HLTH 2501: insulin and diabetes mellitus Flashcards
the most common cause of endocrine disorders
the development of a benign tumor or adenoma; can be secretory (causing excess) or destructive (causing a deficit)
two types of endocrine problems
an excessive amount of a hormone or a deficit
resistant target cells
can cause hormonal deficits, resulting from a genetic disorder, an autoimmune response, or excessive demand on the target cells
tropic hormones
hormones that have a stimulating effect on other endocrine glands
what must be evaluated to determine an endocrine disorder
levels of tropic hormones secreted by the pituitary gland and levels of hormones secreted by the target gland
ectopic
an outside source causing an excessive amount of hormone, ex. bronchogenic cancer
what are diagnostic tests for hormones?
blood tests that make use of radioimmunoassay methods or immunochemical methods, as well as urine tests, scans, ultrasounds, and MRIs
hormone treatment
can be treated with replacement therapy, ex. insulin; or adenomas can be removed when they cause excessive secretions
diabetes mellitus
is caused by a relative deficit of insulin secretion from the beta cells in the islets of langerhans or by the lack of response by cells to insulin (insulin resistance)
what kind of hormone is insulin?
an anabolic hormone, meaning it is building up of synthesis or complex substances
what does deficient insulin result from?
abnormal carbohydrate, protein, and fat metabolism because the transport of glucose and amino acids into cells is impaired, as well as the synthesis of protein and glycogen
what diabetes type is more severe?
type 1
different names for type 1 diabetes
insulin-dependent diabetes mellitus, diabetes mellitus, or juvenile diabetes
what is the common population for type 1 diabetes?
children and adolescents
what does type 1 diabetes result from?
genetic factors and an insulin deficit that results from destruction of the pancreatic beta cells in an autoimmune reaction, resulting in an absolute deficit of insulin
acute complications with type 1 diabetes
hypoglycemia, ketoacidosis, or long-term complications like vascular disease which arises from degenerative changes in the tissues
risk factors for those with diabetes type 1
strokes, heart attacks, peripheral vascular disease, amputation, kidney failure, and blindness
other names for type 2 diabetes
non insulin-dependent, type II diabetes mellitus, or mature-onset diabetes
what is type 2 diabetes based on?
a decreased effectiveness of insulin or a relative deficit of insulin, resulting from decreased pancreatic beta cells production of insulin, increased resistance of body cells to insulin, or increased production of glucose by the liver
how is type 2 diabetes managed?
regulating diet, increasing the use of glucose through exercise, reducing insulin resistance, and stimulating the beta cells of the pancreas to produce more insulin
who does type 2 diabetes develop in?
often in older adults, the majority of them overweight
metabolic syndrome
is becoming common in younger adults in which this is a complex of several pathophysiological conditions marked by obesity, cardiovascular changes, and significant insulin resistance due to increased adipose tissue
gestational diabetes
may develop during pregnancy and disappears after delivery of the child; some of these women develop
prediabetes
an early manifestation of type 2 diabetes
latent autoimmune diabetes
occurs in adults and is a slow-onset type 1 autoimmune diabetes
maturity-onset diabetes
occurs in the young and is a rare form caused by a mutation in an autosomal dominant gene
diabetes insipidus
diabetes not related to blood sugar levels, but to an oversensitivity of the kidneys to ADH
what events occur in an insulin deficit?
insulin deficit results in decreased transportation of glucose, causing blood glucose levels to rise (hyperglycemia); excess spills into the urine (glucosuria) as the kidneys cannot absorb all of it; osmotic pressures in the filtrate result in the loss of fluid and electrolytes; this results in dehydration of cells, causing thirst and stimulating appetite, and possibly diabetic ketoacidosis
glucosuria
when excess glucose spills into the urine
polyuria
large amounts of urine excreted due to high glucose levels that create osmotic pressures
polydispia
glucose levels cause dehydration which causes thirst
polyphagia
lack of nutrients entering the cells due to glucose excess causes appetite
what happens is the insulin deficit is prolonged and severe?
diabetic ketoacidosis may develop
diabetic ketoacidosis
lack of glucose in cells results in catabolism of fats and proteins, leading to excessive amounts of fatty acids and their metabolites (known as ketones) in the blood
who does diabetic ketoacidosis occur more commonly in?
type 1
what do ketones consist of?
acetone and two organic acids (beta-hydroxybutyric acid and acetoacetic acid)
how do ketones cause low pH?
they bind with HCO3- buffer in the blood, leading to decreased serum HCO3- and eventually to a decrease in the pH of body fluids
ketonuria
when ketoacids are excreted in the urine
why can diabetic ketoacidosis be so dangerous?
because as dehydration develops, the GFR decreases and excretion of acids becomes more limited; this results in decompensated metabolic acidosis
signs and symptoms in all diabetes types
hunger, fatigue, thirst, polyuria, dry mouth, itchy skin, and blurred vision; type 2 gains weight and type 1 may lose weight
what signifies the onset of diabetes?
the three Ps; polyuria, polydipsia, and polyphagia
testing for diabetes
fasting blood glucose level, the glucose tolerance test, and the glycosylated hemoglobin test
what blood sugar level confirms a diagnosis of diabetes?
> 126 mg/dL
how are long term blood glucose levels monitored?
the test for HbA1c and this should be repeated every 3 months
how do diabetes patients check their own glucose levels?
with a blood sample from a portable monitoring machine, ex. glucometer
treatment for diabetes
maintaining normal blood glucose levels through 3 levels of control 1. diet and exercise 2. oral medication to increase insulin secretion or reduce insulin resistance 3. insulin replacement
diet for diabetes
more complex carbs with a low glycemic index, adequate protein, low cholesterol and lipids, and increased fibre
exercise for diabetes
a regular moderate exercise program is important, as exercise helps to increase the uptake of glucose by muscles without an increase in insulin use; also helps to control weight, reduce stress, and improve cardiovascular health
risk of exercise for diabetes
risk of hypoglycemia developing with prolonged exercise
oral medications for diabetes
metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP-4 inhibitors, GLP-1 receptors, and SGLT2 inhibitors
metformin
aka glucophage; usually is the first medication prescribed for type 2 diabetes; it works to reduce insulin resistance and glucose production
sulfonylureas
help the body to create more glucose; ex. glyburide (DiaBeta), glipizide (Glucotrol), and glimepiride (amaryl)
meglitinides
includes repaglinide (Prandin_ and nateglinide (Starlix) which stimulate insulin production
thiazolidinediones
reduce insulin resistance; ex. rosiglitazone (Avandia) and pioglitazone (Actos)
DPP-4 inhibitors
sitagliptin (januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta) which help to reduce blood sugar levels
GLP-1 receptor agonists
slow digestion and help to lower blood sugar levels; ex. exenatide (Byetta) and liraglutide (Victoza)
SGLT2 inhibitors
prevent the kidneys from reabsorbing sugar into the blood; ex. canagliflozin (Invokana) and dapagliflozin (Farxiga)
how is insulin administered?
subcutaneously because it is a protein that is destroyed in the GI tract if taken orally
primary form of insulin used
biosynthetic form which is identical to human insulin (Humulin)
3 forms of insulin for replacement
rapid-onset, short-acting; intermediate-acting; and slow-onset and long-acting
example of rapid-onset and short-acting insulin
lente
example of slow-onset and long-acting insulin
protamine zinc or ultralente
when may insulin dosage change?
during special circumstances, such as infection with a high fever or vomiting, or at the time of surgery
what may complications associated with glucose levels arise from?
variations in diet and exercise, the presence of infections, and alcohol use
what is hypoglycemia?
is an excess of insulin which causes a deficit in glucose
who is hypoglycemia more common in?
type 1 diabetes individuals
why might hypoglycemia occur?
due to strenuous exercise, error in dosage, vomiting, or skipping a meal after taking insulin
what are the results of hypoglycemia?
the nervous system cannot function well due to neurons not being able to use fats or protein as an energy source
why does excess insulin cause less glucose?
because this excess transports glucose into cells
clinical signs of hypoglycemia
neulogic signs are poor concentration, slurred speech, and lack of coordination; the SNS systems are weakness, pallor, diaphoresis, tremors, and tachycardia
hypoglycemic shock
hypoglycemia triggers the SNS which increased gluconeogenesis, causing glucose to not be taken up and for neurons to not function
what may occur if hypoglycemia is left untreated?
loss of consciousness, seizures, and death
treatment for hypoglycemia
immediate administration of a concentrated carbohydrate such as fruit juice or candy; if the person remains unconscious, glucose or glucagon may be given parenterally
what may ketoacidosis result from?
infection, stress, error in dosage, or overindulgence in food or alcohol; develops over a few days
signs of diabetic ketoacidosis
all signs are related to dehydration, metabolic acidosis, and electrolyte imbalances and include thirst, dry, rough oral mucosa, warm, dry skin, rapid but weak pulse, low BP, and oliguria (decreased urine output)
what may ketoacidosis lead to?
rapid, deep respirations, acetone breath (fruity, sweet), lethargy, and decreased responsiveness
when does metabolic acidosis occur?
as ketoacids bind with bicarbonate
signs of metabolic acidosis
decreased serum HCO3- and decreased serum pH, renal compensation, and loss of consciousness; electrolyte imbalance signs are abdominal cramps, nausea, vomiting, and lethargy or weakness
treatment of diabetic ketoacidosis
administration of insulin and replacing fluids and electrolytes (especially HCO3- as this reverses the acidosis)
hyperosmolar hyperglycemic nonketotic coma
can develop in those with type 2 diabetes and often when the patient is elderly with an infection or has overindulged in carbohydrates, thereby using more insulin
why might one go into a hyperosmolar hyperglycemic nonketotic coma
because there are dehydrated, leading to severe cellular dehydration, causing neurological deficits, muscle weakness, difficulties with speech and abnormal reflexes
why do vascular problems occur with diabetes?
because generation of metabolism leads to atherosclerosis in large arteries as a result of hyperlipidemia and hypertension
microangiopathy
occurs when the capillary basement membrane becomes thick and hard, causing obstruction or rupture of capillaries and small arteries, resulting in tissue necrosis and loss of function; can affect the kidneys, eyes, and the nervous system
retinopathy
is the leading cause of blindness and occurs as a result of microaneurysms, neovascularization, and fibrosis
diabetic nephropathy
is vascular degeneration (thickening of the capillary basement membrane) in the kidney glomeruli, eventually leading to chronic renal failure
macroangiopathy
affects the large arteries, leading to a high incidence of heart attacks, strokes, and peripheral vascular disease in diabetics; if obstruction occurs in the legs, it can result in ulcers
peripheral neuropathy
is a common problem for diabetics and leads to impaired sensation, numbness, tingling, weakness, and muscle wasting (can also impair autonomic nerve function like bladder incompetence); results from ischemia and altered metabolic processes
infections and diabetes
are more common and severe in diabetics and this is because of vascular impairment, which decreases tissue resistance and healing time due to deficit insulin and increased glucose
common infections in diabetics
tuberculosis, infections in the feet and legs (due to vascular impairment), candida fungal infections, periodontal tissue, and dental caries
cataracts
clouding of the lens of the eye which results in accumulated sorbitol and water in the lens, destroying the transparency and can lead to blindness; is more common in diabetics due to abnormal glucose metabolism
diabetics and pregnancy
complications for both mother and fetus may occur due to difficulty controlling the continual hormones and metabolic changes; fetus may be larger and predisposed to conditions and the mother may experience loss of the baby
