Diseases of the Endocrine System PDF

Page 2 Saturday, September 21, 2024 8:11 PM Diseases of the Parathyroid Gland - Hyperparathyroid hormone secretion ○ Primary hyperparathyroidism ▪ Causes □ Primary adenoma, where the parathyroid gland is the problem ▪ Effects...

Page 2 Saturday, September 21, 2024 8:11 PM Diseases of the Parathyroid Gland - Hyperparathyroid hormone secretion ○ Primary hyperparathyroidism ▪ Causes □ Primary adenoma, where the parathyroid gland is the problem ▪ Effects □ Increased PTH with hypercalcemia □ Metastatic hypercalcemia where calcification occurs wide-spread □ Osteitis fibrosa cystica ○ Secondary hyperparathyroidism ▪ Causes □ The most common cause is due to renal failure, not a problem with the parathyroid gland □ Low vitamin D synthesis/ low calcium reabsorption ▪ Effects □ Increased PTH with normal or low levels of calcium □ Decreased blood calcium with a lack of calcium reabsorption leads to an increase in PTH which pulls calcium from the bone This leads to renal osteodystrophy - Hypoparathyroid hormone secretion ○ Hypoparathyroidism ▪ Causes □ DiGeorge syndrome Aka congenital thymic aplasia Classified by an absence of the 3rd/ 4th pharyngeal pouches □ Iatrogenic with thyroidectomy □ Idiopathic ▪ Effects □ Hypocalcemia which leads to tetany and convulsions Can be demonstrated by Trousseau's sign and Chvostek's sign ○ Pseudohypoparathyroidism ▪ Nothing is wrong with the parathyroid gland, but has signs of hypoparathyroidism ▪ Causes □ Genetic disorder that makes the receptor sites for PTH insensitive ▪ Effects □ High PTH and soft tissue calcification □ Albright's hereditary osteodystrophy Signs/ symptoms ◊ Patients are short stature and neck, while being obese ◊ Brachydactyly and mental retardation ◊ They can't calcify bone, but can calcify tissue (dystrophic calcification) Diseases of the Adrenal Cortex - Hyperfunction of adrenals ○ Adrenogenital syndrome ▪ This is both congenital and genetic as it relates to deficiency in the enzyme 21- hydroxylase ▪ Disease affects glucocorticoid metabolism Exam 1 Page 1  ▪ Disease affects glucocorticoid metabolism □ Decreased glucocorticoids causes an increased ACTH □ The disease cannot increase glucocorticoids but can increase androgens It blocks the zona glomerulosa which stops aldosterone production It blocks the zona fasciculata which stops cortisol production It does NOT block the zona reticularis which produces androgens ▪ Signs/ symptoms □ Infant males have enlarged genitalia, referred to as "infant Hercules" □ Infant females have ambiguous external genitalia □ Produces sex characteristics that are exaggerated ○ Hyperaldosteronism ▪ Most common cause is due to a functional adenoma of the zona glomerulosa ▪ Leads to Conn's Syndrome □ Condition of a functional adenoma of the zona glomerulosa producing excess aldosterone Aldosterone's purpose is to reabsorb sodium in the kidneys □ Signs/ symptoms Hypertension due to water following sodium and increasing pressure in vessels Hypokalemia and hypernatremia ○ Cushing's disease ▪ 70% of Cushing's is due to functional adenoma of the pituitary ▪ Most common cause is a functional adenoma in the pituitary, producing excess ACTH ▪ ACTH levels will be elevated ○ Cushing's syndrome ▪ ACTH levels will be decreased ▪ Causes □ Most common cause is iatrogenic when patient is on corticosteroid therapies □ Small-cell lung cancer malignant tumor producing ACTH-like substance □ Functional adrenal adenoma - Hypofunction of adrenals ○ Addison's disease ▪ Classified as primary adrenocortical deficiency □ Idiopathic atrophy, where you have infiltrating lymphocytes with circulating autoantibodies ▪ The receptor sites of cortisol are insensitive ▪ Increased ACTH, decreased cortisol □ Increased ACTH leads to increased MSH as well ○ Secondary adrenocortical deficiency ▪ Corticosteroid-induced hypoadrenalism ▪ Nelson's syndrome □ Syndrome is due to a removal of the adrenals to treat Cushing's syndrome when the patient actually presents with Cushing's disease ▪ Waterhouse-Friderichsen syndrome □ Bilateral hemorrhaging into the adrenal glands with septicemia □ Most commonly associated with meningococcal meningitis □ Usually fatal Diseases of the Adrenal Medulla - Pheochromocytoma ○ This is a neoplasm of chromaffin cells that produce catecholamines ○ Produces hypertension ▪ 200/120 blood pressure ○ Vanillylmandelic acid (VMA) is found in urine - Ganglioneuroma Exam 1 Page 2  - Ganglioneuroma ○ Benign tumor with neural crest cell origin - Neuroblastoma ○ This is the third most common malignancy in children ○ Top 3 most common malignancies in children ▪ Acute lymphoblastic leukemia, nephroblastoma, neuroblastoma ○ Can spread to eyes, liver, and bone marrow Multiple Endocrine Neoplasia Syndromes - MEN type I ○ Wermer syndrome ▪ More common type ▪ Autosomal dominant on chromosome #11 ▪ Consist of tumors of the □ Parathyroid Hypercalcemia □ Pancreas Producing excess insulin -> hyperglycemia Zollinger-Ellison which is ulcers throughout the GI from the stomach to jejunum □ Pituitary Hyperprolactinemia - MEN type IIa ○ Sipple syndrome ▪ Consists of tumors of the □ Thyroid Medullary carcinoma that produces excess calcitonin □ Parathyroid Hypercalcemia □ Adrenal medulla Pheochromocytoma - MEN type IIb ○ William syndrome ▪ Don’t need to know this one, it makes a good wrong answer ▪ Tumors of the thyroid, adrenal, and ganglioneuromas of extra-endocrine sites Exam 1 Page 3