Understanding Tuberculosis

Tuberculosis (Consumption, Wasting Disease, White Plague)

On the Front Line as Health-Care Workers

It is crucial that health-care workers:

• Understand TB - its symptoms, how it’s spread and how it’s treated.
• Take precautions - to prevent getting, or giving, the disease while at work.
• Avoid undue alarm – it’s important to base ones attitude and approach on facts, not fears.

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Organism/Bacteria

Mycobacterium Tuberculosis (M. tuberculosis, also called tubercle bacilli (TB)) is the causative agent of tuberculosis. It most commonly involves the lungs. 85% of TB cases are pulmonary.

M.tuberculosisis a type of Mycobacterium and is a relatively slow-growing bacilli characterized by acid-fast staining. There are many types of mycobacterium other than M. tuberculosis (e.g. M. avium, M. bovis, M. favescens, M. gordonae).

Frequently, a patient is placed in "rule-out TB Airborne Isolation" when acid-fast bacilli are found in the sputum, or cultured from the lungs. Until the type of mycobacterium is identified, Pulmonary TB disease is suspected.

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TB Infection (Latent TB)

TB infection begins when the tubercle bacilli multiply in the small air sacs of the lungs. A small number enter the bloodstream and spread throughout the body, but the body’s immune system usually keeps the bacilli under control. People who have TB infection, but not TB disease, do not have symptoms of TB and they cannot spread TB to others. They usually have a positive reaction to the tuberculin skin test. About 10% of people who have TB infection will develop disease at some point, but the risk is greatest in the first year or two after infection. Appropriate treatment can reduce the risk of developing TB disease by 95%.

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TB Disease (Active TB)

In some people who have TB infection, the immune system cannot keep the tubercle bacilli under control and the bacilli begin to multiply rapidly, causing TB disease. TB disease usually occurs in the lungs (pulmonary TB), but it can also occur in other places in the body (extrapulmonary TB). Miliary TB occurs when tubercle bacilli enter the bloodstream and are carried to all parts of the body, where they grow and cause disease in multiple sites.

There are four steps in diagnosing TB disease.

1. Medical history
2. TB skin test
3. Chest x-ray
4. Bacteriologic examination /li>

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How TB is Spread

TB is spread from person to person through the air. When a person who has Pulmonary TB disease coughs, sneezes, shouts, or speaks, tiny particles containing M. tuberculosis may be expelled into the air. These particles, called droplet nuclei, are about 1-5 microns in diameter – less than 1/5000 of an inch. Droplet nuclei can remain suspended in the air for several hours, depending on the environment. If another person inhales air that contains these droplet nuclei, transmission may occur. Anyone who is around a person with Pulmonary TB disease can become infected, but usually it takes days of close, unprotected, contact.

Not everyone who is exposed to a patient with Pulmonary TB disease becomes infected with it. The probability that TB will be transmitted depends on three factors:

People with Pulmonary TB disease are most likely to spread it to people they spend time with every day, such as family members or co-workers. On average, about 30% of people who spend a lot of time with someone who has Pulmonary TB disease (close contacts) become infected with M. tuberculosis. However, people with TB disease vary in their infectiousness/communicability; some infect most or all their close contacts, whereas others infect few or none of their contacts.

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Groups at High Risk for TB

Infectiousness of People Known to Have or Suspected of Having TB Disease*

*Infectiousness depends on a variety of factors. Clinicians should consider all of these factors when determining whether a TB patient should be considered infectious.

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Symptoms of TB

Fever, night sweats, fatigue (weak and sick feeling), weight loss, a persistent cough and (sometimes) coughing up blood. Other symptoms depend on the particular part of the body that is affected.

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Reporting TB to Clinical Epidemiology and Infection Prevention (CEIP) and the County Public Health Department

As soon as TB is suspected from any body site, CEIP needs to be contacted. This ensures proper placement according to the level of communicability suspicion.

Suspect and confirmed cases of TB disease are reportable by law to the County Public Health Department within 1 day of identification. The County Public Health Department begins a contact investigation to identify people exposed to the patient with TB disease; screening them for infection and disease and providing treatment and preventive therapy as needed. They also work together with the LLUH to ensure there is a plan for patients to receive follow-up care after they are discharged/transferred.

See section: "Obtaining Clearance from the County Public Health Department"

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Placement of patients with Suspect or Known TB Disease

Placement of patients with suspect or known TB disease is done on an individual patient basis in consultation with Patient Placement Services and CEIP.

See section: "Before Removing Patient from TB Isolation"

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Preventing TB Transmission Where You Work

Quick Identification

All sites with TB disease are important and are reportable to the County Public Health Department. But of primary concern, because of the potential to spread droplet nuclei through the air throughout the hospital, are those patients with Pulmonary TB disease. It is for this reason that those with suspect, or known, Pulmonary TB disease are put into Airborne Isolation as soon as possible. Airborne Isolation lasts until Pulmonary TB disease is either ruled out, or until treatment renders them non-infectious (usually after completing 1-3 weeks of treatment and they have 3 consecutive negative sputum cultures, at least 24 hours apart).

See section: "Before Removing Patient from TB Isolation".

People Exposed to TB
		Because about half the risk of developing TB disease is concentrated in the first 2 years after infection, it is important to detect new infection early. People with TB infection can be given treatment to prevent them from getting TB disease.
NO TB INFECTION	TB INFECTION
Negative Skin Test Reaction	Positive Skin Test Reaction	During the first 2 years after infection, people with TB infection are at high risk of developing TB disease
NOT Infectious	NOT Infectious
Remain                    Remain			TB Disease
			May be INFECTIOUS
		After the first 2 years, the risk is lower, but people with TB infection can develop TB disease at any point in their lives. Some medical conditions increase the risk for TB disease
NO TB INFECTION NOT Infectious	TB INFECTION NO TB DISEASE NOT Infectious

TB "Airborne"Isolation

A patient with suspected or known Pulmonary TB disease is placed in TB Airborne Isolation until considered no longer infectious. These isolation rooms are rooms in the facility that have special characteristics to prevent the spread of droplet nuclei expelled by a Pulmonary TB patient. These characteristics include:

• Doors are to be kept closed to maintain negative pressure
• Patients are to be placed in an appropriate room where the air is vented directly to the outside
• Everyone entering the room must wear special facemasks.

Once a physician makes a diagnosis of "high-suspicion" or known pulmonary TB disease, family and close contacts will also need evaluated for their TB status before allowed to enter the hospital to visit. They will be required to get "clearance" from either their County Public Health Department or a personal physician before being allowed to visit the patient. Here is a list of county clinics where testing for family and close contacts can seek TB testing. Here is a list of county clinics where testing for family and close contacts can seek TB testing.

Prompt Treatment

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Adopt Safe Work Practices

1. Encourage TB patients to cover their mouth and nose when they cough or sneeze. This simple measure is an effective way keeping TB bacteria out of the air
2. Take care when moving TB patients – make sure the patient wears a properly fitting surgical mask when being moved from isolation (for tests and other procedures).
3. Be aware of high-risk procedures that can easily send TB bacteria into the air:
   • Cough- and sputum-producing procedures (suctioning)
   • Administering aerosol drugs which cause coughing
   • Certain autopsy procedures
   • Bronchoscopy
4. As few people as possible should be allowed to enter the airborne isolation room.

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Treatment

Preventive therapy is given to those with TB infection to reduce the risk of contracting TB disease later by 95%. It is very important that people take their preventive treatment as soon as the doctor recommends. It takes from six months to a year to kill all the TB bacteria. Remember a person with TB infection will always have TB bacteria in the body unless the bacteria are killed with the right medication.

TB disease must be treated for at least 6 months; in some cases, treatment lasts even longer. In most areas of the country, the initial regimen for treating TB disease should include four drugs: isoniazid, rifampin, pyrazinamide and either ethambutol or streptomycin. When the drug susceptibility results are available, clinicians may change the regimen accordingly. TB disease must be treated with at least two drugs to which the bacilli are susceptible. Using only one drug to treat TB disease can create a population of tubercle bacilli that is resistant to that drug. Drug resistance can also develop when patients do not take treatment as prescribed. Thus, to prevent relapse and drug resistance, clinicians must prescribe an adequate regimen and make sure that patients adhere to treatment.

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Before Removing a Patient from TB Isolation

Before a patient is removed from TB Airborne Isolation, the following questions need to be answered:

Has Epidemiology been contacted and concur with discontinuing of isolation?

Has Pulmonary TB disease been ruled-out by the attending physician?

Is the patient on adequate therapy?

Has the patient had a favorable clinical response to therapy?

Has the patient had three consecutive negative sputum smears from sputum collected on different days?

Is there an order on the chart to discontinue Airborne Isolation?

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Obtaining Clearance from the California Department Of Public Health (CDPH) when Discharging/Transferring a Patient with Suspect or Known TB Disease

Those with a diagnosis of suspect or known TB disease at the time of discharge home, or being transferred to another facility, need to obtain clearance/permission before the move is made. This clearance is obtained by/through Case Management. Case Management has the appropriate forms and information to do this. The Case Manager will be contacted within 24 hours by the County Health Department as to when, or if, the patient can be discharged/transferred.

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Prolonged, Unprotected Employee Exposure Follow-up

Follow-up is done through Employee Health Services/Occupational Medicine.

Employee Health Services/Occupational Medicine and CEIP work together on the decision of when prolonged, unprotected exposure to someone with high-suspect, or known, TB disease has taken place. Employee Health Services/Occupational Health Clinic contacts and coordinates follow-up for those employees recognized as having prolonged unprotected exposure.

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References

American Thoracic Society, Treatment of tuberculosis and tuberculosis infection in adults and children, Am J Respir Crit Care Med 1994; 149:1359-1374.

Centers for Disease Control and Prevention. Division of Tuberculosis Elimination Publications www.cdc.gov/nchstp/tb

Centers for Disease Control and Prevention. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care facilities, MMWR 1994;43(No.RR-13)

Centers for Disease Control and Prevention. Progress Toward the Elimination of Tuberculosis. MMWR 1999:48(33):732-36

Centers for Disease Control and Prevention. National Center for HIV, STD and TB Prevention Division of Tuberculosis Elimination, Public Health Practice Program Office, Division of Media and Training Services, Self-Study Modules on Tuberculosis.

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