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04.03 Ammonia

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Overview

  1. Ammonia
    1. Normal Value Range
    2. Pathophysiology
    3. Special considerations
    4. Too High: Causes, Symptoms, Treatments
    5. Too Low: Causes, Symptoms, Treatments

Nursing Points

General

  1. Normal value range
    1. 19-60 mcg/dL
  2. Pathophysiology
    1. Byproduct of protein metabolism
      1. Proteins → ammonia
      2. Ammonia → urea via the liver
      3. Urea excreted to the kidneys
    2. If ammonia is not converted to urea
      1. Ammonia ↑ in bloodstream
      2. Causes hepatic encephalopathy
        1. Neurotoxic
        2. ↓ Level of consciousness
        3. Confusion
        4. Altered mental status
      3. Refer to Neuro lesson 03.06 Encephalopathies
  3. Special considerations
    1. Sent in either green or lavender tube
    2. Typically sent on ice
    3. Discuss with facility lab or unit
  4. Elevations in ammonia
    1. Liver failure
      1. Treatment:
        1. Lactulose
          1. Ammonia binding agent
          2. Given PO or PR
          3. Ammonia excreted via stool
    2. Hepatic encephalopathy
    3. TPN
    4. GI hemorrhage
    5. Reye’s syndrome
  5. Decreased ammonia levels
    1. Antibiotics

Assessment

  1. Assess patient’s cognition and level of consciousness
  2. Assess patient’s ability to swallow and protect airway

Therapeutic Management

  1. Lactulose via rectal tube or PO if patient can tolerate oral medications and follow directions

Nursing Concepts

  1. Lab Values
  2. Gastrointestinal/Liver Metabolism

Reference Links

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Video Transcript

We are going to talk about ammonia and ammonia is a pretty cool lab value, but I want to warn you and let you know that taking care of a patient who has really elevated ammonia levels can be kind of a complicated situation. But it’s pretty cool level I want to talk to you about how it works and what’s going to elevate it and how we treat it and stuff.

The normal range for ammonia is 19 to 60 micrograms per deciliter. We don’t generally worry about a low level, what we’re really focusing on here are these high levels and I’ll show you why in just a second. You might see it written as NH3, but a lot of times you’re really just going to see people writing ammonia versus like, we do with potassium things or write just K or whatever. A lot of times people just write ammonia like that.

So what is ammonia? First of all, ammonia is a byproduct of protein metabolism in the body. So what happens here is we take in proteins, right? The proteins then go to the GI tract where they’re broken down and then turn into ammonia. That ammonia is then supposed to travel to the liver and in the liver it gets converted to urea, which is then excreted via the kidneys and that’s why we look at, in the kidneys we look at BUN or Blood Urea Nitrogen. So ammonia is this byproduct of protein metabolism on its way to the liver to be converted to urea. What happens if the liver is not working? Well, the liver is not working, what’s going to happen to ammonia level? Well, it’s going to go up, because that ammonia is never able to be converted. So we’re going to start seeing higher and higher levels of ammonia. Remember our normal level is 60, we’re going to start seeing that level start to climb. Now why is that a problem? Well ammonia is very neurotoxic. So those higher levels of ammonia become damaging to a neuro system.

So we’re going to start seeing decreased levels of consciousness. We’re going to start seeing confusion in our patients, and we’re going to start seeing altered mental status or AMS. Now this can get very severe. In some patients you can see ammonia go up as high as 300 where these patients would normally be a liver patient or a med surg patient, they’re going to be transferred to the neuro ICU because their ammonia so high. Their level of consciousness is so low that we’re even putting on breathing machines and things like that because they’re not able to function neurologically. So some things to keep in mind with this patient we’re going to send the little lab in a green or lavender top EDTA tube. Sometimes it’s going to be sent on ice, so make sure you check with your facility about how they want the lab sent and what they want gathered in.

When are we going to see high ammonia levels? What should you be thinking about all the time with ammonia? You should be thinking about your liver. The only time it’s going to raise is if our liver is not able to process that ammonia into urea. So when are you going to see it? We’re going to see it raised with liver failure. How do we treat this? Well, the way treat it, we treat it with a medication called lactulose, which is actually a laxative and here’s the way it works. We either give a PO or PR, which means per rectum. A lot of times like the neuro ICU, these patients will have like a rectal tube and we get the lactulose through there and what happens is, this ammonia travels to the GI system, right? It’s in the GI system there. It binds to the feces that’s probably when the only time you’ll see feces written on educational lecture, but the ammonia binds to the feces and then leaves the body that way.

So it’s kind of cool where you bring this protein in, it’s supposed to, it turns into ammonia, is supposed to go through the liver and then transfer out into the kidneys through urea. However, because it doesn’t do that, we then give this lactulose, which causes it to bind to the feces and then leave the body that way via the stool. So you’re going to see increased levels with a hepatic encephalopathy. So if you have this patient who’s having this unknown encephalopathy, right? So there’s something going on with their neuro status. We’re not sure why one lab value we might look at would be ammonia. Maybe they’re ammonia’s 300, if it’s greater than 60, we know something’s going on there. We might see it with total parenteral nutrition because maybe the liver can’t break down all that protein, we might see it with GI hemorrhage because blood is sitting in the GI rather than going to the liver to be processed. We can also see it with Radio Syndrome in babies, do delivers in ability to break down this ammonia.

I want you to think liver, and I want you to think protein. Protein’s got to be broken down in the liver. If it’s not, we’re going to see increased ammonia, and the big concern we have here is our neuro status. That’s a big concern we’re going to have with these patients. So what are some things to keep in mind here? I want you to keep in mind lab values as a concept. Of course, it’s important to understand our lab values as we understand them, we can start making sense of everything. Another concept would be GI and liver metabolism.
So let’s go over our key points here really quick. Normal values are 19 to 60, we’re really concerned about this elevated level and how does it become elevated.

Well, protein is supposed to be broken down in the liver and converted to urea and go out. If it does not do that, our ammonia is going to climb and we need to get rid of it. So we’re going to send the lab to the lab facility, a lot of times on ice check on that, and we got to get rid of this urea or we’re going to get rid of this ammonia, because if we do not, we’re going to see our patient develop hepatic encephalopathy where they’re going to get decreased levels of consciousness, decrease neuro status, ultra mental status, all that stuff. So how do we get rid of it? We give lactulose. Lactulose binds the ammonia to the feces, gets rid of VR, GI tract. So it’s kind of a need lab, it’s kind of need to see how those different systems in the body interact and it’s important to keep it in mind. Check it with your liver patients, check if your patient has altered mental status and really keep your patients safe by getting rid of extra ammonia. We really don’t want to climb it up in our patients.

Alright guys, I hope that helps. I hope that gets it all cleared up in your mind. Now, make sure you check everything out in this lesson and as always, go out and be your best self today. Happy Nursing.

  • Question 1 of 2

A nurse is caring for a client who is scheduled for a urea breath test. The nurse knows that this test detects which of the following substances?

  • Question 2 of 2

A nurse is providing dietary discharge teaching to a client who has been diagnosed with cirrhosis who has had an elevated ammonia level. Which of the following statements by the client demonstrate that more education is required?