Chapter 14 Endocrine disorders Flashcards
What is the Endocrine System?
○ maintains metabolic equilibrium by continuously adjusting mutually opposing forces, a process known as homeostasis
○ It does this by secreting hormones that stimulate a target organ, which in turn secretes its own hormone(s) to achieve the desired end effect
The normal endocrine system
○ pituitary secretes multiple hormones.
○ The thyroid gland regulates metabolic rate.
○ The adrenal cortex secretes corticosteroids.
○ The adrenal medulla is anatomically and
○ functionally distinct from the cortex.
○ The parathyroid glands regulate calcium metabolism.
Pituitary adenomas usually cause what?
Hyperpituitarism
Hyperpituitarism
○ excretion of excess trophic hormones and can be caused by hyperplasia, adenoma, or carcinoma of any of the cell types of the anterior pituitary
○ more common than hypopituitarism
Hypopituitarism
○ decreased secretion of pituitary hormones
○ failure of the anterior pituitary and do not involve the posterior pituitary
Prolactinoma
○ most common functioning pituitary tumor
○ accounting for about 30% of adenomas
○ causes galactorrhea
galactorrhea
milk secretions from the breast of a male or nonpregnant female
Null Cell Adenoma
○ do not secrete hormones and come to attention because of mass effect
○ originate from any of the cell types in the anterior pituitary
ACTH Adenoma
○ account for about 15% of pituitary adenomas
○ associated with excessive secretion of cortisol and related hormones from the adrenal cortex
○ produce a combination of clinical findings known as Cushing syndrome
- Growth Hormone Adenoma
○ secrete GH and also prolactin
○ Often the early clinical manifestations are subtle
GH adenoma causes which two syndromes?
○ Acromegaly
○ Gigantism
Acromegaly
○ conspicuous growth of bones in the hands, feet, face, skull, and jaw
○ growth of liver, heart, thyroid, adrenals, and other viscera
○ and expansion of the skin and soft tissue.
○ Patients have prominent brows and chin, gapped teeth, and huge feet and hands with thick fingers.
Gigantism
○ general increase in body size, with especially long arms and legs
○ occurs when a child or teenager develops an adenoma that secretes GH before growth plates close at the ends of long bones
TSH Adenoma
secrete TSH and are rare stimulates thyroid release of T3 and T4, which causes hyperthyroidism
TSG adenoma treatments
○ surgical or radiotherapeutic ablation of the lesion
○ drug treatment to counteract the effects of increased T3 and T4
Hyperthyroidism
increased blood TSH and radiographic imaging of the Sella turcica
What is a sign of posterior pituitary failure?
evidence of failure of the posterior pituitary in the form of diabetes insipidus (DI) due to secretion of too little or too much ADH
Diabetes Insipidus
○ a syndrome of ADH deficiency and features excessive production of dilute urine
○ Patients are frequently dehydrated and have high blood sodium and osmolarity and low urine specific gravity
inappropriate ADH secretion (SIADH)
○ associated with excessive ADH production, usually from a nonpituitary neoplasm
○ Symptoms are essentially due to water intoxication
○ low serum sodium, while having concentrated urine with high urine sodium
pituitary apoplexy
○ Sudden pituitary hemorrhage
○ usually as a consequence of some other pathologic process in the pituitary
Sheehan syndrome
○ Ischemic infarction of pregnancy
○ physiologic demands of pregnancy cause pituitary hyperplasia
Thyrotoxicosis
○ a hypermetabolic state caused by excess thyroid hormone
○ caused by increased levels of blood T3 and/or T4, no matter the source
Graves disease
○ the most common cause of hyperthyroidism
○ an autoimmune disease caused by the production of multiple antithyroid antibodies
○ thyroid-stimulating immunoglobulin (TSI)
When does Graves disease occur?
○ between ages 20 and 40
○ Women are affected about 10 times more often than men
Cretinism
congenital hypothyroidism
Myxedema
○ hypothyroidism that develops in an older child or an adult
○ thyroid is usually not enlarged
○ accumulations of thick (myxomatous) fluid in various organs
○ The skin is cool and pale
Hashimoto Thyroiditis
○ a chronic autoimmune disease
○ the most common type of thyroiditis
○ occurs as a nontoxic goiter and almost exclusively in middle aged women
Hypothyroidism
thyroid hormone underproduction by the thyroid gland
Thyroiditis
inflammation of the thyroid gland
Nontoxic goiters
impaired synthesis of thyroid hormone
Neoplasms of the thyroid are?
common and usually not aggressive
Euthyroid Sick Syndrome
Patients with severe nonthyroidal illness may have abnormally low thyroid function tests but are clinically euthyroid
goiter
○ an enlarged thyroid gland
The three most common types of thyrotoxicosis are
○ glandular hyperplasia
○ Multinodular goiter
○ Adenoma of the thyroid with overproduction of hormones
Thyroid follicular adenomas
○ are benign neoplasms of the epithelial cells that line thyroid follicles
○ reveal themselves as a solitary, painless mass in an otherwise healthy woman with no evidence of thyroid hormone excess or thyroid failure
Thyroid Carcinomas
○ arise from the epithelium that lines the thyroid follicles
○ Most occur in adults; females are more affected than males
Thyroid Carcinomas types
○ Papillary carcinomas: are the most common
○ Follicular carcinomas: malignant neoplasms of follicular epithelium arranged into follicles
○ Anaplastic carcinoma: a highly aggressive, almost uniformly fatal malignancy of follicular epithelium
○ Medullary carcinomas:
Adrenocortical hyperfunction
excess cortical hormones.
Adrenocortical failure
causes cortisol insufficiency
Cushing syndrome
exogenous—glucocorticoid medical therapy
○ suppress pituitary production of ACTH and the cortex becomes thin and atrophic
Cushing syndrome: Signs and Symptoms
hypertension, obesity, round (moon) facial features, diabetes, skin marks (striae), excess body and facial hair (hirsutism), and menstrual and mental abnormalities
Adrenocortical insufficiency
results in concurrent deficiency of all three corticosteroids
Primary acute cortical failure
○ occurs in three clinical settings and is invariably fatal without quick diagnosis and cortisol replacement
○ withdrawal of corticosteroid therapy. This is perhaps the most common cause of acute cortical failure
(Waterhouse-Friderichsen syndrome
Bilateral acute hemorrhagic destruction of the adrenal glands
Addison Disease
○ Primary chronic cortical failure
○ attributable to one of four conditions: autoimmune adrenalitis, TB, AIDS, or metastatic carcinoma
Hyperparathyroidism
overactivity of the parathyroid glands
Hypoparathyroidism
underactivity of the parathyroid glands
MEN-1 syndrome (Wermer)
Abnormal function of parathyroid, pancreas, pituitary, and duodenal gastrin-secreting cells
MEN-2 syndrome
Several subvarieties according to the glands involved
