Nelson Syndrome
Adrenocorticotropic Hormone
Adenoma, Chromophobe
Gold Radioisotopes
Cushing Syndrome
Pituitary Neoplasms
Pituitary ACTH Hypersecretion
Serotonin Syndrome
Serotonin Uptake Inhibitors
Serotonin
Monoamine Oxidase Inhibitors
Encyclopedias as Topic
Adrenergic Uptake Inhibitors
Pituitary tumors: pathophysiology, clinical manifestations and management. (1/26)
Pituitary tumors are frequently encountered intracranial neoplasms. They present with a variety of clinical manifestations that include symptoms and signs of excessive hormone secretion by the tumor, signs of hormone deficits by the normal pituitary gland and others related to expansion of the tumor mass and the resulting compression of surrounding structures such as the optic chiasm and cranial nerves. Advances in molecular biology, immunocytochemical staining and imaging, and the introduction of new treatment options have improved our understanding of the natural history of these adenomas and their management. Available treatments include surgical, medical and radiation therapy. Although the primary treatment for each tumor type may vary, it is important to consider all available options and select the most applicable for that patient. The interaction of all members of management team, including the primary care provider, the endocrinologist and the neurosurgeon in selecting the treatment course can only improve therapeutic outcome. Regardless of the initial choice of treatment,follow-up of all patients should be maintained indefinitely. The managing physician should be familiar with the natural history and long-term complications of pituitary adenomas, and with the side effects of treatments given over the years. (+info)Expression of 5'-deiodinase enzymes in normal pituitaries and in various human pituitary adenomas. (2/26)
OBJECTIVE: Local 5'-deiodination of l-thyroxine (T(4)) to active thyroid hormone 3,3',5-tri-iodothyronine (T(3)) catalyzed by the two 5'-deiodinase enzymes (D1 and D2) regulates various T(3)-dependent functions in the anterior pituitary and has been well studied in rodents. Only limited information about deiodinase expression and its cellular distribution in human anterior pituitaries is available. DESIGN: We examined 5'-deiodinase enzyme activities in pituitary adenomas (18 non-functioning, seven TSH-producing, one GH- and TSH-producing, five GH-producing, eight prolactin (PRL)-producing, two adenomas each from patients with Cushing's disease and Nelson's syndrome) and three normal anterior pituitaries. METHODS: Activities were measured as release of (125)I(-) from tyrosyl-ring labeled reverse T(3) with or without propylthiouracil, a potent inhibitor of D1 which does not influence D2 activities. RESULTS: Most of the adenomas and normal tissues expressed both isoenzymes, with D2 activity higher than D1. In a few tissues D1 activity was higher than D2 and some tissues did not express D1 activity at all. Highest activities of both enzymes were found in TSH- and PRL-producing adenomas but absolute activities and the D1/D2 ratio were variable in the same kind of tumor in different patients. CONCLUSION: The finding that all examined tissues expressed 5'-deiodinase activity, most of them expressing both isoenzymes, implies that both enzymes are still active in tumors and that local deiodination is important for the function and feedback regulation of human anterior pituitary. (+info)Microsurgical treatment of Nelson's syndrome. (3/26)
OBJECTIVE: To discuss the etiology, diagnostic criteria and treatment of Nelson's syndrome. METHODS: Twenty-three patients with Nelson's syndrome who were treated in our department over the last 19 years were analyzed retrospectively. Removal of adenoma by the transsphenoidal approach was done in 21 patients and by transfrontal craniotomy in 2. The follow-up period ranged from six months to nine years. RESULTS: The incidence of Nelson's syndrome was 7.7% in a series of 300 patients with Cushing's disease treated by microsurgery in the same period. Hyperpigmentation was relieved and adrenocorticotropic hormone (ACTH) levels decreased in all patients after tumor excision. Eight patients with visual disturbance improved after surgery. The curative and remission rates were 56.5% and 26.1%, respectively. CONCLUSIONS: Transsphenoidal microsurgical removal of pituitary ACTH adenoma is the first choice in the prevention and treatment of Nelson's syndrome. Regular follow-up examinations should be performed over a long time. (+info)Rosiglitazone for prevention or adjuvant treatment of Nelson's syndrome after bilateral adrenalectomy. (4/26)
OBJECTIVE: To investigate the effect of Rosiglitazone in three patients treated with bilateral adrenalectomy followed by hyperpigmentation and hypersecretion of ACTH. PATIENTS AND METHODS: One patient had increasing ACTH after previous transsphenoidal surgery for Nelson's syndrome, and two patients without pituitary adenomas had recurrence of Cushing's disease after primary and repeated transsphenoidal surgery with need for bilateral adrenalectomy. The patients developed hyperpigmentation and increasing ACTH at nadir 2-4 h after morning hydrocortisone dose. ACTH during Rosiglitazone therapy (4 mg/day for 4 weeks and then 8 mg/day) was measured at regular intervals 24 h after the latest dose of hydrocortisone. RESULTS: In two patients there was a decrease in ACTH by 40% after 5 months. The first of these patients showed an escape with increasing ACTH to the initial value after 11 months. In the third patient no effect was observed. Tumour development or progression on magnetic resonance imaging was not observed. CONCLUSION: Rosiglitazone might represent an adjuvant therapy in patients with ACTH hypersecretion. Larger long-term studies are needed. (+info)Nelson's Syndrome. (5/26)
Nelson's syndrome is a potentially severe complication of bilateral adrenalectomy performed in the treatment of Cushing's disease, and its management remains difficult. Of all of the features of Nelson's syndrome, the one that causes most concern is the development of a locally aggressive pituitary tumour, which, unusually for pituitary disease, may occasionally cause death from the tumour itself. This feature is especially pertinent given the increasing use in Cushing's disease of laparoscopic bilateral adrenal surgery as a highly effective treatment modality to control cortisol-excess. Despite numerous studies and reports, there is no formal consensus of what defines Nelson's syndrome. Thus, some will define Nelson's syndrome according to the classical description with an evolving pituitary mass after bilateral adrenalectomy, whereas others will rely on increasing plasma ACTH levels, even in the absence of a clear pituitary mass lesion on MRI. These factors need to be borne in mind when considering the reports of Nelson's syndrome, as there is great heterogeneity, and it is likely that overall the modern 'Nelson's syndrome' represents a different disease entity from that of the last century. In the present paper, clinical and epidemiological features of Nelson's syndrome, as well as its treatment modalities, are reviewed. (+info)Treatment of adrenocorticotropin-dependent Cushing's syndrome: a consensus statement. (6/26)
(+info)Treatment of Nelson's syndrome with temozolomide. (7/26)
(+info)Gamma knife stereotactic radiosurgery of Nelson syndrome. (8/26)
(+info)Nelson's syndrome is a rare condition that occurs in some patients with a history of Cushing's disease who have undergone bilateral adrenalectomy (removal of both adrenal glands). Following the surgery, these patients may develop enlargement of the pituitary gland (pituitary tumor) and increased production of ACTH (adrenocorticotropic hormone) from the remaining pituitary tissue. This results in hyperpigmentation of the skin due to the melanocyte-stimulating property of ACTH, as well as other symptoms related to hormonal imbalance. It is named after the endocrinologist Don Nelson who first described this condition in 1958.
Adrenocorticotropic Hormone (ACTH) is a hormone produced and released by the anterior pituitary gland, a small endocrine gland located at the base of the brain. ACTH plays a crucial role in the regulation of the body's stress response and has significant effects on various physiological processes.
The primary function of ACTH is to stimulate the adrenal glands, which are triangular-shaped glands situated on top of the kidneys. The adrenal glands consist of two parts: the outer cortex and the inner medulla. ACTH specifically targets the adrenal cortex, where it binds to specific receptors and initiates a series of biochemical reactions leading to the production and release of steroid hormones, primarily cortisol (a glucocorticoid) and aldosterone (a mineralocorticoid).
Cortisol is involved in various metabolic processes, such as regulating blood sugar levels, modulating the immune response, and helping the body respond to stress. Aldosterone plays a vital role in maintaining electrolyte and fluid balance by promoting sodium reabsorption and potassium excretion in the kidneys.
ACTH release is controlled by the hypothalamus, another part of the brain, which produces corticotropin-releasing hormone (CRH). CRH stimulates the anterior pituitary gland to secrete ACTH, which in turn triggers cortisol production in the adrenal glands. This complex feedback system helps maintain homeostasis and ensures that appropriate amounts of cortisol are released in response to various physiological and psychological stressors.
Disorders related to ACTH can lead to hormonal imbalances, resulting in conditions such as Cushing's syndrome (excessive cortisol production) or Addison's disease (insufficient cortisol production). Proper diagnosis and management of these disorders typically involve assessing the function of the hypothalamic-pituitary-adrenal axis and addressing any underlying issues affecting ACTH secretion.
A chromophobe adenoma is a type of benign (non-cancerous) tumor that typically arises in the pituitary gland, which is a small endocrine gland located at the base of the brain. The term "chromophobe" refers to the appearance of the cells under a microscope - they lack pigment and have a characteristic appearance with abundant clear or lightly stained cytoplasm.
Chromophobe adenomas are slow-growing tumors that can vary in size, and they may cause symptoms due to pressure on surrounding structures or by producing excess hormones. The most common hormone produced by chromophobe adenomas is prolactin, leading to symptoms such as menstrual irregularities, milk production (galactorrhea), and decreased sexual function in women, and decreased libido, erectile dysfunction, and infertility in men.
Treatment for chromophobe adenomas typically involves surgical removal of the tumor, often through a transsphenoidal approach (through the nose and sphenoid sinus). In some cases, radiation therapy or medical management with hormone-blocking drugs may also be necessary. Regular follow-up with an endocrinologist is important to monitor for any recurrence or hormonal imbalances.
Gold radioisotopes are unstable forms of gold that emit radiation as they decay into more stable elements. They are not typically used for medical purposes, but there have been some experimental uses in the treatment of cancer. For example, Gold-198 is a radioisotope that has been used in the brachytherapy (internal radiation therapy) of certain types of tumors. It releases high-energy gamma rays and is often used as a sealed source for the treatment of cancer.
It's important to note that the use of radioisotopes in medicine, including gold radioisotopes, should only be performed under the supervision of trained medical professionals and radiation safety experts due to the potential risks associated with radiation exposure.
Cushing syndrome is a hormonal disorder that occurs when your body is exposed to high levels of the hormone cortisol for a long time. This can happen due to various reasons such as taking high doses of corticosteroid medications or tumors that produce cortisol or adrenocorticotropic hormone (ACTH).
The symptoms of Cushing syndrome may include:
* Obesity, particularly around the trunk and upper body
* Thinning of the skin, easy bruising, and purple or red stretch marks on the abdomen, thighs, breasts, and arms
* Weakened bones, leading to fractures
* High blood pressure
* High blood sugar
* Mental changes such as depression, anxiety, and irritability
* Increased fatigue and weakness
* Menstrual irregularities in women
* Decreased fertility in men
Cushing syndrome can be diagnosed through various tests, including urine and blood tests to measure cortisol levels, saliva tests, and imaging tests to locate any tumors. Treatment depends on the cause of the condition but may include surgery, radiation therapy, chemotherapy, or adjusting medication dosages.
Pituitary neoplasms refer to abnormal growths or tumors in the pituitary gland, a small endocrine gland located at the base of the brain. These neoplasms can be benign (non-cancerous) or malignant (cancerous), with most being benign. They can vary in size and may cause various symptoms depending on their location, size, and hormonal activity.
Pituitary neoplasms can produce and secrete excess hormones, leading to a variety of endocrine disorders such as Cushing's disease (caused by excessive ACTH production), acromegaly (caused by excessive GH production), or prolactinoma (caused by excessive PRL production). They can also cause local compression symptoms due to their size, leading to headaches, vision problems, and cranial nerve palsies.
The exact causes of pituitary neoplasms are not fully understood, but genetic factors, radiation exposure, and certain inherited conditions may increase the risk of developing these tumors. Treatment options for pituitary neoplasms include surgical removal, radiation therapy, and medical management with drugs that can help control hormonal imbalances.
Pituitary ACTH hypersecretion, also known as Cushing's disease, is a condition characterized by the excessive production of adrenocorticotropic hormone (ACTH) from the pituitary gland. This results in an overproduction of cortisol, a steroid hormone produced by the adrenal glands, leading to a constellation of symptoms known as Cushing's syndrome.
In Cushing's disease, a benign tumor called an adenoma develops on the pituitary gland, causing it to release excess ACTH. This in turn stimulates the adrenal glands to produce more cortisol than necessary. The resulting high levels of cortisol can cause various symptoms such as weight gain, particularly around the trunk and face (central obesity), thinning of the skin, bruising, weakness, fatigue, mood changes, high blood pressure, and an increased risk of infections.
It is important to distinguish Cushing's disease from other causes of Cushing's syndrome, such as cortisol-producing adrenal tumors or exogenous sources of corticosteroid use, as the treatment approach may differ. Treatment for Cushing's disease typically involves surgical removal of the pituitary tumor, with additional medical management and/or radiation therapy in some cases.
Adrenalectomy is a surgical procedure in which one or both adrenal glands are removed. The adrenal glands are small, triangular-shaped glands located on top of each kidney that produce hormones such as cortisol, aldosterone, and adrenaline (epinephrine).
There are several reasons why an adrenalectomy may be necessary. For example, the procedure may be performed to treat tumors or growths on the adrenal glands, such as pheochromocytomas, which can cause high blood pressure and other symptoms. Adrenalectomy may also be recommended for patients with Cushing's syndrome, a condition in which the body is exposed to too much cortisol, or for those with adrenal cancer.
During an adrenalectomy, the surgeon makes an incision in the abdomen or back and removes the affected gland or glands. In some cases, laparoscopic surgery may be used, which involves making several small incisions and using specialized instruments to remove the gland. After the procedure, patients may need to take hormone replacement therapy to compensate for the loss of adrenal gland function.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
Serotonin syndrome is a potentially life-threatening condition that arises from excessive serotonergic activity in the central nervous system (CNS) and peripheral nervous system. It is typically caused by the interaction of medications, illicit substances, or dietary supplements that increase serotonin levels or enhance serotonin receptor sensitivity.
The diagnostic criteria for serotonin syndrome include:
1. Presence of a serotonergic medication or drug known to cause the syndrome
2. Development of neuromuscular abnormalities, such as hyperreflexia, myoclonus, tremor, rigidity, or akathisia
3. Autonomic dysfunction, including diaphoresis, tachycardia, hypertension, dilated pupils, and hyperthermia
4. Mental status changes, such as agitation, confusion, hallucinations, or coma
5. Symptoms that develop rapidly, usually within hours of a change in serotonergic medication or dosage
Serotonin syndrome can range from mild to severe, with the most severe cases potentially leading to respiratory failure, rhabdomyolysis, disseminated intravascular coagulation (DIC), and death. Treatment typically involves discontinuation of the offending agent(s), supportive care, and pharmacologic interventions such as cyproheptadine or cooling measures for hyperthermia.
Methylergonovine is a medication that belongs to a class of drugs called ergot alkaloids. It is primarily used to prevent and treat uterine bleeding after childbirth. Medically, it is defined as a semi-synthetic ergopeptide analog with oxytocic properties, which stimulates myometrial contractions and reduces postpartum hemorrhage.
Methylergonovine works by stimulating the smooth muscle of the uterus, causing it to contract. This helps to return the uterus to its pre-pregnancy size and also helps to control bleeding after childbirth. It is important to note that methylergonovine should only be used under the supervision of a healthcare provider, as it can have serious side effects if not used properly.
Serotonin uptake inhibitors (also known as Selective Serotonin Reuptake Inhibitors or SSRIs) are a class of medications primarily used to treat depression and anxiety disorders. They work by increasing the levels of serotonin, a neurotransmitter in the brain that helps regulate mood, appetite, and sleep, among other functions.
SSRIs block the reuptake of serotonin into the presynaptic neuron, allowing more serotonin to be available in the synapse (the space between two neurons) for binding to postsynaptic receptors. This results in increased serotonergic neurotransmission and improved mood regulation.
Examples of SSRIs include fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), citalopram (Celexa), and escitalopram (Lexapro). These medications are generally well-tolerated, with side effects that may include nausea, headache, insomnia, sexual dysfunction, and increased anxiety or agitation. However, they can have serious interactions with other medications, so it is important to inform your healthcare provider of all medications you are taking before starting an SSRI.
Serotonin, also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter that is found primarily in the gastrointestinal (GI) tract, blood platelets, and the central nervous system (CNS) of humans and other animals. It is produced by the conversion of the amino acid tryptophan to 5-hydroxytryptophan (5-HTP), and then to serotonin.
In the CNS, serotonin plays a role in regulating mood, appetite, sleep, memory, learning, and behavior, among other functions. It also acts as a vasoconstrictor, helping to regulate blood flow and blood pressure. In the GI tract, it is involved in peristalsis, the contraction and relaxation of muscles that moves food through the digestive system.
Serotonin is synthesized and stored in serotonergic neurons, which are nerve cells that use serotonin as their primary neurotransmitter. These neurons are found throughout the brain and spinal cord, and they communicate with other neurons by releasing serotonin into the synapse, the small gap between two neurons.
Abnormal levels of serotonin have been linked to a variety of disorders, including depression, anxiety, schizophrenia, and migraines. Medications that affect serotonin levels, such as selective serotonin reuptake inhibitors (SSRIs), are commonly used to treat these conditions.
Monoamine oxidase inhibitors (MAOIs) are a class of drugs that work by blocking the action of monoamine oxidase, an enzyme found in the brain and other organs of the body. This enzyme is responsible for breaking down certain neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are chemicals that transmit signals in the brain.
By inhibiting the action of monoamine oxidase, MAOIs increase the levels of these neurotransmitters in the brain, which can help to alleviate symptoms of depression and other mood disorders. However, MAOIs also affect other chemicals in the body, including tyramine, a substance found in some foods and beverages, as well as certain medications. As a result, MAOIs can have serious side effects and interactions with other substances, making them a less commonly prescribed class of antidepressants than other types of drugs.
MAOIs are typically used as a last resort when other treatments for depression have failed, due to their potential for dangerous interactions and side effects. They require careful monitoring and dosage adjustment by a healthcare provider, and patients must follow strict dietary restrictions while taking them.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Adrenergic uptake inhibitors are a class of medications that work by blocking the reuptake of neurotransmitters, such as norepinephrine and dopamine, into the presynaptic neuron. This results in an increase in the amount of neurotransmitter available to bind to postsynaptic receptors, leading to an enhancement of adrenergic transmission.
These medications are used in the treatment of various medical conditions, including depression, attention deficit hyperactivity disorder (ADHD), and narcolepsy. Some examples of adrenergic uptake inhibitors include:
* Tricyclic antidepressants (TCAs): These medications, such as imipramine and amitriptyline, were developed in the 1950s and are used to treat depression, anxiety disorders, and chronic pain.
* Selective serotonin-norepinephrine reuptake inhibitors (SNRIs): These medications, such as venlafaxine and duloxetine, were developed in the 1990s and are used to treat depression, anxiety disorders, and chronic pain.
* Norepinephrine-dopamine reuptake inhibitors (NDRIs): These medications, such as bupropion, are used to treat depression and ADHD.
It's important to note that these medications can have side effects and should be used under the supervision of a healthcare provider.