Endocrine Disorders PDF

Pathophysiology (2) (MBS 253) Lecture 11 Endocrine disorders-B Pituitary, thyroid &adrenal glands Textbook ;Pathophysiology for the Health Professions, 4th edition, 2011 Chapter 25 (p.545-572)  Endocrine Disorders lecture outline Endocrine Disord...

Pathophysiology (2) (MBS 253) Lecture 11 Endocrine disorders-B Pituitary, thyroid &adrenal glands Textbook ;Pathophysiology for the Health Professions, 4th edition, 2011 Chapter 25 (p.545-572)  Endocrine Disorders lecture outline Endocrine Disorders of: 1. Pituitary Hormones 2. Growth Hormone 3. Antidiuretic Hormone (Vasopressin)  Diabetes Insipidus  Inappropriate ADH Syndrome 4. Thyroid Disorders  Goiter  Hyperthyroidism (Graves’ Disease)  Hypothyroidism  Diagnostic Tests 5. Adrenal Glands  Adrenal Medulla  Adrenal Cortex  Cushing’s Syndrome  Addison’s Disease  Endocrine Disorders After studying this lecture, the student is expected to: 1.Describe the possible effects of a pituitary disorders – an excess and a deficit of growth hormone in a child and an adult. – List the causes and effects of diabetes insipidus and inappropriate ADH syndrome. 2. Describe the pathophysiology of thyroid gland – causes of goiter. – the effects of an excess and a deficit of thyroid hormones. 3. Describe the pathophysiology of Adrenal gland – List the possible causes of Cushing’s syndrome. – Compare the effects of Cushing’s and Addison’s diseases. 4.Describe the effect of ovarian hormones on menstruation – List the hormonal changes in menopause and pregnancy – Describe the pathophysiology of endometriosis PITUITARY HORMONES  Pituitary disorders 1- Benign adenomas: most common cause of pituitary disorders  make up more than 10% of intracranial tumors.  They occur primarily in persons 30 to 50 years of age.  They lead to two groups of manifestations in the patient: – The effect of the mass as it enlarges and causes pressure in the skull (increased intracranial pressure) Signs of pressure on brain tissues include – increasing headaches, seizures, and drowsiness. – Visual defects such as hemianopia (loss of half of field of vision) are common. – The effect of the tumor on hormone secretion. Depend on which specific cells in the pituitary are involved and their location. Sometimes more than one hormone is secreted. In some cases, the adenoma may destroy an area of pituitary cells, causing a deficit of a particular hormone With some tumors, hemorrhage or infarction can occur, causing a sudden increase in intracranial pressure and destroying part of the pituitary (pituitary apoplexy).  Pituitary disorders Untreated adenomas eventually destroy all types of cells, resulting in panhypopituitarism. – Tumors are usually removed by surgery or radiation therapy. – Replacement of one or more hormones is necessary after this therapy or any time that deficits develop. 2. Vascular thrombosis and infarction associated with obstetric delivery or other cardiovascular disorders damages the pituitary, causing hypopituitarism. 3. Hypothalamic disorders include tumors or infection.  GROWTH HORMONE Dwarfism, or short stature, may be caused by a number of factors, one of which is a deficit of growth hormone (GH, somatotropin) or somatotropin-releasing hormone – Usually the pituitary dwarf has normal intelligence, normal body proportions, and some delay in skeletal maturation and puberty. – Replacement therapy for GH deficiency in a child before closure of the epiphyses is available. Gigantism, or tall stature, results from excess GH before puberty and fusion of the epiphyses  GROWTH HORMONE Acromegaly; excess GH secretion from pituitary adenoma in the adult – Overgrowth of bones and soft tissues resulting in: broad and heavy bones enlarged hands and feet, changes in the facial features, protruding mandible or jaw large tongue – Complications include; Carpal tunnel syndrome (pain and weakness at the wrist and hand), overgrowth of bones and cartilage Arthritis. Diabetes; GH affects glucose metabolism and the effectiveness of insulin Hypertension and cardiovascular disease also develop with untreated acromegaly.  ANTIDIURETIC HORMONE (VASOPRESSIN) 1- DIABETES INSIPIDUS Results from a deficit of anti-diuretic hormone (ADH). – Head injury or surgery may cause a temporary condition. – The condition is considered to be nephrogenic, when the renal tubules do not respond to the hormone. – may be genetic or linked to electrolyte imbalance or drugs. The clinical manifestations include : – polyuria with large volumes of dilute urine and – Polydipsia( thirst), eventually causing severe dehydration. (Note that glucose is not present in the urine with diabetes insipidus as it is in cases of diabetes mellitus.) Replacement therapy for ADH is available. ‫ المريض‬.‫الحالة التي ال يستطيع الجسم االحتفاظ ما يكفي من المياه‬... ‫بالعطش بشكل مفرط ويتغوط كميات كبيرة من البول‬  ANTIDIURETIC HORMONE(VASOPRESSIN) 2- Inappropriate ADH syndrome, (SIADH) Due to excess ADH, the urine is very concentrated. Not enough water is excreted and there is too much water in the blood. This dilutes many substances in the blood such as sodium. A low blood sodium level is the most common cause of symptoms of too much ADH. It is also the most common clue that a person may have SIADH. – In some cases, ADH excess is temporary, triggered by stress, – or may be secreted by an ectopic source (e.g., a bronchogenic carcinoma). Signs & Symptoms: nausea, vomiting, headache, problems with balance that may result in falls and mental changes, such as confusion, memory problems, strange behavior, Seizures or coma, in severe cases. Treatment: Diuretics and sodium supplements are used to correct the problem, as well as investigating any underlying cause.  Disorders of Pituitary Gland Growth Hormone: Hyper: gigantism-acromegaly Hypo: pituitary dwarfism Prolactin Hormone: lactogenic hormone Hyper: Galactorrhea Antidiuretic Hormone: Hypo : diabetes insipidus Excess: Inappropriate ADH syndrome Panhypopituitarism: Deficiency (decrease level) of all pituitary gland hormones  THYROID DISORDERS Thyroid gland secretes Two hormones : – Thyroxine (T4) and triiodothyronine (T3) Increases metabolic rate in all cells Increase oxygen consumption Essential for mental development – Calcitonin decreases levels of calcium and phosphate in the blood through – Decreases release of calcium from the bone – Decreases calcium reabsorption from the kidney  THYROID DISORDERS The two thyroid hormones, thyroxine and triiodothyronine, – secreted by the thyroid gland in response to hypothalamic-pituitary secretion of thyroid- stimulating hormone (TSH) Thyroid disorders may result from dysfunction of: – pituitary gland , – hypothalamus, – thyroid gland Goiter : (thyromegaly) An enlargement of the thyroid gland, visible externally as a swelling on the front of the neck. Goiters are caused by various hypothyroid and hyperthyroid conditions. 1- Non toxic goiter: A- Endemic goiter – may affect large groups of people in a specific geographical area. – It is a hypothyroid condition that occurs in regions where there are low iodine levels in the soil and food (e.g., mountainous areas or around the Great Lakes). Normally iodine is “trapped” by the thyroid gland and used to synthesize triiodothyronine (T3) and thyroxine (T4) – This dietary deficiency leads to: Low T3 and T4 (thyroid hormone) production and Compensatory increase in thyroid stimulating hormone (TSH) from the pituitary, producing hyperplasia and hypertrophy in the thyroid gland. – The use of iodized salt has solved this problem to a large extent. B- Sporadic goiter : Results from ingestion of certain food in large amounts or drugs, called Goitrogens which block synthesis of T3 and T4 but increase TSH secretion. TSH causes hyperplasia of the gland and goiter formation Foods include cabbage, turnips, and other related vegetables. Lithium and fluoride may also be goitrogenic. 2-Toxic goiter – is a hyperthyroid condition – One or more nodules of the thyroid become overactive, and secretes excess thyroid hormone – The enlarged thyroid gland develops small rounded masses, produces a large nodular gland (toxic nodular goiter or secondary toxic goiter). Endemic Goiter and Hypothyroidism  HYPERTHYROIDISM 1- GRAVES’ DISEASE : Occurs more frequently in women over 30 years of age – related to an autoimmune factor. (antibodies stimulate TSH receptors in gland) – Signs of : Hypermetabolism (weight loss & muscle wasting) Exophthalmos: presence of protruding, staring eyes and decreased blink and eye movements – It results from increased tissue mass in the orbit pushing the eyeball forward and from increased sympathetic stimulation affecting the eyelids. – If untreated, visual impairment may result from optic nerve damage or corneal ulceration. Increased stimulation of the sympathetic nervous system (sweating, tachycardia, nausea, diarrhea and tremors)  HYPERTHYROIDISM 2- Thyrotoxic crisis, or thyroid storm an acute situation in a patient with uncontrolled hyperthyroidism, usually precipitated by infection or surgery. It is life threatening because of the resulting hyperthermia, tachycardia, heart failure and delirium. Treated by a course of radioactive iodine, surgical removal of the thyroid gland, or the use of antithyroid drugs. Following treatment, there is a risk that patients may develop hypothyroidism or hypoparathyroidism  HYPOTHYROIDISM Mild hypothyroidism is very common and is easily treated by replacement doses of thyroid hormone. Severe hypothyroidism occurs in several forms: 1- Hashimoto’s thyroiditis, a destructive autoimmune disorder 2- Myxedema, severe hypothyroidism in adults – non pitting edema manifested as facial puffiness and a thick tongue – myxedema coma refers to acute hypothyroidism resulting in – hypotension, hypoglycemia, hypothermia, and loss of consciousness, – a life-threatening complication occurring in undiagnosed or untreated elderly patients.  HYPOTHYROIDISM 3- Cretinism, Untreated congenital hypothyroidism, may be related to iodine deficiency during pregnancy or may be a developmental defect. The thyroid gland may be nonfunctional or absent. Lack of treatment results in severe impairment of all aspects of growth and development. – The child may have difficulty feeding, delayed tooth eruption, malocclusion, and a large protruding tongue, demonstrating stunted skeletal growth and extreme lethargy Neonatal screening is standard in many areas; it leads to early treatment and prevents the mental retardation that accompanies early hypothyroidism. Forms infant; cretinism Graves’disease adult; myxedema Etiology congenital Autoimmune; adult; Thyroid-stimulating antibodies autoimmune (Hashimoto’s disease) Adenoma ; surgical removal drugs thyroid or pituitary Toxic goiter  THYROID DISORDERS DIAGNOSTIC TESTS Serum blood levels of T4 and T3, as well as serum TSH levels, Uptake of radioactive iodine (T3 uptake test). Scans may be used to search for the presence of tumor nodules. Antibody assays may also be required to confirm a specific diagnosis.  ADRENAL MEDULLA disorders Pheochromocytoma: is a benign tumor of the adrenal medulla that secretes epinephrine, norepinephrine, and sometimes other substances. It may be bilateral or unilateral. It is a relatively rare tumor, but it is one of the "curable” causes of hypertension if it is diagnosed. The signs it produces; – Headache, heart palpitations, sweating, and intermittent or constant anxiety—are related to elevated blood pressure. – Frequently catecholamines are released intermittently, causing : sudden hypertension and severe headache.  ADRENAL CORTEX disorders Cushing’s Syndrome caused by an excessive amount of glucocorticoids (e.g., hydrocortisone or cortisol) for long time. Excess glucocorticoids may result from: – Adrenal cortex adenoma – Pituitary adenoma or Cushing’s disease (increase ACTH) – An ectopic carcinoma that causes paraneoplastic syndrome – Iatrogenic conditions, such as administration of large amounts of glucocorticoids for many chronic inflammatory conditions  ADRENAL CORTEX disorders Typical changes associated with Cushing’s syndrome include: Characteristic change in the person’s appearance; a moon face (round and puffy) and a heavy trunk with fat at the back of the neck (buffalo hump) and wasting of muscle in the limbs Fragile skin that may have red streaks as well as increased hair growth (hirsutism)  ADRENAL CORTEX disorders Catabolic effects such as osteoporosis and decreased protein synthesis, which delays healing Metabolic changes include increased gluconeogenesis and insulin resistance, which may lead to glucose intolerance; this may result in diabetes mellitus or exacerbate an existing diabetic state. Retention of sodium and water (mineral corticoid effect), leading to hypertension, edema, and possible hyperkalemia Suppression of the immune response and the inflammatory response with atrophy of the lymphoid tissue, predisposing the client to infection Stimulation of erythrocyte production Emotional lability and euphoria  ADRENAL CORTEX disorders Two concerns for health care professionals are: 1. The risk of infection in the patient with Cushing’s syndrome and need for precautions; infection may be local or systemic (e.g., tuberculosis) 2. A decreased stress response in a patient with iatrogenic Cushing’s syndrome due to atrophy of the adrenal cortex; therefore the doses of medication may have to be increased before and during a stressful event. 3.Similarly dosage must be gradually reduced over a period of time to permit resumption of normal secretory function by the gland Treatment depends on the underlying cause  ADRENAL CORTEX disorders; Addison’s Disease  Adrenal hypofunction or adrenal insufficiency  Decrease or deficiency of adrenocortical secretions (glucocorticoids, mineralocorticoids , and androgens) Etiology : – An autoimmune reaction…..common. – Hemorrhage into the adrenal gland – meningococcal, viral, tuberculosis, or histoplasmosis infections. – Destructive tumors. ADRENAL CORTEX disorders; Addison’s Disease The major effects of these hormonal deficits include: – Cortisol deficit; hypoglycemia (decrease in hepatic glucose output), poor stress response, fatigue, weight loss, GIT disturbances (vomiting and diarrhea)and frequent infections. – Mineralocorticoid (aldosterone) deficit; hyponatremia, hypotension, hyperkalemia, cardiac arrhythmias, shock and failure. – Decreased body hair due to lack of androgens – Hyperpigmentation in the extremities, skin creases, buccal mucosa, and tongue, because of increased ACTH and melanostimulating hormone resulting from low cortisol secretion. ADRENAL CORTEX disorders; Addison’s Disease Replacement therapy with the necessary hormones controls the diseases. Increased doses may be required in times of stress.  Q. For each of the following disorders, identify the etiology (i.e.hyposecretion or hypersecrtion of a specific hormone) 1. Graves 'disease 2. Gigantism 3. Myxedema 4. Diabetes insipidus 5. Acromegaly 6. Cushing’s syndrome 7. Dwarfism 8. Diabetes mellitus 9. Addison’s disease 10. Cretinism  Q. For each of the following characteristics, identify the endocrine disorder or disorders in which they occur; Increased basal metabolic rate, tachycardia and palpitations Intolerance to cold Mental retardation Predisposition to renal calculi Hyperpigmentation of the skin and oral mucosa Development of exophthalmos Presence of a goiter Enlarged hands and feet Hypocalcemia