,000 pregnancies in the 1960s. Disorder is rare in modern obstetric practice but the occasional case is still reported every year.

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.

The cardinal characteristics for diagnosis are loss of sexual function, asthenia, and low basal metabolic rate. Patients usually have lack of lactation and amenorrhea postpartum. There is a characteristic facies, described as waxy white and sallow, as a result of a lack of melatonin. There is a loss of pubic and axillary hair, the skin is dry, the eyebrows thin. The thyroid may be impalpable. 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.

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 as hypotension, hypoxia, and hypothermia. These patients are reported to have increased sensitivity to barbiturates and opioids, even into the postoperative period. Although not reported, regional techniques would seem beneficial ...