Pituitary Failure (Hypopituitarism) is loss or under functioning of the pituitary gland in which one or more pituitary hormones are deficient
Hypopituitarism refers to under-function of the pituitary gland. The term refers to both anterior and posterior pituitary gland dysfunction. It may be temporary or permanent. Panhypopituitarism refers to complete loss of all pituitary function. Patients with pan-hypopituitarism should carry a Medic Alert bracelet at all times to notify health care personnel of this problem in case of an emergency.
At the Pacific Pituitary Disorders Center we have one of the world’s largest and most extensive experiences in diagnosing and treating patients with hypopituitarism. Our team of pituitary endocrinologists and neurosurgeons work closely together to preserve or restore pituitary gland function and quality of life, whether it is from from a pituitary adenoma, a brain tumor, hypophysitis, pituitary surgery, radiation treatment or a traumatic brain injury.
Causes of Pituitary Failure
Loss of pituitary function can result from damage to the pituitary gland, the pituitary stalk or the hypothalamus. The hypothalamus contains releasing and inhibitory hormones that control the pituitary and reach the gland via the pituitary stalk (infundibulum). Injury to the pituitary gland, pituitary stalk or hypothalamus can occur from:
- A pituitary tumor
- Brain tumor
- Brain or pituitary surgery
- Radiation to the pituitary
- Pituitary apoplexy (hemorrhage)
- Pituitary inflammation (hypophysitis)
- Autoimmune disorders
There appears to be a somewhat predictable loss of hormonal function: the growth hormone (GH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secreting cells appear most vulnerable while thyroid stimulating (TSH) and adrenocorticotropic hormone (ACTH) secreting cells are less vulnerable.
Based on our large surgical experience published in 2008 of over 400 patients treated with endonasal pituitary adenoma removal, gland recovery and loss of function can be reliably predicted.
- Approximately 50% of patients will have some recovery of pituitary function after adenoma removal
- 45% will have no change in function
- 5% will have diminished pituitary function
The most important factor in loss of function was tumor size: for endocrine inactive adenomas, 3 cm or greater in diameter, 2-3 cm in diameter, or under 2 cm in diameter, gland function loss was approximately 14%, 7%, and 0%, respectively.
Types of Hormone Deficiencies
The clinical presentation of anterior pituitary hormonal deficiency depends on the acuity of the presentation, the severity of the hormonal deficiency and the number of cells affected. Hormones deficiencies include:
ACTH and cortisol deficiency:
Adrenocorticotropic hormone deficiency is a form of adrenal insufficiency that results in decreased cortisol production by the adrenal glands and can be serious and life-threatening.
Symptoms of ACTH and cortisol deficiency
With gradual onset of deficiency over days or weeks, symptoms may include:
- Weight loss
- Loss of appetite
- Abdominal pain
As ACTH deficiency becomes more severe or has a more rapid onset, (Addisonian crisis) symptoms may include:
- Serum electrolyte changes (low serum sodium and/or elevated serum potassium)
- Vascular collapse
- Shock and death
In addition to ACTH and serum cortisol testing, in some instances additional confirmatory test is required to determine the cause of adrenal insufficiency.
Adrenal insufficiency can be classified as primary when the adrenal gland function is impaired, or secondary, when the ACTH secretion is impaired at the pituitary gland.
In our institute, patients can undergo Cortrosyn stimulation test and Metyrapone stimulation test. These tests are the gold standard for the diagnosis of primary and secondary adrenal insufficiency respectively.
Treatment ACTH and cortisol deficiency
Treatment consists of glucocorticoids (hydrocortisone or prednisone). For patients with acute adrenal insufficiency (Addisonian crisis), rapid intravenous administration of high dose steroids is essential.
Thyroid stimulating hormone deficiency:
Thyroid stimulating hormone deficiency results in decrease thyroxine secretion by the thyroid gland, this condition is known as central hypothyroidism. Decrease thyroid hormone secretion can be serious and life-threatening.
Symptoms of Thyroid stimulating hormone deficiency
Symptoms tend to be unspecific and may include:
- Decreased energy level
- Increased need to sleep
- Cold intolerance
- Dry skin
- Muscle aches
- Mood swings and memory loss
Treatment of Thyroid stimulating hormone deficiency
This is a very serious and disabling hormonal deficiency that often causes patients with pituitary disease to seek medical attention. Treatment with thyroxin reverses the symptoms and signs over days or weeks and requires careful monitoring of free T4 and total T3.
Inappropriately low or normal FSH and LH with low estradiol levels in women or low testosterone in men.
Symptoms and Treatment of Gonadotropins deficiency:
Women with hypogonadism develop:
- Menstrual irregularities
- Absence of periods (amenorrhea)
- Decreased libido
- Vaginal dryness
Our center individualizes care based on family history and concurrent cardiovascular risk or presence of other conditions with estradiol with or without progesterone therapy as clinically indicated. Physiologic hormonal supplementation can alleviate these symptoms and optimize quality of life.
Men with hypogonadism develop:
- Decreased libido
- Erectile dysfunction in some cases
- Mood swings
- Muscle and hair loss
- Weakness and Fatigue
Physiologic Testosterone replacement tend to alleviate these symptoms and restore quality of life.
Growth hormone (GH) deficiency:
GH is necessary in children for growth, and in adults to maintain body composition, muscle mass, energy level, cardiovascular status and possibly some mental functions.
Symptoms of Growth hormone deficiency
Symptoms of GH deficiency in adults include:
- Exercise tolerance
- Muscle mass loss
- Increased fat mass
- Decreased bone quality
- Poor quality life
Our center offers dynamic endocrinology testing to confirm growth hormone deficiency in challenging clinical scenarios. Dynamic testing with glucagon stimulation test (4 hours) or Macrilen (1.5 hours) after an individualized neuroendocrinology evaluation, can lead to higher insurance approval rates and decreased out of pocket cost when considering growth hormone supplementation in adults.
Central Diabetes Insipidus:
Patients with diabetes insipidus (DI) have a decreased vasopressin hormone (also known as antidiuretic hormone) secretion by the posterior pituitary gland.
Vasopressin is synthetized in the hypothalamus and stored in the posterior pituitary gland. Central DI typically occurs when the posterior pituitary gland, pituitary stalk or hypothalamus are manipulated or injured during surgery or impacted by a brain tumor, a traumatic brain injury, infiltration or inflammation of the pituitary gland or stalk.
Insufficient Vasopressin, symptoms and causes:
- An inability to concentrate urine at the kidney and results in high urinary volumes
- Diluted urine and excessive thirst
The high urinary volume, can lead to dehydration and serum sodium abnormalities including altered mental status, coma, seizures or death.
Treatment of Central Diabetes Insipidus
Treatment is provided with a targeted fluid balance, intravenous fluids and desmopressin (DDAVP) replacement.
Central DI may occur transiently in up to 25% of patients after transsphenoidal pituitary adenoma surgery but is typically only transient (lasting for 1 to several days) but is permanent in 1-3% of patients after pituitary adenoma surgery.
In contrast it is seen in many patients with a craniopharyngioma both before and more often after surgery (in up to 40-50% of patients) as these tumors typically arise along the pituitary stalk.
Replacement of ADH resolves the high urine output of DI. Treatment with DDAVP (a synthetic type of vasopressin) can be given by:
- Subcutaneous injection
- Intranasal spray
- Tablet, typically taken once or twice a day with a weekly breakthrough in dosing
Our multidisciplinary team monitors serum Na closely and has experience in DDAVP dosing and titration.
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