The pituitary gland in the brain produces and releases several hormones into the bloodstream to control other functions in the body. Hypopituitarism is the general term to describe when the pituitary fails to produce enough of its hormones.
When it fails to produce two or more hormones, it’s often known as Multiple Pituitary Hormone Deficiency (MPHD). If all hormones are affected, it’s known as panhypopituitarism.
The pituitary gland has two sections – the anterior (front) and the posterior (back) which produce the following hormones:
- adrenocorticotropic hormone , which signals the adrenal glands to produce cortisol
- growth hormone, which looks after the body’s growth and metabolism
- luteinising hormone and follicle-stimulating hormone (also known as gonadotropins ), which stimulate sex hormone production in women and men respectively
- prolactin, which helps the breasts produce milk
- thyroid-stimulating hormone, which signals the thyroid gland to produce and release thyroid hormones
- anti-diuretic hormone (also known as vasopressin), which takes care of the body’s blood pressure and water balance
- oxytocin, which helps the body during labour and breastfeeding
Hypopituitarism is a rare condition that affects between 300 and 455 people in a million. It’s usually chronic and lifelong unless the underlying causes are treated effectively and normal pituitary function is restored.
What are the causes?
A number of things can affect pituitary function but the most common cause is benign (non-cancerous) tumours on the pituitary gland or the hypothalamus. The direct pressure of the tumour might make the pituitary underactive or the surgery or radiotherapy to treat it can damage the blood supply to the gland.
Trauma to the head or strokes can cause damage to the pituitary and genetic conditions might also prevent the pituitary from producing hormones such as Kallmann’s syndrome which prevents a person from starting or fully completing puberty.
Other causes can include congenital conditions and malformations of the gland, inflammation and infections, such as meningitis.
What are the typical symptoms?
General hypopituitarism symptoms include tiredness and low energy, muscle weakness, headaches, constipation, sensitivity to cold and problems with menstruation, impotence and fertility. Other symptoms, however, depend on which specific hormones are deficient, and whether the problem began in childhood or later in life.
Low adrenocorticotropic hormone often leads to decreased cortisol and people may experience low blood sugar and low sodium levels, dizziness and blackouts, weight loss, nausea, vomiting and diarrhoea.
Low or deficient growth hormone can stunt children’s growth and cause changes in body fat and muscles in adults. Deficient gonadotropin hormone can delay puberty in children or prevent it altogether and in adults, it can decrease libido, affect menstruation and cause infertility.
When it comes to a decrease in thyroid hormone, symptoms can be visible in the skin and hair, causing them to become dry and coarse. It can also cause weight gain, constipation, memory loss, depression as well as a feeling of being cold all the time.
The symptoms of low anti-diuretic hormone differ again and can include severe thirst and passing large amounts of urine.
Diagnosing and treating hypopituitarism
The diagnosis and treatment of hypopituitarism depend on the specific hormonal deficiency and the underlying cause for the gland malfunction and there are different tests to diagnose this. Some of these tests are called “dynamic” tests because levels are taken before and after the gland is stimulated.
For example, to check the adrenal glands a synacthen test is done whereby they inject synacthen to stimulate the glands to produce cortisol and then do a blood test to see if the glands reacted as they should do.
To check the thyroid, a TSH test is done to see whether the pituitary gland is failing to signal the thyroid to produce hormones. A free T4 test may also be done but not always.
When there are symptoms of a lack of the anti-diuretic hormone, doctors sometimes carry out regular blood and urine tests while their patient goes without water for between 8 – 24 hours to diagnose the problem.
On the other hand, when symptoms are non-specific , it’s common for people to undergo vision tests and CT and MRI scans to diagnose the underlying cause.
Treatment is also specific to the hormone deficiency and generally involves replacing targeted hormones through the following means:
- Low adrenocorticotropic hormone is treated with oral hydrocortisone tablets which replace cortisol. It’s required that people in this situation carry a ‘steroid card’ and wear medic-alert jewellery at all times.
- Low growth hormone is usually treated with self-administered injections.
- Anti-diuretic hormone deficiency is usually treated with desmopressin, a medication that replaces the hormone.
- A deficiency of sex hormones can be treated with a range of therapies, including the contraceptive pill or hormone replacement therapy for women, and testosterone patches, gels or injections for men.
- Low TSH and thyroid hormone levels are treated with levothyroxine tablets which are the standard treatment and taken orally every day.
An increased mortality rate in hypopituitary patients is documented but the actual cause of this is still not clear. The general prognosis for hypopituitarism is good, however, as long as hormones are adequately replaced and the underlying cause is treated. Hypopituitarism is often a life-long condition that requires daily medication and regular check-ups and, like other chronic conditions, can impair quality of life for many people.
There are also increased risks associated with the condition, including heart disease and strokes due to physical symptoms such as weight gain, high cholesterol and circulation problems. A healthy diet, exercise and weight loss usually helps fight these risks.
Brittle bones and osteoporosis can also be more of a risk for people with hypopituitarism, but again, exercise and a diet rich in vitamin D and calcium can help decrease this.
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