Clinical presentation of hypopituitarism depends on the severity of the disease. It can be asymptomatic or mild to severe as in the case of a hypopituitary coma or an acute pituitary failure. In most patients the hypopituitarism presents itself as an endocrine dysfunction such as:

Adrenocorticotrophic deficiency

Acute symptoms include weakness, nausea, dizziness, vomiting, fever, circulatory collapse and shock. Chronic symptoms are fatigue, anorexia, weight loss and pallor. In children delayed puberty, failure to thrive, hypotension, anemia, hypoglycemia, lymphocytosis, eosinophilia and hyponatremia may occur.

Thyroid stimulating hormone deficiency

Various symptoms include weight gain, hypotension, bradycardia, cold intolerance, constipation, hair loss, cognitive slowing hoarseness and dry skin.

Growth hormone deficiency

Deficiency of growth hormone may result in a short stature, reduced muscle mass and strength, fatigue, visceral obesity, dyslipidemia, atherosclerosis, impaired memory and attention and a decreased quality of life. In children severe growth restriction has been documented.

Antidiuretic hormone deficiency

The symptoms of decreased antidiuretic hormone secretion include, a reduced urine osmolality, polydipsia, polyuria and hypernatremia.

Diagnosis of hypopituitarism is made based on various imaging and laboratory tests. Some of them are, MRI, CT Scan, levels of various hormones such as free thyroxin (FT4), thyroid-stimulating hormone (TSH), prolactin, luteinizing hormone (LH), testosterone and estradiol for men and women respectively in the blood.

Moreover the cortisol levels are assessed using provocative testing of the adrenal-pituitary axis. In some individuals the insulin tolerance tests may be required for a better assessment of the adrenocorticotropic hormone (ACTH), growth hormone (GH) and prolactin levels [9].

Treatment of hypothyroidism is based on replacing the deficient hormones. Glucocorticoids must be administered in case of ACTH deficiency, in the case of an emergency such as a pituitary apoplexy or an obstetric pituitary hemorrhage. Gonadotropin deficiency is corrected by replacing the sex appropriate hormones, such as testosterone in men and estrogen replacement in women with or without progesterone replacement.

Growth hormone is not replaced often in adults unless symptom of GH deficiency arises [10]. Growth hormones are replaced in children whenever appropriate. Secondary hypothyroidism can be treated efficiently by thyroid replacement. In hospitalized patients on corticosteroids, the dose can be simply doubled up in case of a surgery.

Prognosis is mostly good, if the hormones are replaced sufficiently [7]. Though there is an increased morbidity among hypopituitarism patients, the reason for morbidity is not yet clearly understood [8].

Complications

The complications associated with hypopituitarism depend on the severity of the deficiency. Infection may be a major cause for complications. Some of the complications of hypopituitarism include amenorrhea, hypothyroidism, hypotension, infertility, osteoporosis, failure to develop during puberty and short stature.

Hypopituitarism can usually develop into hypopituitary coma due to pituitary apoplexy. Some of the clinical features of hypopituitary coma include meningism, hormonal deficiencies, hypotension, ophthalmoplegia, reduced consciousness, visual field defects, hypoglycemia and hypothermia.

Hypopituitarism can be caused by several factors as given below.

• Trauma of the head
• Brain surgery [1]
• Brain tumor [2]
• Radiation therapy [3]
• Stroke
• Inflammation or an infection of the brain tissues
• Tumor of the pituitary gland or the hypothalamus 
• Subarachnoid hemorrhage [4]

Apart from this hypopituitarism can also be caused by rare immune or metabolic diseases such as hemochromatosis, histiocytosis X, lymphocytic hypophysitis, sarcoidosis and a very rare condition following a pregnancy called the Sheehan`s syndrome.

Hypopituitarism is listed under the rare diseases by the National institute of health (NIH), as less than 200,000 people are affected by this in the United States. It has been estimated that 4.2 cases per 100,000 people are being reported every year, internationally [5].

According to a study conducted by Regal et al, it has been estimated that there is a prevalence of 45.5 cases for every 100,000 of the adult population [6].

The pituitary gland produces the trophic stimulus to the target glands. Hence when the trophic stimulus is impaired, the hormone production from the target gland is impaired resulting in the secondary failure of the target glands.

In normal cases, the secretion of the tropic stimulus is based on the subphysiological hormonal levels, by a feedback mechanism. But in case of hypopituitarism the levels of the trophic hormones are suboptimal or absent, resulting in reduced production of the target gland hormones.

Hypopituitarism can never be prevented, though it can be treated efficiently if detected early. Trauma to the pituitary gland can be minimized if hypophyseal surgery is carried out under high resolution microscopes. Obstetric pituitarism can be minimized by proper postpartum care. Minimum exposure of the pituitary gland during radiation therapy is mandatory to prevent hypopituitarism due to radiation exposure.

Hypopituitarism is a condition, where there is a decrease in hormones secreted by the pituitary gland. The pituitary gland is a small gland located below the brain. It secretes a number of important hormones such as the growth hormone, thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone, prolactin and adrenocorticotropic hormone.

These hormones play a major role in growth and development of the body and regulating the blood pressure and metabolism. Insufficient secretion of any of these hormones, can result in a dysfunction of that particular area, and is manifested by specific symptoms. Treatment includes the replacement of the deficient hormones by hormone replacement therapy.

Definition

Pituitary is a small pea-sized gland situated at the base of the brain. It is connected to the hypothalamus of the brain by a small stalk. The pituitary gland secretes a number of hormones such as the adrenocorticotropic hormone (ACTH), growth hormone (GH), prolactin, antidiuretic hormone and thyroid-stimulating hormone (TSH). 

Cause

Hypopituitarism occurs when there is a deficient secretion of one or many of these hormones. Some of the causes for hypopituitarism include, a tumor of the pituitary gland, radiation therapy involving the pituitary gland, trauma of the pituitary due to road accidents, autoimmune disorders affecting the pituitary, surgery involving the pituitary gland, severe infections such as meningitis that can affect the pituitary and many such. 

Symptoms

Hypopituitarism is marked by various symptoms like fatigue, undue tiredness, blackouts, loose stools, low blood pressure and such as a result of deficient ACTH. Deficiency of growth hormone may result in stunted growth, weakness and tiredness in adults. Low sex hormones can result in less sex drive in women and loss of libido in men, impotence, and irregular or absent menstrual periods. Less thyroid hormone can result in dry skin and tiredness. Lack of antidiuretic hormone can result in increased thirst and copious urine output.

Diagnosis

Hypopituitarism is usually diagnosed using blood tests to detect the hormone levels, visual field checks for ruling out tumors of the pituitary gland, MRIs and CT scans. 

Treatment

Treatment of hypopituitarism is done mainly by hormone replacement therapy.

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