Dehydration

Dehydration is a condition resulting from excessive loss of body water relative to intake, leading to inadequate fluid in the body's compartments. It can arise from insufficient drinking, excessive sweating, diarrhea, vomiting, fever, burns, or medications such as diuretics. It is commonly categorized by severity as mild, moderate, or severe, and by electrolyte balance as isotonic, hypotonic, or hypertonic dehydration.

Signs and symptoms vary by age and severity. In adults, thirst, dry mouth, reduced urination, dark urine, dry skin, fatigue, dizziness, and lightheadedness are common, while severe dehydration can cause rapid heart rate, low blood pressure, confusion, and fainting. In infants and young children, few wet diapers, sunken eyes or fontanelle, and irritability may occur. Diagnosis combines clinical assessment with laboratory tests of electrolytes, kidney function, and urine concentration.

Treatment depends on severity. Mild to moderate dehydration is typically managed with oral rehydration solutions that replace water, electrolytes, and glucose. Severe dehydration requires urgent medical care with intravenous fluids, usually isotonic saline, to restore circulating volume and correct electrolyte imbalances, with careful monitoring to avoid rapid shifts. Prevention focuses on regular fluid intake, especially during heat or physical activity, prompt treatment of gastroenteritis, and attention to at-risk groups such as the elderly.