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Hypernatremia in Nursing Practice: What Every Nurse Should Know

Critical care Fluids & Electrolytes Labs and Diagnostics Nephro
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Hypernatremia means there’s too much sodium in the blood. Nurses see this a lot, especially with very sick and older patients in the hospital. Let’s learn more! 👇🏻

Normal Sodium Levels & Hypernatremia

Sodium helps our body work right, like keeping our fluids balanced and helping our muscles move. Usually, the salt level in our blood is between 135 and 145. If it goes above 145, it’s too high and can be harmful to our cells.

Hypernatremia

  • Normal Levels: 135 – 145 mEq/L
  • Mild Hypernatremia: 146 – 150 mEq/L
  • Moderate Hypernatremia: 151 – 159 mEq/L
  • Severe Hypernatremia: > 160 mEq/L

Acute vs Chronic Hypernatremia

When treating hypernatremia in the blood, we need to know if it happened fast or slow.
Acute means the salt levels went up quickly in the last 2 days. This can be bad for our brain and other cells because they don’t have time to get used to it. We treat this kind of high salt level more urgently.
Chronic means the salt levels went up slowly over more than 2 days. Our body cells have time to get used to this. So, when treating it, we are more careful and slow.

Causes of Hypernatremia

Hypernatremia always has an underlying cause, like every electrolyte abnormality. Let’s dive into some of the usual suspects that lead to this condition:

A kidney with low levels of water

Fluid Loss

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)

Decreased Water intake

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.

A cell with molecules diffusing across the cell membrane

Water Shifts

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.

A picture of a box of salt

Too Much Sodium

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

Pituitary gland and hypothalamus

"Adipsic" Diabetes Insipidus

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.

Nursing Assessment of Hypernatremia

Symptoms

Hypernatremia often comes with tell-tale signs, including:

A brain with water in it's thought bubble, indicating thirst

Thirst

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.

A very dry tongue, indicating dehydration and dry mucous membranes

Dry Mouth

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

A silhouette of a head with red and orange markings above the head, indicating anxiety

Restless & Irritable

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.

A muscle with red electric bolts indicating pain

Muscle Twitching

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!’

A picture of a brain with a question mark on it

Altered Mental Status

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.

A blue brain with yellow lightning bolts depicting a seizure

Seizure

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.

Physical Assessment

When performing a physical exam for a patient suspected of having hypernatremia, the nurse should assess for the following:

Vital Signs

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

A neuro checklist with a brain to indicate neuro assesment

Neuro Assessment

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.

a gloved hand palpating unspecified skin

Skin Assessment

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

Treatment for Hypernatremia

The treatment of hypernatremia depends on what caused the hypernatremia (similar to hyponatremia). In severe cases, typically nephrology is consulted on in these patients.

The treatment also depends on if it is Chronic (developed over 48 hours ago) or Acute (developed within the last 48 hours). Nearly all patients with hypernatremia fall into the chronic category.

The kidneys, with the left one transected so you can see the inside

Address Underlying Causes

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.

Correction Goal

The goal is to lower the serum sodium by ~10 meQ/L in about 24 hours.

IV Fluids

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.

Rapid Correction

For really serious cases of too much salt in the blood (and known acute cases), especially if someone has seizures or becomes unconscious, we need to treat this quicker. Typically the rate would be corrected quicker with faster fluids, aiming to drop the sodium by 1-2 mEq/L every hour. But they have to be careful! Lowering salt too fast can cause swelling in the brain, which can be deadly!

Desmopressin

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

Monitoring of Hypernatremia

As a nurse, it is essential to monitor patients with hypernatremia closely to identify and manage any potential complications. The following parameters should be observed:

A Gold top blood vial filled with blood

Lab Tests

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.

A neuro checklist with a brain to indicate neuro assesment

Neuro Status

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

A Gold top blood vial filled with blood

Intake & Output

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

Summary of Hypernatremia

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.

That wraps up our discussion on hypernatremia. As nurses, we are often the first to identify and address these issues, and our knowledge and keen observation can make a significant difference. So, let’s stay sharp and keep our patients safe from the repercussions of hypernatremia!

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