Pulmonary Tuberculosis (PDF)

Pulmonary Tuberculosis Dr. Mohamed Elmutasim Microbiology Department Oct. 18. 2022 What is TB? TB is a bacteria (single-cell organism) More specifically, it is a type of mycobacteria “myco” means waxy in latin and refers to TB’s waxy...

Pulmonary Tuberculosis Dr. Mohamed Elmutasim Microbiology Department Oct. 18. 2022 What is TB? TB is a bacteria (single-cell organism) More specifically, it is a type of mycobacteria “myco” means waxy in latin and refers to TB’s waxy cell wall There are 70 different types of mycobacteria The scientific name for the TB microbe is Mycobacterium tuberculosis or M.TB What is TB? Beneath a microscope, it has a long rod-like shape or ‘bacillus’ The thick waxy cell wall allows the germ to spread through the air in water droplets What is TB? How is TB transmitted? TB is transmitted through the air TB bacteria are coughed up from the lungs of an infected person into the air Once the TB bacteria are inhaled, they push their way into the lungs TB Infection and Disease Transmission of TB Droplet nuclei containing mycobacteria inhaled Not all TB infections lead to TB disease Latent TB infection (aka LTBI) occurs when the immune system has contains TB and prevents disease. Active TB disease refers to the time when TB breaks out and causes disease. TB Definitions Latent TB infection (LTBI) TB bacilli live dormant inside the lung, but do not cause destruction of organs No signs or symptoms of disease Not infectious TB disease TB bacilli progressively invade and damage a part(s) of the body Signs and symptoms of disease appear Can be infectious What is the risk of LBTI progressing to active disease? In HIV-negative persons, the body’s immune system usually keeps TB infection under control. Only 5-10% of LTBI cases progress to active TB during their lifetime. People living with HIV with LTBI have a 5-10% risk of developing TB disease each year. TB Disease The TB germ can "wake up" at any time (usually within 1-2 years) and make a person sick More likely to get TB disease when a persons body is weakened from: HIV Diabetes Poor Nutrition Cancer medications Steroids Drug use Smoking Old Age What happens during active TB disease? Active TB disease may occur in the lungs (pulmonary TB) and/or in other parts of the body (extrapulmonary TB). Pulmonary TB is the most common form of TB disease and is the infectious form The damage caused by pulmonary TB sends pus containing TB bacilli into the lungs, which a person with TB may cough up in spit or sputum Extrapulmonary TB is normally rare but occurs in up to 40% of TB cases among people living with HIV Definitions: Patients with TB Pulmonary TB (PTB) -Disease involves the lung tissue -Smear-positive: visible TB bacilli in sputum, very infectious -Smear-negative: no visible TB bacilli in sputum, less Infectious Extra-pulmonary TB (EPTB) -Disease involving an organ other than the lung, includes pleural TB -Not infectious unless also have pulmonary TB What are symptoms of TB disease? Due to general infection and immune response Fever Night sweats Weight loss Due to direct damage Pulmonary TB Cough Sputum – white, grey, green, red Extrapulmonary Just about anything…..depending on site People living with HIV develop symptoms late and are less likely to present with coughing. PULMONARY TUBERCULOSIS PULMONARY TUBERCULOSIS ASSESSMENT AND DIAGNOSTIC FINDINGS Biopsy of the affected tissue (rare) Bronchoscopy Chest CT scan and Chest x-ray Tuberculin test Interferon-gamma blood test such as the QFT-Gold test to test for TB infection Sputum examination and cultures Thoracentesis Acid fast stain (ZN stain) Tuberculin test PPD- Mantoux Tuberculin test. The PPD (purified protein derivative) tuberculoprotein was injected intradermally at this site 48 hours previously. The erythema and induration (>10 mm) that are present indicate the development of delayed-type (type IV) hypersensitivity. (Reproduced with permission from Nester EW: Microbiology: A Human Perspective, 6 thedition. 2009.) Culture of TB Tuberculosis Case definition TB case - A patient in whom tuberculosis has been confirmed by bacteriology or diagnosed by a clinician. Smear positive pulmonary TB case - A patient with one or more positive sputum smear examinations (direct smear microscopy) AFB+. Smear negative pulmonary TB case – A patient with two sputum smear examinations negative for AFB; X ray suggests TB, unresponsive to a course of broad-spectrum antibiotics (except in a patient with strong clinical evidence of HIV infection); and a decision by a clinician to treat with anti tuberculosis chemotherapy; or positive culture but negative AFB sputum examinations. Extrapulmonary TB case - one culture-positive specimen, or histological or strong clinical evidence. Followed by decision by a clinician to treat with a full course of anti-tuberculosis chemotherapy Important note for Diagnosis of TB Early detection and treatment is the priority, especially for people living with HIV. Anybody with symptoms suggestive of TB should be investigated. Close contacts of TB patients should also be checked by health staff Active versus passive case finding Treatment TB is treatable and curable, even in people living with HIV Treatment Divided into two phases: Intensive phase (all 4 drugs) for 2-3 months depending on if the patient has been treated before. Continuation phase (rifampicin and isoniazid) for 4-6 months, depending on whether you have been treated before. Treatment The Aims of anti-TB Treatment To cure the patient of TB To prevent death from active TB or its late effects To prevent TB relapse or recurrent disease To prevent the development of drug resistance To decrease TB transmission to others. Treatment Support for: Essential for: -Monitoring side effects - Encouraging the patient to keep taking treatment - Provision of extra care needed (psycho-social) Prevention of Tuberculosis 1. Early diagnosis and prompt effective treatment of infectious cases 2. Good infection control 3. Isoniazid preventive therapy 4. Other factors better housing, nutrition, alcohol reduction…. Isoniazid Preventive Therapy Isoniazid treatment for 6 months given to PLHIV can reduce by 40-60% The effect is more pronounced in people with a positive Tuberculin test. Screening for TB is needed first to exclude active disease. Prevention of TB Infection Control 1. Involve patients & community in advocacy Campaigns 2. Infection control plan 3. Safe sputum collection 4. Cough etiquette and cough hygiene 5. Triage TB suspects to fast tract or separation Infection Control 6. Rapid TB diagnosis and Treatment 7. Improve room air Ventilation 8. Protect health care workers (Screen, IPT) 9. Capacity building 10. Monitor infection control practices. Thank You