Med-Surg Respiratory System, part 9: Tuberculosis
by Cathy Parkes August 27, 2021 Updated: December 07, 2022 3 min read
Signs and symptoms
Symptoms of tuberculosis can include a cough that lasts for more than three weeks, purulent (pus) or bloody sputum, unexplained weight loss, night sweats, and lethargy.
Note that these are the symptoms that all patients are screened for at the hospital during admission to establish if they may have tuberculosis. If they answer "yes" to the symptoms listed above, they are put on airborne precautions until tuberculosis can be ruled out.
Labs and diagnostics
In terms of diagnostics related to tuberculosis, there are a number of labs that may be run, including the quantiferon gold blood test, the mantoux skin test, an acid-fast bacilli culture, and a chest x-ray.
QuantiFERON Gold blood test
A quantiferon gold blood test is a simple blood test that aids in the detection of Mycobacterium tuberculosis.
Mantoux skin test
A Mantoux skin test is an intradermal injection, read within 48 – 72 hours, that checks for induration (hardening) at the site. An induration of 10 mm is a positive result, that is, the patient either has an active TB infection or had a previous infection with tuberculosis. For immunocompromised patients, 5 mm is a positive result. This is because an immunocompromised patient's body isn't able to mount enough of an immune response to get a 10 millimeter area of induration.
Note that patients who have lived internationally and have received a BCG vaccine (Bacillus Calmette-Guérin vaccine, primarily used against tuberculosis) may show a false positive result.
Acid-fast bacilli culture
Acid-fast bacilli (AFB) testing is the process of inoculating a clinical specimen onto culture media, then examining it for bacterial growth. When taking samples for this test, use three early morning sputum samples.
A chest x-ray may be used to check for the presence of active lesions in the lungs.
Treatment of tuberculosis includes a combination drug therapy. Patients will take up to four antibiotics for a period of 6 – 12 months.
The medications commonly used to treat TB include rifampin, isoniazid, pyrazinamide, and ethambutol. A handy mnemonic for this quartet is "ripe orange." The letters “r” “i” “p” “e” match the first letters of the four medications, and "orange" refers to the orange discoloration of secretions expected with rifampin use.
In terms of nursing care for a patient with tuberculosis, place them in a negative airflow room, because they will be on airborne precautions. Anyone entering the room should wear an N-95 mask. And if the patient must leave their room, they should wear a surgical mask. This is to protect the patient or people entering the patient’s room.
Screen the patient's family for TB because it is an extremely contagious disease.
Teach the patient that throughout their therapy, they will have to provide a sputum sample every few weeks. Patients are no longer considered infectious after three negative sputum cultures.
Hi, I'm Cathy with Level Up RN. In this video, we are going to talk about tuberculosis or TB. At the end of the video, I'll give you guys a little quiz and ask you a few questions about TB to see how well you picked up on some of the key facts I'll be presenting in this video. So definitely stay tuned for that.
So tuberculosis is an infectious disease of the lungs that is caused by Mycobacterium tuberculosis. The mode of transmission is airborne. And the bacteria will adhere to the alveoli, and it triggers an immune response and the development of granulomas or lesions in the lungs. Symptoms can include a cough that lasts for more than three weeks, purulent or bloody sputum, unexplained weight loss, night sweats, and lethargy. And these are the actual exact symptoms that we screen all of our patients for at the hospital during admission to check and see if they may have tuberculosis. And if they answer, "Yes, I've had night sweats and bloody sputum and a cough for the last month," then we're going to put them on airborne precautions until tuberculosis can be ruled out. In terms of diagnostics related to tuberculosis, we can run a QuantiFERON gold blood test, we can also do a Mantoux skin test. So this is where we put that injection in, intradermally, and then we have the patient come back in 48 to 72 hours to check for induration at the site. So if we see a 10 millimeter area induration - and when I say induration, it's a hardened area - then that is a positive result. And when I say positive result, I don't mean good, meaning the patient either has an active TB infection or had a previous infection with tuberculosis.
So 10 millimeters or more is a positive result. If we're dealing with an immunocompromised patient, then their body isn't able to mount enough of an immune response to get a 10 millimeter area of induration, so if we see a 5-millimeter area of induration in an immunocompromised patient, then that is also a positive result. I also want to mention that people who have lived internationally and have received a BCG vaccine may end up with a false positive result. We can also run an acid-fast bacilli culture using three early morning sputum samples, and then we can also do a chest X-ray to check for the presence of active lesions in the lungs. Treatment of tuberculosis will include a combination drug therapy. So they will be taking up to four antibiotics for a long period of time, possibly a full year. Medications that are commonly used to treat TB include rifampin, isoniazid, pyrazinamide, and ethambutol. And the way I remember these medications is I think of a ripe orange. So 'ripe' will help you remember the first letter of each of these medications. And then I write 'orange' will help you remember that orange discoloration of secretions is expected with rifampin, which is the first of the medications that I mentioned. If you haven't already done so, then definitely go over to my pharmacology playlist after this and watch the video on tuberculosis medications.
Okay, so in terms of nursing care, we're going to want to place the patient in a negative airflow room, so they'll be on airborne precautions. Any time you go in that room, you want to wear an N-95 mask. And if the patient must leave their room, they should wear a surgical mask. We're going to want to screen the patient's family for TB because it's very contagious. And then we need to let the patient know that throughout therapy, we're going to need them to come in and provide a sputum sample every couple weeks. And once we have three negative sputum cultures, the patient is considered no longer infectious.
All right, time for a quiz.
First question, with a Mantoux skin test, an induration of blank millimeters indicates a positive result.
If you said '10'... that is correct. And just as a side note, if the patient is immunocompromised, they may only have a 5-millimeter area of induration, and that would be a positive result.
Question number two, which four antibiotics are used to treat tuberculosis?
If you answered... rifampin, isoniazid, pyrazinamide, and ethambutol, you are correct. Think of a ripe orange.
Third question - it's a true/false question - a patient with tuberculosis is considered no longer infectious after one negative sputum culture. True or false?
The answer is... 'false'. It will require three negative sputum cultures before the patient is considered no longer infectious.
All right. That's it for tuberculosis. Hope this video is helpful. I hope you like these little quizzes too. Let me know in the comments. Take care and good luck studying.
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