Tuberculosis (TB) – Infectious Diseases – Merck Manuals Professional Edition


*Specific regimens are discussed in text.
†Daily is considered either 5 or 7 days/wk. All dosing 35 yr, alcoholics, postpartum women, and patients with chronic liver disease. Monthly liver function testing is not recommended unless patients have risk factors for liver disease. Patients with unexplained fatigue, anorexia, nausea, vomiting, or jaundice may have hepatic toxicity; treatment is suspended and liver function tests are done. Those with symptoms and any significant aminotransferase elevation (or asymptomatic elevation > 5 times normal) by definition have hepatic toxicity, and INH is stopped.After recovery from mild aminotransferase elevations and symptoms, patients can be safely challenged with a half-dose for 2 to 3 days. If this dose is tolerated (typically in about half of patients), the full dose may be restarted with close monitoring for recurrence of symptoms and deterioration of liver function. If patients are receiving INH, RIF, and PZA, all drugs must be stopped, and the challenge done with each drug separately. INH or PZA, rather than RIF, is the more ly cause of hepatotoxicity.Peripheral neuropathy can result from INH-induced pyridoxine (vitamin B6) deficiency, most ly in pregnant or breastfeeding women, undernourished patients, patients with diabetes mellitus or HIV infection, alcoholics, patients with cancer or uremia, and the elderly. A daily dose of pyridoxine 25 to 50 mg can prevent this complication, although pyridoxine is usually not needed in children and healthy young adults.INH delays hepatic metabolism of phenytoin, requiring dose reduction. It can also cause a violent reaction to disulfiram, a drug occasionally used for alcoholism. INH is safe during pregnancy.Rifampin (RIF), given orally, is bactericidal, is well-absorbed, penetrates well into cells and CSF, and acts rapidly. It also eliminates dormant organisms in macrophages or caseous lesions that can cause late relapse. Thus, RIF should be used throughout the course of therapy.Adverse effects of rifampin include cholestatic jaundice (rare), fever, thrombocytopenia, and renal failure. RIF has a lower rate of hepatotoxicity than INH. Drug interactions must be considered when using RIF. It accelerates metabolism of anticoagulants, oral contraceptives, corticosteroids, digitoxin, oral antihyperglycemic drugs, methadone, and many other drugs. The interactions of rifamycins and many antiretroviral drugs are particularly complex; combined use requires specialized expertise. RIF is safe during pregnancy.The following newer rifamycins are available for special situations:
  • Rifabutin is used for patients taking drugs (particularly antiretroviral drugs) that have unacceptable interactions with RIF. Its action is similar to RIF, but it affects the metabolism of other drugs less. When used with clarithromycin or fluconazole, rifabutin has been associated with uveitis.
  • Rifapentine is used in one dose/wk regimens (see Table: Dosing of Oral First-Line Anti-TB Drugs*) but is not used in children or patients with HIV (because of unacceptable treatment failure rates) or extrapulmonary TB. It is also used in a 12-dose, once/wk DOT regimen with INH for TB prophylaxis. This prophylactic combination is not recommended for children < 2 yr, HIV-infected patients receiving antiretroviral treatment, pregnant women, or women expecting to become pregnant during treatment because safety in these groups is unknown.

Pyrazinamide (PZA) is an oral bactericidal drug. When used during the intensive initial 2 mo of treatment, it shortens the duration of therapy to 6 mo and prevents development of resistance to RIF.The major adverse effects of pyrazinamide are GI upset and hepatitis. It often causes hyperuricemia, which is generally mild and only rarely induces gout. PZA is commonly used during pregnancy, but its safety has not been confirmed.Ethambutol (EMB) is given orally and is the best-tolerated of the first-line drugs. Its main toxicity is optic neuritis, which is more common at higher doses (eg, 25 mg/kg) and in patients with impaired renal function. Patients with optic neuritis present initially with an inability to distinguish blue from green, followed by impairment of visual acuity. Because both symptoms are reversible if detected early, patients should have a baseline test of visual acuity and color vision and should be questioned monthly regarding their vision. Patients taking EMB for > 2 mo or at doses higher than those listed in the table above should have monthly visual acuity and color vision testing. Caution is warranted if communication is limited by language and cultural barriers. For similar reasons, EMB is usually avoided in young children who cannot read eye charts but can be used if needed because of drug resistance or drug intolerance. Another drug is substituted for EMB if optic neuritis occurs. Ethambutol can be used safely during pregnancy. Resistance to EMB is less common than that to the other first-line drugs.


Tuberculosis (TB)


Tuberculosis — or TB, as it’s commonly called — is a contagious infection that usually attacks your lungs. It can spread to other parts of your body, your brain and spine. A type of bacteria called Mycobacterium tuberculosis causes it.

In the early 20th century, TB was a leading cause of death in the United States. Today, most cases are cured with antibiotics. But it takes a long time. You have to take meds for at least 6 to 9 months.

In the 20th century, TB was a leading cause of death in the United States. Today, most cases are cured with antibiotics. But it takes a long time. You have to take meds for at least 6 to 9 months.

A TB infection doesn’t mean you’ll get sick. There are two forms of the disease:

Latent TB. You have the germs in your body, but your immune system stops them from spreading. That means you don’t have any symptoms and you’re not contagious. But the infection is still alive in your body and can one day become active.

If you’re at high risk for re-activation — for instance, you have HIV, your primary infection was in the past 2 years, your chest X-ray is abnormal, or your immune system is compromised — your doctor will treat you with antibiotics to lower the risk for developing active TB.  

Active TB. This means the germs multiply and can make you sick. You can spread the disease to others. Ninety percent of adult cases of active TB are from the reactivation of a latent TB infection.

There aren’t any for latent TB. You’ll need to get a skin or blood test to find out whether you have it.

There are usually signs if you have active TB disease. They include:

If you have any of these symptoms, see your doctor to get tested. Get medical help right away if you have chest pain.

Tuberculosis is caused by bacteria that spread through the air, just a cold or the flu. When someone who has it coughs, sneezes, talks, laughs, or sings, tiny droplets that contain the germs are released. If you breathe in these germs, you can get it.

TB can spread from person to person, but it isn’t easy to catch. You usually have to spend a lot of time around someone who has a lot of bacilli in their lungs. You’re most ly to catch it from co-workers, friends, and family members.

Tuberculosis germs don’t thrive on surfaces. You can’t get the disease from shaking hands with someone who has it or by sharing their food or drink. 

There are two common tests for tuberculosis, but they don’t tell you whether you have latent or active TB:

  • Skin test. This is also known as the Mantoux tuberculin skin test. A health care worker injects a small amount of fluid into the skin of your lower arm. After 2 or 3 days, they’ll check for swelling in your arm to determine your results. If your results are positive, you probably have been infected with TB bacteria. But the results can be false positive. If you’ve gotten a tuberculosis vaccine called bacillus Calmette-Guerin (BCG), the test could say you have TB when you really don’t. The results can also be false negative, saying that you don’t have TB when you really do, if your infection is recent. You might get this test more than once.
  • Blood test. These tests, also called interferon-gamma release assays or IGRAs, measure the response when TB proteins are mixed with a small amount of your blood.

If you have a positive skin or blood test, your doctor will probably give you a chest X-ray or CT scan to look for changes in your lungs. They also might test for TB bacteria in your sputum, the mucus that comes up when you cough. These results will help diagnose latent or active TB.

Your treatment will depend on whether you have latent TB or active TB.

  • If you have latent TB, your doctor will probably give you medications to kill the bacteria so you don’t develop active TB. If you start to see any of the symptoms of active TB, call your doctor right away.
  • Your doctor will treat active TB with a combination of medications. You’ll take them for 6 to 12 months.

Whether you have latent or active TB, it’s important to finish taking all of your medications, even if you feel better after starting them.

You can get TB only if you come into contact with others who have it. Other things that could increase your risk include:

  • A friend, co-worker, or family member has active TB.
  • You live in or have traveled to an area where TB is common, Russia, Africa, Eastern Europe, Asia, Latin America, and the Caribbean.
  • You’re part of a group in which TB is more ly to spread, or you work or live with someone who is. This includes homeless people, people with HIV, people in jail or prison, and people who inject drugs into their veins.
  • You work or live in a hospital or nursing home.
  • You’re a health care worker for patients at high risk of TB.
  • You’re a smoker.Tuberculosis Complications

A healthy immune system fights the TB bacteria. But if you have any of the following, you might not be able to fend off active TB disease:

Babies and young children also are at greater risk because their immune systems aren’t fully formed.

To help stop the spread of TB:

  • If you have latent TB, take all of your medication so you don’t develop active TB, which is contagious.
  • If you have active TB, limit your contact with other people at work, school, or home. Cover your mouth when you laugh, sneeze, or cough. Wear a surgical mask when you’re around other people during the first weeks of treatment.
  • If you’re traveling to a place where TB is common, avoid getting close to or spending a lot of time in crowded places with people who have TB.

Children in countries where TB is common often get the BCG vaccine. It isn’t recommended in the United States. Other vaccines are being developed and tested.


Brian W. Christman, MD, professor and vice-chair, Vanderbilt University Medical Center; volunteer national spokesperson, American Lung Association.

CDC: “Tuberculosis.”

American Lung Association: “Learn About Tuberculosis.”

Mayo Clinic: “Tuberculosis.”

World Health Organization: “Tuberculosis,” “Smoking and tuberculosis: a dangerous combination.”


U.S. Preventive Services Task Force Recommendation Statement: “Screening for Latent Tuberculosis Infection in Adults.”

© 2019 WebMD, LLC. All rights reserved. Tuberculosis Symptoms




Tuberculosis is an infectious disease caused by a type of bacteria called Mycobacterium tuberculosis. Tuberculosis (often called “TB”) mainly infects the lungs, but can affect other organs.

Tuberculosis (too-bur-kyuh-LOW-sis) was one of the worst diseases of the 19th century. It became much rarer as living conditions and medical care got better in the United States. But it's making a comeback today, particularly among the homeless, those in prison, and people whose immune systems are weakened (for instance, from HIV infection).

Is Tuberculosis Contagious?

Yes. When someone with untreated TB coughs or sneezes, it sends droplets with the bacteria into the air. Inhaling these infected droplets is the usual way a person gets TB.

But not everyone who inhales infected droplets will get sick. That's why doctors categorize TB as either:

  • latent TB infection: This is when people have the M. tuberculosis bacteria in their bodies, but they don't feel sick or have symptoms. They also cannot pass TB to others.or
  • TB disease: This is when people with M. tuberculosis bacteria become sick and have symptoms. Sometimes it can happen if a latent TB infection was not treated. They can spread TB to others.

What Are the Signs & Symptoms of Tuberculosis?

Someone with TB disease might have these symptoms:

  • unexplained weight loss
  • loss of appetite
  • night sweats
  • fever or chills
  • tiredness
  • coughing for 3 weeks or longer (and might cough up blood)
  • chest pain

How Is Tuberculosis Diagnosed?

A latent tuberculosis infection causes no signs or symptoms, and a chest X-ray won't show any signs of infection. Doctors can diagnose both latent TB infections and TB disease by doing a:

  • Tuberculin skin test (TST): This is how doctors usually test kids for TB. It's done in two steps. First, the health care provider injects a small amount of fluid (called tuberculin) into the skin on the lower part of the arm. Then, the person returns 48–72 hours later, when the provider checks the skin for a reaction. A raised, hard area or swelling means the person has TB bacteria in the body.
  • Blood test: The health care provider will take a blood sample to be checked in a lab for TB bacteria. This option doesn't need a second step.

Someone with a positive tuberculin test (PPD) will need more testing to see whether they have a latent TB infection or TB disease.

Who Should Get Tested for TB?

Health experts recommend TB testing for people at higher risk for TB disease, such as those who:

  • have symptoms of TB disease
  • were around someone with TB disease
  • have HIV or another condition that weakens the immune system
  • use illegal drugs
  • live in areas where the disease is common (including some countries in Asia, Latin America, Eastern Europe, and Africa)
  • live or work in settings where TB disease is more common (such as homeless shelters and prisons)

How Is Tuberculosis Treated?

Most people with tuberculosis don't need treatment in a hospital and can be cared for at home. Doctors usually treat TB with oral (taken by mouth) antibiotics. Killing all the TB bacteria takes time, though, so most people need to take medicine for 6–9 months. Sometimes doctors use a combination of bacteria-killing medicines to treat active TB.

It's important to take the antibiotics for as long as the doctor prescribed, even if someone feels better in a few weeks. That is the best way to kill the harmful bacteria.

Stopping treatment too soon or skipping doses can give the remaining bacteria a chance to become resistant to the antibiotic.

Drug resistance can lead to more dangerous types of tuberculosis that are harder to treat.

Doctors also might treat people with a latent infection and no symptoms. This is called preventive therapy. It kills the bacteria so they can't cause health problems later. The most common preventive therapy is a daily dose of an antibiotic called isoniazid taken for 6–9 months. Doctors also sometimes give isoniazid to people at risk for getting TB again.

Can Tuberculosis Be Prevented?

The prevention of TB depends on:

  • avoiding contact with people who have the active disease
  • using medicines as a preventive measure in high-risk cases
  • maintaining good living standards

To prevent the spread of germs that cause TB and other infections, encourage everyone in your family to:

  • Wash their hands well and often.
  • Sneeze or cough into a tissue or their elbow, not into their hands.
  • Use separate towels, drinking glasses, and eating utensils rather than sharing these items.

When Should I Call the Doctor?

Call the doctor if anyone in your family has:

  • had contact with someone who has tuberculosis
  • a long-lasting fever
  • night sweats
  • a long-lasting cough

Reviewed by: Aledie A. Navas, MD

Date reviewed: September 2019


Tuberculosis and HIV co-infection


•    Tuberculosis (TB) is one of the most common co-infections that people living with HIV can develop.

•    Testing for TB can be easily done with a blood test or by taking a sample of mucus or other bodily fluid.

•    If you are diagnosed with active TB, you will be offered treatment with a course of antibiotics.

TB is an infection which most commonly attacks the lungs or throat (pulmonary TB). It can also attack other parts of the body (extra-pulmonary TB), such as the lymph nodes, spine or brain.

If you're living with HIV, it means that:

  • you’re more ly to develop TB because of a weakened immune system.
  • you can reduce the risk of TB by taking your HIV treatment correctly to keep your immune system strong and healthy.
  • get tested for TB regularly.

How do you get TB?

There are two types of TB infection; 'active' and 'inactive'. If someone with ‘active’ TB coughs or sneezes, the bacteria in these tiny droplets can be passed on to another person through the air.

Active TB and HIV

Active TB means it’s spreading throughout the body, and the immune system can’t prevent symptoms and illness. Symptoms of active TB include:

  • a cough for more than 3 weeks
  • extreme tiredness
  • fever
  • night sweats
  • loss of appetite
  • weight loss.

Symptoms of active extra-pulmonary TB often include swollen glands or pain in the affected area.

Inactive TB and HIV

If a person has inactive (or latent) TB, it means their immune system has been able to fight the disease and stop it from causing illness. They don’t have symptoms and can't pass it on to other people.

In some people, TB remains inactive for their whole life. In others, TB may become active if their immune system weakens – for example by having HIV.

HIV and TB co-infection – the risks

If you're living with HIV and also have TB, you are said to have a co-infection. This means that TB:

  • is harder to diagnose
  • spreads faster / can spread to other parts of the body
  • is more ly to be fatal if left untreated
  • is more ly to return after being treated
  • is harder to treat if you have a drug-resistant strain.

How can I prevent TB?

It's difficult to prevent TB because it can be passed on via air. Covering your mouth with your hand or a tissue when coughing or sneezing can help to stop the spread of TB.

The most effective way to prevent TB is to get tested and treated.

The BCG vaccine against TB

The BCG vaccine is around 80% effective but only for 15 years, so it’s being phased out in some countries where TB is not a major problem.

Can I get tested for TB?

There are many types of TB tests. Usually TB is diagnosed by a blood test. However, other options could be a sample of sputum (the mucus that is coughed up) or another body fluid. Other tests involve a small amount of TB protein being injected under the skin to see if there's a reaction.

Your healthcare professional may also recommend a chest x-ray to see if TB has scarred your lungs.

Treating active TB

Active TB can almost always be cured with antibiotics. For pulmonary TB, antibiotics are usually taken daily for six months. For people with TB in other parts of their body, treatment will last longer.

Treating inactive TB

Treatment is not required for most people with inactive TB. However, if you're living with HIV, TB treatment is always necessary to prevent TB causing illness and to cure it. A similar course of treatment to active TB will be recommended.

Treating TB and HIV at the same time

If you have TB and HIV it can be difficult to take drugs for both at the same time because of the number of drugs and how often they need to be taken, and because of the interactions between them. Your healthcare professional can advise you on this.

Sometimes you may be asked to take your treatment in the presence of a healthcare professional to check you’re taking it correctly.

What if I don't take my TB treatment correctly?

If you don't, or can't, take your treatment properly, or stop taking it before the end of your course of treatment, TB becomes resistant to the drugs and they stop working.

At this point, treatment options are limited as the other available drugs are less effective. You’ll be closely monitored throughout treatment to ensure it's working,

It's important you take your course of TB treatment correctly so that TB doesn’t become resistant to the antibiotics.

If you’re worried about taking your HIV and TB treatment correctly then talk to your healthcare professional who can help and support you to get into a routine where your medication will be effective.

© Photos are used for illustrative purposes. They do not imply any health status or behaviour on the part of the people in the photo.



Tuberculosis (TB): Practice Essentials, Background, Pathophysiology


Tuberculosis (TB), a multisystemic disease with myriad presentations and manifestations, is the most common cause of infectious disease–related mortality worldwide. The World Health Organization (WHO) has estimated that 2 billion people have latent TB and that globally, in 2009, the disease killed 1.7 million people. [11] (See Epidemiology.) [12]

Although TB rates are decreasing in the United States, the disease is becoming more common in many parts of the world. In addition, the prevalence of drug-resistant TB is also increasing worldwide. Coinfection with the human immunodeficiency virus (HIV) has been an important factor in the emergence and spread of resistance. [13] (See Treatment.)

Mycobacterium tuberculosis, a tubercle bacillus, is the causative agent of TB. It belongs to a group of closely related organisms—including M africanum, M bovis, and M microti —in the M tuberculosis complex. (See Etiology.) An image of the bacterium is seen below.

Under a high magnification of 15549x, this scanning electron micrograph depicts some of the ultrastructural details seen in the cell wall configuration of a number of Gram-positive Mycobacterium tuberculosis bacteria. As an obligate aerobic organism, M. tuberculosis can only survive in an environment containing oxygen. This bacterium ranges in length between 2-4 microns, with a width between 0.2-0.5 microns. Image courtesy of the Centers for Disease Control and Prevention/Dr. Ray Butler.

The lungs are the most common site for the development of TB; 85% of patients with TB present with pulmonary complaints. Extrapulmonary TB can occur as part of a primary or late, generalized infection. (See Pathophysiology and Presentation.)

The primary screening method for TB infection (active or latent) is the Mantoux tuberculin skin test with purified protein derivative (PPD).

An in vitro blood test interferon-gamma release assay (IGRA) with antigens specific for M tuberculosis can also be used to screen for latent TB infection.

Patients suspected of having TB should submit sputum for acid-fast bacilli (A) smear and culture. (See Workup.)

The usual treatment regimen for TB cases from fully susceptible M tuberculosis isolates consists of 6 months of multidrug therapy.

Empiric treatment starts with a 4-drug regimen of isoniazid, rifampin, pyrazinamide, and either ethambutol or streptomycin; this therapy is subsequently adjusted according to susceptibility testing results and toxicity.

Pregnant women, children, HIV-infected patients, and patients infected with drug-resistant strains require different regimens. (See Treatment and Medication.)

Laws vary from state to state, but communicable-disease laws typically empower public health officials to investigate suspected cases of TB, including potential contacts of persons with TB. In addition, patients may be incarcerated for noncompliance with therapy.

New TB treatments are being developed, [14] and new TB vaccines are under investigation. (See Epidemiology and Treatment.)

TB is an ancient disease. Signs of skeletal TB (Pott disease) have been found in remains from Europe from Neolithic times (8000 BCE), ancient Egypt (1000 BCE), and the pre-Columbian New World.

TB was recognized as a contagious disease by the time of Hippocrates (400 BCE), when it was termed “phthisis” (Greek from phthinein, to waste away). In English, pulmonary TB was long known by the term “consumption.

” German physician Robert Koch discovered and isolated M tuberculosis in 1882.

The worldwide incidence of TB increased with population density and urban development, so that by the Industrial Revolution in Europe (1750), it was responsible for more than 25% of adult deaths.

In the early 20th century, TB was the leading cause of death in the United States; during this period, however, the incidence of TB began to decline because of various factors, including the use of basic infection-control practices (eg, isolation).

The US Centers for Disease Control and Prevention (CDC) has been recording detailed epidemiologic information on TB since 1953. Beginning in 1985, a resurgence of TB was noted.

The increase was observed primarily in ethnic minorities and especially in persons infected with HIV.

TB control programs were revamped and strengthened across the United States, and rates again began to fall. (See Epidemiology.)

As an AIDS (acquired immunodeficiency syndrome)–related opportunistic infection, TB is associated with HIV infections, with dual infections being frequently noted.

Globally, coinfection with HIV is highest in South Africa, India, and Nigeria. Persons with AIDS are 20-40 times more ly than immunocompetent persons to develop active TB.

[15] Correspondingly, TB is the leading cause of mortality among persons infected with HIV. [16]

Worldwide, TB is most common in Africa, the West Pacific, and Eastern Europe. These regions are plagued with factors that contribute to the spread of TB, including the presence of limited resources, HIV infection, and multidrug-resistant (MDR) TB. (See Epidemiology.)

MDR-TB is defined as resistance to isoniazid and rifampin, which are the 2 most effective first-line drugs for TB. In 2006, an international survey found that 20% of M tuberculosis isolates were MDR.

[16] A rare type of MDR-TB, called extensively drug-resistant TB (XDR-TB), is resistant to isoniazid, rifampin, any fluoroquinolone, and at least one of 3 injectable second-line drugs (ie, amikacin, kanamycin, or capreomycin).

[11] XDR-TB resistant to all anti-TB drugs tested has been reported in Italy, Iran, and India. [17]

Multiple factors contribute to the drug resistance of M tuberculosis, including incomplete and inadequate treatment or adherence to treatment, logistical issues, virulence of the organism, multidrug transporters, host genetic factors, and HIV infection. A study from South Africa found high genotypic diversity and geographic distribution of XDR-TB isolates, suggesting that acquisition of resistance, rather than transmission, accounts for between 63% and 75% of XDR-TB cases. [18]


In a 2008 report by the WHO, the proportion of TB cases in which the patient was resistant to at least 1 antituberculosis drug varied widely among different regions of the world, ranging from 0% to over 50%; the proportion of MDR-TB cases ranged from 0% to over 20%. The WHO calculated that the global population-weighted proportion of MDR-TB was 2.9% in new TB cases, 15.3% in previously treated patients, and 5.3% in all TB cases. [19]

In the United States, the percentage of MDR-TB cases has increased slowly, from 0.9% of the total number of reported TB cases in 2008 to 1.3% of cases in 2011. Although the percentage of US-born patients with primary MDR-TB has remained below 1% since 1997, the proportion of cases in which the patient was foreign born increased from 25.3% in 1993 to 82.7% in 2011. [20]

XDR-TB is becoming increasingly significant. [19] According to the US National TB Surveillance System (NTSS), between 1993 and 2006 a total of 49 cases (3% of evaluable MDR-TB cases) met the revised case definition for XDR-TB. The largest number of XDR-TB cases was found in New York City and California.

Cure rate

The cure rate in persons with MDR-TB is 50-60%, compared with 95-97% for persons with drug-susceptible TB. [16] The estimated cure rate for XDR-TB is 30-50%.

[11] In people who are also infected with HIV, MDR-TB and XDR-TB often produce fulminant and fatal disease; time from TB exposure to death averages 2-7 months.

In addition, these cases are highly infectious, with conversion rates of as much as 50% in exposed health-care workers.

As previously stated, multidrug resistance has been driven by poor compliance with TB therapies , resulting in difficulties in controlling the disease.

Consequently, a threat of global pandemic occurred in the late 1980s and early 1990s.

Reacting to these signals, the WHO developed a plan to try to identify 70% of the world's cases of TB and to completely treat at least 85% of these cases by the year 2000.

these goals were born major TB surveillance programs and the concept of directly observed therapy (DOT), which requires a third party to witness compliance with pharmacotherapy. With worldwide efforts, global detection of smear-positive cases rose from 11% (1991) to 45% (2003), with 71-89% of those cases undergoing complete treatment.

Despite the importance of early isolation of patients with active TB, a standardized triage protocol with acceptable sensitivities has yet to be developed.

[21] Moran et al demonstrated that among patients with active TB in the emergency department (ED), TB was often unsuspected, and isolation measures were not used.

[22] The difficulty in establishing such a protocol only highlights the importance of the emergency physician’s role in the prompt identification and isolation of active TB.

A large percentage of ED patients are at increased risk for having active TB, including homeless/shelter-dwelling patients, travelers from endemic areas, immunocompromised patients, health-care workers, and incarcerated patients. Therefore, emergency physicians must consider the management and treatment of TB as a critical public health measure in the prevention of a new epidemic. [23]

For high-risk cases, prehospital workers can assist in identifying household contacts who may also be infected or who may be at high risk of becoming infected.

Prehospital workers should be aware that any case of active TB in a young child indicates disease in 1 or more adults with close contact, usually within the same household. TB in a child is a sentinel event indicating recent transmission.

Extrapulmonary involvement occurs in one fifth of all TB cases; 60% of patients with extrapulmonary manifestations of TB have no evidence of pulmonary infection on chest radiographs or in sputum cultures.

The incidence of cutaneous TB appears low. In areas such as India or China, where TB prevalence is high, cutaneous manifestations of TB (overt infection or the presence of tuberculids) have been found in less than 0.1% of individuals seen in dermatology clinics.

TB can affect any structure in the eye and typically presents as a granulomatous process. Keratitis, iridocyclitis, intermediate uveitis, retinitis, scleritis, and orbital abscess are within the spectrum of ocular disease.

Choroidal tubercles and choroiditis are the most common ocular presentations of TB. Adnexal or orbital disease may be seen with preauricular lymphadenopathy.

Because of the wide variability in the disease process, presenting complaints will vary.

Most often, patients will complain of blurry vision that may or may not be associated with pain and red eye.

In the rare case of orbital disease, proptosis, double vision, or extraocular muscle motility restriction may be the presenting complaint. Preseptal cellulitis in children with spontaneous draining fistula may also occur.

In cases of both pulmonary and extrapulmonary TB, there may be ocular findings without ocular complaints.


What is tuberculosis?

Tuberculosis is a bacterial disease usually affecting the lungs (pulmonary TB). Other parts of the body can also be affected, for example lymph nodes, kidneys, bones, joints, etc. (extrapulmonary TB).

Who gets tuberculosis?

Tuberculosis can affect anyone of any age.

Once a person has TB infection but does not appear sick, he or she has a higher chance of developing TB disease if the person has HIV infection, is younger than 5 years old, was infected with TB germs within the last 2 years, has other health problems diabetes that make it hard for the body to fight germs, abuses alcohol or drugs, or was not treated correctly for TB disease in the past.

How is tuberculosis spread?

Tuberculosis is spread through the air when a person with untreated TB disease of the lungs coughs, sneezes, laughs, or sings. A person must be in close contact with someone with untreated TB disease of the lungs for a long period of time and needs to breathe in TB germs for infection to occur. TB is NOT spread by sharing silverware or cups, or sharing saliva when kissing someone.

What is the difference between latent tuberculosis infection and tuberculosis disease?

Latent tuberculosis infection (LTBI) means the person has the TB germs in the body (usually lungs), but he/she is not sick and has no symptoms because the germs are sleeping in the body.

In latent TB, the person has a positive TB skin test or TB blood test, a normal chest x-ray, no symptoms of tuberculosis, and no TB germs found in the sputum (phlegm).

Tuberculosis disease is when the person has symptoms, a positive TB skin test or TB blood test, a chest x-ray showing TB disease (if disease is in the lungs), and have TB germs in the sputum (phlegm). In order to spread the TB germs, a person must have TB disease of the lungs or throat.

Having latent TB infection is not enough to spread the germ. However, people with latent TB infection may develop TB disease in the future. To prevent developing TB disease, people with latent TB infection should take medicine.

What are the symptoms of tuberculosis?

The symptoms of TB include a low-grade fever, night sweats, weakness or tiredness, and weight loss. If TB is in the lungs, the person may also cough, have chest pain, shortness of breath or might be coughing up blood. Other symptoms depend on the part of the body affected by the TB germs.

How soon do symptoms appear?

Most people infected with the germ that causes TB never develop TB disease. If TB disease does develop, it can occur two to three months after infection or years later. The risk of TB disease lessens as time passes. Treatment can prevent the development of disease.

When and for how long is a person able to spread tuberculosis?

A person with TB disease may be able to spread the TB germs until he/she has been on medicine for several weeks. However, a person with latent TB infection, but not disease, cannot spread the infection to others, since there are no TB germs in the sputum (phlegm).

What is the treatment for tuberculosis?

People with latent TB infection should be seen by a health care provider for treatment, which usually includes taking medication for three to nine months. People with TB disease must take several medications for six months or more.

Initial medications include at least four anti-TB drugs, and medications may be altered laboratory test results. The exact medication plan must be determined by a health care provider.

Directly observed therapy (DOT) programs are recommended for all persons with TB disease to help them complete their treatment.

What is Directly Observed Therapy (DOT)?

DOT is when a person with TB disease meets with a health care worker every day or several times per week. The person with TB disease and the health care worker meet at a place that both agree on. Medicines are taken at this place while the health care worker watches the person with TB disease. DOT helps in several ways.

The health care worker can help the person with TB disease remember to take all his/her medicines and complete treatment. This means the person with TB disease will get well as soon as possible. The health care worker will make sure that the medicines are working as they should.

This health care worker will also watch for side effects and answer questions that the person with disease may have about TB.

What can be the effect of not being treated for tuberculosis?

In addition to spreading the disease to others, an untreated person may become severely ill or die.

What can be done to prevent the spread of tuberculosis?

The most important way to stop the spread of tuberculosis is for people with TB disease to cover the mouth and nose when coughing, and to take all the TB medicine exactly as instructed by the health care provider. It is also important that people with latent TB infection be treated so they do not get TB disease later and spread it to others.

What is multidrug-resistant tuberculosis (MDR-TB)?

This refers to the ability of some strains of TB to grow and multiply even in the presence of certain drugs which would normally kill them.

What is extensively drug-resistant tuberculosis (XDR-TB)?

Extensively drug-resistant TB (XDR-TB) is a subset of MDR-TB in which the strains of TB bacteria are resistant to nearly all medicines used to treat TB disease. These strains are very difficult to treat.

Who gets MDR-TB?

People with drug sensitive TB disease may develop drug resistant tuberculosis if they fail to take their TB medications as instructed, as well as people with TB disease who have not been given a treatment plan that works against the TB germs. People with MDR-TB can transmit the drug resistant germs to other people.

What is the treatment for multidrug-resistant tuberculosis?

People with disease due to drug resistant germs, should have a health care provider who is an expert in treating drug resistant TB. People with drug resistant disease must be treated with special medications which are not as good as the usual medications for TB. Treatment takes much longer than regular TB and drugs have more side effects.

What can be done to prevent the spread of MDR-TB?

Ensuring people with MDR-TB take all their medication and teaching patients to cover their mouth and nose when coughing and sneezing can reduce the risk of spread of MDR-TB. In addition, directly observed therapy should be used to ensure people with drug resistant TB complete their treatment.