What Is Hypopituitarism?
Hypopituitarism is a condition, in which the pituitary gland is unable to produce its hormones or their production is insufficient. It is also called as underactive pituitary gland. In this condition, the deficiency of one or more of the hormones produced by pituitary gland can affect the body's normal functioning. Some of the basic functions affected include growth and development, reproduction, metabolism and regulation of blood pressure.
About Pituitary Gland
Pituitary gland, which appears like a small bean shaped structure is located just below the brain. The gland is connected to hypothalamus in the brain, which controls the functioning of the pituitary gland. Pituitary gland is responsible for producing important hormones that control some of the major functions required for our body's normal growth and development.
The Hormones Released By Pituitary Gland Are:
- Adrenocorticotropic Hormone (ACTH) – This stimulates adrenal gland to release cortisol, which helps to maintain blood pressure and sugar.
- Growth Hormone (GH) – Regulates growth and development.
- Thyroid Stimulating Hormone (TSH) – Controls thyroid gland for releasing thyroid hormones, which influence the body's metabolism.
- Antidiuretic Hormone (ADH)– Regulates water absorption and excretion from kidneys.
- Follicle Stimulating Hormone (FSH) – Controls reproductive functions in males and females
- Luteinizing Hormone (LH) - Controls reproductive functions.
- Oxytocin – Responsible for uterine contractions during labor and breast milk production.
- Prolactin – Stimulates development of breast and milk production in females.
Causes Of Hypopituitarism
Some Of The Common Causes Of Hypopituitarism Include
- Tumors of pituitary gland, brain or hypothalamus
- Pituitary aplasia or hypoplasia
- Head injuries
- Brain surgeries
- Infections of brain and nearby tissues like meningitis
- Aneuryms leading to hemorrhage
- Congenital conditions like Kallmann's syndrome
- Sheehan syndrome (blood loss during childbirth)
- Genetic mutations
Symptoms Of Hypopituitarism
Clinical Features of Hypopituitarism
As pituitary gland releases some of the main hormones, the symptoms vary and can affect many organs under the umbrella of the gland. Clinical presentation depends on the number of hormones affected and the organs under their control. The severity of the symptoms can range from being asymptomatic to having acute pituitary failure, which has a rapid onset and lead to acute coma.
Some Of The Symptoms Noted In Hypopituitarism, Based On The Affected Hormone, Include:
- ACTH Deficiency – Chronic fatigue, dizziness, anorexia, weight loss, hypoglycemia, hypotension, anemia. In children, failure to thrive and delayed puberty may be seen.
- GH Deficiency – As growth is affected, short stature, decreased muscle mass and power, fatigue, impaired memory and attention difficulties may be seen.
- TSH Deficiency – As in hypothyroidism, weight gain, decreased metabolism, cold intolerance, tired feeling, constipation and hypotension may be seen. In children, developmental delays, retarded growth and cognitive impairment may be seen.
- ADH Deficiency - increased urination and thirst, hypernatremia.
- In case of deficiency of hormones controlling reproductive function, scanty menstruation, infertility and osteoporosis can be seen in women. In men, loss of facial or scrotal hair, reduced muscle mass, affected sexual function can be seen. In children puberty can be delayed.
Some other symptoms depending on the underlying cause like headaches, visual defects in case of tumors or increased thirst and affected urine secretion in case of defects in hypothalamus can be seen.
Acute pituitary failure can sometimes result in hypopituitary coma, which can progress rapidly in previously known cases of hypopituitarism. This can be triggered due to trauma, infection, surgeries or hemorrhage. Along with hormone deficiencies, the patient may present with hypotension, hypothermia and may also affect consciousness.
Diagnosis Of Hypopituitarism
Decreased levels of particular hormones controlled by pituitary gland are suggestive of some problem with the gland. Exact diagnosis can be made by performing investigations to find out the specific underlying cause. Pituitary function tests can be performed.
Blood tests are performed to detect blood glucose, renal function and electrolyte balance. Hormone assays are performed, where hormone levels are detected for example, serum levels of ACTH, TSH, thyroid hormones (T3, T4), cortisol, FSH, LH, estrogen, testosterone, insulin-like growth factor (IGF-1). Dynamic testing is a specialized endocrine evaluation, done to detect the hormone secretion after having taken certain medications specific to that test.
Cranial MRI or CT scan may be ordered to detect tumors or any other problems with the pituitary gland or nearby tissues. Vision tests are used to detect visual defects due to growing pituitary tumor.
Treatment Of Hypopituitarism
Treatment of hypopituitarism is based on the cause. In case of hormone deficiencies, the concerned hormone needs to be replaced; for example corticosteroids, thyroid hormone, testosterone, estrogen or growth hormone may be given as required. These medicines may have side effects and any inappropriate discontinuation can be harmful; hence physician's advice should be followed properly.
Symptomatic treatment may be required and is managed appropriately. In case of fertility, specific treatment can be given. The underlying cause needs to be treated; a tumor may require surgical removal following which radiation therapy may also be required.
Prevention Of Hypopituitarism
Hypopituitarism occurring after delivery can be minimized by taking proper obstetric care. For known patients of hypopituitarism, regular monitoring and dose adjustment during periods of stress, infections may be required; so regular follow-up is essential. Being prepared for emergency situations can help to prevent adverse outcomes. It is worth to consider wearing a medical alert bracelet or carrying an identity card with details of disorder and medicines.