1. Tuberculosis

2. TB Transmission
Transmission is defined as the spread of an organism, such as M. tuberculosis, from one person to another.

3. Tuberculosis Second most common cause of death from infectious disease
In US, higher prevalence in areas with large population of Native Americans
Health care workers are considered to be at high risk.
Resurgence
High rates of TB with HIV infection
Multidrug-resistant strains of M. tuberculosis
Worldwide, TB occurs disproportionately in the poor, the underserved, and minorities.
In the United States, persons at risk include the homeless, residents of inner-city neighborhoods, foreign-born persons, older adults, those in institutions (long-term care facilities, prisons), IV injecting drug users, persons at poverty level, and those with poor access to health care. 3

4. TB Transmission Types of Mycobacteria
M. tuberculosis causes most TB cases in U.S.
Mycobacteria that cause TB:
M. tuberculosis
M. bovis
M. africanum
M. microti
M. canetti
Mycobacteria that do not cause TB
M. avium complex
M. tuberculosis

5. TB Transmission
TB is spread person to person through the air via droplet nuclei
M. tuberculosis may be expelled when an infectious person:
Coughs
Sneezes
Speaks
Sings
Transmission occurs when another person inhales droplet nuclei

6. Dots in air represent droplet nuclei containing
TB Transmission
Dots in air represent droplet nuclei containing
M. tuberculosis

7. TB Transmission Probability that TB will be transmitted depends on:
Infectiousness of person with TB disease
Environment in which exposure occurred
Length of exposure
Virulence (strength) of the tubercle bacilli
The best way to stop transmission is to:
Isolate infectious persons
Provide effective treatment to infectious persons as soon as possible

8. TB Pathogenesis
Pathogenesis is defined as how an infection or disease develops in the body.

9. TB Pathogenesis Latent TB Infection (LTBI)
Occurs when tubercle bacilli are in the body, but the immune system is keeping them under control
Detected by the Mantoux tuberculin skin test (TST) or by blood tests such as interferon-gamma release assays (IGRAs) which include:
QuantiFERON®-TB Gold test (QFT-G)
QuantiFERON®-TB Gold In-Tube (QFT-GIT)
T-Spot®.TB test (T-SPOT)
People with LTBI are NOT infectious

10. TB Pathogenesis TB Disease
Develops when immune system cannot keep tubercle bacilli under control
May develop very soon after infection or many years after infection
About 10% of all people with normal immune systems who have LTBI will develop TB disease at some point in their lives
People with TB disease are often infectious

11. TB Pathogenesis
Droplet nuclei containing tubercle bacilli are inhaled, enter the lungs, and travel to small air sacs (alveoli)

12. Tubercle bacilli multiply in alveoli, where
TB Pathogenesis
Tubercle bacilli multiply in alveoli, where
infection begins

13. TB Pathogenesis
A small number of tubercle bacilli enter bloodstream and spread throughout body

14. TB Pathogenesis LTBI
Within 2 to 8 weeks the immune system produces special immune cells called macrophages that surround the tubercle bacilli
These cells form a barrier shell that keeps the bacilli contained and under control (LTBI)

15. TB Pathogenesis TB Disease
If the immune system CANNOT keep tubercle bacilli under control, bacilli begin to multiply rapidly and cause TB disease
This process can occur in different places in the body

16. Latent TB Infection (LTBI) TB Disease (in the lungs)
LTBI vs. TB Disease
Latent TB Infection (LTBI)
TB Disease (in the lungs)
Inactive, contained tubercle bacilli in the body
Active, multiplying tubercle bacilli in the body
TST or blood test results usually positive
Chest x-ray usually normal
Chest x-ray usually abnormal
Sputum smears and cultures negative
Sputum smears and cultures may be positive
No symptoms
Symptoms such as cough, fever, weight loss
Not infectious
Often infectious before treatment
Not a case of TB
A case of TB

17. Progression to TB Disease
Risk of developing TB disease is highest the first 2 years after infection
People with LTBI can be given treatment to prevent them from developing TB disease
Detecting TB infection early and providing treatment helps prevent new cases of TB disease

18. Progression to TB Disease
Some conditions increase probability of LTBI progressing to TB disease
Infection with HIV
Chest x-ray findings suggestive of previous TB
Substance abuse
Recent TB infection
Prolonged therapy with corticosteroids and other immunosuppressive therapy, such as prednisone and tumor necrosis factor-alpha [TNF-α] antagonists
Organ transplant
Silicosis
Diabetes mellitus
Severe kidney disease
Certain types of cancer
Certain intestinal conditions
Low body weight

19. Progression to TB Disease
People Exposed to TB
Not TB Infected
Latent TB Infection (LTBI)
Not Infectious
Not Infectious
Negative TST or QFT-G test result
Positive TST or QFT-G test result
No TB Infection
May go on to develop TB disease
Latent TB Infection
Figure 1.5

20. Progression to TB Disease TB and HIV
In an HIV-infected person,
TB can develop in one of
two ways:
Person with LTBI becomes infected with HIV and then develops TB disease as the immune system is weakened
Person with HIV infection becomes infected with M. tuberculosis and then rapidly develops TB disease
Image credit: Mississippi State Department of Health

21. Progression to TB Disease TB and HIV
People who are infected with both M. tuberculosis and HIV are much more likely to develop TB disease
TB infection and NO risk factors
TB infection and HIV infection
(pre-Highly Active Antiretroviral Treatment [HAART])
Risk is about 5% in the first 2 years after infection and about 10% over a lifetime
Risk is about 7% to 10% PER YEAR, a very high risk over a lifetime

22. Bacilli may reach any part of the body, but common sites include:
Sites of TB Disease
Bacilli may reach any part of the body, but common sites include:

23. Sites of TB Disease Location Frequency Pulmonary TB Extrapulmonary TB
Lungs
Most TB cases are pulmonary
Extrapulmonary TB
Places other than lungs such as:
Larynx
Lymph nodes
Pleura
Brain
Kidneys
Bones and joints
Found more often in:
HIV-infected or
other
immunosuppressed
persons
Young children
Miliary TB
Carried to all parts of body, through bloodstream
Rare

24. TB Classification System
Based on pathogenesis of TB
Class
Type
Description
No TB exposure
Not infected
No history of TB exposure
Negative result to a TST or IGRA 1
TB exposure
No evidence of infection
History of TB exposure
Negative result to a TST (given at least 8-
10 weeks after exposure) or IGRA 2
TB infection
No TB disease
Positive result to a TST or IGRA
Negative smears and cultures (if done)
No clinical or x-ray evidence of active
TB disease

25. TB Classification System
Based on pathogenesis of TB
Class
Type
Description 3
TB, clinically active
Positive culture (if done) for M. tuberculosis Positive result to a TST or IGRA, and clinical, bacteriological, or x-ray evidence of TB disease 4
Previous TB disease (not clinically active)
Medical history of TB disease
Abnormal but stable x-ray findings
Positive result to a TST or IGRA
Negative smears and cultures (if done) No clinical or x-ray evidence of active TB disease 5
TB suspected
Signs and symptoms of TB disease, but evaluation not complete

26. Clinical Manifestations
Early stages are usually free of symptoms.
People with LTBI have a positive skin test but are asymptomatic. 26

27. Clinical Manifestations
Fatigue
Malaise
Anorexia
Weight loss
Low-grade fevers
Night sweats
People with LTBI have a positive skin test but are asymptomatic. 27

28. Clinical Manifestations
Cough becomes frequent.
Hemoptysis is not common and is usually associated with advanced disease.
Dyspnea is unusual. 28

29. Clinical Manifestations
Acute symptoms (generalized flu symptoms)
High fever
Chills
Pleuritic pain
Productive cough 29

30. Complications Miliary TB
Large numbers of organisms invade the bloodstream and spread to all organs.
Acute or chronic symptoms
It can occur as a result of primary disease or reactivation of latent infection.
Acute symptoms include fever, dyspnea, and cyanosis.
Chronic symptoms include the systemic manifestations of weight loss, fever, and gastrointestinal (GI) disturbance. Hepatomegaly, splenomegaly, and generalized lymphadenopathy may be present. 30

31. Complications Pleural effusion Empyema
Caused by bacteria in pleural space
Inflammatory reaction with plural exudates of protein-rich fluid
Empyema
Pleural TB can result from either primary disease or reactivation of a latent infection.
Empyema is less common than effusion but may occur from large numbers of tubercular organisms in the pleural space. 31

32. Complications TB pneumonia
Large amounts of bacilli discharging from granulomas into lung or lymph nodes
The clinical manifestations are similar to those of bacterial pneumonia. 32

33. Complications Other organ involvement CNS—Meninges
Bone and joint tissue
Kidneys 33

34. Complications Other organ involvement Adrenal glands Lymph nodes
Genital tracts 34

35. Diagnostic Studies Skin testing
Intradermal administration of tuberculin
Induration at injection site indicates exposure.
Sensitivity remains for life, and individual should not be tested again.
The test is administered by injecting 0.1 mL of PPD intradermally on the dorsal surface of the forearm.
The test is read by inspection and palpation 48 to 72 hours later for the presence or absence of induration.
The indurated area (if present) is measured and recorded in millimeters with 0 for no induration.
The reaction occurs 2 to 12 weeks after initial exposure to the organisms. 35

36. Diagnostic Studies Skin testing
Response ↓ in immune compromised patients
Reactions ≥5 mm considered positive 36

37. Diagnostic Studies Skin testing
Two-step testing recommended for health care workers getting repeated testing and those with decreased response to allergens.
In these people, a second TST may cause an accelerated response (“booster effect”) that may be misinterpreted as a new conversion. 37

38. Diagnostic Studies Chest x-ray Cannot make diagnosis solely on x-ray
Upper lobe infiltrates, cavitary infiltrates, and lymph node involvement suggest TB. 38

39. Diagnostic Studies Bacteriologic studies
Stained sputum smears examined for acid-fast bacilli
Required for diagnosis
The culture to grow the organisms for confirmatory diagnosis can take up to 8 weeks. 39

40. Diagnostic Studies Bacteriologic studies
On different days, three consecutive sputum samples
Could also be collected from
Gastric washings
CSF
Fluid from an abscess or effusion 40

41. Collaborative Care Hospitalization not necessary for most patients
Drug therapy used to prevent or treat active disease
Promoting and monitoring compliance are critical for treatment to be successful. 41

42. Drug Therapy Active disease
Four drugs are used in initial phase for maximum effectiveness.
Treatment is aggressive to combat resistant strains of TB.
In most circumstances, the treatment regimen for patients with previously untreated TB consists of a 2-month initial phase with four-drug therapy (INH, rifampin [Rifadin], pyrazinamide [PZA], and ethambutol).
If drug susceptibility test results indicate that bacteria are susceptible to all drugs, ethambutol may be discontinued. 42

43. Drug Therapy Directly observed therapy (DOT)
Noncompliance is major factor in multidrug resistance and treatment failures.
Requires watching patient swallow drugs
Preferred to ensure adherence
In many areas, the public health nurse administers DOT at a clinic site. 43

44. Drug Therapy Active disease
Patients should be taught about side effects and when to seek medical attention.
Liver function should be monitored.
The major side effect of isoniazid, rifampin, and pyrazinamide is nonviral hepatitis. 44

45. Drug Therapy Latent TB infection
Usually treated with INH for 6 to 9 months
HIV patients should take INH for 9 months.
Because a person with LTBI has fewer bacteria, treatment is much easier. Usually, only one drug is needed.
Drug therapy regimens for LTBI are presented in Table
The 9-month regimen is more effective, but compliance issues may make the 6-month regimen preferable.
An alternative 4-month therapy with rifampin may be indicated if the patient is resistant to INH. 45

46. Drug Therapy
Vaccine
Bacille Calmette-Guérin (BCG) vaccine to prevent TB is currently in use in many parts of the world.
In United States, not recommended
Can result in positive PPD reaction 46

47. Nursing Assessment Assess for Productive cough Night sweats
Afternoon temperature elevation
Weight loss
Pleuritic chest pain
Crackles over apices of lungs
If the patient has a productive cough, early morning is the ideal time to collect sputum specimens for an acid-fast bacillus smear. 47

48. Nursing Diagnoses Ineffective breathing pattern
Imbalanced nutrition: Less than body requirements
Noncompliance 48

49. Nursing Diagnoses Ineffective health maintenance Activity intolerance49

50. Planning Goals Comply with therapeutic regimen.
Have no recurrence of disease.
Have normal pulmonary function.
Take appropriate measures to prevent spread of disease. 50

51. Nursing Implementation
Ultimate goal in the United States is eradication.
Selective screening programs in high-risk groups to detect TB
Identify contacts of patient with TB.
The person with a positive tuberculin skin test should have a chest x-ray to assess for the presence of active TB disease. 51

52. Nursing Implementation
Acute intervention
Airborne isolation
Appropriate drug therapy
Immediate medical workup
Medical workup includes chest x-ray, sputum smear, and culture.
Isolation requires a single-occupancy room with negative pressure and airflow of 6 to 12 exchanges per hour. 52

53. Nursing Implementation
Teach patient
Cover nose and mouth with tissue when coughing, sneezing, or producing sputum
Hand washing after handling sputum-soiled tissues
The tissues should be thrown into a paper bag and disposed of with the trash, burned, or flushed down the toilet.
Close contacts of the person with TB should be screened (usually with the TST). If the person has LTBI or active TB disease, he or she should be treated with anti-TB drugs. 53

54. Nursing Implementation
Ambulatory and home care
Ensure that patient can adhere to treatment.
Teach symptoms of recurrence.
Patients who have responded clinically are discharged home (even with positive cultures) if their household contacts have already been exposed and the patient is not posing a risk to susceptible persons.
The public health nurse will be responsible for follow-up on household contacts and assessment of the patient for compliance. If compliance is an issue, the public health agency may be responsible for DOT.
5% of individuals experience relapses. 54

55. Evaluation Expected outcomes Complete resolution of disease
Normal pulmonary function
Absence of any complications
No transmission of TB 55