Question

what are the five main effects of dehydration?

Answer 1

The five main effects of dehydration (and their causes) are:

• 1. Hypovolemia: Due to dehydration, blood volume is reduced as the total body fluids are depleted. This results in hypovolemia and in severe dehydration cases, hypovolemic cadiac shock may occur.  
• 2. Decreased cardiac output: As cardiac output is a function of product of Heart rate and Stroke Volume, loss of body fluids and hypovolemia results in reduced heart rate and cardiac output.
• 3. Hypotension: Blood pressure is a product of Cardiac output and systemic vascular resistance. As cardiac output is reduced due to dehydration, blood pressure also falls resulting in Hypotension giving a thready pulse
• 4. Decreased perspiration: Sweat production is reduced as a compensatory mechanism to combat the fluid loss. This results in increased core temperature.
• 5. Water and Sodium retention: Water and sodium are retained and urine output is decreased to compensate for the fluid loss due to dehydration

Signs and symptoms of dehydration are:

• Dry and Hot skin
• Dry tongue and increased thirst
• Dark colored and less volume of urine
• Faster breath rate
• Sleepy and irritable
• Loss of skin turgor
• Sunken and depressed fontanelle in infants
• Headache, dizziness,
• Cramps in extremities

Additional information:

Causes of Dehydration:

• Severe diarrhea/ vomiting
• Excess urinary output due to other underlying conditions like Diabetes mellitus, Diabetes insipidus, adrenal imbalance etc
• Insufficient water intake
• Prolonged exercise without water consumption especially in hot environment
• Severe sweating

Classification of Dehydration:

Based on extent of total fluid loss, dehydration can be classified into:

• Mild dehydration: Total fluid loss is about 5%
• Moderate dehydration: Total fluid loss is about 10%
• Severe dehydration:Total fluid loss is about 15%

Based on Sodium or water loss present, dehydration can be classified into:

• Isotonic dehydration: Both sodium and water loss occurs. Ex. Dehydration due to Diarrhea or vomiting
• Hypertonic dehydration: More water loss than the sodium loss. Ex. Dehydration due to fever
• Hypotonic Dehydration: More sodium loss than the water loss. Ex. Dehydration due to excess use of Diuretics