Volume depletion in adults

Volume depletion is characterized by a reduction in extracellular fluid volume that occurs when salt and fluid losses exceed intake on a sustained basis.

The most common etiologies are hemorrhage, vomiting, diarrhea, diuresis, or third-space redistribution of fluids .

A detailed history and physical exam are crucial in determining the etiology.

Signs and symptoms may include: postural dizziness, fatigue, confusion, muscle cramps, postural hypotension, and tachycardia. Clinical symptoms usually do not manifest until large fluid losses have occurred.

Without proper assessment and timely resuscitation, volume depletion can lead to circulatory collapse and shock.

Resuscitation should be tailored based on the etiology of volume loss and concurrent acid-base and electrolyte disorders.

This topic refers to volume depletion in adults. For children, see Volume Depletion in Children.

Volume depletion is a reduction in extracellular fluid volume that occurs when salt and fluid losses exceed intake on a sustained basis.[1]Mange K, Matsuura D, Cizman B, et al. Language guiding therapy: the case of dehydration versus volume depletion. Ann Intern Med. 1997 Nov 1;127(9):848-53. http://www.ncbi.nlm.nih.gov/pubmed/9382413?tool=bestpractice.com [2]McGee S, Abernethy WB 3rd, Simel DL. The rational clinical examination: is this patient hypovolemic? JAMA. 1999 Mar 17;281(11):1022-9. http://www.ncbi.nlm.nih.gov/pubmed/10086438?tool=bestpractice.com [3]Batlle D, Chen S, Haque S. Physiological principles in the clinical evaluation of electrolyte, water, and acid-base disorders. In: Alpern RJ, Caplan MJ, Moe OW, eds. Seldin and Giebisch's the kidney: physiology and pathophysiology. 5th ed. San Diego, CA: Academic Press; 2012:2477-512.​ It may result from renal losses (diuresis) or extrarenal losses (from the gastrointestinal tract, skin, or third-space redistribution of fluids).[4]Kellum JA, Romagnani P, Ashuntantang G, et al. Acute kidney injury. Nat Rev Dis Primers. 2021 Jul 15;7(1):52. http://www.ncbi.nlm.nih.gov/pubmed/34267223?tool=bestpractice.com [5]Do C, Evans GJ, DeAguero J, et al. Dysnatremia in gastrointestinal disorders. Front Med (Lausanne). 2022 May 13;9:892265. https://pmc.ncbi.nlm.nih.gov/articles/PMC9136014 http://www.ncbi.nlm.nih.gov/pubmed/35646996?tool=bestpractice.com [6]Kate V, Sureshkumar S, Gurushankari B, et al. Acute upper non-variceal and lower gastrointestinal bleeding. J Gastrointest Surg. 2022 Apr;26(4):932-49. http://www.ncbi.nlm.nih.gov/pubmed/35083723?tool=bestpractice.com ​​[7]McCubbin AJ. Exertional heat stress and sodium balance: Leaders, followers, and adaptations. Auton Neurosci. 2021 Nov;235:102863. http://www.ncbi.nlm.nih.gov/pubmed/34391123?tool=bestpractice.com [8]Bhagat M, Singh A, Bazzi T, et al. Bronchorrhea, a rare and debilitating symptom of lung cancer: case report and review of the treatment. JTO Clin Res Rep. 2022 Oct;3(10):100398. https://pmc.ncbi.nlm.nih.gov/articles/PMC9508333 http://www.ncbi.nlm.nih.gov/pubmed/36164316?tool=bestpractice.com ​Without proper assessment and timely resuscitation, volume depletion can lead to circulatory collapse and shock.​[9]Cannon JW. Hemorrhagic shock. N Engl J Med. 2018 Jan 25;378(4):370-79.[10]Vincent JL, De Backer D. Circulatory shock. N Engl J Med. 2013 Oct 31;369(18):1726-34. https://www.nejm.org/doi/10.1056/NEJMra1208943 [11]Rossaint R, Afshari A, Bouillon B, et al. The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition. Crit Care. 2023 Mar 1;27(1):80. https://pmc.ncbi.nlm.nih.gov/articles/PMC9977110 http://www.ncbi.nlm.nih.gov/pubmed/36859355?tool=bestpractice.com

Dehydration and volume depletion are not the same, although they can coexist in the same patient at the same time.[12]Lacey J, Corbett J, Forni L, et al. A multidisciplinary consensus on dehydration: definitions, diagnostic methods and clinical implications. Ann Med. 2019 May-Jun;51(3-4):232-51. https://pmc.ncbi.nlm.nih.gov/articles/PMC7877883 http://www.ncbi.nlm.nih.gov/pubmed/31204514?tool=bestpractice.com ​​ Although often used interchangeably, it is important to distinguish one from the other. Dehydration implies a total body water deficit, alone or in excess of sodium loss, with a subsequent increase in plasma tonicity that usually comes to clinical attention as hypernatremia.[12]Lacey J, Corbett J, Forni L, et al. A multidisciplinary consensus on dehydration: definitions, diagnostic methods and clinical implications. Ann Med. 2019 May-Jun;51(3-4):232-51. https://pmc.ncbi.nlm.nih.gov/articles/PMC7877883 http://www.ncbi.nlm.nih.gov/pubmed/31204514?tool=bestpractice.com ​ This hypertonicity implies intracellular water contraction whereas volume depletion implies blood volume contraction.[13]Bhave G, Neilson EG. Volume depletion versus dehydration: how understanding the difference can guide therapy. Am J Kidney Dis. 2011 Aug;58(2):302-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4096820 http://www.ncbi.nlm.nih.gov/pubmed/21705120?tool=bestpractice.com Hypertonicity (pure water loss), most frequently occurs due to insufficient water intake (impaired thirst or access to water) or excess urinary output (osmotic diuresis or diabetes insipidus). Symptoms arise from the effects of increased osmolality and reflect the cellular responses to hypertonicity, including confusion, thirst, impaired sensorium, and, in more extreme cases, coma or seizures.[12]Lacey J, Corbett J, Forni L, et al. A multidisciplinary consensus on dehydration: definitions, diagnostic methods and clinical implications. Ann Med. 2019 May-Jun;51(3-4):232-51. https://pmc.ncbi.nlm.nih.gov/articles/PMC7877883 http://www.ncbi.nlm.nih.gov/pubmed/31204514?tool=bestpractice.com [14]Hooper L, Abdelhamid A, Attreed NJ, et al. Clinical symptoms, signs and tests for identification of impending and current water-loss dehydration in older people. Cochrane Database Syst Rev. 2015 Apr 30;2015(4):CD009647. https://pmc.ncbi.nlm.nih.gov/articles/PMC7097739 http://www.ncbi.nlm.nih.gov/pubmed/25924806?tool=bestpractice.com ​​​​​ In contrast, clinical symptoms of volume depletion are a result of the hemodynamic effects of the reduction in intravascular volume and usually do not involve neurological changes.