Dehydration

The following characteristics are distinguished

Isotonic dehydration

The loss of water and electrolytes such as sodium are balanced. In isotonic dehydration, serum osmolality is normal. This means that the concentration of particles is not increased in relative terms due to the lack of water, as the electrolyte concentration is also lowered. Since there are other substances in the urine, the specific urine weight is increased.

Hypotone dehydration

In hypotonic dehydration, the loss of electrolytes and salt (sodium) is greater than the loss of water. Due to the hypotension of the extracellular fluid, intracellular edema formation occurs due to osmosis. Clinically, in addition to symptoms of hypovolemia, which can also be observed with isotonic dehydration, there are also cerebral symptoms that are due to an incipient cerebral edema. These include drowsiness, confusion, and seizures.

Hypertone dehydration

Hypertonic dehydration is characterized by a stronger water than electrolyte deficiency. Due to the hypertension of the extracellular fluid, there is an osmotic outflow of water from the cell into the extracellular space.

Symptoms

• Lack of concentration
• Strongly coloured to dark urine, decrease in amount of urine
• Brittle to cracked lips
• Thirst, dry mouth and dry tongue
• Headache
• Fatigue, weakness
• Dizziness
• Dry, itchy skin
• Weight loss

In the case of an exsiccosis :

• Low blood pressure due to decrease in blood volume
• Strongly decreasing amount of urine
• Kidney pain, renal function disorders
• Chronic constipation
• Muscle cramps, seizures

Risk factors/causes

• Too low drinking, especially during physical exertion under hot temperatures
• Diarrhoea (e.g. gastroenteritis)
• vomiting
• Diabetic coma
• Blood poisoning (sepsis)
• Combustion
• Addison’s disease
• Acute renal failure (polyuric phase)
• Diabetes insipidus

Urine diagnostics

• Measurement of miction parameters (quantity, frequency)
• Specific density in urine
• Creatinine value in urine

Therapy

• The therapy consists in a substitution of water by intravenous infusion, adapted to the respective form of dehydration. Depending on the clinical symptoms, the substitution of 2-4 l, sometimes much more water is necessary. Subcutaneous infusions are also used in nursinghomes and geriatric care.
• In isotonic dehydration, an isotonic solution for infusion such as the ringer solution can be used relatively easily for rehydration.
• In hypotonic dehydration, sodium should be substituted at sodium levels below 125 mmol/l in addition to the isotonic solution
• In hypertonic dehydration, the substitution of free water takes place, for example by 5-degree glucose solution.