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
Reye-Sheehan Syndrome; Postpartum Panhypopituitarism
Syndrome; Postpartum Hypophyseogenic Myxedema.
Described by Harold Leeming Sheehan, English pathologist,
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 ...