The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. The study of the endocrine system and its disorders is known as endocrinology.
Diabetes insipidus (DI) is a condition characterized by large amounts of dilute urine and increased thirst. The amount of urine produced can be nearly 20 liters per day. Reduction of fluid has little effect on the concentration of the urine. Complications may include dehydration or seizures.
In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a pea and weighing, on average, 0.5 grams (0.018 oz) in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The hypophysis rests upon the hypophysial fossa of the sphenoid bone in the center of the middle cranial fossa and is surrounded by a small bony cavity covered by a dural fold. The anterior pituitary is a lobe of the gland that regulates several physiological processes including stress, growth, reproduction, and lactation. The intermediate lobe synthesizes and secretes melanocyte-stimulating hormone. The posterior pituitary is a lobe of the gland that is functionally connected to the hypothalamus by the median eminence via a small tube called the pituitary stalk.
Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to glucocorticoids such as cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, a round red face, a fat lump between the shoulders, weak muscles, weak bones, acne, and fragile skin that heals poorly. Women may have more hair and irregular menstruation. Occasionally there may be changes in mood, headaches, and a chronic feeling of tiredness.
Gigantism, also known as giantism, is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood, resulting in people 2.4 to 2.9 m in height.
Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones, primarily cortisol; but may also include impaired production of aldosterone, which regulates sodium conservation, potassium secretion, and water retention. Craving for salt or salty foods due to the urinary losses of sodium is common.
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, is hypopituitarism, caused by ischemic necrosis due to blood loss and hypovolemic shock during and after childbirth.
Pituitary adenomas are tumors that occur in the pituitary gland. Pituitary adenomas are generally divided into three categories dependent upon their biological functioning: benign adenoma, invasive adenoma, and carcinomas. Most adenomas 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 benign tumor (adenoma) of the pituitary gland that produces a hormone called prolactin. It is the most common type of functioning pituitary tumor. Symptoms of prolactinoma are due to too much prolactin in the blood (hyperprolactinemia), or those caused by pressure of the tumor on surrounding tissues. Based on size, a prolactinoma can be classified as a microprolactinoma or a macroprolactinoma.
Martin Heinrich Rathke was a German embryologist and anatomist. Along with Karl Ernst von Baer and Christian Heinrich Pander, he is recognized as one of the founders of modern embryology. He was the father of chemist Bernhard Rathke (1840–1923).
In embryogenesis, Rathke's pouch is an evagination at the roof of the developing mouth in front of the buccopharyngeal membrane. It gives rise to the anterior pituitary (adenohypophysis), a part of the endocrine system.
A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence rates are childhood-onset at 5–14 years and adult-onset at 50–74 years. People may present with bitemporal inferior quadrantanopia leading to bitemporal hemianopsia, as the tumor may compress the optic chiasm. It has a point prevalence around two per 1,000,000. Craniopharyngiomas are distinct from Rathke's cleft tumours and intrasellar arachnoid cysts.
Nelson's syndrome is a rare disorder that sometimes occurs in patients in about 15-25% of patients who have had both adrenal glands removed to treat Cushing's disease. In patients with pre-existing adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas, loss of adrenal feedback following bilateral adrenalectomy can trigger the rapid growth of the tumor, leading to visual symptoms and hyperpigmentation. The severity of the disease is dependent upon the effect of ACTH release on the skin, pituitary hormone loss from mass compression, as well as invasion into surrounding structures around the pituitary gland.
Empty sella syndrome is the condition when the pituitary gland shrinks or becomes flattened, filling the sella turcica with cerebrospinal fluid instead of the normal pituitary. It can be discovered as part of the diagnostic workup of pituitary disorders, or as an incidental finding when imaging the brain.
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.
Oral and maxillofacial pathology refers to the diseases of the mouth, jaws and related structures such as salivary glands, temporomandibular joints, facial muscles and perioral skin. The mouth is an important organ with many different functions. It is also prone to a variety of medical and dental disorders.
Shona Holmes, or Shona Robertson-Holmes, is a Canadian woman who underwent treatment for a Rathke's cleft cyst in the United States, and claimed the condition threatened her life. Her cyst was removed August 1, 2005. Holmes sought treatment in the US claiming that she was unable to get timely treatment in Canada. Holmes sued the Ontario provincial government seeking payment for her medical and travel expenses. She has given testimony before members of the US Congress during a Republican-sponsored hearing about healthcare legislation, and has appeared in ads seeking to repeal the Patient Protection and Affordable Care Act and defeat President Obama in the 2012 presidential election.
Galactorrhea hyperprolactinemia is increased blood prolactin levels associated with galactorrhea. It may be caused by such things as certain medications, pituitary disorders and thyroid disorders. The condition can occur in males as well as females. Relatively common etiologies include prolactinoma, medication effect, kidney failure, granulomatous diseases of the pituitary gland, and disorders which interfere with the hypothalamic inhibition of prolactin release. Ectopic (non-pituitary) production of prolactin may also occur. Galactorrhea hyperprolactinemia is listed as a “rare disease” by the Office of Rare Diseases of the National Institutes of Health. This means that it affects less than 200,000 people in the United States population.
Endoscopic endonasal surgery is a minimally invasive technique used mainly in neurosurgery and otolaryngology. A neurosurgeon or an otolaryngologist, using an endoscope that is entered through the nose, fixes or removes brain defects or tumors in the anterior skull base. Normally an otolaryngologist performs the initial stage of surgery through the nasal cavity and sphenoid bone; a neurosurgeon performs the rest of the surgery involving drilling into any cavities containing a neural organ such as the pituitary gland. The use of endoscope was first introduced in Transsphenoidal Pituitary Surgery by R Jankowsky, J Auque, C Simon et al. in 1992 G.
