| Hypophysitis | |
|---|---|
 | |
| Pituitary gland is located at the base of the human brain. | |
| Specialty | Endocrinology |
Hypophysitis refers to an inflammation of the pituitary gland. Hypophysitis is rare and not fully understood.
| Hypophysitis | |
|---|---|
| | |
| Pituitary gland is located at the base of the human brain. | |
| Specialty | Endocrinology |
Hypophysitis refers to an inflammation of the pituitary gland. Hypophysitis is rare and not fully understood.
There are four categories of symptoms and signs. Most commonly, the initial symptoms are headaches and visual disturbances. Some symptoms are derived from the lesser functioning of the adenohypophyseal hormones. Of the adenohypophyseal hormones, the most frequently affected are corticotropes, lactotropes and gonadotropes, all which are found in the anterior pituitary. Polyuria is also a common symptom – which results in very dilute urine, as well as polydipsia which means having extreme thirst. Another symptom is hyperprolactinemia, which is when there are abnormally high prolactin levels in the blood. Usually, a mass will be found located on the sella turcica and loss of hormonal function. [1]
Hypophysitis may have an underlying autoimmune aetiology, as in the case of autoimmune hypophysitis, [2] and lymphocytic hypophysitis. [3] [4]
Mainly, the diagnosis of hypophysitis is through exclusion – patients often undergo surgery because they are suspected of having a pituitary adenoma. But, the most accurate diagnosis is using Magnetic Resonance Imaging (MRI) to find any mass or lesions on the sella turcica. [5] It is a known side-effect of the new immune checkpoint inhibitors of the CTLA-4 inhibitor and PD-L1 inhibitor classes, used for the treatment of melanoma, and should be considered in patients on these drugs who present with endocrine dysfunction.[ citation needed ]
It was shown through various testing that administration of bromocriptine can improve field of vision defects and lower prolactin levels. It was also found that when using corticosteroids, there was a decrease in size of the gland, and relieved compression on the dura mater. These corticosteroids were also found to have an immunosuppressive effect which helped with reducing the autoimmune reaction of the gland. [6]
The prognosis for hypophysitis was variable for each individual. The depending factors for hypophysitis included the advancement of the mass on the sella turcica, percentage of fibrosis, and the body's response to corticosteroids. Through the use of corticosteroids, the vision defects tend to recover when the gland size began to decrease. The prognoses of the limited number of reported cases were usually good. [5]
The first reported case was in 1962, with a 22-year-old who died of adrenal insufficiency 14 months after giving birth to her second child. Her symptoms began 3 months postpartum, with lassitude (weakness/lack of energy), goitre (iodine deficiency) and amenorrhea (absence of a menstrual period). This was originally reported by Goudie and Pinkerton in Glasgow, UK. There have only been approximately just over 100 cases reported. Majority of these cases were female, and usually began noticing symptoms late into their pregnancies and in early postpartum. [5]
Macroprolactin is the term used to describe complexed forms of the pituitary hormone prolactin which are found in blood. The most common complex found in blood consists of prolactin and immunoglobulin G (IgG). While the free prolactin hormone is active, prolactin in the macroprolactin complex does not have any biological activity in the body and is considered benign. However, macroprolactin is detected by all Laboratory tests that measure prolactin in blood. This leads to misdiagnosis of hyperprolactinaemia in many people, especially those with other symptoms, such as infertility or menstrual problems.
Cushing's disease is one cause of Cushing's syndrome characterised by increased secretion of adrenocorticotropic hormone (ACTH) from the anterior pituitary. This is most often as a result of a pituitary adenoma or due to excess production of hypothalamus CRH that stimulates the synthesis of cortisol by the adrenal glands. Pituitary adenomas are responsible for 80% of endogenous Cushing's syndrome, when excluding Cushing's syndrome from exogenously administered corticosteroids. The equine version of this disease is Pituitary pars intermedia dysfunction.
Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal glands—also referred to as the adrenal cortex—normally secrete glucocorticoids, mineralocorticoids, and androgens. These hormones are important in regulating blood pressure, electrolytes, and metabolism as a whole. Deficiency of these hormones leads to symptoms ranging from abdominal pain, vomiting, muscle weakness and fatigue, low blood pressure, depression, mood and personality changes to organ failure and shock. Adrenal crisis may occur if a person having adrenal insufficiency experiences stresses, such as an accident, injury, surgery, or severe infection; this is a life-threatening medical condition resulting from severe deficiency of cortisol in the body. Death may quickly follow.
Growth hormone deficiency (GHD), or human growth hormone deficiency, is a medical condition resulting from not enough growth hormone (GH). Generally the most noticeable symptom is that an individual attains a short height. Newborns may also present low blood sugar or a small penis size. In adults there may be decreased muscle mass, high cholesterol levels, or poor bone density.
Anovulation is when the ovaries do not release an oocyte during a menstrual cycle. Therefore, ovulation does not take place. However, a woman who does not ovulate at each menstrual cycle is not necessarily going through menopause. Chronic anovulation is a common cause of infertility.
Hypopituitarism is the decreased (hypo) secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is known as selective hypopituitarism. If there is decreased secretion of most or all pituitary hormones, the term panhypopituitarism is used.
Sheehan's syndrome, also known as postpartum pituitary gland necrosis, occurs when the pituitary gland is damaged due to significant blood loss and hypovolemic shock usually during or after childbirth leading to decreased functioning of the pituitary gland (hypopituitarism). The pituitary gland is an endocrine organ, meaning it produces certain hormones and is involved in the regulation of various other hormones. This gland is located in the brain and sits in a pocket of the sphenoid bone known as the sella turcica. The pituitary gland works in conjunction with the hypothalamus, and other endocrine organs to modulate numerous bodily functions including growth, metabolism, menstruation, lactation, and even the "fight-or-flight" response. These endocrine organs release hormones in very specific pathways, known as hormonal axes. For example, the release of a hormone in the hypothalamus will target the pituitary to trigger the release of a subsequent hormone, and the pituitary's released hormone will target the next organ in the pathway. Hence, damage to the pituitary gland can have downstream effects on any of the aforementioned bodily functions.
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms and the estimated prevalence rate in the general population is approximately 17%.
A prolactinoma is a tumor (adenoma) of the pituitary gland that produces the hormone prolactin. It is the most common type of functioning pituitary tumor. Symptoms of prolactinoma are due to abnormally high levels of prolactin in the blood (hyperprolactinemia), or due to pressure of the tumor on surrounding brain tissue and/or the optic nerves. Based on its size, a prolactinoma may be classified as a microprolactinoma or a macroprolactinoma.
Thyroid hormone resistance (also resistance to thyroid hormone (RTH), and sometimes Refetoff syndrome) describes a rare syndrome in which the thyroid hormone levels are elevated but the thyroid stimulating hormone (TSH) level is not suppressed, or not completely suppressed as would be expected. The first report of the condition appeared in 1967. Essentially this is decreased end organ responsiveness to thyroid hormones. A new term "impaired sensitivity to thyroid hormone" has been suggested in March 2014 by Refetoff et al.
Adrenocorticotropic hormone deficiency is a rare disorder characterized by secondary adrenal insufficiency with minimal or no cortisol production and normal pituitary hormone secretion apart from ACTH. ACTH deficiency may be congenital or acquired, and its symptoms are clinically similar to those of glucocorticoid deficiency. Symptoms consist of weight loss, diminished appetite, muscle weakness, nausea, vomiting, and hypotension. Low blood sugar and hyponatremia are possible; however, blood potassium levels typically remain normal because affected patients are deficient in glucocorticoids rather than mineralocorticoids because of their intact renin-angiotensin-aldosterone system. ACTH may be undetectable in blood tests, and cortisol is abnormally low. Glucocorticoid replacement therapy is required. With the exception of stressful situations, some patients with mild or nearly asymptomatic disease may not require glucocorticoid replacement therapy. As of 2008 about two hundred cases have been described in the literature.
Hyperpituitarism is a condition due to the primary hypersecretion of pituitary hormones; it typically results from a pituitary adenoma. In children with hyperpituitarism, disruption of growth regulation is rare, either because of hormone hypersecretion or because of manifestations caused by local compression of the adenoma.
Pituitary apoplexy is bleeding into or impaired blood supply of the pituitary gland. This usually occurs in the presence of a tumor of the pituitary, although in 80% of cases this has not been diagnosed previously. The most common initial symptom is a sudden headache, often associated with a rapidly worsening visual field defect or double vision caused by compression of nerves surrounding the gland. This is often followed by acute symptoms caused by lack of secretion of essential hormones, predominantly adrenal insufficiency.
POU class 1 homeobox 1, also known as pituitary-specific positive transcription factor 1 (PIT1), POU domain, class 1, transcription factor 1 (POU1F1) and growth hormone factor 1 (GHF1), is a transcription factor for growth hormone encoded by the gene POU1F1.
Homeobox protein prophet of PIT-1 is a protein that in humans is encoded by the PROP1 gene.
Growth hormone 2 (GH2), also known more commonly as placental growth hormone (PGH) or growth hormone variant (GH-V), is a protein that in humans is encoded by the GH2 gene. It is produced by and secreted from the placenta during pregnancy, and becomes the predominant form of growth hormone (GH) in the body during this time. Its cogener is growth hormone 1 (GH1), or pituitary growth hormone.
Autoimmune hypophysitis is defined as inflammation of the pituitary gland due to autoimmunity.
Thyroid stimulating hormone, beta also known as TSHB is a protein which in humans is encoded by the TSHB gene.
Tuber cinereum hamartoma is a benign tumor in which a disorganized collection of neurons and glia accumulate at the tuber cinereum of the hypothalamus on the floor of the third ventricle. It is a congenital malformation, included on the spectrum of gray matter heterotopias. Formation occurs during embryogenesis, typically between days 33 and 41 of gestation. Size of the tumor varies from one to three centimeters in diameter, with the mean being closer to the low end of this range. It is estimated to occur at a frequency of one in one million individuals.