Download 9.1 Chapter 18 Alterations of Hormonal Regulation

Alterations of Hormonal
Regulation
Chapter 18
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Mechanisms of Hormonal
Alterations
Elevated or depressed hormone levels can
arise from:
 Dysfunctions of endocrine secreting
tissues
 Target cell failure
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Dysfunctions of Endocrine
Secreting Tissues
Mechanisms that can cause this include:
1. Faulty feedback systems
 Gland is not receiving signals for release of
appropriate levels of hormone
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Dysfunctions of Endocrine
Secreting Tissues
2. Dysfunction of the gland
 Secretory cells are unable to produce,
obtain, or convert hormone precursors
 Gland synthesizes or releases excessive
amounts of hormone
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Dysfunctions of Endocrine
Secreting Tissues
3. Altered metabolism of hormones
 Increased hormone degradation or
inactivation
4. Production of hormones from nonendocrine
tissues
 Ectopic hormone release
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Target Cell Failure
Mechanisms that can cause target cells to
fail to respond to hormones include:
1. Cell surface receptor-associated disorders





Decrease in number of receptors
Impaired receptor function
Presence of antibodies against specific
receptors
Antibodies that mimic hormone action
Unusual expression of receptor function, for
example on tumor cells
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Target Cell Failure
2. Intracellular disorders in messenger
systems within the target tissue
3. Circulating inhibitors - generally antibodies
that bind to the hormone and prevent
binding
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Hormone Delivery
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Alterations of the
Hypothalamic-Pituitary System

Most commonly caused by interruption of the
connection between the hypothalamus and
pituitary, the pituitary stalk (infundibulum).
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Alterations of the
Hypothalamic-Pituitary System
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Diseases of the Posterior
Pituitary


Rare, usually related to abnormal
secretion of antidiuretic hormone (ADH).
Antidiuretic hormone - controls serum
osmolality, increases permeability of the
renal tubules to water, and causes
vasoconstriction when administered
pharmacologically in high doses.
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Diseases of the Posterior
Pituitary
Syndrome of inappropriate antidiuretic
hormone secretion (SIADH)
 Hypersecretion of ADH
 High ADH levels interfere with renal free
water clearance, leading to abnormally
concentrated urine, and dilute blood
plasma (hypoosmolality), especially
sodium (hyponatremic).
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Diseases of the Posterior
Pituitary

Etiology – SIADH can be caused by:
 Cancer
cells ectopically secreting ADH
(Ex. small cell carcinoma) - most common
 Brain trauma or infection
 Infectious pulmonary diseases

Symptoms are due to the hyponatremia
(low serum sodium).
 This
can cause irreversible neurological
damage.
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Diseases of the Posterior
Pituitary
Diabetes insipidus
 Insufficiency of ADH
 Causes partial or total inability to concentrate
the urine
 Low ADH levels cause formation of large
quantities of dilute urine, and increased
plasma concentration (hyperosmolality).
Dehydration results.
 Symptoms - polyuria (excessive urination),
thirst and polydipsia (excessive drinking)
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Diseases of the Posterior
Pituitary
Three types of diabetes insipidus:
1. Neurogenic - caused by insufficient amounts of
ADH
 Due
to damage to the hypothalamus or pituitary.
2. Nephrogenic - caused by an inadequate
response to ADH
 Due
to diseases that damage renal tubules
(example – pyelonephritis) or drugs such as
methoxyflurane anesthesia, lithium, or
demeclocycline.
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Diseases of the Posterior
Pituitary
Types of diabetes insipidis (cont.)
3. Psychogenic (primary polydipsia) – caused
by excessive intake of fluids
 Due
to psychological disorders
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Diseases of the Anterior Pituitary
Hypopituitarism – insufficient secretion of one or
more pituitary hormones.
 Etiology – pituitary infarction, head trauma,
infections, and tumors
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Diseases of the Anterior Pituitary

Panhypopituitarism – decreased or absent
secretion of all pituitary hormones.
deficiency – causes cortisol deficiency (lifethreatening).
 TSH deficiency – causes thyroid hormone
deficiency.
 FSH and LH deficiency – causes gonadal failure
and loss of secondary sex characteristics.
 GH deficiency – causes pituitary dwarfism.
 ADH deficiency – causes diabetes insipidus.
 ACTH
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Diseases of the Anterior Pituitary
Hyperpituitarism
 Etiology – commonly caused by a benign
slow-growing pituitary adenoma.


Hypersecretes the hormone of the cell type
from which it arose, independent of regulation.
Manifestations:



Headache and fatigue
Visual changes
Hyposecretion of neighboring anterior pituitary
hormones due to pressure atrophy
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Diseases of the Anterior Pituitary
Hypersecretion of growth hormone (GH)
 Acromegaly - hypersecretion of GH during
adulthood (after closure of epiphyseal plates)
 Proliferation
of connective tissue and bony
matrix creates course facial features, large
hands and feet, etc.
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Acromegaly
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Diseases of the Anterior Pituitary
Hypersecretion of growth hormone (cont.)
 Gigantism - hypersecretion of GH in children
and adolescents
 Excessive
skeletal growth, with some
individuals becoming 8 or 9 feet tall.

Long term hypersecretion of GH causes
renal, thyroid, and reproductive dysfunction.
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Diseases of the Anterior Pituitary

Hypersecretion of growth hormone (GH)
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Diseases of the Anterior Pituitary
Hypersecretion of prolactin
 Caused by prolactinomas – most common
hormone-secreting pituitary tumor
 Manifestations:
 In
females - amenorrhea, galactorrhea (milk
production without pregnancy), hirsutism, and
osteopenia
 In males - hypogonadism, erectile dysfunction,
impaired libido, oligospermia, and diminished
ejaculate volume
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Alterations of Thyroid Function
Hyperthyroidism
 Thyrotoxicosis - general condition in which
elevated thyroid hormone (TH; T3 and T4)
levels cause greater than normal physiologic
responses.
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Alterations of Thyroid Function
Hyperthyroidism (cont.)
 Manifestations of thyroid hormone excess:

Enlarged thyroid gland
 Increase in metabolic rate and heat production
(causes flushed skin and perspiration)
 Nervous excitability and insomnia
 Increased heart rate and cardiac dysrhythmias;
heart failure (in extreme cases)
 Weight loss
 GI hyperactivity, diarrhea & vitamin deficiencies
 Thinning of hair and skin
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Alterations of Thyroid Function
Graves disease
 Most common form of hyperthyroidism.
 Tends to occur in women in their 30s and 40s.
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Alterations of Thyroid Function
Graves disease (cont.)
 Etiology - type II autoimmune hypersensitivity
disorder involving stimulation of the thyroid
gland by antibodies against the TSH receptor
(thyroid-stimulating immunoglobulins (TSI)).
 Antibodies
stimulate enlargement of thyroid with
goiter formation and hypersecretion of TH.
 Increased levels of thyroid hormone feed back
on the pituitary to turn off TSH production.
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Thyroid Regulation
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Alterations of Thyroid Function
Graves disease (cont.)
 Ocular symptoms - infiltration of the orbital
contents causes orbital edema
 Produces
protruding eyes (exophthalmos),
muscle palsies, and damage to the optic nerve.


Pretibial myxedema - caused by infiltration of
subcutaneous tissues of the anterior lower leg
which results in a “doughy” edema.
Treatment includes partial thyroidectomy or
ablation of the gland with radioactive iodine.
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Symptoms of Graves Disease
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Alterations of Thyroid Function
Thyrotoxic crisis (thyroid storm)
 Rare but dangerous worsening of the thyrotoxic
state, in which death occurs within 48 hours
without treatment.
 Usually occurs in individuals who have
undiagnosed or partially treated Graves
disease and are subjected to excessive stress,
Including:
 Surgery,
infection, pulmonary or cardiovascular
disorders, emotional distress, physical stress.
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Alterations of Thyroid Function
Thyrotoxic crisis (cont.)
 Manifestations:
 Hyperthermia;
tachycardia, especially atrial
tachydysrhythmias; high-output heart failure;
agitation or delirium; and nausea, vomiting, or
diarrhea contributing to fluid volume depletion.

Treatment is designed to:
a. Reduce circulating TH levels by inducing a
block of TH synthesis.
b. Provide symptomatic and supportive care.
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Alterations of Thyroid Function
Hypothyroidism
 Insufficient secretion of TH by the thyroid gland.
 Manifestations of thyroid hormone deficiency:
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

Size of thyroid gland varies, depending on cause;
may be small, normal or enlarged.
Decreased metabolic rate and body temperature;
cold intolerance.
Weaker, more sluggish muscle contractions, which
cause constipation and decreased cardiac
contractility
Slow heart rate and decreased cardiac output
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Alterations of Thyroid Function
Hypothyroidism
 Manifestations of thyroid hormone deficiency
(cont.):
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
Increased body weight
Rise in blood cholesterol levels (contributes to
atherosclerosis)
Decreased sex drive, and menstrual irregularities
Depression of mental functioning and sleepiness
Course, brittle hair and hair loss
Severity is proportional to degree of hyposecretion.
Myxedema
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Alterations of Thyroid Function
Hypothyroidism
 Myxedema
 Characteristic
sign of severe of long-standing
hypothyroidism.
 Altered composition of the dermis and other
tissues.
 Produces a nonpitting, boggy edema, especially
around the eyes, hands, and feet.
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Myxedema
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Alterations of Thyroid Function
Primary Hypothyroidism
 Loss of thyroid tissue leads to decreased
production of TH (low T3 and T4), increased
secretion of TSH, and goiter.
 Etiology – primary hypothyroidism can be due to:
 Congenital
defects
 Defective hormone synthesis resulting from
autoimmune thyroiditis, endemic iodine
deficiency, or antithyroid drugs
 Loss of thyroid tissue after surgical or radioactive
treatment for hyperthyroidism
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Goiter
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Alterations of Thyroid Function
Primary Hypothyroidism
a. Acute thyroiditis - inflammation of the thyroid
gland, often caused by a bacterium, that can
result in hypothyroidism.
b. Subacute thyroiditis - self-limiting nonbacterial
inflammation of the thyroid gland.
 Inflammatory
process damages follicular cells,
causing leakage of T3 and T4.
 Hyperthyroidism then is followed by transient
hypothyroidism, which is corrected by cellular
repair and a return to normal levels in the thyroid.
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Alterations of Thyroid Function
Primary Hypothyroidism (cont.)
c. Autoimmune thyroiditis (Hashimoto disease)
 Results
in destruction of thyroid tissue by
circulating thyroid antibodies and infiltration of
lymphocytes.
 May be caused by an inherited immune defect.
 Goiter formation is common.
 Most common cause of hypothyroidism in adults.
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Alterations of Thyroid Function
Secondary Hypothyroidism
 Usually caused by the pituitary's failure to
synthesize adequate amounts of thyroidstimulating hormone (TSH).
 Pituitary tumors are the most common cause.
 Results in low levels of both TSH and TH (T3
and T4)
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Alterations of Thyroid Function
Myxedema coma
 Diminished level of consciousness associated
with severe hypothyroidism.
 Often due to untreated hypothyroidism.
 Symptoms include hypothermia without
shivering, hypoventilation, hypotension,
hypoglycemia, and lactic acidosis.
 Potentially fatal without treatment.
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Alterations of Thyroid Function
Congenital hypothyroidism
 Absence of thyroid tissue during fetal
development or defects in hormone synthesis.
 Thyroid hormone is essential for embryonic
growth, particularly of brain tissue.
 Infant will be mentally retarded if there is no
thyroxine (TH) during fetal life.
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Alterations of Thyroid Function
Congenital hypothyroidism (cont.)
 Overall growth is stunted.
 This can be partially reversed if thyroxine (TH) is
given immediately after birth.
 If untreated this results in cretinism.
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Cretinism
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Alterations of Thyroid Function
Thyroid carcinoma
 Relatively rare.
 Associated with exposure to ionizing radiation,
especially in childhood.
 T3 and T4 levels are usually normal.
 Typically discovered as a small thyroid nodule or
metastatic tumor in the lungs, brain, or bone.
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Alterations of
Parathyroid Function


Cause profound effects on calcium
homeostasis and bone health.
Parathyroid hormone (PTH) helps to
maintain normal serum calcium levels by
stimulating the breakdown of bone and by
increasing renal and gastric absorption of
calcium.
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Alterations of
Parathyroid Function
Hyperparathyroidism
 Excess secretion of PTH causes
hypercalcemia and bone destruction.
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Alterations of
Parathyroid Function



Primary hyperparathyroidism
Excess secretion of PTH from one or more
parathyroid glands
Usually caused by an adenoma of the
chief cells in the parathyroid gland.
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Alterations of
Parathyroid Function


Primary hyperparathyroidism (cont.)
Manifestations:
 Very
high serum levels of calcium cause
neurologic, gastric, and muscular dysfunction.
 Bone resorption leads to osteopenia,
osteoporosis, bone fragility, and pathologic
fractures.
 Hypercalcemia and hypercalciuria can
contribute to the formation of renal calculi.
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Alterations of
Parathyroid Function



Secondary hyperparathyroidism (cont.)
Increase in PTH secondary to a chronic
disease.
Usually a result of chronic renal failure.
 Kidney
cannot activate vitamin D and cannot
adequately reabsorb calcium from tubules.
 Persistent hypocalcemia results in increased
PTH secretion, causing osteopenia
 They exhibit bone fragility but without the
signs and symptoms of hypercalcemia.
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Alterations of
Parathyroid Function
Hypoparathyroidism
 Abnormally low PTH level causes inability
to maintain normal serum calcium levels.
 Usually caused by parathyroid injury or
removal during thyroid surgery
 Lack of PTH causes depressed serum
calcium levels, increased serum
phosphate levels, decreased bone
resorption, and eventual hypocalciuria.
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Alterations of
Parathyroid Function
Hypoparathyroidism (cont.)
 Manifestations are primarily those of
hypocalcemia:
 Lowered
threshold for nerve and muscle
excitation, causing muscle spasms,
hyperreflexia, clonic-tonic convulsions,
laryngeal spasms, and, in severe cases,
death by asphyxiation.
 Also dry skin, alopecia, poor dentition,
skeletal deformity.
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Dysfunction of the Endocrine
Pancreas
Types of Diabetes Mellitus:
 Diabetes mellitus is a group of disorders
characterized by glucose intolerance, chronic
hyperglycemia, and disturbances of
carbohydrate, protein, and fat metabolism.
 Classic signs and symptoms are often
present as well (polyuria, polydipsia,
polyphagia).
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Type 1 Diabetes Mellitus




Insulin dependent diabetes mellitus (IDDM)
Results from a severe, absolute lack of insulin
caused by loss of pancreatic beta cells.
Usually occurs in younger people.
About 10% of DM cases.


Type 1A – immune-mediated (about 9%)
Type 1B – idiopathic (about 1%)
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Type 1 Diabetes Mellitus

Pathophysiology of Type1A:
 In
genetically vulnerable individuals an
environmental trigger causes:
• Production of autoantibodies against beta
cells and insulin.
• Cellular and cytokine-mediated injury (type
IV hypersensitivity)
• Destruction of insulin-secreting beta cells
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Type 1 Diabetes Mellitus

Pathophysiology (cont.)
 Alpha
cells produce excess glucagon (raises
blood sugar)
 Low insulin and high glucagon causes
hyperglycemia and ketoacidosis
 Ketoacidosis - acidosis accompanied by the
accumulation of ketone bodies in the body
tissues and fluids; caused by increased
metabolism of fats and proteins.
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Type 1 Diabetes Mellitus

Manifestations:
 Hyperglycemia,
polydipsia, polyuria,
polyphagia, weight loss, and fatigue.

Diagnosis is based on:
 Symptoms
and family history.
 Elevated fasting plasma glucose levels and
glucose tolerance tests (GTT).
 Elevated glycosylated hemoglobin (HbA1C)
levels (indicates average glucose level to
which RBCs have been exposed).
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Type 1 Diabetes Mellitus

Exercise allows uptake of glucose without
insulin, so can cause hypoglycemia or reduce
insulin requirement.
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Type 2 Diabetes Mellitus






Non-insulin dependent diabetes mellitus (NIDDM)
Results from a combination of insulin resistance
and declining insulin secretion.
About 90% of DM cases.
Usually diagnosed later in life, although
increasing in younger groups.
Strong genetic component; very common in
certain ethnic groups.
Triggered by environmental factors, including
obesity, poor diet, and lack of exercise.
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Type 2 Diabetes Mellitus

Pathophysiology:
 In
the obese, insulin has a diminished ability to
influence glucose uptake and metabolism (insulin
resistance of target tissues).
 Some insulin production continues in type 2
diabetes mellitus, but the size and number of
beta cells decrease. Initially insulin secretion may
be high, but it declines with time.
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Type 2 Diabetes Mellitus

Pathophysiology (cont.):
 Low
insulin and high glucagon causes
hyperglycemia, but usually not ketoacidosis.
 Increased lipid metabolism results in high levels
of circulating lipids; risk of atherosclerosis.
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Gestational Diabetes


Occurs when a woman not previously
diagnosed with diabetes shows glucose
intolerance during pregnancy.
Can cause potentially life threatening
complications for both mother and fetus.
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Acute Complications of
Diabetes Mellitus

Hypoglycemia
 Occurs
in >90% of type 1 diabetics due to
administration of too much insulin.
 “Insulin shock”
 Decreased blood glucose (45 to 60mg/dl)
causes pallor, tremor, anxiety, tachycardia,
palpitations, sweating, headache, dizziness,
irritability, fatigue, poor judgment, confusion,
visual disturbances, hunger, seizures, and
ultimately coma.
 Treatment - replacement of glucose.
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Acute Complications of
Diabetes Mellitus

Diabetic ketoacidosis (DKA)
 Complication
of type 1 diabetes.
 Occurs when the body cannot use glucose as a
fuel source because the body has no insulin or
not enough insulin, and fat is used instead.
 Byproducts of fat breakdown, called ketones,
build up in the body.
 This leads to severe metabolic acidosis that, in
association with hyperglycemia and dehydration,
can result in coma, shock, and even death.
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DKA and HHNKS
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Acute Complications of
Diabetes Mellitus

Hyperosmolar hyperglycemic nonketotic syndrome

Complication of type 2 diabetes mellitus.
 Occurs more often in the elderly, or those with
infections or cardiovascular or renal disease.
 Poor glucose control results in high levels of glucose
(more than 500 mg/dl) and high osmotic pressures
that lead to severe dehydration, low blood volume,
and low perfusion pressures.
 Ketosis is uncommon because there is enough
insulin to prevent lipolysis and protein catabolism.
 High overall mortality rate.
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Chronic Complications of
Diabetes Mellitus
Mechanisms of damage - alterations in
carbohydrate, protein, and lipid metabolism
(primarily hyperglycemia) adversely affects
tissue in three ways:
a. Glycation
b. Induction of the polyol pathway
c. Activation of protein kinase C
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Chronic Complications of
Diabetes Mellitus
a. Glycation



Glycation - attachment of glucose to proteins,
lipids, and nucleic acids in blood vessels, nerves,
lenses, and other tissues, forming advanced
glycation end products (AGEs).
AGEs stimulate cellular injury, inflammation,
oxidation of lipoproteins, dysfunction of the
endothelium (decreased vasodilators and
anticoagulants) and thickening of the basement
membrane.
Contributes to immunologic deficiencies and
autoimmunity.
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Chronic Complications of
Diabetes Mellitus
b. Induction of the polyol pathway
 Causes
conversion of glucose to sorbitol (and
then slowly to fructose).
 Sorbitol increases intracellular osmotic
pressure, causing cellular edema and tissue
dysfunction.
 This process is especially important in renal
cells, red blood cells, eye lens, and nerves.
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Chronic Complications of
Diabetes Mellitus
c. Activation of protein kinase C
 Protein
kinase C (PKC) - a family of different
intracellular signaling proteins.
 Inappropriately activated by hyperglycemia.
 Contributes to insulin resistance, tissue
inflammation and edema, and production of
mitogens and degradative enzymes.
 These effects contribute to tissue remodeling
and vascular dysfunction.
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Sequelae of Chronic Diabetes
Mellitus
a. Diabetic neuropathies – nerve degeneration
and delayed conduction.
b. Microvascular disease – thickening and
damage to the capillary wall.
 Retinopathy
– ischemia causes damage to
retina.
 Diabetic nephropathy – including end-stage
renal disease; caused by damage to glomeruli.
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Sequelae of Chronic Diabetes
Mellitus
c. Macrovascular disease – diabetes
increases severity of atherosclerosis.
artery disease – high rate of CAD
and myocardial infarction.
 Stroke – twice as common for diabetics.
 Peripheral arterial disease – results in
gangrene and amputation.
 Coronary
d. Infection - increased risk due to poor
circulation and immune deficiencies.
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Hyperfunction Disorders of the
Adrenal Cortex
Hypercortisolism – disorders that result from
high levels of cortisol secretion.
 Cushing disease – excessive anterior
pituitary secretion of ACTH.
 Usually

due to a pituitary adenoma.
Cushing syndrome – excessive level of
cortisol, regardless of cause.
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Hyperfunction Disorders of the
Adrenal Cortex

Cushing syndrome – excessive level of
cortisol, regardless of cause.
 Usually
due to an adenoma of adrenal cortex
(ACTH independent; low ACTH levels).
 Could be from ectopic production of
adrenocorticotropic hormone (ACTH) from a
tumor elsewhere in the body (e.g., small-cell
lung cancer).
 Prolonged glucocorticoid therapy.
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Hyperfunction Disorders of the
Adrenal Cortex

Manifestations:
 Obesity
with fat deposition in face (“moon
face”), neck and abdomen (truncal obesity).
 Protein breakdown for gluconeogenesis
causes muscle weakness, bone loss, and
bruising.
 High levels of glucocorticoids cause insulin
insensitivity and impaired glucose tolerance.
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Cushing Syndrome
Elsevier items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Cushing Syndrome
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Hyperfunction Disorders of the
Adrenal Cortex

Manifestations (cont.):
 At
high levels, glucocorticoids mimic
aldosterone, causing sodium and water
retention (hypertension) and potassium
excretion.
 Gonadocorticoids may also be in excess,
causing menstrual dysfunctions and
masculinization in females.
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Cushing Syndrome
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Hyperfunction Disorders of the
Adrenal Cortex
Hyperaldosteronism



Primary hyperaldosteronism (Conn disease)
 Caused by an abnormality of the adrenal cortex
Secondary hyperaldosteronism
 Caused by activation of the renin-angiotensinaldosterone system in conditions such as heart
failure, renal failure, hypertension, and hepatic
cirrhosis.
Aldosterone causes increased renal sodium and
water retention with excess potassium secretion.
Elsevier items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc.
Hyperfunction Disorders of the
Adrenal Cortex
Hyperaldosteronism
 Manifestations:
 Hypertension
- can lead to an increased risk for
atherosclerosis and congestive heart failure.
 Hypernatremia
 Hypokalemia - can be severe enough to cause
cardiac dysrhythmias and muscle weakness.
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Hyperfunction Disorders of the
Adrenal Cortex
Hypersecretion of adrenal androgens and
estrogens
 Usually due to an adrenal tumor.
 Feminization – can result in males.
 Virilization – development of male
characteristics can result in females.
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Virilization
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Hypofunction Disorders of the
Adrenal Cortex
Hypocortisolism - low levels of cortisol secretion.
 Due to either:
 Inadequate
stimulation of the adrenal glands by
ACTH
 Primary adrenal insufficiency - inability of the
adrenals to produce and secrete the
adrenocortical hormones.
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Hypofunction Disorders of the
Adrenal Cortex
Hypocortisolism (cont.)
 May be partial dysfunction so only synthesis of
aldosterone or androgens is affected.
 May affect glucocorticoid or mineralocorticoid
secretion or both.
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Hypofunction Disorders of the
Adrenal Cortex
Primary adrenal insufficiency (Addison disease)
 Inadequate production of cortisol and
aldosterone
 Caused by autoantibodies and cell-mediated
immunity cause destruction of the adrenal
cortex.
 Associated with other autoimmune diseases
such as Hashimoto thyroiditis and pernicious
anemia.
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Hypofunction Disorders of the
Adrenal Cortex
Primary adrenal insufficiency (Addison disease)
 Manifestations:
 Metabolic
abnormalities (e.g., hypoglycemia,
hyponatremia, and hyperkalemia)
 Hypovolemia and hypotension (can be lifethreatening)
 Orthostatic dizziness, weakness and fatigue
 Anorexia, nausea, abdominal pain
 Changes in mental status like confusion and
apathy due to hypoglycemia
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Hypofunction Disorders of the
Adrenal Cortex


Addisonian crisis – in response to an acute
stressor, the patient experiences fever, nausea,
vomiting, hyponatremia, hyperkalemia,
hypotension, and dehydration, which could
result in circulatory shock.
In individuals with primary Addison disease, the
lack of feedback on the pituitary results in
increased compensatory secretion of ACTH
which can cause hyperpigmentation of the skin.
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Disorders of the Adrenal Medulla



Adrenal medulla hyperfunction - usually
caused by a:
Pheochromocytoma – a catecholamineproducing tumor of the adrenal medulla.
Most are benign, although 10% are malignant
and may metastasize.
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Disorders of the Adrenal Medulla

Symptoms of catecholamine excess are
related to their sympathetic nervous system
effects:
 Hypertension
 Tachycardia,
palpitations
 Glucose intolerance
 Excessive sweating
 Constipation
 Weight loss
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Disorders of the Adrenal Medulla

With exposure to certain foods (containing
tyrosine) or excessive physiologic stress
(e.g., surgery), episodes of extreme
hypertension can occur with potential for
cerebral and cardiovascular complications.
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