Pathophysiology of Endocrine System Disorders PDF

Pathophysiology of Endocrine System Disorders Lecture # 9 Prepared By Prof. Zeinab Al-Wahsh HU Summer 2024  Major Endocrine Glands  Hypothalamus  Pituitary gland  Pineal gland  Thyroid  Parathyroid glands  Thymu...

Pathophysiology of Endocrine System Disorders Lecture # 9 Prepared By Prof. Zeinab Al-Wahsh HU Summer 2024  Major Endocrine Glands  Hypothalamus  Pituitary gland  Pineal gland  Thyroid  Parathyroid glands  Thymus  Adrenal glands  Pancreas  Ovaries  Testes Copyright © 2019 by Elsevier Inc. All rights reserved. 2 Location of Endocrine Glands Copyright © 2019 by Elsevier Inc. All rights reserved. 3  Endocrine System  Hormones as chemical messengers  Target receptors  Negative feedback systems 4  Classification by Source  Hypothalamus  Pituitary  Thymus  Thyroid  Parathyroid  Adrenal gland  Pancreas  Ovaries  Testes 5  Hormone Release  Most often controlled by negative feedback mechanisms Endocrine and nervous systems work together to regulate metabolic activities. Complex system for some hormones Secretion may be controlled by more than one mechanism. Rate and timing of secretion may vary. Cyclic patterns 6  Endocrine Disorders  All disorders reflect impaired control or feedback.  Excess hormone levels Tumor produces high levels Excretion by liver or kidney is impaired. Congenital condition produces excess hormone. 7  Endocrine Disorders (Cont.)  Deficit of hormone or reduced effects Tumor produces too little hormone. Inadequate tissue receptors present Antagonistic hormone production is increased. Malnutrition Atrophy, surgical removal of gland Congenital deficit 8  Diagnostic Tests  Blood tests Check serum hormone levels Radioimmunoassay Immunochemical methods  Urine tests  Stimulation or suppression tests  Scanning, ultrasound, magnetic resonance imaging (MRI)  Biopsy 9  Insulin and Diabetes Mellitus  Diabetes mellitus—basic problem is inadequate insulin effects in receptor tissues Deficit of insulin secretion Production of insulin antagonists  Diabetes results in abnormal carbohydrate, protein, and fat metabolism.  Some tissues can transport glucose in the absence of insulin: CNS, kidney, myocardium, gut, skeletal muscle Skeletal muscle can partially meet tissue needs without insulin. 10  Types of Diabetes  Type 1 Autoimmune destruction of beta cells in pancreas Insulin replacement required Acute onset in children and adolescents Not linked to obesity Genetic factors may play a role. 11  Type 1 Diabetes  Metabolic changes Catabolism of fats and proteins Excessive amounts of fatty acids and metabolites Ketones in the blood Ketonuria Decreased serum bicarbonate Decrease in pH of body fluids Ketoacids excreted in urine Decompensated metabolic acidosis 12  Types of Diabetes  Type 2 Noninsulin-dependent Oral hypoglycemic medications may be used. Caused by decreased production of insulin and/or increased resistance by body cells to insulin Onset is slow and insidious, usually in those older than 50 years. Associated with obesity Component of metabolic syndrome Increasing incidence in teens and young adults 13  Type 2 Diabetes  May be controlled by adjusting: Dietary intake Increase body’s use of glucose That is, with exercise Reducing insulin resistance Stimulating the beta cells of the pancreas to produce more insulin 14 Control of Type 2 Diabetes (Cont.)  Monitoring blood glucose levels as ordered  Medication to stimulate the beta cells of the pancreas to produce more insulin  If insulin-dependent—proper administration of insulin to maintain glucose levels in normal range 15  Initial Stage  Insulin deficit Results in decreased transportation and use of glucose in many cells  Blood glucose levels rise (hyperglycemia)  Excess glucose found in urine  Large urine volume  Fluid loss through urine, resulting in dehydration  Dehydration causes thirst. 16  General Manifestations  Insulin deficit results in decreased transport and use of glucose in many cells. Polyphagia Fatigue  Blood glucose levels rise—hyperglycemia  Excess glucose in urine—glucosuria Dehydration results from hyperosmolar filtrate. Polyuria Polydipsia 17  Treatment Principles  Maintenance of blood glucose levels in normal range Helps reduce complications  Diet and exercise Exercise reduces blood glucose level as skeletal muscle uses glucose.  Oral medication Increase insulin secretion. Reduce blood glucose levels.  Insulin replacement 18  Complications  Complications are directly related to duration and extent of abnormal blood glucose levels.  Many factors lead to fluctuations in serum glucose levels. Variations in diet and alcohol use Change in physical activity Infection Vomiting  Complications may be acute or chronic. 19  Acute Complications  Hypoglycemia (insulin shock) More common with insulin replacement treatment Can occur because of excess oral hypoglycemic drugs Excess insulin in circulation Glucose deficit in blood Can be life-threatening or cause brain damage if untreated Often follows strenuous exercise Dosage error Vomiting Skipping meal after taking insulin 20  Hypoglycemic Shock: Signs and Symptoms  Disorientation and change in behavior  May appear impaired  Anxiety or decreased responsiveness  Decreased blood glucose level  Decreased BP, increased heart rate  Decreasing level of consciousness Note: Immediate administration of glucose is required to prevent brain damage. 21  Emergency Treatment for Hypoglycemic Shock  If conscious, immediately give sweet fruit juice, honey, candy, or sugar.  If unconscious, give nothing by mouth. Intravenous glucose 50% is required.  Note: Diabetic ketoacidosis (diabetic coma or hyperglycemia) also causes loss of consciousness. The emergency treatment is insulin, fluid, and sodium bicarbonate. Assessment should be done to differentiate the cause. 22  Diabetic Ketoacidosis (DKA)  Occurs in insulin-dependent clients  More commonly seen in type 1 diabetes  Result of insufficient insulin in blood  High blood glucose levels  Mobilization and use of lipids to meet cellular needs result in production of ketoacids  May be initiated by infection or stress  May result from error in dosage, infection, change in diet, alcohol intake, or exercise 23  Signs and Symptoms  Thirst  Dry, rough oral mucosa  Warm, dry skin  Rapid pulse, but weak and thready  Blood pressure is low as the vascular volume decreases.  Oliguria (decreased urine output) indicates that compensation mechanisms to conserve fluid in the body are taking place. 24  Ketoacidosis  Rapid, deep respirations (Kussmaul respirations)  Acetone breath (a sweet, fruity smell)  Lethargy and decreased responsiveness indicate depression of the central nervous system owing to acidosis and decreased blood flow. 25  Metabolic Acidosis  Decreased serum bicarbonate levels and decreased serum pH  Dehydration progresses, renal compensation is reduced, acidosis becomes decompensated.  Serum pH falls.  Loss of consciousness 26  Electrolyte Imbalances  Primarily abdominal cramps  Nausea, and vomiting  Lethargy and weakness 27  Treatment  Insulin administration  Replacement of fluid and electrolytes 28  Hyperosmolar Hyperglycemic Nonketotic Coma (HHNK)  Occurs in type 2 diabetes  Insidious in onset and diagnosis may be missed  Often occurs in older clients and assumed to be cognitive impairment  Results in severe dehydration and electrolyte imbalances 29  HHNK Manifestations  Hyperglycemia  Severe dehydration Increased hematocrit Loss of turgor Increased heart rate and respirations  Electrolyte imbalances result in neurologic deficits. muscle weakness. difficulties with speech. abnormal reflexes. 30  Chronic Complications of Diabetes  Vascular problems Increased incidence of atherosclerosis Changes may occur in small and large arteries.  Microangiopathy—changes in microcirculation Obstruction or rupture of small capillaries and arteries Tissue necrosis and loss of function Neuropathy and loss of sensation Retinopathy—leading cause of blindness Chronic renal failure—degeneration in glomeruli of kidney 31 Chronic Complications of Diabetes (Cont.)  Macroangiopathy—affects large arteries Result of abnormal lipid levels High incidence of heart attacks, strokes, peripheral vascular disease May result in ulcers on feet and legs—slow-healing Frequent infections and gangrenous ulcers Amputation may be necessary.  Peripheral neuropathy Common complication caused by ischemia in microcirculation to peripheral nerves Impaired sensation, numbness, tingling, weakness, muscle wasting 32 Diabetic Retinopathy Copyright © 2019 by Elsevier Inc. All rights reserved. 33  Neuropathy  Peripheral neuropathy is a common problem for diabetes.  Leads to impaired sensation. numbness. tingling. weakness. muscle weakness. 34 Neuropathic Diabetic Foot Ulcer Copyright © 2019 by Elsevier Inc. All rights reserved. 35  Chronic Complications of Diabetes (Cont.)  Infections Common and often more severe in diabetics Infections in feet and legs caused by vascular and neurologic impairment Fungal infections common Caused by Candida In vagina and/or oral cavity Urinary tract infections Dental caries Gingivitis and periodontitis 36 Chronic Complications of Diabetes (Cont.)  Cataracts Opacity of lens in eye Related to abnormal metabolism of glucose  Pregnancy Complications in both mother and fetus may occur. Increased incidence of spontaneous abortions Infants born to diabetic mothers increased size and weight for date. may experience hypoglycemia in first hours postnatally. 37 Potential Complications of Diabetes Mellitus Copyright © 2019 by Elsevier Inc. All rights reserved. 38  Parathyroid Hormone and Calcium  Hypoparathyroidism Leads to hypocalcemia Weak cardiac muscle contractions Increased excitability of nerves— spontaneous contractions of skeletal muscle Causes Tumor Congenital lack of parathyroid Surgery or radiation in neck region Autoimmune disease 39 Normal Control and Feedback of Calcium Copyright © 2019 by Elsevier Inc. All rights reserved. 40 Calcium and Parathyroid Hormone Relationships Copyright © 2019 by Elsevier Inc. All rights reserved. 41  Parathyroid Hormone and Calcium (Cont.)  Hyperparathyroidism Results in hypercalcemia Forceful cardiac contractions Osteoporosis Predisposition to kidney stones Causes Tumor Secondary to renal failure Paraneoplastic syndrome 42  Pituitary Hormones  Adenomas are the most common cause of pituitary disorders.  Effect of mass May cause pressure in the skull Headaches, seizures, drowsiness, visual deficits  Effect on hormone secretion Dependent on cells and location involved May cause excessive or decreased release of hormones 43  Growth Hormone (GH)  Dwarfism Deficit in growth hormone production and release  Gigantism Excess GH prior to puberty and fusion of epiphysis  Acromegaly Excess GH secretion in adults Often associated with adenoma Bones become broader and heavier. Soft tissue grows. Enlarged hands and feet, change in facial features 44 Primary Gigantism Copyright © 2019 by Elsevier Inc. All rights reserved. 45 Acromegaly Copyright © 2019 by Elsevier Inc. All rights reserved. 46  Antidiuretic Hormone (ADH)  Diabetes insipidus—deficit of ADH Adenoma May originate in the neurohypophysis Head injury or surgery Possible genetic problem Replacement treatment required  Inappropriate ADH syndrome Excess ADH May be temporary, triggered by stress; may be secreted by an ectopic source, such as a tumor Treatment Diuretics Sodium supplements 47  Thyroid Disorders  Two thyroid hormones  Released in response to TSH  Disorders may result from pituitary or thyroid gland dysfunction  Goiter  Hyperthyroidism (Graves Disease)  Hypothyroidism 48 Hypothalamus-Pituitary-Thyroid Gland Feedback Copyright © 2019 by Elsevier Inc. All rights reserved. 49  Hyperthyroidism  Related to autoimmune factor  Hypermetabolism and increased stimulation of SNS Increased body temperature Sweating Soft silky hair and skin Reduced BMI Insomnia Hyperactivity 50  Hyperthyroidism (Cont.)  Toxic goiter  Exophthalamos Presence of protruding, staring eyes, decreased blink and eye movement Result of increased tissue mass in the orbit May result in visual impairment 51 Exophthalmos Copyright © 2019 by Elsevier Inc. All rights reserved. 52  Hypothyroidism  Iodine deficit  Hashimoto thyroiditis Autoimmune disorder  Tumor Surgical removal or treatment of gland  Cretinism Results in short stature and severe cognitive deficits Untreated congenital hypothyroidism May be related to iodine deficiency during pregnancy 53  Hypothyroidism Manifestations  Goiter if cause is endemic iodine deficiency  Intolerance to cold  Increased BMI  Lethargy and fatigue  Decreased appetite  Myxedema in severe, untreated hypothyroidism Nonpitting edema in face, thickened tongue Myxedema coma—acute hypotension, hypoglycemia, and hypothermia result in loss of consciousness; life- threatening if untreated 54  Adrenal Medulla  Benign tumor of the adrenal medulla—secretes epinephrine, norepinephrine, and possibly other substances  Occasionally, multiple tumors  Headache, heart palpations, sweating, intermittent or constant anxiety 55  Adrenal Cortex  Cushing syndrome Caused by an excessive level of glucocorticoids; possible result of: Adrenal adenoma Pituitary adenoma Ectopic carcinoma Substance abuse 56  Cushing Syndrome  Changes associated with Cushing syndrome Change in person’s appearance Round face, with ruddy color Truncal obesity, with fat pad between scapulae Thin limbs Thin hair Fragile skin 57  Cushing Syndrome (Cont.) Retention of sodium and water Suppression of the immune response Stimulation of erythrocyte production Emotional lability and euphoria Increased catabolism of bone and protein Delayed healing Increased insulin resistance and possible glucose intolerance 58 Cushing Syndrome (Cont.) Copyright © 2019 by Elsevier Inc. All rights reserved. 59  Addison Disease  Deficiency of adrenocorticoid secretions  Autoimmune reaction is a common cause.  Adrenal gland may be destroyed by hemorrhage or infection. Copyright © 2019 by Elsevier Inc. All rights reserved. 60  Manifestations  Decreased blood glucose levels  Inadequate stress response  Fatigue  Weight loss, frequent infections  Low serum sodium concentration  Decreased blood volume  Hypotension  High potassium levels Copyright © 2019 by Elsevier Inc. All rights reserved. 61