Makindo Medical Notes

Related Subjects: | Prolactin | Prolactinoma | Sheehan's Syndrome

About

• Sheehan's syndrome is a rare condition resulting from ischaemic necrosis of the pituitary gland due to severe postpartum hemorrhage.
• It is often confused with pituitary apoplexy but is distinct in its etiology and presentation.
• Sheehan's syndrome may go unrecognized for years, making early diagnosis challenging.
• Clues to diagnosis include postpartum failure to lactate and amenorrhea, followed by the gradual appearance of signs and symptoms of hypopituitarism.

Aetiology

• During the later stages of pregnancy, the anterior pituitary enlarges due to hyperplasia and hypertrophy of lactotrophs, increasing its vulnerability to ischaemia.
• The blood supply to the enlarged pituitary does not proportionally increase, making it susceptible to reduced perfusion.
• Postpartum hemorrhage can lead to rapid blood volume depletion and hypotension, impairing blood flow to the anterior pituitary.
• This impaired blood supply results in pituitary ischaemia and infarction, primarily affecting the anterior lobe, though the posterior lobe may also be involved in rare cases.

Clinical Features

• The endocrine presentation is highly variable, depending on the extent of pituitary damage.
• Common symptoms include failure of lactation (agalactia), chronic fatigue, loss of vigor, and amenorrhea.
• Over time, patients may experience loss of pubic and axillary hair due to adrenal androgen deficiency.
• Involvement of the posterior pituitary can lead to diabetes insipidus, characterized by excessive thirst and urination.
• Notably, up to 70% loss of the anterior pituitary mass may occur without immediate symptoms, delaying diagnosis.

Investigations

• Hormonal assays typically reveal multiple pituitary hormone deficiencies, including low levels of TSH, prolactin (PRL), LH, FSH, and GH.
• Magnetic Resonance Imaging (MRI) of the pituitary gland may show an empty sella or an atrophic pituitary.
• Sheehan's syndrome is unique in its clinical significance associated with low serum prolactin levels.
• Other tests may include adrenal function tests and thyroid function tests to assess the extent of hypopituitarism.

Management

• Hormone replacement therapy is the cornerstone of management, tailored to the specific deficiencies identified. This may include:
  • Glucocorticoids (e.g., hydrocortisone) for adrenal insufficiency
  • Levothyroxine for hypothyroidism
  • Sex hormone replacement (e.g., estrogen or testosterone) for hypogonadism
  • Growth hormone supplementation in selected cases
• Desmopressin may be required if diabetes insipidus is present due to posterior pituitary involvement.
• Regular follow-up is essential to monitor hormone levels and adjust replacement therapy as needed.
• Supportive care, including psychological support and patient education, can improve quality of life.