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Endocrine Module
Endocrine Module
72
Medical
Undergraduate 3
04/10/2012

Additional Medical Flashcards

 


 

Cards

Term
Anterior Pituitary
Definition

1. Thyroid Stimulating Hormone (TSH or thyrotropin)

2. Follicle Stimulating Hormone (FSH, a gonadotropin)

3. Luteinizing Hormone (LH, a gonadotropin)

4. Adrenocorticotropic Hormone (ACTH, or corticotropin)

5. Growth Hormone (GH)

6. Prolactin (PRL)

Term
Targets and Functions of the Anterior Pituitary Hormones
Definition

1. TSH – target thyroid gland and stimulates secretion of thyroid hormone (TH).

2. FSH – targets follicles in the ovaries of females and stimulates growth of follicle and production of estrogen. In males it targets the testes and stimulates sperm cell production.

3. LH – targets follicle, triggers ovulation and increases secretion of progesterone. In males, it stimulates testosterone production.

4. ACTH – targets the adrenal cortex and causes the secretion of glucocorticoids.

5. GH - targets most bodily tissues and stimulates metabolism and growth of those tissues.

6. PRL - targets the breasts in females. Stimulates breast development and lactation.

Of the six anterior pituitary hormones, four directly stimulate other endocrine glands and are known as tropic hormones (TSH, ACTH, FSH, LH).

Term
Posterior Pituitary
Definition

Targets and Functions of the Posterior Pituitary Hormones

1. ADH- antidiuretic hormone (vasopressin) – stimulates water reabsorption by kidneys.

2. Oxytocin – stimulates labor contractions during birth.

Term
Hormonal Regulation
Definition

Hypothalamic-Pituitary (hypophysis) Regulation

• Controls many functions of several endocrine glands

• Produces releasing hormones that stimulate the production of trophic hormones by anterior pituitary

Term
Negative
Definition

One of the most important features of the endocrine system is its regulation (control) by negative feedback. This means that the glands within the endocrine system that stimulate the release of a hormone (for example, the pituitary) from another gland (for example, the thyroid) are eventually shut off, in a sense, so that too much hormone is not produced and a hormone imbalance is avoided.

An example of negative feedback is the regulation of the blood calcium level. The parathyroid glands secrete parathyroid hormone, which regulates the blood calcium amount. If calcium decreases, the parathyroid glands sense the decrease and secrete more parathyroid hormone. The parathyroid hormone stimulates calcium release from the bones and increases the calcium uptake into the bloodstream from the collecting tubules in the kidneys. Conversely, if blood calcium increases too much, the parathyroid glands reduce parathyroid hormone production. Both responses are examples of negative feedback because in both cases the effects are negative (opposite) to the stimulus.

Term
Positive
Definition

A small number of hormones are regulated by the positive feedback mechanism. This occurs when rising levels of a hormone cause another gland to release a hormone that is stimulating to the first.

An example of positive feedback can be found in childbirth. The hormone oxytocin stimulates and enhances labor contractions. As the baby moves toward the vagina (birth canal), pressure receptors within the cervix (muscular outlet of uterus) send messages to the brain to produce oxytocin. Oxytocin travels to the uterus through the bloodstream, stimulating the muscles in the uterine wall to contract stronger (increase of ideal normal value). The contractions intensify and increase until the baby is outside the birth canal. When the stimulus to the pressure receptors ends, oxytocin production stops and labor contractions cease.

Also, exogenous forms of hormones (drugs) can influence the normal feedback control of hormones production and release. 

Term

Disorders of the Endocrine System

Definition
Disorders of the endocrine system are divided up into two categories: hyposecretion and hypersecretion.
Term
Hyposecretion
Definition
can be caused by congenital defects, disruption of blood flow, infection, inflammation, autoimmune responses, aging, or atrophy related to drugs or unknown.
Term
Hypersecretion
Definition
associated with excessive hormone production. Causes can be a hormone producing tumor or excessive stimulation and hyperplasia of the endocrine gland. Dysfunction, either hyposecretion or hypersecretion, may originate in the hypothalamus/pituitary, the hormone-producing gland, or the target tissue
Term
Endocrine disorders can further categorized as
Definition
primary, secondary or tertiary.
Term
Primary Endocrine disorders
Definition
Primary defects originate in the target gland responsible for producing the hormone.
Term
Secondary Endocrine Disorders
Definition
Secondary defects means the target gland is functioning normally but is altered by defective levels of stimulating hormones or releasing factors from the pituitary.
Term
Tertiary Endocrine Disorders
Definition
Tertiary defects occur when both the pituitary and target organ are understimulated.
Term

Pituitary

Definition
The pea-size pituitary gland is called the "master gland" because it regulates many key functions. The pituitary gland has an adenohypophysis (anterior lobe) and a neurohypophysis (posterior lobe).
Term
Pituitary Tumors
Definition

The most frequent cause of pituitary disorders is pituitary gland tumors. The pituitary gland is made of several cell types. Sometimes these cells grow too much or produce small growths.

These growths are called pituitary tumors, and they are fairly common in adults. These are not brain tumors and are not a form of cancer. In fact, cancerous tumors of this sort are extremely rare. Pituitary tumors, however, can interfere with the normal formation and release of hormones.

Two types of tumors exist - secretory and non-secretory.

Term
Secretory tumors
Definition
produce too much of a hormone, creating an imbalance of proper hormones in the body.
Term
Non-secretory tumors
Definition
cause problems because of their large size or because they interfere with normal function of the pituitary gland.
Term
The problems caused by pituitary tumors fall into three general categories:
Definition

Hypersecretion

Hyposecretion

Tumor mass effects

Term
Hypersecretion
Definition
Too much of any hormone secreted into the body is usually caused by a secretory pituitary gland tumor. Many secretory tumors make too much prolactin, the hormone that triggers milk production in new mothers. Other tumors may affect the adrenal glands, making too much of the hormones that stimulate them and causing a hormone imbalance. Tumors also can make excess growth hormone or too much of the hormone that stimulates the thyroid gland leading to overproduction of thyroid hormones.
Term
Hyposecretion
Definition
Too little of any hormone secreted into the body is usually caused by a non-secretory pituitary gland tumor, which interferes with the ability of the normal pituitary gland to create hormones. It can, however, also be caused by a large secretory tumor. Hyposecretion can also happen with surgery or the radiation of a pituitary gland tumor.
Term
Tumor mass effects
Definition
As a pituitary gland tumor grows and presses against the normal pituitary gland or other areas in the brain, it may cause headaches, vision problems, or other health effects related to hyposecretion. Tumor mass effects can be seen in any type of pituitary tumor that grows large enough. Injuries, certain medications, and other conditions can also affect the pituitary gland. Loss of normal pituitary function also has been reported after major head trauma.
Term
Growth Hormone (GH)
Definition
It is also called somatotropin. It is necessary for growth and contributes to the regulation of metabolic functions. GH is responsible for all growth including linear bone growth, periosteal growth, muscles, and organ and tissue growth. GH facilitates the rate of protein synthesis by all cells body, enhances fatty acid mobilization and maintains or increases blood glucose levels.
Term
Growth Hormone Deficiency in Children
Definition
  • GH levels (normal or elevated)
  • Decreased birth length
  • Decreased growth rate
  • Normal intelligence
  • Short stature
  • Obesity with immature facial features
  • Delay in skeletal maturation
  • Delayed puberty
Term
Growth Hormone Deficiency in Adults
Definition
  • Present in childhood or adult onset
  • Increased cardiovascular mortality
  • CV risk factors (central adiposity, insulin resistance and dyslipidemia-metabolic syndrome)
Term
The effect of excessive secretion of growth hormone is also very dependent on the age of onset and is seen as two distinctive disorders:
Definition

Gigantism

Acromegaly

Term
Acromegaly
Definition
results from excessive secretion of growth hormone in adults, usually the result of benign pituitary tumors. It occurs after the long epiphyses of the long bones are closed. The onset of this disorder is typically insidious, occurring over several years. Clinical signs of acromegaly include overgrowth of extremities, soft-tissue swelling, abnormalities in jaw structure and cardiac disease. The excessive growth hormone and IGF-I (insulin-like growth factor) also lead to a number of metabolic derangements, including hyperglycemia. Note the changes below of a person with acromegaly.
Term
Gigantism
Definition
is the result of excessive growth hormone secretion that begins in young children or adolescents (before puberty). It occurs before the epiphyseal plates are closed. It is a very rare disorder, usually resulting from a tumor of somatotropes. One of the most famous giants was a man named Robert Wadlow. He weighed 8.5 pounds at birth, but by 5 years of age was 105 pounds and 5 feet 4 inches tall. Robert reached an adult weight of 490 pounds and 8 feet 11 inches in height. He died at age 22.
Term

Thyroid Disorders

Definition

The thyroid gland has two lobes connected by an isthmus (small connecting stalk) and is in the lower part of the neck just below the larynx. The thyroid gland is the biggest gland in the neck. The thyroid gland takes the shape of a butterfly with the two wings being represented by the left and right thyroid lobes which wrap around the trachea. Thyroid hormone has two major functions:  it increases metabolism and protein synthesis and it is necessary for growth and development in children.

The thyroid gland produces three hormones:

  • Thyroxine (T4)
  • Triiodothyronine (T3)
  • Calcitonin

T4 and T3 help oxygen get into cells, and make your thyroid the master gland of metabolism. The thyroid has the only cells in the body capable of absorbing iodine. The thyroid takes in iodine, obtained through food, iodized salt, or supplements, and combines it with the amino acid tyrosine. The thyroid then converts the iodine/tyrosine into the hormones T3 and T4. The "3" and the "4" refer to the number of iodine molecules in each thyroid hormone molecule. Once released by the thyroid, the T3 and T4 travel through the bloodstream. The purpose is to help cells convert oxygen and calories into energy.

The secretion of the thyroid hormone is regulated by the hypothalamic-pituitary-thyroid feed. The hypothalamus senses low circulating levels of thyroid hormone (T3 and T4) and responds by releasing thyrotropin-releasing hormone (TRH). The TRH stimulates the pituitary to produce thyroid-stimulating hormone (TSH). The TSH, in turn, stimulates the thyroid to produce thyroid hormone until levels in the blood return to normal. Thyroid hormone exerts negative feedback control over the hypothalamus as well as anterior pituitary, thus controlling the release of both TRH from hypothalamus and TSH from anterior pituitary gland.

Term
Hypothyroidism
Definition
Underactivity of the thyroid gland.
Term

Hypothyroidism:

CLINICAL MANIFESTATIONS

Definition
Caused by a generalized decrease in metabolism and includes nonpitting edema, slowed mentation, weight gain, dry skin, constipation, decreased heart rate, low blood pressure, lethargy, coarse hair, and menstrual irregularities. Myxedema is a life-threatening, end-stage expression of hypothyroidism. It occurs in severe or prolonged thyroid deficiency. They will present with altered mental state with alterations in thermoregulation. It is characterized by coma, hypothermia, cardiovascular collapse, hypoventilation and severe metabolic disorders (hyponatremia, hypoglycemia and lactic acidosis).
Term

Hypothyroidism:

ETIOLOGY

Definition
Primary causes include congenital agenesis, autoimmune destruction, irradiation, trauma, surgical removal of the gland, or iodine deficiency (iodine is essential for the formation of T4 and T3). The secondary cause is pituitary hyposecretion of thyroid-stimulating hormone (TSH). The tertiary cause is decreased secretion of thyroid-releasing hormone (TRH) by the hypothalamus.
Term

Hypothyroidism:

PATHOGENESIS

Definition
Both primary and secondary causes result in decreased thyroid hormone production. The blood level of TSH is used to differentiate between primary (high TSH- because of the lack of negative feedback exerted by T3 and T4) and secondary (low TSH) causes. Low serum T3 and T4 levels confirm the diagnosis.
Term
Hyperthyroidism
Definition
Overactivity of the thyroid gland.
Term

Hyperthyroidism

ETIOLOGY

Definition
Primary causes include Graves disease and autoimmune, tumor-related, and inflammatory disorders. The secondary cause is pituitary hypersecretion of TSH. Graves disease is a state of hypothyroidism, goiter and ophthalmopathy.
Term

Hyperthyroidism:

PATHOGENESIS

Definition
Both primary and secondary causes result in either increased thyroid hormone synthesis and secretion or release of T3 and T4 from cell destruction. The blood level of TSH is used to differentiate between primary (low TSH) and secondary (high TSH) causes. High serum T3 and T4 levels confirm the diagnosis.
Term

Hyperthyroidism:

CLINICAL MANIFESTATIONS

Definition
Caused by a generalized increase in metabolism and includes hyperactivity, irritability, insomnia, weight loss, increased appetite, heat intolerance, diarrhea, palpitations, and enlarged thyroid gland. Exophthalmos (enlargement of retro-orbital muscles causing protrusion of the eyes) occurs with Graves disease. Thyroid storm is an extreme and life-threatening condition caused when excessive amounts of thyroid hormones are acutely released into the circulation. Thyroid storm is characterized by tachycardia, hypertension, high temperature, and cardiac dysrhythmias.
Term

Parathyroid Disorders

Definition

Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. Parathormone is the parathyroid hormone. This hormone plays a key role in regulating and maintaining a balance of your body's levels of two minerals — calcium and phosphorus. Parathyroid glands control the calcium in our bodies--how much calcium is in our bones, and how much calcium is in our blood. Calcium is the most important element in our bodies (we use it to control many systems), so calcium is regulated very carefully. Parathyroid glands (we all have 4 of them) are normally the size of a grain of rice. Occasionally they can be as large as a pea and still be normal.

Serum calcium levels provide the feedback necessary to regulate parathyroid hormone (PTH) secretion. A decrease in serum calcium causes a release of PTH. An elevated serum calcium level leads to suppression of PTH secretion. Not under the control of the hypothalamic-pituitary system.

Term
Hyperparathyroidism
Definition
excessive production of parathyroid hormone.
Term

Hyperparathyroidism:

ETIOLOGY

Definition
Can be genetic, from an adenoma or hyperplasia of the parathyroid.
Term

Hyperparathyroidism:

PATHOGENSIS

Definition
In hyperparathyroidism, despite an elevated serum calcium level, PTH continues to be secreted. It causes an increase in serum calcium concentrations by stimulating the breakdown of bone and by increasing calcium reabsorption by the kidneys.
Term

Hyperparathyroidism:

CLINICAL MANIFESTATIONS

Definition
Hypercalcemia, polyuria, dehydration, anorexia, nausea, vomiting, constipation, bradycardia, heart block, decreased neuromuscular excitability and cardiac arrest are clinical manifestations for hyperparathyroidism.
Term
Hypoparathyroidism
Definition
Hypoparathyroidism is not enough production of parathyroid hormone.
Term

Hypoparathyroidism:

ETIOLOGY

Definition
Can occur from the removal of parathyroid glands or thyroid gland during surgery, autoimmune or idiopathic.
Term

Hypoparathyroidism:

PATHOGENESIS

Definition
Hypoparathyroidism results in decreased mobilization of calcium from bone, decreased reabsorption of calcium by kidney tubule cells, decreased absorption of calcium by the gastrointestinal tract, and increased reabsorption of phosphate by kidney tubule cells. This abnormal pattern of calcium and phosphate regulation results in low serum calcium concentrations (hypocalcemia) and high serum phosphate concentrations.
Term

Hypoparathyroidism:

CLINICAL MANIFESTATIONS

Definition

The manifestations of acute hypocalcemia include numbness, paresthesias of the distal extremities, muscle cramps, fatigue, anxiety and depression. Severe symptoms include carpopedal spasm, laryngospasm, and seizures. You will also neuromuscular irritability. This neuromuscular instability can also be displayed through the elicitation of the Chvostek's sign and Trousseau's sign.

Hypercalcemia, polyuria, dehydration, anorexia, nausea, vomiting, constipation, bradycardia, heart block, and cardiac arrest.

Term

Adrenal Glands

Definition
which are also called suprarenal glands, are small, triangular glands located on top of both kidneys. An adrenal gland is made of two parts: the outer region is called the adrenal cortex and the inner region is called the adrenal medulla.
Term
Function of the adrenal glands:
Definition

The adrenal glands work interactively with the hypothalamus and pituitary gland in the following process:

  • the hypothalamus produces corticotropin-releasing hormones, which stimulate the pituitary gland.
  • the pituitary gland, in turn, produces corticotropin hormones, which stimulate the adrenal glands to produce corticosteroid hormones.
  • the glucocorticoids and the adrenal androgens is controlled by the ACTH secreted by the anterior pituitary gland
Term
adrenal cortex
Definition

the outer portion of the adrenal gland, secretes hormones that have an effect on the body's metabolism, on chemicals in the blood, and on certain body characteristics. The adrenal cortex secretes corticosteroids and other hormones directly into the bloodstream. The hormones produced by the adrenal cortex include:

  • Glucocorticoids (corticosteroid hormones)- regulated by the negative feedback mechanism of the hypothalamic-pituitary-adrenal system (HPA). 
  • hydrocortisone hormone - this hormone, also known as cortisol, controls the body's use of fats, proteins, and carbohydrates.
  • corticosterone - this hormone, together with hydrocortisone hormones, suppresses inflammatory reactions in the body and also affects the immune system.
  • Mineralocorticoids (aldosterone hormone) - this hormone inhibits the level of sodium excreted into the urine, maintaining blood volume and blood pressure. Regulates potassium and sodium levels and water balance. Regulated by the renin-angiotension mechanism and blood levels of potassium.
  • Adrenal Androgens (androgen hormones) - these hormones have minimal effect on the development of male characteristics.
Term
adrenal medulla
Definition

the inner part of the adrenal gland, is not essential to life, but helps a person in coping with physical and emotional stress. The adrenal medulla secretes the following hormones:

  • epinephrine (also called adrenaline) - this hormone increases the heart rate and force of heart contractions, facilitates blood flow to the muscles and brain, causes relaxation of smooth muscles, helps with conversion of glycogen to glucose in the liver, and other activities.
  • norepinephrine (also called noradrenaline) - this hormone has little effect on smooth muscle, metabolic processes, and cardiac output, but has strong vasoconstrictive effects, thus increasing blood pressure.
Term
Addison disease
Definition
Adrenal Cortical Insufficiency- adrenal hormones are deficient.
Term

Addison disease:

ETIOLOGY

Definition
Can be primary or secondary.  Primary- destruction of the adrenal gland. Secondary cause from the inadequate secretion of ACTH from the anterior pituitary. Tertiary cause from a lack of CRH secretion from the hypothalamus due to hypothalamic malfunction or injury.
Term

Addison disease:

PATHOGENESIS

Definition
In Addison's disease, your adrenal glands produce too little cortisol and often insufficient levels of aldosterone as well.
Term

Addison disease:

CLINICAL MANIFESTATIONS

Definition
The slowly progressive loss of cortisol and aldosterone secretion usually produces a chronic, steadily worsening fatigue, a loss of appetite, and some weight loss. Blood pressure is low and falls further when a person is standing, producing lightheadedness. Nausea, sometimes with vomiting, and diarrhea are common. The muscles are weak and often go into spasm. There are often emotional changes, particularly irritability and depression. Because of salt loss, a craving for salty foods is common. So, they will experience hyponatremia and hyperkalemia. Finally, the increase in ACTH due to the loss of cortisol will usually produce a darkening of the skin that may look like an inappropriate tan on a person who feels very sick.
Term

Cushing Syndrome:

ETIOLOGY

Definition
Cushing Syndrome is a disease caused by an excess of cortisol production or by excessive use of cortisol.
Term

Cushing Syndrome:

PATHOGENESIS

Definition

When too much cortisol is produced in the adrenal glands, or an excess is taken in treating other diseases, significant changes occur in all of the tissues and organs of the body. All of these effects together are called Cushing Syndrome.

Spontaneous overproduction of cortisol in the adrenals is divided into two groups - those due to an excess of ACTH and those that are independent of ACTH.

Term

Cushing Syndrome:

CLINICAL MANIFESTATIONS

Definition
Common signs and symptoms involve progressive obesity and skin changes, such as: weight gain and fatty tissue deposits, particularly around the midsection and upper back, in the face (moon face) and between the shoulders (buffalo hump), pink or purple stretch marks (striae) on the skin of the abdomen, thighs, breasts and arms, thinning and fragile skin that bruises easily, slow healing of cuts, insect bites and infections, and acne. Women with Cushing syndrome may experience: thicker or more visible body and facial hair (hirsutism), and irregular or absent menstrual periods. Men with Cushing syndrome may experience: decreased libido, decreased fertility and erectile dysfunction. Other signs and symptoms include: fatigue, muscle weakness, depression, anxiety and irritability, cognitive difficulties and bone loss.
Term

Pheochromocytoma:


Definition
a tumor that results in the excessive production and release of catecholamines.
Term

Pheochromocytoma:

PATHOGENSIS

Definition
The tumor cells of a pheochromocytoma produce and secrete the catecholamines epinephrine and norepinephrine in response to sympathetic stimulation.
Term

Pheochromocytoma:

CLINICAL MANIFESTATIONS

Definition
Hypertension is the most common problem with pheochromocytoma. The classic triad of a headache, tachycardia, and diaphoresis strongly suggest the diagnosis. Other symptoms include tremor, nervousness, pallor fatigue, fever, weight loss.
Term
Diabetes mellitus
Definition
endocrine disorder diagnosed by the presence of chronic hyperglycemia. Diabetes is diagnosed if any of the following conditions occurs on more than one occasion: a random sampling of blood glucose above 200 mg/dl with classic signs and symptoms, a fasting blood glucose level of greater than 126 mg/dl, or a blood glucose concentration greater than 200 mg/dl 2 hours after a 75-g oral glucose load.
Term
The classification of diabetes mellitus includes two broad categories:
Definition
(1) actual glucose intolerance and (2) the risk of glucose intolerance.
Term
actual glucose intolerance
Definition
include type 1, type 2, other specific types, and gestational diabetes. Pre-diabetes categories include individuals with impaired glucose tolerance and those with impaired fasting glucose tolerance.
Term
the risk of glucose intolerance
Definition
a history of glucose intolerance and those with a positive family history, obesity, or other risk factors.
Term
Persons with type 1 diabetes
Definition
have an absolute insulin deficiency caused by pancreatic β-cell failure. Immune-mediated type 1 diabetes is associated with a specific HLA genetic makeup and may be autoimmune. Idiopathic type 1 diabetes is not an autoimmune process. Type 1 diabetes may affect people individuals of any age. Classic manifestations include polyuria, polydipsia, polyphagia, and weight loss. Persons Individuals with type 1 diabetes are more prone to the development of ketoacidosis because of lipolysis associated with absolute insulin deficiency.
Term
Persons with type 2 diabetes
Definition
have a relative insulin deficiency caused by decreased tissue sensitivity and decreased responsiveness to insulin. A decreased number of insulin receptors or abnormal translocation of glucose transporters is suspected. As the disease progresses, pancreatic insulin production may become impaired. Obesity, female sex, family history, older age, and lack of exercise are risk factors. Individuals with type 2 diabetes are prone to the development of nonketotic hyperglycemic hyperosmolar coma.
Term
Gestational diabetes
Definition
disorder of glucose intolerance that is diagnosed during pregnancy. Placental hormones and weight gain are contributing factors. High infant birth weight and neonatal hypoglycemia are common complications. Gestational diabetes is a risk factor for the later development of type 2 diabetes.
Term
Ketoacidosis
Definition
occurs primarily in type 1 diabetes mellitus as a result of increased lipolysis and conversion to ketone bodies. Excessive ketones result in metabolic acidosis, which is recognized by a fall in pH and bicarbonate levels. Ketoacidosis may occur in patients with type 2 diabetes mellitus under severe stress, such as concomitant sepsis, stroke, or myocardial infarction. Acidosis-induced hyperkalemia and compensatory hyperventilation (Kussmaul respirations) resulting in reduced arterial carbon dioxide are associated findings.
Term
Hyperosmolar coma
Definition
more common in type 2 diabetes because endogenous insulin suppresses ketone formation and thus prevents ketoacidosis. Hyperglycemia may go untreated for a time and result in persistent glycosuria with osmotic diuresis. Dehydration may be manifested as high osmolality and hemoconcentration of erythrocytes, proteins, and creatinine.
Term
Diabetes Mellitus (DM), Types 1 and 2
Definition
An endocrine disorder, characterized by glucose intolerance that affects the metabolism of all the energy nutrients; classified in two broad categories: (1) actual glucose intolerance (including types 1 and 2 DM) and (2) the risk of glucose intolerance.
Term

Diabetes Mellitus (DM), Types 1 and 2:

ETIOLOGY

Definition

Type 1: Characterized by an absolute insulin deficiency caused by pancreatic cell failure; two forms include immune-mediated and idiopathic DM.

Type 2: Characterized by a relative insulin deficiency caused by decreased tissue sensitivity and responsiveness to insulin; risk factors include aging, sedentary lifestyle, obesity, and genetic predisposition.

Term

Diabetes Mellitus (DM), Types 1 and 2:

PATHOGENESIS

Definition

Type 1: bCells of the pancreas are destroyed, resulting in loss of insulin production.

Immune mediated: Associated with certain HLA genetic makeup; may be autoimmune; viral infection or exposure to a toxic agent may be a responsible environmental influence.

Idiopathic: Associated with b-cell destruction without autoimmune markers.

Type 2: Relative insulin deficiency is caused by decreased tissue sensitivity and responsiveness to insulin; a decreased number of insulin receptors or abnormal translocation of glucose transporters is suspected; as the disease progresses, insulin production may become impaired.

Term

Diabetes Mellitus (DM), Types 1 and 2:

CLINICAL MANIFESTATIONS

Definition

Diagnosed if any of the following occur more than once: random blood glucose level ³200 mg/dl with classic signs and symptoms; fasting blood glucose level >126 mg/dl ´ 2, or blood glucose level >200 mg/dl 2 hours after a 75 g oral glucose load is given.

Classic signs and symptoms include polyuria, polydipsia, polyphagia, and weight loss (less severe in type 2). Type 1 is more prone to development of ketoacidosis; type 2 is more prone to development of hyperglycemic hyperosmolar nonketotic syndrome (HHNS).

Chronic complications of DM are primarily caused by vascular and neuropathic dysfunction; complications include coronary artery disease, stroke, peripheral vascular disease, retinopathy, nephropathy, and neuropathy.

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