Written by Dr.M.D.Mazumdar, MD
Sheehan's Syndrome, also known as Postpartum Hypopituitarism or Postpartum Pituitary Necrosis, is a rare condition in which hypopituitarism develops after severe bleeding ('Postpartum hemorrhage') during or immediately after childbirth .
Blood loss generally has to be more than 800ml for Sheehan's Syndrome to develop. But in certain women, even minimal bleeding seems to cause this condition.
What is Sheehan's Syndrome?
Sheehan's syndrome is an uncommon and rare condition which occurs due to damage to the pituitary gland, especially the anterior pituitary gland.
The pituitary gland is situated just under the hypothalamus of the brain. It is the 'master gland' which not only secretes hormones that spur important processes in the body but also stimulates the secretion of hormones by other glands in the body.
It helps regulate processes that impact the brain, skin, energy, mood, reproductive organs, growth of muscle and tissues , control of body temperature and more.
A damage to the gland, either partially or fully, will affect the levels of most of the hormones in the body leading to a multitude of symptoms.
Cause of Sheehan's Syndrome
Sheehan's syndrome occurs due to necrosis of the anterior lobe of the pituitary gland.
This part of the gland secretes important hormones like the ACTH, TSH, FSH, LH, growth hormones, endorphins and prolactin.
During normal pregnancy, the anterior pituitary lobe increases greatly in size since it is required to secrete larger amounts of these hormones, especially FSH, LH and prolactin.
The blood supply of the gland does not increase simultaneously with the enlarging size of the gland. Due to this irregularity, the blood supply to this part of the pituitary gland is in a compromised state during pregnancy. If heavy bleeding occurs at any time during or after pregnancy or childbirth, the blood supply becomes inadequate and the cells undergo necrosis.
It is also believed that the acute loss of blood causes spasm in the arteries supplying the anterior pituitary leading to further necrosis.
The secretion of all the hormones produced by the anterior pituitary ( ACTH, TSH, FSH, LH, growth hormones, endorphins and prolactin) is affected to a greater or lesser extent.
Which hormones are affected?
The pituitary gland is the "master" gland of the endocrine system - it controls the functions of many of the other endocrine glands. If the pituitary gland is affected, the hormone levels secreted by other glands are also affected.
Hormones affected in Sheehan's Syndrome
- Thyroid-stimulating hormone (TSH): The TSH stimulates the thyroid gland to produce hormones like Thyroxine, T3 and T4. These hormones regulate the metabolism of the body. A low level can cause conditions like hypothyroidism with all its symptoms.
- Follicle-stimulating hormone (FSH ): FSH is produced by the anterior pituitary gland. It stimulates the ovaries to produce follicles (eggs). The ovaries then also produces estrogen and regulates the menstrual cycle.
- Luteinizing hormone (LH): Together with FSH, this hormone is also released by the anterior pituitary gland. It causes lueitinisation of the follicles after ovulation - this causes the ovaries to produce progesterone.
- Growth hormone (GH): GH controls organ and tissue growth helps to regulate body composition, body fluids, muscle and bone growth, sugar and fat metabolism.
- Adrenocorticotropic hormone (ACTH): ACTH stimulates the adrenal glands to release cortisol, an important hormone that controls how the body responds to stress. It helps to maintain blood pressure, immune function and the body's anti-inflammatory processes.
- Prolactin : Prolactin stimulates milk production from the breasts. Women with Sheehans syndrome fails to initiate breastfeeding or breastfeeding may fail within a few days.
- Antidiuretic hormone (ADH or vasopressin): This hormone is produced by the posterior pituitary glaand but is often seen to be affected in Sheehan's syndrome. It regulates and balances water and sodium levels in the body. Low levels of ADH can cause diabetes insipidus.
What are the Risk factors?Sheehans syndrome is a uncommon condition . But some women may have risk factors which make her more prone to develop this condition.
- A history of heavy bleeding during earlier childbirth : Women who have had heavy blood loss in earlier childbirths are more likely to have heavy blood loss again.
- Prolonged labor: Prolonged labor can cause the muscles of the uterus to become atonic and fail to contract adequately after childbirth. This can lead to massive blood loss.
- Excessively distended uterus: The uterus can become very enlarged and distended in conditions like a very large baby, excessive fluid (hydramnios), multiple pregnancies like twin pregnancies. This can cause the muscles to become lax and fail to contract adequately.
- Conditions which can increase blood loss: placenta previa, placental abruption and assisted labor like forceps delivery.
- Pre-eclampsia (PET) : PET causes increase in blood pressure which may cause increased blood loss during childbirth.
- Coagulation Defects : Coagulation defects of the blood like von Willebrand disease may lead to blood loss.
Symptoms of Sheehan's Syndrome
The symptoms depend on the degree of necrosis of the cells.
The common features are:
- amenorrhea (failure to have normal periods)
- loss of axillary and pubic hair
- appearance of wrinkles around the eyes and lips
- weakness and loss of weight
- early aging
- dryness of the skin
- loss of pigmentation
- Fatigue and trouble concentrating
- Low sex drive
- Dry skin
Less common, but more severe symptoms include:
- Circulatory collapse
- Severe lowering of blood sodium levels, or hyponatremia
- Diabetes insipidus or passage of excessive quantities of dilute urine due to the lack of anti-diuretic hormone from the posterior pituitary
- Congestive heart failure
- Severe mental changes
Diagnosis of Sheehan's Syndrome
Sheehan's Syndrome is diagnosed by a combination of medical history, physical examination, blood tests and Imaging studies.
- Medical History: Careful questioning will expose a history of heavy bleeding and/or shock during childbirth. There may also be a history of anemia, PET, prolonged labor or twin pregnancy.
- Physical examination: Physical examination may show symptoms like pallor, dry skin and hair, low blood pressure and a general appearance of ill health.
- Blood Tests: Blood tests will show low levels of TSH, ACTH, FSH, and LH with low levels of T4, cortisol, and estradiol in the blood. Low levels of IGF-I (Insulin like growth factor) suggests GH deficiency.
- Imaging Studies: An MRI is the gold standard of diagnosis of Sheehan's syndrome. It will show emptiness of the sella turcica - the sella is a small groove in the bottom of the hypothalamus in which the pituitary gland is present. 'Empty sella syndrome' is a condition in which the pituitary gland shrinks or becomes flattened.
Treatment of Sheehan's Syndrome
Treatment is essentially by replacing the hormones that the pituitary gland fails to produce. Hormones like corticosteroids, thyroid hormones and estrogens and medicines to control diabetes become necessary to maintain normal functioning of the body. Any minor illnesses like influenza or even a common cold can cause a crisis and may require adjustment of these hormones.
Hormone replacement therapy may include:
- Adrenocorticotropic hormone (ACTH) replacement to stimulate the adrenal glands to produce cortisol
- Thyroid hormone replacement to replace the thyroid hormones T3 and T4
- Growth hormone replacement to stimulate growth and bone formation
- Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) replacement to restore menstrual periods and fertility
- Prolactin replacement to stimulate milk production in breastfeeding women
Can Sheehan's Syndrome be prevented?
Preventing Sheehan's syndrome can be difficult because it is not possible to predict who will haemorrhage during childbirth. However, some preventive steps can be taken:
- Careful monitoring of any risk factors during pregnancy like high blood pressure, anemia, twins etc.
- Careful monitoring during labor and childbirth to prevent excessive bleeding
- Ensuring adequate oxygen saturation even if bleeding did occur.
- Timely intervention during prolonged or difficult labor to prevent the mother from going without oxygen for too long.
- Since cesarean sections are less likely to lead to Sheehan's syndrome, it is ideal for women at risk to undergo cesarean section rather than a normla labor.
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