When we lose too much water from our body, it can lead to hypernatremia. This can happen from:

• Increased sweating
• Vomiting or "osmotic" diarrhea
• Excessive urination - usually because of high blood sugar, certain medicines, or a condition called diabetes insipidus (different than diabetes mellitus)

Some people with hypernatremia might not feel thirsty or can’t drink enough when they do. Older people or those who are very sick might not drink enough water, and this can make their salt levels go up.

Sometimes, after a big workout or a seizure, water in our body moves to different places, like inside our cells. This can make the salt level in our blood go up for a short time.

It’s rare, but if someone eats or gets too much salt, it can cause hypernatremia.

There’s a condition called ‘Adipsic diabetes insipidus’ where the body doesn’t produce enough of the hormone (ADH) that helps control water in our body, and also, the person doesn’t feel thirsty. People with this can get hypernatremia more often, and they might not notice symptoms because the change in their salt levels happens gradually.

People with hypernatremia can feel super thirsty, like they’ve been out in the sun without water for a long time. This is because the body wants more water to balance out the high salt levels.

Hypernatremia can cause very dry mouth and other mucous membranes including dry eyes and nose, because the body doesn’t have enough water. 

People might experience restlessness or become easily annoyed. This is because the nervous system is hypersensitive when the sodium level in the body is too high.

Sodium helps our muscles work right. When there’s too much salt, muscles can twitch or act up. It’s like they’re saying, ‘Hey, that’s too much salt for us!’

Sodium helps our brain work too. With too much salt in the body, people might get confused or lost. In really bad cases, they could even become unconscious.

When there’s too much salt, our brain cells get too active. This can make the brain have sudden, strong electric bursts, which might cause a seizure.

Monitor for hypertension (high blood pressure) and tachycardia (fast heart rate), as the body may attempt to compensate for the dehydration.

Hypernatremia affects the nervous system, so check for changes in mental status, such as restlessness, irritability, or confusion. In severe cases, patients may experience seizures or even coma.

Look for signs of dehydration, such as dry skin, decreased skin turgor, or sunken eyes, which are all clues to hypernatremia.

The first thing to do when treating too much salt in the blood (hypernatremia) is to find out what caused it. Looking at the patient’s fluid balance helps! We might need to give them more or less water based on what is found.

When treating too much salt in the blood (hypernatremia), it’s super important to manage the patient’s water levels. This usually means giving the patient more fluids.
They might need to drink more water or get fluids through special solutions like 1/2 NS (hypotonic solution). This helps make the salt in their blood less concentrated.
Recommended fluid/rate: D5W at 100ml/hr for 70kg patient (1.35 ml/kg/hr, max 150ml/hr).
If they have ongoing fluid losses, then this should be factored in as well.

Sometimes Desmopressin (DDAVP) might be ordered in cases such as central Diabetes Insipidus.

In acute hypernatremia, sodium and glucose levels (if getting dextrose) should generally be checked every 1-3 hours to make sure the sodium is falling at the appropriate rate.
In chronic hypernatremia, sodium levels should be checked every 4-6 hours, and eventually every 12-24 hours. Patients with ongoing fluid losses should be watched more closely.

Regular neurological assessments should be performed to monitor for changes in consciousness, orientation, strength, and coordination. Any sudden changes, such as confusion, seizures, or loss of consciousness, should be reported immediately

Intake and output (I&Os) should be documented thoroughly to monitor the patient’s fluid balance.

Causes

Hypernatremia is usually caused by dehydration and excess fluid loss. Normal healthy adults' bodies tell them that they're thirsty, but older and altered minds sometimes cannot listen to those same cues.

Symptoms

Symptoms of hypernatremia include thirst, dry mouth, muscle twitches, irritability, altered mental status, and even seizures.

Physical Assessment

Vital signs may be consistent with fluid deficit, so tachycardia can occur. Close attention to neuro assessments should be made, and skin assessment will show dry mucous membranes or decreased skin turgor

Treatment

Treatment of hypernatremia involves addressing underlying causes, replacing fluid volume deficit (usually with hypotonic fluids like D5W), and accounting for ongoing fluid losses.

Monitoring

Labs, primarily a BMP or CMP, should be monitored frequently, depending on the correction rate and severity. Cardiac monitoring is usually not super important with sodium abnormalities, as it doesn't affect the heart rhythm as much as potassium, magnesium, or calcium.