Key points
- Tuberculosis (TB) is an infection that usually affects the lungs.
- TB is a major cause of illness and death in people with HIV all over the world.
- TB can be very serious, particularly for people living with HIV who have a low CD4 count.
- TB can be treated and cured.
Tuberculosis (TB) is an infection caused by bacteria. It usually affects the lungs, but can affect other parts of the body, including the stomach, bones, and nervous system.
It can be passed on when someone who has TB in their lungs coughs or sneezes. This pushes out bacteria in little droplets into the air.
TB is a serious illness, but it can be cured.
How is TB related to HIV?
Tuberculosis (TB) is a major cause of illness and death in people with HIV all over the world.
In people living with HIV, TB is an AIDS-defining illness. This means that a person living with HIV is said to have advanced HIV or AIDS if they are also diagnosed with TB. In the UK, TB is one of the most common AIDS-defining illnesses.
A healthy immune system can usually fight off TB. However, people living with HIV are more at risk of becoming unwell from TB when it gets into their body.
If someone becomes ill with TB, this is called ‘active TB’ or ‘TB disease’. People with active TB can pass it on to other people.
Sometimes, TB remains in the lungs after getting into the body, but it is kept under control by the immune system. This is called ‘latent TB’ or ‘TB infection’. Latent TB doesn’t cause any symptoms, and people with latent TB can’t pass it on to others.
However, some people with latent TB will develop ‘reactivation TB’. This is when TB bacteria in the lungs causes symptoms years after it first gets inside the body. Having a weakened immune system makes reactivation TB much more likely. People with HIV are at higher risk of developing reactivation TB.
Symptoms of TB
TB most often affects the lungs, causing symptoms such as:
- a cough lasting for more than three weeks (often with mucus, which may have blood in it)
- loss of appetite (not feeling as hungry as usual)
- weight loss
- tiredness
- night sweats
- fever
- swellings in the neck.
The TB bacteria may spread to other parts of the body, causing symptoms including a long-lasting headache, pain and stiffness in the joints, swollen glands, confusion, and tummy pain.
TB in other parts of the body is more common in people with a low CD4 cell count.
Active TB can cause a large increase in HIV viral load in people not taking HIV treatment. This usually decreases again once the TB is properly treated.
Without treatment, TB is a potentially life-threatening condition.
Preventing TB
Simple measures, like opening windows, can reduce the risk of TB being passed on. Although TB is infectious, it is not as contagious as illnesses such as the common cold. You need to spend a lot of time in close contact with someone with active TB to be at risk of infection.
People are most at risk of getting TB if they live in close contact, especially in crowded conditions, and if they have a weakened immune system. This may be from a low CD4 cell count, but can also include people who are very young or very old, or who have poor health for other reasons, including their diet, alcohol, or drug use.
It is important to avoid close contact with people who have active TB until they are no longer infectious. If you think you have been exposed to TB, you should see your doctor as soon as possible.
For HIV-negative people there is a live vaccine against TB known as the BCG vaccine. This is usually only given to people under 16, as it does not work well in adults. It should not be given to people living with HIV, because there is a small chance that it might cause a TB-like illness.
Tests for TB
There are several ways to test for TB. The way you are tested will depend on whether you have symptoms.
If you have symptoms of having TB in your lungs, you might have:
- a chest X-ray
- a sample taken of your mucus (phlegm)
- urine tests
- biopsy (taking a small amount of tissue)
- CT and other scans.
If you do not have symptoms, there are other types of tests that can check for latent TB. These include:
- A skin test (a PPD or Mantoux test). A small amount of liquid is injected into your skin. A reaction to this liquid means you’ve been exposed to TB. However, some people living with HIV don’t respond to skin tests because of damage to their immune system.
- An interferon gamma release assay (IGRA). This is a blood test that the current British HIV Association guidelines recommend for people living with HIV who need to be tested for latent TB.
If you’ve had the BCG vaccine, you may get a positive result from a skin test even though you have not been exposed to TB.
If your CD4 cell count is under 200, you might have both an IGRA test and a skin test.
Treating latent TB
If screening shows that you have latent TB (TB infection), you will be given treatment even though you don’t have symptoms. Taking this treatment will stop TB from becoming active and causing disease.
The most common drugs prescribed for TB treatment are isoniazid, rifampicin, and rifapentine. Treatment will last between three months and thirty-six months. You will usually take your treatment daily, but some types of treatment can be taken twice a week.
The treatment you are given will depend on where in the world you live, how common TB is where you live, which HIV medication you take, and your medical history.
Treating active TB
If you have active TB (TB disease), you’ll be given treatment to get rid of TB and help you feel better. This will usually be four to six months of medication that you take every day as tablets. Some people might have to take medication for nine months.
TB is treated with specific antibiotics, including:
- ethambutol
- isoniazid
- moxifloxacin
- pyrazinamide
- rifampicin/ rifampin
- rifapentine.
Your treatment will be a combination of some of these drugs. The drugs you are prescribed and how long you have to take treatment for will depend on your medical history and which country you live in.
Like all medications, TB treatment can cause side effects. Common side effects include feeling sick, dizziness, skin rashes, and pins and needles. If side effects are causing you problems, speak to your doctor.
You should no longer be infectious after two weeks of treatment for TB, but it is important that you continue with your treatment until the end of the course.
It’s very important that TB treatment is taken as prescribed.
What is directly observed therapy?
Doctors sometimes recommend TB treatment is taken at a hospital or somewhere else where a healthcare professional can make sure your drugs are taken at the right time and for the whole course. Or, instead of travelling to take your medicine, you take it on video, which is shared with your hospital or clinic.
This is called Directly Observed Therapy, Short-course (DOTS). DOTS programmes help ensure your treatment is as effective as possible.
Drug-resistant TB
Active TB can develop resistance to drugs, meaning they no longer work as treatment. Some strains are resistant to several different drugs.
These strains can cause very serious disease called multidrug-resistant TB (MDR-TB). If you have active TB, tests will show whether or not the TB you have is resistant to any medications. If it is, you’ll be given treatment that avoids those drugs.
Some strains of TB are resistant to the most commonly used TB drugs and many of the drugs used as alternatives. This is called extensively drug-resistant TB (XDR-TB), and it more commonly occurs in people living with HIV. Most treatments for drug-resistant TB take six or nine months.
Is TB and HIV treated at the same time?
Yes. It is recommended that all people living with HIV and TB start HIV treatment as soon as their TB is diagnosed, if they are not already taking it.
Taking TB treatment and HIV treatment together will help your body fight TB by improving your immune system.
However, if you have TB in your brain or spinal cord you might have to wait eight weeks before starting your HIV medicine.
Taking HIV treatment when you have active TB can sometimes cause immune reconstitution inflammatory syndrome (IRIS). This can make you ill and cause unpleasant symptoms. If you develop IRIS, you might be given steroids to help you feel better.
If you’re already taking anti-HIV medication when you start TB treatment, it usually won’t need to be changed.
Some TB treatments can affect the way HIV medication works. This means it’s important the person deciding which TB medicine you need knows the type of anti-HIV medication you take, including whether or not you take the boosting agents ritonavir or cobicistat.