Sheehan Syndrome

Introduction

• Description: Sheehan syndrome (named for Harold Leeming Sheehan, who characterized the syndrome ) is characterized by the loss of pituitary function, resulting from damage or necrosis that occurs through anoxia, thrombosis, or hemorrhage. When associated with pregnancy, it is called Sheehan syndrome; when unrelated to pregnancy, it is called Simmonds disease.

• Prevalence: Rare; less than 1/10,000 deliveries.

• Predominant Age: Reproductive age.

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: Anoxia, thrombosis, or hemorrhage that results in damage or necrosis of the pituitary gland. The pituitary gland enlarges as pregnancy progresses and is prone to infarction from hypovolemic shock. The exact mechanism of pituitary damage is unknown, and pituitary damage can rarely occur even in the absence of hemorrhage. Even more rarely it can follow snake bite (Russell viper). Symptoms may manifest immediately or up to several years later.

• Risk Factors: Postpartum hemorrhage with hypotension.

Signs and Symptoms

• Secondary amenorrhea

• Secondary hypothyroidism

• Adrenal insufficiency (the degree of pituitary damage and resultant loss is highly variable; as a result, the reduction of adrenal and thyroid hormone production seen is also variable, from slight to virtually complete loss)

• Postpartum failure of lactation and loss of pubic and axillary hair (lactation following delivery virtually precludes pituitary necrosis)

• Uterine superinvolution

Diagnostic Approach