Dehydration

Dehydration
Nurses encourage a patient to drink an oral rehydration solution to treat the combination of dehydration and hypovolemia secondary to cholera. Cholera leads to GI loss of both excess free water (dehydration) and sodium (hence ECF volume depletion—hypovolemia).
Specialty	Critical care medicine
Symptoms	Increased thirst, tiredness, decreased urine, dizziness, headaches, and confusion[1]
Complications	Low blood volume shock (hypovolemic shock), coma, seizures, urinary tract infection, kidney disease, heatstroke, hypernatremia, metabolic disease,[1] hypertension.[2]
Causes	Loss of body water
Risk factors	Physical water scarcity, heatwaves, disease (most commonly from diseases that cause vomiting and/or diarrhea), exercise
Treatment	Drinking clean water
Medication	Saline

In physiology, dehydration is a lack of total body water,^[3] with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mild dehydration can also be caused by immersion diuresis, which may increase risk of decompression sickness in divers.

Most people can tolerate a 3-4% decrease in total body water without difficulty or adverse health effects. A 5-8% decrease can cause fatigue and dizziness. Loss of over 10% of total body water can cause physical and mental deterioration, accompanied by severe thirst. Death occurs at a loss of between 15 and 25% of the body water.^[4] Mild dehydration is characterized by thirst and general discomfort and is usually resolved with oral rehydration.

Dehydration can cause hypernatremia (high levels of sodium ions in the blood) and is distinct from hypovolemia (loss of blood volume, particularly blood plasma).

Chronic dehydration can contribute to the formation of kidney stones as well as the development of chronic kidney disease.^[5][6]