# Tuberculosis --- **Tuberculosis** or **TB** is a [[disease]] caused by a pathogenic [[bacteria]], _Mycobacterium tuberculosis_. Though it largely effects the [[lungs]], it has the potential to infect several other systems as well, including the [[spinal cord]] and the [[bone|bones]]. Tuberculosis is treatable, but fatal if left un- or undertreated. It is a disease of [[social determinants of health|poverty]], affecting 1/3 of the world, the majority of which are in developing nations. In affluent countries TB is seen in most in unhoused populations. The WHO's goal is reduce the incidences to 3.5 case per 100,000 people, which is quite lofty. Even the US and Canada have cases up to 9.9, and countries in Sub-Saharan Africa can get over 500 cases per 100,000 people. ![[tuberculosis.png]] The bacteria *M tuberculosis* is infamous for being able to survive even if they encounter a [[macrophages|macrophage]]. Once in the [[phagocytosis|phagosome]], it can produce a substances that hinders the macrophage from producing a protein called "calcineurin", which is necessary to fuse the phagosome with the [[lysosome]], so they just sort of hang out. Sometimes the macrophages can eliminate the bacteria, but if they can't they will form a [[macrophages|granuloma]], which is visible on an X-ray. Although they are better than a full blown infection, these granuloma can also cause fibrotic changes to the lungs which make it harder to breathe. Often times, if a person has a TB contained to granulomas and they become sick, the infection takes advantage from they weakened immune system and strikes. ![[TB granuloma.png]]( ## Risk Factors The risk factors for TB track with other [[social determinants of health]] - being immunocompromised - especially with HIV, cancer or steroid medications - being in close contact with others - it is airborne - especially in crowded and substandard living conditions - chronic illnesses - having [[heart failure]] doubles the risk of contracting TB - [[smoking]] - substance use - being from somewhere with high TB rates - there is a social stigma associated with having TB - previous TB infection - it could very well be latent - living in or working in health care facilities, treatment centers, institutions ## Signs & Symptoms The signs and symptoms of a tuberculosis infection may be vague or hidden. - night sweats - hallmark - cough with purulent or blood sputum - hallmark - wasting - anorexia - pallor - dyspnea - pleuritic chest pain - other symptoms depending on the system involved ## Diagnostic Tests Diagnosing tuberculosis is not straightforward because it exists on a dynamic continuum. Some people may have the infection latently, or they have it and are carriers, or have full blown active tuberculosis infection. Depending on whether an individual has had a tuberculosis infection in the past, has it currently, if it's latent or not all affect different types of TB tests. Additionally, depending on what type of TB infection will determine what type of treatment that is recommended. A physical exam is always a first start for diagnostics, but a really good history--particularly a _travel_ history is especially important here. This includes the travel history of their contacts as well. A chest [[x-ray]] can be done to look for fibrotic changes in the lungs that indicate a formation of a [[macrophages|granuloma]]. A bone x-ray or scan can look for systemic TB A **sputum culture** to dectect the presence of **acid vast bacillus** or **AFB**. This is definitive but it takes 6-8 weeks, and you need to take three different cultures on three different days. A lung biopsy can be done to confirm as well. Screening tests: - [[Tuberculin skin test]] (or a TST, or sometimes PPD for "purified protein derivitave") is given where a small amount of protein is injected into the skin and the bump that forms is interpreted. - Kind of a pain because you have to have the injection then wait for it to be read. - Even more of a pain because to be really accurate you ahve to do it twice. - Will show positive if someone has had the BCG vaccine - **QuantiFERON Gold Test** (QFT-G), sometimes called **IGRA** is done with just a lab draw. - Results are ready in 24 hours and it's pretty accurate. - Will _not_ show positive if someone has had the BCG vaccine.  - For someone who has never had TB, all tests will be negative - For someone who has an [[immunity]] (i.e. they have had TB in the past but it's gone now), they will trigger a skin test or Quanteferon Gold. - All other tests are negative - For someone with **latent** TB they might trigger those tests, and a granuloma may be found on a chest Xray - They typically show no symptoms and are not infectious. - The infection may become active if their immune system becomes stressed. - Treatment involves preventing the infection from becoming active. - **Subclinical TB** is when someone has small amounts of TB not in granulomas (I think, it was kind of vague) - Their TST/Quantiferon test will be positive, but they may havea negative culture or sputum test. - They typically show evidence on a chest X-ray but sputum is negative. - They may or may not have symptoms, and are sporadically infectious - Treatement is typically multidrug therapy - **Active TB** is a full blown infection. A culture will show positive. - Ironically a skin test and quanteferon gold may not have a positive result, because those look at immune reactions to TB, which may be weakened in response to the TB infection itself. - People with active TB have mild to severe sympoms and are infectious. - If untreated, 1/3 of people with active TB will die. ## Prevention There is a [[vaccine]] for TB called the BCG vaccine. It is variably effective, and not used much in the US due to our relatively low infection count. If you have had the vaccine, you will likely show positive on a [[tuberculin skin test|TST]] or a blood test. ## Treatment - Treatment for **latent TB** is a multidrug therapy, with 3, 4, 6 or 9 month options. - Treatment for **active TB** is two or more anti-TB agents for 6-9 months. - There is an **initial** or **induction phase** which consists of eliminating any dividing bacteria. This lasts a 2-3 weeks and makes a person no longer infectious. - The second phase is the **continuation phase** that gets rid of any remaining bacteria. ### Medications The medications for TB have some difficult side effects and need to be taken for long courses. This makes compliance pretty difficult. They are typically prescribed alongside one another as well, as TB can readily develop [[antibiotic resistance]]. There are a lot of MDRO TB strains out there. Anti-tuberculosis agents: - **isoniazid** - Very [[hepatotoxic substances|hepatotoxic]] - must have liver labs drawn regularly - cannot drink alcohol when taking isoniazid - likely will cause a [[vitamin B|vitamin B6]] deficiency - isoniazid competes with the same enzyme that activates B6 - B6 deficiency leads to peripheral neuropathy - will likely be getting B6 injections - **rifampin** - GI irritation - causes bodily secretions (urine, tears, sweat) orange - this can actually permanently stain contacts - **ethambutol** - can decrease visual acuity - can make color hard to discern - peripheral neuropathy - confusion - GI irritation - should be taken with food ### Healthcare Worker Exposure Healthcare facilities typically have employee health nurses that coordinate events such as a healthcare worker exposure to TB. In the case that a healthcare worker has been exposed to TB, they will do contact tracing and testing. Like pretty much everything else with TB this is not a cut and dry process. If the individual has had a had a past negative TST: - Take a new TST within two weeks - If its negative, repeat up to 3 times If the individual has had a past positive TST: - Do not retake the TST - If symptoms develop, do a chest X-ray If these tests are positive, a 6-12 course of isonaizid is usually indicated. ## Nursing Consideration - Risk for [[ineffective health maintenance]] related to the prescribed therapy, related to the duration of treatment and side effects of medications. Sometimes we will practice **directly observed therapy** or **DOT**, where a healthcare worker will keep really close tabs on someone to make sure they take their medicines. - [[infection control]] - education on hand hygiene or isolation of possible - make sure doors are closed - negative airflow if possible - wearing masks - [[activity intolerance]] - promote bedrest until sputum comes up negative - pace activities - [[social isolation]] related to the stigma - especially in immigrant communities - [[imbalanced nutrition: less than body requirements]] - monitor weight - I/Os - oral care ---