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Endocrine Disorders
Bio 375
Pathophysiology
Endocrine Disorders
Two categories of endocrine disorders
Excessive production of hormone Deficient production of hormone
Manifestations of hormonal disorders
reflect the actions of the hormone
May alter appearance of the individual Disorder beginning in children Disorder beginning in adult May alter metabolism of the individual
Most common cause of endocrine
disorders is benign tumor or adenoma
Adenoma may be secretory producing excess hormone Adenoma may be destruction causing a hormonal deficit
Target cells may be resistant or
insensitive to the hormone creating the
effect of a deficit (e.g. Type II Diabetes
mellitus)
Other causes of hormonal problems:
Congenital defects in the glands Hyperplasia of the glands Infection of the glands Abnormal immune reactions Vascular problems Ectopic sources of hormones, e.g bronchogenic (lung) cancer produces PTH or ACTH
Negative Feedback Mechanism with
Glucose and Insulin and Glucagon
Insulin and Diabetes Mellitus
Common chronic disorder
Major factor predisposing to:
Strokes (CVA) Heart attacks (MI) Peripheral vascular disease Amputation Kidney failure Blindness
Types of Diabetes Mellitus
Two major types:
Type I (Insulin-dependent diabetes mellitus) (IDDM) formerly called juvenile onset diabetes Type II (Non-insulin-dependent diabetes mellitus) (NIDDM) formerly called mature onset diabetes Gestational diabetes may develop during pregnancy and disappear following delivery
Type I Diabetes Mellitus
About 10% of cases of Diabetes Mellitus Peak age of onset: 11-13 yr Acute onset Autoimmune: genetic and environmental factors result in gradual destruction of beta cells in pancreas Individuals tend to be normal to thin Severe insulin deficiency or no insulin Requires insulin replacement Amount of insulin needed dependent on dietary intake of glucose and metabolic activity
Questions 1-
Type II Diabetes Mellitus
About 90% of cases of Diabetes Mellitus Age of onset: 40-70 yr Insidious onset
Genetic susceptibility exacerbated by long- duration obesity
Insulin resistance not clearly understood Insulin levels are typically high at diagnosis but decline over the course of the illness
Treatment consists of dietary control, exercise and sometimes medication
USA Today 4/10/
Parathyroid Hormone Control
Parathyroid Hormone
Hypoparathyroidism leads to
hypocalcemia or low serum calcium levels
Hypocalcemia affects nerve and muscle
function in several ways
Weak cardiac muscle contractions Increase in the excitability of nerves leading to spontaneous contraction (tetany) of skeletal muscle
Hyperparathyroidism causes
hypercalcemia or high serum calcium
levels
Hypercalcemia leads to forceful cardiac
contractions
Increased PTH concentrations cause
demineralization of osseus tissue
leading to osteoporosis
It also predisposes to kidney stones
Immobility may lead to hypercalcemia
along with low PTH
Severe kidney disease results in
hyperphosphatemia, hypocalcemia and
high serum PTH
Pituitary Dwarf (^) Gigantism
Acromegaly
Antidiuretic Hormone
Diabetes insipidus
May be caused by deficit of ADH Sometimes results from renal tubules that do not respond to ADH
Manifestations
Polyuria (no glucose) Thirst Severe dehydration
Inappropriate ADH Syndrome
Also called Syndrome of Inappropriate
ADH (SIADH)
Due to excess ADH
Complication of closed head trauma
Sometimes excess secreted by ectopic
source, e.g bronchogenic carcinoma
Manifestations:
Severe hyponatremia Mental confusion irritability
Questions 6-
Thyroid Secretion Control
Hypothyroidism
Mild hypothyroidism is
common and easily
treated
Severe
hypothyroidism
Hashimoto’s thyroiditis Myxedema Cretinism
Adrenal Cortex
Cushing’s Syndrome due to excessive
glucocorticoids
Pituitary tumor (75-80%) Adrenal tumor Ectopic carcinoma (paraneoplastic syndrome) Iatrogenic conditions from administration of large amounts of glucocorticoids for chronic inflammatory conditions
Changes in persons appearance Obesity with moon face Sodium and water retention Heavy trunk Fatty hump on neck (buffalo hump) Muscle wasting in limbs Fragile skin Osteoporosis Immune suppression with increased infections Decreased stress response Changes in mental status; including irritability, clinical depression and schizophrenia.
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