1. 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

2. Dehydration occurs when body does not have as much water and fluids as it needs. Dehydration is classified as mild, moderate, or severe DEHYDRATION

3. In average young adult male: Body Composition % of body weightBody composition 18%Protein, & related substances 15%Fat 7%Mineral 60%Water

4. Body Fluids

5. 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

6. Body Fluids: Intake and Output

7. 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

8. 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

9. Dehydration: Causes

11. Control of body fluids  Thirst  Sweating  Renal control (aldosterone)  Neuronal (osmoreceptors, baroreceptors)

12. Control of body fluids

13. Control of body fluids: ADH Role

14. Control of body fluids

16. 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).

17. Dehydration

18. Dehydration: Clinical Features

22. Dehydration: Adverse Effects

25. Dehydration:

26. Dehydration: Assessment and Management

27. 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.