Tuberculosis

notes on tuberculosis

1. TUBERCULOSIS DR.VINOLI.S.G PROFESSOR& HOD MEDICAL SURGICAL NURSING DEPARTMENT UNIVERSAL COLLEGE OF NURSING, BANGALORE

2. Definition Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. It primarily affects the lung parenchyma. It also may be transmitted to other parts of the body, including the meninges , kidneys, bones, and lymph nodes.

3. Incidence TB is a primary cause of death worldwide from a potentially curable infectious disease. It is the leading cause of mortality in patients with HIV infection. Worldwide, more than two billion people (one third of the population) are currently infected with TB TB is a worldwide public health problem that is closely associated with poverty, malnutrition, overcrowding, substandard housing, and inadequate health care

4. According to the WHO, an estimated 1.6 million deaths resulted from TB in 2005 (WHO, 2007). In the United States, almost 15,000 cases of TB are reported annually to the CDC (2005a).

5. Transmission TB spreads from person to person by airborne transmission. An infected person releases droplet nuclei (usually particles 1 to 5 micro meters in diameter) through talking, coughing, sneezing, laughing, or singing. Larger droplets settle; smaller droplets remain suspended in the air and are inhaled by a susceptible person.

6. Risk factors Close contact with someone who has active TB. Immuno compromised patients Substance abuse (IV or injection drug users and alcoholics) Any person without adequate health care Preexisting medical conditions or special treatment ( eg , diabetes, chronic renal failure, malnourishment, selected malignancies, hemodialysis , transplanted organ, gastrectomy , or jejunoileal bypass)

7. Immigration from countries with a high prevalence of TB Institutionalization ( eg , long-term care facilities, psychiatric institutions, prisons) Living in overcrowded, substandard housing Being a health care worker performing high-risk activities

8. Pathophysiology

9. A susceptible person inhales mycobacterium bacilli and becomes infected. The bacteria are transmitted through the airways to the alveoli, where they are deposited and begin to multiply. The bacilli also are transported via the lymph system and bloodstream to other parts of the body (kidneys, bones, cerebral cortex) and other areas of the lungs (upper lobes). The body’s immune system responds by initiating an inflammatory reaction. .

10. Phagocytes ( neutrophils and macrophages) engulf many of the bacteria, and TB-specific lymphocytes lyse (destroy) the bacilli and normal tissue. This tissue reaction results in the accumulation of exudate in the alveoli, causing bronchopneumonia. The initial infection usually occurs 2 to 10 weeks after exposure Granulomas , new tissue masses of live and dead bacilli, are surrounded by macrophages, which form a protective wall around the granulomas . Granulomas are then transformed to a fibrous tissue mass, the central portion of which is called a Ghon tubercle.

11. The material (bacteria and macrophages) becomes necrotic, forming a cheesy mass. This mass may become calcified and form a collagenous scar. At this point, the bacteria become dormant, and there is no further progression of active disease

12. Active disease also may occur with reinfection and activation of dormant bacteria. In this case, the Ghon tubercle ulcerates, releasing the cheesy material into the bronchi. The bacteria then become airborne, resulting in further spread of the disease. Then the ulcerated tubercle heals and forms scar tissue. This causes the infected lung to become more inflamed, resulting in further development of bronchopneumonia and tubercle formation.

13. Classification TB can also be classified according to its (1) presentation (primary, latent, or reactivated) and (2) whether it is pulmonary or extrapulmonary . Primary infection occurs when the bacteria are inhaled and initiate an inflammatory reaction Latent TB infection (LTBI) occurs in a person who does not have active TB disease. These individuals are asymptomatic and cannot transmit the TB bacteria to others

14. If the initial immune response is not adequate, the body cannot contain the organisms, the bacteria replicate, and active TB disease results. When active disease develops within the first 2 years of infection, it is termed primary TB . Post primary TB, or reactivation TB , is defined as TB disease occurring 2 or more years after the initial infection.

15. CLASSIFICATION OF TUBERCULOSIS (TB)

16. Class Exposure or Infection Description No TB exposure No TB exposure, not infected (no history of exposure, negative tuberculin skin test) 1 TB exposure, no infection TB exposure, no evidence of infection (history of exposure, negative tuberculin skin test) 2 Latent TB infection, no disease TB infection without disease (significant reaction to tuberculin skin test, negative bacteriologic studies, no x-ray findings compatible with TB, no clinical evidence of TB) 3 TB, clinically active TB infection with clinically active disease (positive bacteriologic studies or both a significant reaction to tuberculin skin test and clinical or x-ray evidence of current disease) 4 TB, but not clinically active No current disease (history of previous episode of TB or abnormal, stable x-ray findings in a person with a significant reaction to tuberculin skin test; negative bacteriologic studies if done; no clinical or x-ray evidence of current disease) 5 TB suspect TB suspect (diagnosis pending); person should not be in this classification for >3 mo

17. LATENT TUBERCULOSIS (TB) INFECTION COMPARED WITH TB DISEASE

18. Latent TB Infection TB Disease Has no symptoms Has symptoms that may include the following: • Bad cough that lasts ≥3 wk • Pain in the chest • Coughing up blood or sputum • Weakness or fatigue • Weight loss • No appetite • Chills • Fever • Sweating at night Does not feel sick Usually feels sick Cannot spread TB bacteria to others May spread TB bacteria to others Usually has a skin test or blood test result indicating TB infection Usually has a skin test or blood test result indicating TB infection Has a normal chest x-ray and a negative sputum smear May have an abnormal chest x-ray or positive sputum smear or culture Needs treatment for latent TB infection to prevent active TB disease Needs treatment for active TB disease

19. Clinical Manifestations Symptoms of pulmonary TB usually do not develop until 2 to 3 weeks after infection or reactivation. The characteristic pulmonary manifestation is an initial dry cough that frequently becomes productive with mucoid or mucopurulent sputum. fatigue, malaise, anorexia, unexplained weight loss, low-grade fevers, and night sweats.

20. Dyspnea is a late symptom that may signify considerable pulmonary disease or a pleural effusion. Hemoptysis , which occurs in less than 10% of patients with TB, is also a late symptom Auscultation of the lungs may be normal or reveal crackles, rhonchi , and/or bronchial breath sounds

21. Complications Miliary TB is the widespread dissemination of the mycobacterium. The bacteria are spread via the bloodstream to distant organs. Pleural TB can result from either primary disease or reactivation of a latent infection. A pleural effusion Acute pneumonia

22. Diagnostic evaluation A complete history, physical examination, tuberculin skin test, acid-fast bacillus smear contains mycobacterium sputum culture are used to diagnose TB. the chest x-ray usually reveals lesions in the upper lobes Interferon-γ Release Assays

23. TUBERCULIN SKIN TEST The Mantoux test is used to determine if a person has been infected with the TB bacillus. Tubercle bacillus extract (tuberculin), purified protein derivative (PPD), is injected into the intradermal layer of the inner aspect of the forearm, approximately 4 inches below the elbow . Then 0.1 mL of PPD is injected, creating an elevation in the skin, a wheal or bleb. The site, antigen name, strength, lot number, date, and time of the test are recorded. The test result is read 48 to 72 hours after injection. A reaction occurs when both induration and erythema (redness) are noted. The diameter of the induration (not erythema ) is measured in millimeters at its widest part, and the size of the induration is documented. Erythema without induration is not considered significant.

24. A reaction of 0 to 4 mm is considered not significant; a reaction of 5 mm or greater may be significant in individuals who are considered at risk. (HIV patients) An induration of 10 mm or greater is usually considered significant in individuals who have normal or mildly impaired immunity.

25. Interferon-γ Release Assays Interferon-γ (INF-γ) release assays (IGRAs) provide another screening tool for TB. These whole blood assays detect INF-γ released from T lymphocytes in response to mycobacterial antigens. Examples of IGRAs include QuantiFERON -TB test and the T-SPOT. TB test . Test results are available in a few hours.

26. Management Most patients with TB are treated on an outpatient basis Many people can continue to work and maintain their lifestyles with few changes. Patients with sputum smear–positive TB are generally considered infectious for the first 2 weeks after starting treatment. Advise these patients to restrict visitors and avoid travel on public transportation and trips to public places. Hospitalization may be needed for the severely ill or debilitated.

27. Pulmonary TB is treated primarily with chemotherapeutic agents ( antituberculosis agents) for 6 to 12 months. A prolonged treatment duration is necessary to ensure eradication of the organisms and to prevent relapse.

28. First-Line Antitubercular Medications COMMONLY USED AGENTS ADULT DAILY DOSAGE* isoniazid (INH) 5 mg/kg (300 mg maximum daily) rifampin ( Rifadin ) 10 mg/kg (600 mg maximum daily) Rifabutin ( Mycobutin ) 5 mg/kg (300 mg maximum daily) streptomycin 15 mg/kg (1 g maximum daily)* pyrazinamide 15 to 30 mg/kg (2.0 g maximum daily)* ethambutol ( Myambutol ) 15 to 25 mg/kg (no maximum daily dose, but base on lean body wt)* Combinations: INH + rifampin ( eg , Rifamate ) 150-mg & 300-mg caps (2 caps daily)

29. Vitamin B (pyridoxine) is usually administered with INH to prevent INH-associated peripheral neuropathy INH also may be used as a prophylactic (preventive) measure for those at risk for significant disease, Prophylactic INH treatment involves taking daily doses for 6 to 12 months. Liver enzyme, blood urea nitrogen, and creatinine levels are monitored monthly. Sputum culture results are monitored for acid-fast bacillus to evaluate the effectiveness of treatment and the patient’s compliance with therapy.

30. DRUG THERAPY Tuberculosis Disease Regimens Initial Phase Continuation Phase Option 1 4-drug regimen consisting of INH, rifampin , pyrazinamide , ethambutol Given daily for 56 doses (8 wk) OR 5 days/wk DOT for 40 doses (8 wk) INH, rifampin daily for 126 doses (18 wk) OR 5 days/wk DOT for 90 doses (18 wk) Option 2 4-drug regimen consisting of INH, rifampin , pyrazinamide , ethambutol Given daily for 14 doses (2 wk), followed by twice weekly for 12 doses (6 wk) OR 5 days/wk DOT for 10 doses (2 wk), then twice weekly for 12 doses (6 wk) INH, rifampin twice weekly for 36 doses (18 wk) OR once weekly for 18 doses (18 wk)

31. Initial Phase Continuation Phase Option 3 4-drug regimen consisting of INH, rifampin , pyrazinamide , ethambutol Given 3 times weekly for 24 doses (8 wk) INH, rifampin 3 times weekly for 54 doses (18 wk) Option 4 3-drug regimen consisting of INH, rifampin , ethambutol Given daily for 56 doses (8 wk) OR 5 days/wk DOT for 40 doses (8 wk) INH, rifampin daily for 217 doses (31 wk) OR 5 days/wk DOT for 155 doses (31 wk) OR twice weekly for 62 doses (31 wk)

32. Latent Tuberculosis Infection Regimens Drugs Duration Interval Minimum Doses isoniazid 9 mo Daily Twice weekly* 270 76 isoniazid 6 mo Daily Twice weekly* 180 52 isoniazid and rifapentine 3 mo Once weekly* 12 rifampin 4 mo Daily 120

33. Directly observed therapy (DOT) Directly observed therapy (DOT) involves providing the anti tuberculous drugs directly to patients and watching as they swallow the medications. It is the preferred strategy for all patients with TB to ensure adherence and is recommended for all patients at risk for non adherence. The risk for reactivation of TB and MDR-TB is increased in patients who do not complete the full course of therapy.

34. Nursing Assessment Obtain history of exposure to TB. Assess for symptoms of active disease productive cough, night sweats, afternoon temperature elevation, unintentional weight loss, pleuritic chest pain. Auscultate lungs for crackles. During drug therapy, assess for liver dysfunction. Question the patient about loss of appetite, fatigue, joint pain, fever, tenderness in liver region, clay-colored stools, and dark urine. Monitor for fever, right upper quadrant abdominal tenderness, nausea, vomiting, rash, and persistent paresthesia of hands and feet. Monitor results of periodic liver function studies.

35. NURSING DIAGNOSES Ineffective breathing pattern related to decreased lung capacity Ineffective airway clearance related to increased secretions, fatigue, and decreased lung capacity Activity intolerance related to fatigue, altered nutritional status, and fever Imbalanced Nutrition: Less Than Body Requirements related to poor appetite, fatigue, and productive cough Noncompliance related to lack of knowledge of disease process, lack of motivation, long-term nature of treatment, and lack of resources Ineffective self-health management related to lack of knowledge about the disease process and therapeutic regimen Risk for Infection related to nature of the disease and patient's symptoms

36. Patient Education and Health Maintenance Review possible complications: hemorrhage, pleurisy, symptoms of recurrence (persistent cough, fever, or hemoptysis ). Instruct patient on avoidance of job-related exposure to excessive amounts of silicone (working in foundry, rock quarry, sand blasting), which increases risk of reactivation.

37. Encourage patient to report at specified intervals for bacteriologic (smear) examination of sputum to monitor therapeutic response and compliance. Instruct patient in basic hygiene practices and investigate living conditions. Crowded, poorly ventilated conditions contribute to development and spread of TB.

38. Encourage regular symptom screening and follow-up chest X-rays for rest of life to evaluate for recurrence. Instruct patient on prophylaxis with isoniazid for people infected with the tubercle bacillus without active disease to prevent disease from occurring, or to people at high risk of becoming infected. Educate asymptomatic people about PPD testing and treatment of latent TB for positive results, based on risk grouping.

39. Thank you