Tuberculosis Overview, Pathophysiology & Etiology PDF

Chronic infectious disease Recurrent Caused by mycobacterium tuberculosis Tuberculosis- Slender, rod-shaped organism- bacilli Waxy outer capsule resists destruction Overview, Slow growing 2-12 weeks to i...

Chronic infectious disease Recurrent Caused by mycobacterium tuberculosis Tuberculosis- Slender, rod-shaped organism- bacilli Waxy outer capsule resists destruction Overview, Slow growing 2-12 weeks to illicit an immune response pathophysiology Acid-fast bacilli (AFB) & Etiology Primary site for infection- lungs (can “seed” into other organs) REPORTABLE DISEASE! Public health concern Epidemiology- Active Tuberculosis Cases in Ohio: 2019 ¬ Not very common! ¬ Lake= 0 cases (same) ¬ Cuyahoga= 25 cases (+6) ¬ Summit= 8 cases (-6) ¬ Geauga= 1 case (+1) ¬ Ashtabula= 0 cases (same) ¬ Ohio: 2018 cases= 178, 2019 cases= 150 (-28) ¬ Foreign-born TB Cases= 103 (68.7%) Pathophysiology & Etiology ¬ Caused by Mycobacterium tuberculosis ¬ Aerosolization of the bacilli enters the lung, implants into an alveolus or respiratory bronchiole, multiples and initiates an inflammatory response. ¬ Phagocytic cells (neutrophils and macrophages) engulf the bacteria, isolating, preventing the spread. ¬ A granulomatous lesion is called a tubercle is formed. ¬ After 2-12 weeks, a cellular immune response can be elicited with a TB skin test.  If you have an adequate immune response, scar tissue will form around the tubercle and bacteria will remain enclosed. J Dormant (Latent) TB Bacteria temporarily inactive, but not dead Pathophysiology Individual infected, but not sick and no symptoms & Etiology If you have an inadequate immune response, the tubercle may rupture and spread the bacteria. L Active TB Unable to encapsulate the tubercle Infectious Severe disease—erosion/cavitation of lung tissue  Active TB Exposed & Infectious Shows clinical manifestations Unable to encapsule the tubercle Dormant (Latent) TB Exposed & noninfectious Classifications No clinical manifestations Strong Immune system Reactivation TB You have latent TB but becomes active later in life due to weaken immune system Due to age, disease (HIV, immunosuppressive diseases), or use of immunosuppressive drugs  Immigrants, foreign-born (in the U.S.) HIV/AIDS Individuals with altered immune function Risk Factors Homelessness, homeless shelters Prison, detention facilities Overcrowded institutions, poor living conditions  Asymptomatic in early stages, initial infection Fever (typically low grade) Night sweats Clinical Dry cough, progressing to hemoptysis (blood-tinged sputum) Manifestations Weight loss Fatigue Cough, pleuritic chest pain Dyspnea (shortness of breath) Prevention and Diagnostic Tests ¬ PPD Skin Test, TST, Mantoux test ¬ Intradermal- read 48-72 hours ¬ Measure INDURATION ¬ >15mm is positive in ALL people ¬ Redness NOT indicative of positive test Prevention and Diagnostic Tests ¬ A positive TB test does not indicate active disease ¬ Sputum and chest x-rays are routinely used ¬ Special procedures and PPE should be used when obtaining sputum specimen ¬ Occasionally, endotracheal suctioning, bronchoscopy, or gastric lavage is necessary to obtain a specimen  Sputum smearà AFB positive (active TB) Prevention Rapid indicator of the tubercle bacillus At least 3 specimens needed, 8-24 and hours apart One sputum should be an early Diagnostic morning specimen Sputum Cultureà confirmatory Tests diagnosis of infection with M. tuberculosis Time consuming: 4-8 weeks for detection (slow growing) Collaboration: Diagnostic Tests ¬ Chest X-Ray ¬ Dense lesions (apical, upper lobe), cavity formation ¬ Interferon-gamma release assays (IGRA) ¬ “QuantiFERON-TB test” or “T-Spot test” ¬ Can be used on those who have received the tuberculosis vaccine ¬ Used for those unable to return to have TST read ¬ Nucleic Acid Amplification (NAA) ¬ Amplifies DNA/RNA segments to rapidly identify the microorganisms in a specimen ¬ Can detect M. tuberculosis in hours **CULTURE remains GOLD STANDARD for laboratory confirmation of tuberculosis**  Provide Spread patient and through the family air- person to education person Collaboration: TB transmission reduced by Airborne isolation- “negative Prevention & direct sunlight/ pressure”; ultraviolet light HEPA filter Precautions Place mask on patient if leaving room N95 masks Keep patient door closed Collaboration: Pharmacologic Therapy ¬ Antibiotics are used to prevent and treat tuberculosis infection ¬ Goals of the pharmacologic treatment of tuberculosis are the following: 1. To make the disease noncommunicable to others 2. To reduce symptoms of the disease 3. To effect a cure in the shortest possible time  Collaboration: Pharmacologic Therapy Isoniazid Rifampin Ethambutol Pyrazinamide A first-line drug for Inhibits RNA Bacteriostatic drug Inferences with treating ACTIVE TB. syntheses which that reduces the bacteria's ability to Helps eradicate prevents bacteria development of synthesis fatty acids dormant tuberculosis from forming resistance to the Can causes bacilli Used in combination bactericidal fist-line hepatotoxicity Can causes peripheral with isoniazid due to agent. neuropathy (Vitamin resists develops Inhibits RNA B-6 & pyridoxine can rapidly syntheses help) Can causes body Can causes optic fluids to turn red neuritis (sweat, urine, saliva, tears) Collaboration: Pharmacologic Therapy ACTIVE TB First 2 months: rifampin, isoniazid, ethambutol, pyrazinamide, rifabutin, and rifapentine After 2 months for at least additional 4-6 months: rifampin and isoniazid Longer for patients with underlying HIV, usually 9 months Increase compliance: Rifatar: combination drug (rifampin, isoniazid & pyrazinamide) Directly Observed Therapy (DOT) Collaboration: Pharmacologic Therapy LATENT TB ¬ Isoniazid—for 6-9 months ¬ Rifampin for 4 months if indicated ¬ Monitoring/surveillance for manifestations  Clinical improvement has been demonstrated Collaboration: TB No Longer Considered On medications for at least 2 weeks Infectious When: Three (3) consecutive AFB smears are negative  Ineffective breathing pattern Ineffective airway clearance Common TB nursing Activity intolerance, fatigue Diagnoses Imbalanced nutrition, less than body requirements Ineffective health maintenance, noncompliance