Last reviewed: March 2020
Last updated: March  2020

Summary

Definition

History and exam

Key diagnostic factors

  • postural dizziness
  • weight loss
  • orthostatic hypotension
  • postural tachycardia
  • signs of shock

Other diagnostic factors

  • decreased urine output
  • diarrhea
  • vomiting
  • melena
  • hematochezia
  • high-volume gastrointestinal drainage
  • polyuria
  • poor oral intake
  • severe sweating
  • burns
  • intestinal obstruction
  • severe pancreatitis
  • crush injuries
  • intra-abdominal bleeding
  • fatigue
  • thirst
  • dry mucous membranes
  • muscle cramps
  • abdominal pain
  • chest pain
  • confusion
  • decreased skin turgor

Risk factors

  • diuretic therapy
  • chronic kidney disease
  • older adult
  • altered mental status
  • high ambient temperature

Diagnostic investigations

1st investigations to order

  • CBC
  • serum electrolytes
  • blood glucose
  • BUN
  • serum creatinine
  • urinalysis
  • random urine sodium
  • fractional excretion of sodium (FENa)
  • random urine chloride
  • random urine creatinine
  • random urine osmolality
  • rectal exam and fecal occult blood test
More 1st investigations to order

Investigations to consider

  • urine urea/fractional excretion of urea (FE urea)
  • arterial blood gases
  • nasogastric lavage
  • stool cultures
  • abdominal ultrasound
  • abdominal CT scan
  • upper gastrointestinal endoscopy
  • colonoscopy
More investigations to consider

Emerging tests

  • saliva osmolality
  • point-of-care magnetic relaxometry
More emerging tests

Treatment algorithm

Contributors

Research Assistant

Division of Nephrology and Hypertension

Northwestern University

Chicago

IL 

Disclosures

AM declares that he has no competing interests.

Research Associate

Northwestern University

Feinberg School of Medicine

Chicago

IL

Disclosures

SKH is an author of a reference cited in this topic.

Professor

Division of Nephrology and Hypertension

Department of Internal Medicine

Northwestern Memorial Hospital

Chicago

IL

Disclosures

DB is an author of a reference cited in this topic.

Dr Alonso Marquez, Dr Syed K. Haque, and Dr Daniel Batlle would like to gratefully acknowledge Dr Maria Aurora Posadas Salas, Dr Jason Eckel, and Dr Arthur Greenberg, previous contributors to this topic. 

Peer reviewersVIEW ALL

Renal Consultant

Infection Control Lead for Medical Directorate

Derby City Hospital

Derby

UK

Disclosures

NK declares that he has no competing interests.

Assistant Professor

Chicago Medical School

Rosalind Franklin University

Lombard

IL

Disclosures

IM declares that he has no competing interests.

Assistant Professor

Department of Internal Medicine

Division of Nephrology

University of Iowa Hospital and Clinics

Iowa City

IA

Disclosures

MS declares that he has no competing interests.

Associate Director

Nephrology

Washington Hospital Center

Washington

DC

Disclosures

JHV declares that she has no competing interests.

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