[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Systemic syndromes](https://durgical.com/en/clinical-exam/#a-systemic) › Dehydration and fluid overload [Clinical exam](https://durgical.com/en/clinical-exam/) · [Systemic syndromes](https://durgical.com/en/clinical-exam/#a-systemic) # Dehydration and fluid overload - Syndrome Too little fluid (thirst, dry mouth, little urine) or too much (swelling, breathlessness): the exam helps tell them apart. Updated 2026-11-01 **See it in 3D:** [Kidneys](https://durgical.com/en/anatomy/kidney/) · [Internal jugular vein](https://durgical.com/en/anatomy/internal-jugular-vein/) · [External jugular vein](https://durgical.com/en/anatomy/external-jugular-vein/) · [Inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/) · [Skin](https://durgical.com/en/anatomy/skin/) ## Key points - Hypovolemia: thirst, dry mucosa, tachycardia, orthostatic hypotension, prolonged capillary refill, flat neck veins and scant, dark urine. - Children: sunken eyes, crying without tears, sunken fontanelle, slow skin-pinch recoil, lethargy and few wet diapers. - Overload: pitting edema in dependent areas (sacrum in bedbound patients), raised jugular venous pressure, crackles, a third heart sound and weight gain. - Weight change over a few days is the best measure of volume change: same time, same scale, similar clothing. - Skin turgor is unreliable in older adults; mucosa, orthostatics and mental state are better guides. - Nursing: fluid intake and output balance and daily weight. ## What it is Volume status is judged at the bedside from vital signs, skin and mucosa, neck veins, lungs, edema, urine output and weight. Dehydration (hypovolemia) and fluid overload have opposite findings but can coexist: a patient can be edematous and still have too little volume inside the vessels. In children, dehydration from diarrhea remains a major cause of preventable death. ## Key findings - Current weight versus previous weight. - Heart rate, lying and standing blood pressure, capillary refill. - Mucosa, tears, eyes, the fontanelle in infants and skin pinch. - Jugular veins and hepatojugular reflux. - Lungs (crackles, effusion), peripheral edema and ascites. - Urine output and color; mental state. ## Pathophysiology - Body water is split between the intracellular and extracellular spaces; the extracellular space includes plasma and interstitial fluid. - Between capillary and interstitium, fluid moves according to hydrostatic pressure (pushes it out) and the oncotic pressure of albumin (holds it in). - Loss of extracellular fluid lowers venous return and cardiac output: tachycardia, vasoconstriction and, when these run out, hypotension; the kidney conserves water and sodium and urine falls. - Edema appears when hydrostatic pressure rises (heart failure, overload) or oncotic pressure falls (cirrhosis, nephrotic syndrome); in the latter, intravascular volume may be low. - A kidney that filters poorly (acute kidney injury or chronic kidney disease) cannot excrete excess sodium and water. ## Dehydration vs fluid overload | Finding | Dehydration | Fluid overload | | --- | --- | --- | | Weight | Falls | Rises | | Pulse and pressure | Tachycardia, orthostatic hypotension | Normal or high pressure; tachycardia possible | | Neck veins | Flat | Distended, hepatojugular reflux | | Mucosa and skin | Dry, slow skin pinch, slow capillary refill | Moist, pitting edema | | Lungs | Clear | Crackles, pleural effusion | | Urine | Scant and dark | Variable; scant if the cause is renal | ## Common causes - Dehydration: diarrhea and vomiting (gastroenteritis, cholera), fever, heavy sweating, burns, diuretics, hyperglycemia with osmotic diuresis and poor intake in older adults or patients with reduced consciousness. - Overload: heart failure, acute kidney injury and chronic kidney disease, cirrhosis, nephrotic syndrome and excess intravenous fluids. - Edema with low circulating volume: cirrhosis, nephrotic syndrome, sepsis with capillary leak and malnutrition. ## Tests that confirm it - Sodium, potassium, urea and creatinine; the urea-to-creatinine ratio rises in dehydration. - Urine specific gravity and urine sodium. - Bedside ultrasound (inferior vena cava, lung B-lines) and natriuretic peptides when heart failure is suspected. ## Memory aid 'Dry outside, flat in the neck; wet at the feet, noisy in the lungs.' ## Test yourself Think of the answer, then tap the question to see it. ## Which signs of dehydration are looked for in an infant? Sunken eyes, crying without tears, dry mouth and tongue, a sunken fontanelle, slow skin-pinch recoil, few wet diapers, irritability or lethargy. ## Why can a patient with cirrhosis be edematous yet have too little volume inside the vessels? Low albumin lowers oncotic pressure, so fluid escapes into the interstitium and peritoneum and effective intravascular volume falls. ## What is the most useful measure for following volume changes from day to day? Daily weight, taken at the same time, on the same scale and in similar clothing, together with the fluid balance. ## Which neck and chest findings suggest fluid overload? Raised jugular venous pressure, a positive hepatojugular reflux, lung crackles, a third heart sound and pleural effusion. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-exam/dehydration-and-fluid-overload/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Kidneys](https://durgical.com/en/anatomy/kidney/) - [Internal jugular vein](https://durgical.com/en/anatomy/internal-jugular-vein/) - [External jugular vein](https://durgical.com/en/anatomy/external-jugular-vein/) - [Inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/) - [Skin](https://durgical.com/en/anatomy/skin/) ## Related - [Hydration status: signs of dehydration](https://durgical.com/en/clinical-exam/hydration-status-signs-of-dehydration/) - [Capillary refill time](https://durgical.com/en/clinical-exam/capillary-refill-time/) - [Orthostatic vital signs](https://durgical.com/en/clinical-exam/orthostatic-vital-signs/) - [Jugular venous pressure and the venous pulse](https://durgical.com/en/clinical-exam/jugular-venous-pressure-and-the-venous-pulse/) - [Hepatojugular (abdominojugular) reflux](https://durgical.com/en/clinical-exam/hepatojugular-reflux/) - [Edema: pitting, grading and distribution](https://durgical.com/en/clinical-exam/edema-pitting-grading-and-distribution/) - [Heart failure syndrome: left- and right-sided signs](https://durgical.com/en/clinical-exam/heart-failure-syndrome-left-and-right-sided-signs/) - [Shock: the clinical signs and the types](https://durgical.com/en/clinical-exam/shock-the-clinical-signs-and-the-types/) ## Related conditions - [Dehydration (fluid volume deficit)](https://durgical.com/en/conditions/dehydration/) - [Dehydration in children (acute diarrhoeal disease)](https://durgical.com/en/conditions/dehydration-in-children/) - [Heart failure](https://durgical.com/en/conditions/heart-failure/) - [Acute (viral) gastroenteritis](https://durgical.com/en/conditions/acute-gastroenteritis/) - [Nephrotic syndrome](https://durgical.com/en/conditions/nephrotic-syndrome/) - [Acute kidney injury](https://durgical.com/en/conditions/acute-kidney-injury/) - [Hypovolaemic shock](https://durgical.com/en/conditions/hypovolaemic-shock/) - [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/) [← All of the clinical exam](https://durgical.com/en/clinical-exam/) Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis. Sources: [Dehydration: MedlinePlus](https://medlineplus.gov/dehydration.html) (MedlinePlus, U.S. National Library of Medicine, 2026); [26.1 Body Fluids and Fluid Compartments](https://openstax.org/books/anatomy-and-physiology-2e/pages/26-1-body-fluids-and-fluid-compartments) (OpenStax, Rice University, 2022). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/clinical-exam/dehydration-and-fluid-overload/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/dehydration-and-fluid-overload/