The pituitary gland produces a number of hormones or chemicals which are released into the blood to control other glands in the body. If the pituitary is not producing one or more of these hormones, or not producing enough, then this condition is known as hypopituitarism.
The term Multiple Pituitary Hormone Deficiency (MPHD) is sometimes used to describe the condition when the pituitary is not producing two or more of these hormones. If all the hormones produced by the pituitary are affected this condition is known as panhypopituitarism.
Hypopituitarism is most often caused by a benign (i.e. not cancerous) tumour of the pituitary gland, or of the brain in the region of the hypothalamus. Pituitary underactivity may be caused by the direct pressure of the tumour mass on the normal pituitary or by the effects of surgery or radiotherapy used to treat the tumour. Less frequently, hypopituitarism can be caused by infections (such as meningitis) in or around the brain or by severe blood loss, by head injury, or by various rare diseases such as sarcoidosis (an illness which resembles tuberculosis).
More information about conditions which result in hypopituitarism can be found in the Rarer Disorders section.
- excessive tiredness and decreased energy
- muscle weakness
- reduced body hair
- irregular periods (oligomenorrhoea) or loss of normal menstrual function (amenorrhoea) - females
- impotence - males
- reduced fertility
- decrease in sex drive
- weight gain
- increased sensitivity to cold
- dry skin
- pale appearance
- low blood pressure and dizziness on standing (postural hypotension)
- vision disturbance
- Diabetes Insipidus
Each of the symptoms described above occur in response to the loss of one or more of the hormones produced by the pituitary. Decrease in the production of only one hormone would not lead to all the symptoms described above.
Sheehan’s Syndrome is also known as postpartum hypopituitarism, or postpartum pituitary insufficiency and may occur in a woman who has severe uterine haemorrhage during childbirth.
The resulting severe blood loss causes tissue death in her pituitary gland and leads to hypopituitarism following the birth. If a woman’s pituitary gland is starved of blood due to her bleeding severely during childbirth, the gland may lose its ability to function properly.
Conditions that increase the risk of an obstetric haemorrhage include multiple pregnancies (twins or triplets) and abnormalities of the placenta.
Blood tests would establish hormone levels and a scan to rule out other abnormalities of the pituitary such as a tumour.
Another cause of hypopituitarism that may be associated with pregnancy is lymphocytic hypophysitis.
This is due to inflammation in the pituitary caused by immune cells. The reasons why this occurs is not understood.
With modern obstetric practice the occurrence of hypopituitarism after childbirth, though uncommon, is more frequently due to this condition than Sheehan’s syndrome.