Tuesday, April 10, 2012

Diseases of the pituitary


Definition 
The pituitary gland or pituitary gland consists of anterior and posterior lobes, whose activity is influenced by the hypothalamus. Anterior pituitary manage Neurohormones synthesized in the hypothalamus and anterior pituitary lobe - regulates the secretion of pituitary hormones from peripheral endocrine organs, thyroid, adrenal glands, sex glands, and the growth and lactation. Posterior lobe pituitary gland - neurohypophysis consists of parts of nerve cells that are originally from the hypothalamus and thus regulates the metabolism of water, milk secretion and uterine contractions.

The clinical picture
Patients with disease of the hypothalamus and pituitary have a combination of symptoms that include: the formation of intracranial symptoms (headache, disorders of the visual field), and excessive or insufficient secretion of one or more pituitary hormones. Symptoms of hypo-and hypersecretion of pituitary hormones usually occur in patients with neoplasma (tumor) of the hypothalamus and pituitary, but the same can also be caused by other causes. At the pathological formation in the hypothalamus and pituitary gland should be suspected when the X-ray images (X-ray) found increased village turcica (Turkish saddle - part of the brain that corresponds accommodation pituitary) or when there are neurological symptoms.

A) Diseases of the pituitary

First Hypofunction
Reduced secretion of pituitary hormones can be generalized, and they speak about, or hypopituitarism can be caused by a lack of one or more pituitary hormones. Generalized hypopituitarism is an endocrine deficiency syndrome due to partial or complete loss of pituitary function. The causes may be different from the development of pituitary tumors via inflammatory and autoimmune processes and idiopathic (unknown cause) a lack of pituitary hormones. Symptoms and signs of hypopituitarism corresponding underlying disease and the symptoms and signs that go along with a lack of pituitary hormones.

Onset can be sudden and dramatic, but it usually goes, and gradually the disease is not recognized immediately.Usually it is stated that first comes to a reduction of gonadotropins (hormones), the resulting disruption and loss of growth hormone (HR), and ultimately reduce the thyrotropin (TSH) and adrenocorticotropic hormone (ACTH). Generalized lack of pituitary hormones must be proved before the patient begins to heal lifelong hormonal supplementation. It is necessary to find the symptoms of hormone deficiency or morphological changes (structural changes) pituitary.

HR deficiency in adults usually causes no symptoms that were clinically recognizable. TSH deficiency results in the development of hypothyroidism, impaired function of the thyroid gland, causing a lack of ACTH hipofunkciju adrenal gland, which is manifested in fatigue, reduced blood pressure, infections and stress intolerance.
Isolated pituitary hormone deficiency is usually detected in childhood or in adolescence because of the slowdown in growth or a delay in sexual maturation.

Diagnosis
For the diagnosis of adenoma methods of choice are CT (computed tomography) and MRI (magnetic resonance).Rating thyroid function is determined by radioimmunoassay, and all hormone levels should be reduced, thyroxine (T4), triiodothyronine (T4) and TSH. If TSH is elevated, the primary disorder of the thyroid. Insulin tolerance test is used to determine ACTH reserve.

Treatment
In any case require the replacement hormone is secreted insufficiently weakened function of the target gland, the pituitary gland under control. If hypopituitarism occurred because of a tumor, the treatment is specifically directed at removing the tumor surgically or with combating drugs (bromocriptine), and also to compensate the target gland hormones, which are hypofunction.

Second Hyperfunction
Excessive secretion of pituitary hormones called hiperpituitarizam, the most common hormones that are secreted without excessive growth hormone (HR), prolactin and ACTH. Increased secretion of HRA results in the appearance of gigantism and acromegaly, and usually is caused by the presence of adenoma (glandular tumor) corresponding pituitary cells.

Excess HRA can occur at any age but most commonly occurs between 30 and 50 years. If excessive secretion occurs in childhood before complete closure of the epiphysis (bone components important for growth) occurs pituitary gigantism, overgrowth. If the increased HR occurs after the close of the epiphysis, resulting coarse facial features, and thickening of the hands and feet, as the first signs of a disease called acromegaly. There are also other symptoms such as hair, coarser and darker skin, excessive sweating, and excessive growth of the lower jaw (mandible) - prognathism.

Diagnosis
There is a determination of excessive levels of serum HRA and hand radiograph showing thickening. The recommended treatment is removal of the tumor by surgery or radiation, and if it is not possible or effective, recommended drug treatment. The most common cause of elevated levels of prolactin, resulting in galactorrhea (secretion of milk in men or women who do not breastfeed), the prolactin, a pituitary tumor that secretes excessive amounts of prolactin. With increased levels of prolactin, gonadotropins are sometimes reduced, and estradiol.

Treatment
It depends on the size of prolactinomas and symptoms, and can be used bromocriptine or conduct surgery or radiotherapy in patients with tumor progression. It takes a patient in any case be kept under surveillance.


B) Diseases of the posterior pituitary
Posterior pituitary lobe is responsible for the secretion of vasopressin, or antidiuretic hormone (ADH). Disease reduces the posterior pituitary levels of vasopressin is secreted causing excessive amounts of very dilute urine (polyuria), and while the present excessive thirst (polydipsia). The disease is called central diabetes insipidus and diabetes and it is characterized by excessive drinking and excessive urination. Treatment may be a hormone, when administered hormone supplements or non-hormonal drugs when used to prevent excessive urination.

No comments:

Post a Comment