Sheehan’s Syndrome

Postpartum Hypopituitarism

Sheehan's syndrome is a condition affecting women who experience life-threatening blood loss during or after childbirth. Severe blood loss deprives your body of oxygen and can seriously damage vital tissues and organs. In Sheehan's syndrome, the damage occurs to the pituitary gland — a small gland at the base of your brain. The result is the permanent underproduction of essential pituitary hormones (hypopituitarism).

Also called postpartum hypopituitarism, Sheehan's syndrome is rare in industrialized nations. But it's still a major threat to women in developing countries.

• For some women, Sheehan's syndrome seems to cause few, if any, symptoms. For others, Sheehan's syndrome can lead to an adrenal crisis — a life-threatening shortage of the hormone cortisol. Treatment of Sheehan's syndrome involves hormone replacement therapy.

• In most cases, the signs and symptoms of Sheehan's syndrome appear slowly, after a period of months or even years. But sometimes — such as in a breast-feeding mother — problems may appear right away.

Signs and symptoms of Sheehan's syndrome include:

• Slowed mental function, weight gain and difficulty staying warm, as a result of an underactive thyroid (hypothyroidism)

• Difficulty breast-feeding or an inability to breast-feed

• No menstrual periods (amenorrhea) or infrequent menstruation (oligomenorrhea)

• Loss of pubic or underarm hair• Low blood pressure• Fatigue• Weight loss

For many women, the symptoms of Sheehan's syndrome are nonspecific and often attributed to other things. Fatigue, for instance, goes hand in hand with being a new mother. You might not realize that you have Sheehan's syndrome until you need treatment for thyroid or adrenal insufficiency.

It's also possible to remain symptom-free with Sheehan's syndrome. Some women unknowingly live for years with pituitary insufficiency, then go into adrenal crisis triggered by extreme physical stressors, such as severe infection or surgery.

Causes:

Although many problems can lead to low pituitary function, Sheehan's syndrome is caused by severe blood loss during or after childbirth. Blood loss at that time can be particularly damaging to the pituitary gland, destroying hormone-producing tissue so that the gland can't function normally.

Experts aren't sure exactly why this is the case. One theory is that since the pituitary gland enlarges during pregnancy, it's more prone to damage. The severe drop in blood pressure (hypotension) that occurs during hemorrhage also could damage the pituitary.

Pituitary hormones regulate the rest of your endocrine system, signaling other glands to increase or decrease production of the hormones that control metabolism, fertility, wound healing and many other vital processes. A lack of any of all of these hormones can cause problems throughout your body — although signs and symptoms may develop so gradually that they escape notice.

Hormones that your pituitary secretes include: • Growth hormone (GH). This hormone controls bone and tissue

growth and maintains the appropriate balance of muscle and fat tissue. • Anti-diuretic hormone (ADH). By regulating urine production, this

hormone manages water balance in your body. A deficiency of ADH results in a condition called diabetes insipidus.

• Thyroid-stimulating hormone (TSH). This hormone stimulates your thyroid gland to produce key hormones that regulate your metabolism. Shortage of TSH results in an underactive thyroid gland (hypothyroidism).

• Luteinizing hormone (LH). In men, LH regulates testosterone production. In women, it fosters production of estrogen.

• Follicle-stimulating hormone (FSH). Working in tandem with LH, FSH helps stimulate sperm production in men, and egg development and ovulation in women.

• Adrenocorticotropic hormone (ACTH). This hormone stimulates your adrenal glands to produce cortisol and other hormones. Cortisol helps your body deal with stress and influences many body functions, including blood pressure, heart function and your immune system. A low level of adrenal hormones is known as Addison's disease.

• Prolactin. This hormone regulates the development of female breasts, as well as the production of breast milk.

Pathophysiology:

• Hypertrophy and hyperplasia of lactotrophs during pregnancy results in the enlargement of the anterior pituitary, without a corresponding increase in blood supply.

• Secondly, the anterior pituitary is supplied by a low pressure portal venous system.

• These vulnerabilities, when affected by major hemorrhage or hypotension during the peripartum period, can result in ischaemia of the affected pituitary regions leading to necrosis.

• The posterior pituitary is usually not affected due to its direct arterial supply.

Risk Factors:Any condition that increases your likelihood

of severe blood loss during childbirth, such as being pregnant with multiples or having an abnormality of the placenta, may increase your risk of Sheehan's syndrome.

Hemorrhage is a rare childbirth complication, however, and Sheehan's syndrome is even more uncommon. Both risks are greatly reduced with proper care and monitoring during labor and delivery.

Diagnosis:

Sheehan's Syndrome is mainly diagnosed by low levels of TSH, ACTH, FSH, and LH with low levels of T4, cortisol, and estradiol in the blood. Low levels of IGF-I suggests GH deficiency.

MRI and CT scans should be carried out to evaluate the pituitary gland for other causes of hypopituitarism like pituitary tumors.

Complications:Because pituitary hormones control so many

aspects of your metabolism, Sheehan's syndrome can cause a number of problems, including:

• Adrenal crisis, a serious condition in which your adrenal glands produce too little of the hormone cortisol

• Low blood pressure• High cholesterol• Unintended weight loss• Menstrual irregularities

Adrenal crisis: Life-threatening situation The most serious complication is adrenal crisis, a sudden, life-threatening state that can lead to extremely low blood pressure, shock, coma and death.

• Adrenal crisis usually occurs when your body is under severe stress — such as during surgery or a serious illness — and your adrenal glands produce too little cortisol, a powerful stress hormone.