Chapter 47: Adult Endocrine Problems

The endocrine system maintains homeostasis through hormonal regulation governed by negative feedback loops, where elevated hormone levels signal glands to reduce secretion. Diagnostic testing includes stimulation and suppression tests, radioactive iodine uptake studies, and metabolic markers such as hemoglobin A1c to assess long-term glycemic control. Pituitary disorders encompass both anterior lobe dysfunction, including growth hormone deficiency requiring lifelong replacement and acromegaly from excessive growth hormone secretion that necessitates surgical intervention with careful postoperative monitoring for cerebrospinal fluid leakage. Posterior pituitary problems involve antidiuretic hormone imbalances, with diabetes insipidus causing excessive dilute urine excretion managed through fluid replacement and synthetic hormone administration, while syndrome of inappropriate antidiuretic hormone secretion produces dangerous water intoxication and hyponatremia requiring fluid restriction and hypertonic saline therapy. Adrenal gland pathology includes Addison's disease, characterized by glucocorticoid and mineralocorticoid deficiency presenting with hyperpigmentation and requiring stress-dose corticosteroid replacement to prevent life-threatening crisis; Cushing's syndrome from cortisol excess causing metabolic and physical deformities; hyperaldosteronism producing severe hypertension and electrolyte imbalances; and pheochromocytoma, a catecholamine-secreting tumor requiring careful physical handling to prevent hypertensive emergency. Thyroid disorders range from hypothyroidism with its slowed metabolic manifestations and risk of myxedema coma to hyperthyroidism and its life-threatening thyroid storm complication. Thyroidectomy necessitates vigilant monitoring for airway compromise, laryngeal nerve injury, and hypocalcemia from inadvertent parathyroid damage. Parathyroid dysfunction affects calcium homeostasis, with hypoparathyroidism causing tetany and hypercalcemia requiring seizure precautions and calcium supplementation, while hyperparathyroidism leads to bone loss and nephrolithiasis. Diabetes mellitus, involving either absolute insulin deficiency or insulin resistance, demands comprehensive management including dietary modification, exercise, pharmacotherapy, and injection site rotation to prevent lipodystrophy. Acute diabetic emergencies include hypoglycemia treated through rapid simple carbohydrate administration, diabetic ketoacidosis managed with insulin and aggressive fluid resuscitation with potassium monitoring, and hyperosmolar hyperglycemic syndrome requiring intensive hydration without acidosis. Chronic hyperglycemia precipitates both macrovascular complications affecting coronary and cerebral circulation and microvascular damage including retinopathy, nephropathy with microalbuminuria, and neuropathy, necessitating rigorous foot care education given impaired sensation and delayed wound healing.