DEHYDRATION Prof. Sultan Ayoub Meo MBBS, M.Phil, Ph.D (Pak), M Med Ed (Dundee), FRCP (London), FRCP (Dublin), FRCP (Glasgow), FRCP (Edinburgh) Professor and Consultant, Department of Physiology and University Diabetes Centre, College of Medicine, King Saud University, Riyadh, KSA
Dehydration occurs when body does not have as much water and fluids as it needs. Dehydration is classified as mild, moderate, or severe DEHYDRATION
In average young adult male: Body Composition % of body weightBody composition 18%Protein, & related substances 15%Fat 7%Mineral 60%Water
Body Fluids
Fluid Compartments 60% of body weight Extracellular fluid ( 1/3) 33% of TBW 20% of body wt Intracellular fluid ( 2/3) 67% of TBW 40% of body wt Interstitial fluid 75% of ECF 15% of body wt Plasma 25% of ECF 5% of body wt Transcellular fluid CSFIntraocularPleuralPeritonealPericardialSynovial Digestive secretions
Body Fluids: Intake and Output
Factors affecting body fluids Water intake & output Age: - infant: 73% - elderly: 45% Gender: - adult male: 60% - adult female: 40-50% Obesity Climate Habits Level of physical activity
Dehydration: Causes Not drinking enough water: Sore throat, mouth sores, difficulty swallowing, and/or a decreased thirst sensation (especially in older adults) Illness: Nausea, vomiting, diarrhea, fever, pain, burn Overheated indoor / outdoor air: Mobility: Inability to get water: Old age Excessive urine output: Uncontrolled diabetes, diuretics Medications: Laxatives, sedatives/sleeping pills/anxiety medications Excessive exercise, heat, humidity
Dehydration: Causes
Control of body fluids Thirst Sweating Renal control (aldosterone) Neuronal (osmoreceptors, baroreceptors)
Control of body fluids
Control of body fluids: ADH Role
Control of body fluids
Dehydration Loss of water from the body, e.g. vomiting, diarrhea, sweating, & polyuria. Leads to in both ECF & ICF volumes. osmolarity in both ECF & ICF. General signs: - Dry tongue - loss of skin elasticity - soft eyeballs (due to lowering of intraocular tension) - blood pressure (if 4-6L loss) - Hb, & Hct (packed cell volume) Treated w fluid replacement (orally, or IV).
Dehydration
Dehydration: Clinical Features
Dehydration: Adverse Effects
Dehydration:
Dehydration: Assessment and Management
Oral rehydration salts: ORS. A solution of glucose -based salt solution used in oral rehydration therapy. WHO and UNICEF recommend a single formulation of glucose-based ORS to treat or prevent dehydration ORS solution contains 75 mEq/l of sodium and 75 mmol/l of glucose, and have a total osmolarity of 245 mOsm/l.