You probably think of dehydration as simply a lack of water in the body. However, it is a much more complex phenomenon. It results from an imbalance between the different fluid compartments of the body and can take several forms. Among them is intracellular dehydration (ICD) , which directly affects cells and disrupts their function. Its effects on health , particularly on the neurological and metabolic systems , are far from negligible.
What is intracellular dehydration?
To better understand, imagine that the fluids in your body circulate between two large spaces: the inside of the cells, called the intracellular space , and the surrounding environment, called the extracellular space , which includes blood plasma and interstitial tissues.
Under normal conditions, these two compartments exchange water and electrolytes according to the principle of osmosis. : fluids move from the environment with the lowest concentration of solutes to the one with the highest concentration, in order to maintain equilibrium.
When the concentration of dissolved particles increases in the blood—for example, in cases of hypernatremia ( excessive sodium levels )—water leaves the cells and enters the external environment. This causes intracellular or hyperosmotic dehydration , which corresponds to a significant decrease in the water volume inside your cells.
Intracellular vs extracellular dehydration: what's the difference?
Conversely, dehydration affecting the fluid surrounding cells manifests primarily as a drop in blood pressure, hypotension , and sometimes hypovolemic shock . It occurs during severe vomiting , severe diarrhea , or hemorrhaging.
In practice, it is not uncommon for the two forms to coexist when both environments are simultaneously affected. This is then referred to as global dehydration .
What are the causes of intracellular dehydration?
Having defined this phenomenon, let us now examine the different factors that cause this imbalance.
Insufficient contributions
When your If intake is too low , the body tries to compensate by drawing on cellular reserves. This situation particularly affects the elderly , infants, and dependent patients .
Diabetes insipidus and hormonal disturbances
Diabetes insipidus is characterized by a deficiency or resistance to the antidiuretic hormone (ADH) , also called vasopressin. Because of this imbalance, you urinate frequently, even if you don't drink enough. This massive urine loss causes a concentration of salts in the plasma, forcing water to leave the cells to correct the osmotic imbalance .
Fever, intense exertion, exposure to heat
In these situations, the body loses a lot of fluid through perspiration and cutaneous evaporation . Without adequate compensation, the blood becomes more concentrated in particles, creating the conditions for secondary hypernatremia .
Diuretic or laxative medications
Some diuretics or laxatives (often prescribed for hypertension or heart failure ) increase diuresis. This raises serum osmolality and causes fluids to move from inside the cells to the outside.
What are the clinical signs of intracellular dehydration?
Now that you understand what it is, let's see how this imbalance can manifest itself and what symptoms should alert you.
Neurological disorders: confusion, drowsiness, agitation
Your brain is one of the first organs affected . That's why the first symptoms are often neurological. You may experience:
- mental confusion ;
- unusual drowsiness ;
- sudden irritability or agitation .
In its acute or severe form, convulsions or even a coma may occur, due to brain damage.
Fatigue, intense thirst, dry mucous membranes
The most obvious indicator is an intense thirst , a sign that your body is trying to correct the situation. This sensation is generally accompanied by dryness of the mucous membranes (dry mouth, coated tongue, etc.) and general fatigue .
Your skin could also lose its normal elasticity. The skin fold After pinching, it takes longer to disappear than normal.
Rapid weight loss, low blood pressure, urinary problems
You can also see:
- rapid weight loss , especially if the imbalance affects both compartments;
- dizziness upon standing, indicating a drop in blood pressure when standing;
- darker and less abundant urine , because your kidneys are trying to retain as much fluid as possible (except in certain specific cases such as diabetes insipidus).
How to diagnose hyperosmotic dehydration?
Faced with these signals, an accurate diagnosis is essential to identify the cause of the imbalance.
Clinical diagnosis: observation of symptoms
Your doctor begins with a careful clinical examination . He will inquire about your hydration habits , check for any fever, review your current treatments , and look for any signs of fluid loss (excessive sweating, diarrhea, gastric reflux).
He then looks for the symptoms mentioned previously: fatigue, confusion, dry mouth or low blood pressure...
This initial assessment often allows us to suspect the problem and estimate its severity ( mild , moderate or severe ).
Additional tests: blood ionogram, osmolarity, urea
To confirm the diagnosis, a number of biological tests may be prescribed:
- Blood ionogram : measures the main electrolytes in the blood (sodium, potassium, chloride, bicarbonates) to identify the type of imbalance.
- Plasma osmolarity : indicates the concentration of dissolved particles in the blood (salts, glucose , urea). High osmolarity generally indicates fluid loss within cells.
- Urea and creatinine : their increase in the blood helps to control kidney function .
Identify intra vs extra imbalances
All of these tests help to determine whether the imbalance mainly concerns the inside of the cells or the outside space.
Sometimes, the results may reveal hyponatremia due to intracellular overhydration , the opposite situation which corresponds more to an excess of water inside your cells.
In some cases, urgent hospitalization is necessary, often in a nephrology or intensive care unit.
Care and prevention
Rehydration: oral solutions or appropriate infusions
In mild to moderate cases , oral rehydration is preferred. Intravenous fluids will be necessary for more severe cases or if you are unable to drink. The type of fluid ( hypotonic or isotonic ) and the rate of administration will be adjusted according to your test results and your overall condition .
Too rapid a correction can be dangerous. Indeed, a sudden influx of fluid into your cells could cause cerebral edema . This is why medical protocols recommend a gradual decrease in blood sodium levels .
In parallel, appropriate treatment of the underlying cause (diabetes insipidus, fever, diarrhea, etc.) should also be offered.
This comprehensive approach makes it possible to correct not only the consequences, but also the origin of the imbalance, thus reducing the risk of recurrence.
Prevention
Prevention remains your best protection . It relies on adapting your fluid intake to your actual needs, which vary according to your age, body mass , level of physical activity and climatic conditions.
- Adults : consume in small sips up to 1.6 to 2 L per day .
- Athletes : drink before, during and after exercise, following a hydration plan adapted to your profile.
- Children and seniors : offer them drinks regularly because they do not always express it spontaneously.
- In case of extreme heat : increase your intake and drink more, even if you don't feel the need.
Avoid counting sugary, alcoholic or overly caffeinated drinks in your fluid intake.
Monitoring in a medical setting
If you are hospitalized, your weight will be regularly monitored. Rapid weight loss may indicate an underlying imbalance that needs to be corrected immediately to prevent further complications .
The nursing staff also monitors your fluid intake and output, checks the color and quantity of your urine, and remains attentive to any signs of fatigue or confusion.
This rigorous monitoring makes it possible to anticipate imbalances before they worsen, particularly in elderly patients or those with chronic illnesses.
Frequently asked questions about intracellular dehydration
What are the signs of intracellular dehydration?
Intense thirst, dry mouth, fatigue, neurological disturbances (confusion, agitation) and coma in severe cases.
What are the causes of hyperosmotic dehydration?
Insufficient intake, endocrine diseases, heat, exertion, diuretic medications or massive losses (gastric reflux, diarrhea).
What can cause cellular dehydration?
Osmosis: if the blood becomes too concentrated in salt or sugar, water leaves the cells to restore balance.
How to recognize intracellular hyperhydration?
It occurs mainly in cases of severe hyponatremia. Its symptoms include headaches, nausea, vomiting, neurological problems, and even cerebral edema in extreme cases.
Conclusion
Intracellular dehydration is a serious imbalance that directly affects your cells. It can result from a simple lack of water, but also from specific illnesses or treatments . To protect yourself, pay attention to the early signs . Medical diagnosis, supported by laboratory tests, allows for quick action and the selection of the right rehydration strategy. By adopting simple practices (drinking regularly, adjusting your intake, and monitoring vulnerable individuals), you significantly reduce the risks and preserve the vital balance of your body.
Bibliography
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