W7 Diabetes Insipidus PDF

Lecture Material is adapted from © 2017 Wolters Kluwer Health, Lippincott Williams & Wilkins Applied Pathophysiology: A Conceptual Approach to the Mechanisms of Disease Chapter 13: Altered Hormonal and Metabolic Regulation Module 4: Clinical Models Dr. Romeo Batacan Jr. MPAT12001 Medical Pathoph...

Lecture Material is adapted from © 2017 Wolters Kluwer Health, Lippincott Williams & Wilkins Applied Pathophysiology: A Conceptual Approach to the Mechanisms of Disease Chapter 13: Altered Hormonal and Metabolic Regulation Module 4: Clinical Models Dr. Romeo Batacan Jr. MPAT12001 Medical Pathophysiology Lecture Series Copyright © 2017 Wolters Kluwer Health | Lippincott Williams &Wilkins  Diabetes Insipidus Pathophysiology Clinical manifestations Diagnostic criteria Treatment  Diabetes Insipidus Pathophysiology Insufficient ADH; inability to concentrate or retain water Causes 1. Neurogenic DI: Insufficient ADH production by hypothalamus Ineffective secretion by posterior pituitary 2. Nephrogenic DI: Inadequate kidney response to ADH 3. Dipsogenic/Psychogenic DI: Water intoxication (large volume of water intake) > lowers osmolality below Polydipsia: ADH secretion threshold excessive thirst Craft AJ, Gordon C, Tiziani A. Understanding pathophysiology. 1st ed. Chatswood, Mosby; 2011  Diabetes Insipidus Clinical Manifestations Degree of manifestations depends on severity: Polyuria > highly dilute with low specific gravity Fluid loss leads to: Serum hyperosmolality Severe dehydration Excessive thirst (polydipsia) If untreated: Hypovolemic shock (type of circulatory shock due to low fluid volume) Death  Diabetes Insipidus Diagnostic Criteria History and physical examination Frequent causes include surgery, trauma Signs of dehydration Skin turgor: slow return after pinch: “tenting” – sign of dehydration Other signs: sticky oral mucosa, dry flushed skin Laboratory tests Elevated serum osmolality [Isotonic (280-300mOsm/kg)] Elevated or low ADH levels Urine specific gravity