Tuberculosis and Lung Abscess COPY Flashcards
Tuberculosis
-Disproportionately among malnourished, homeless, and marginally housed
-compromised- spread rapidly -> progression of early active disease is more frequent
-competent- organisms do not find suitable area to proliferate
-survival in areas of high oxygen content/blood flow
primary pulmonary tuberculosis: AKA Primary TB disease
10%
Clinical illness shortly follows infection = lymphangitic and hematogenous spread before immune system kicks in
Quick spread = MIDDLE and LOWER Lobe MC
Severe cases (5%): Progressive Primary Tuberculosis
- central portion of granuloma undergoes necrosis & cavitation
Primary tuberculosis: AKA TB infection
-90%
-latent
*TB reaching alveoli are ingested by alveolar macrophages and T cells and FORM GRANULOMAS
- CONTAINED AND NOT ERADICATED- LATENT TB
*Within 3-6 weeks host develops immunity to reinfection (+ppd) - BUT CANT ELIMINATE
secondary or reactivation (or postprimary tuberculosis) + which segment of lungs
-more infectious than primary disease due to CAVITATION
-reactivation occurs if hosts immune defenses impaired
-very infectious
APICAL and posterior segments of UPPER lobes (higher o2 in apices)
postprimary disease/reactivation - bad TB
Up to 1/3 of untreated pts die within few weeks- months
- Miliary TB- its everywhere, seed-like appearance
-Others have spontaneous remission or chronic progressively debilitating course (usually)
clinical feature of active TB
Chronic cough MC:
-Dry then productive -> blood streaked
-Slowly progressive: malaise, anorexia, weight loss, fever, and night sweats
-Chest exam:
-No physical findings specific for tuberculosis
approach to TB diagnosis
-clinical suspicion for disease -> risk factors, compatible H and P
- order chest radiograph -> if imaging suggest TB…
- order 3 sputum specimens (8 hrs apart)
-send for culture- will take a long time
Testing for Acid-Fast Bacilli, but does not confirm diagnosis - TST or interferon-gamma release assay (IGRA)
TB: Definitive diagnosis:
Definitive diagnosis:
-M tuberculosis from cultures
- DNA or RNA amplification techniques (PCR)
and:
-Acid-fast bacilli on sputum smear does not confirm a diagnosis -> can also be mycobacterium
-Bronchoscopy
drug susceptibility testing of culture isolates is routine to tailor tx for MDR
-First isolate of M tuberculosis- neg pressure room until AFB sputum smear is neg
-if Treatment regimen is failing -> concern for drug resistance
-Sputum cultures that remain positive after 2 months of therapy -> concern for drug resistance
resolution of active TB CXR
Dense nodules in hila
Upper lobe fibronodular scarring
Bronchiectasis w/ volume loss
Ghon: Calcified primary focus
Ranke Complex: Calcified primary focus and Calcified hilar lymph node
reactivation tuberculosis: radiographic manifestations
Fibrocavitary apical disease
Nodules, and pneumonic infiltrates
Findings typically in apical or posterior segment of upper lobes
tuberculin skin test + criteria
TST: Tuberculin Skin Test
Diagnosis of TB by diameter of induration
Does not distinguish Active vs Latent
QuantiFERON-TB hold in-tube (QFT-GIT) assay
Preferred over TST
- High sensitivity (> 95% for active and 80% for latent)
- Recommended for those who received the BCG vaccine
treatment of tuberculosis in HIV neg person: for primary or reactivation
Phase 1: 2 month course
Rifampin, Isoniazid,, Pyrazinamide, Ethambutol
+ Pyridoxine
Phase 2: Minimum 4 month continued course of Rifampin + Isoniazid + Pyridoxine
Until 3 months after negative TB sputum
Isoniazid has PNS and CNS side effects so Pt must be supplemented with Pyridoxine (B6)
treatment of tuberculosis in HIV + pts
Longer duration of therapy
Must account for drug interactions between rifamycin derivatives
Directly Observed Therapy should be used
tx of drug resistant tuberculosis
-Need expert
-Some experts recommend at least 18– 24 months of a three-drug regimen
tx of extrapulmonary tuberculosis
Same as pulmonary TB, with recommendations of at least 9 months
If skeletal TB = Early surgical drainage and debridement of necrotic bone
Corticosteroid Therapy:
- Prevent cardiac constriction secondary to pericarditis
- Reduce neurologic complications secondary to meningeal TB
before and during tx of TB
-before tx: baseline bilirubin, hepatic enzymes, BUN, creatinine, CBC measured
-Consider Hep B, C, and HIV
-During treatment:
-Monthly questioning for symptoms of drug toxicity (hepatotoxicity)
-Rash, numbness in hands or feet, jaundice, abdominal pain, nausea, vomiting, or anorexia
-MDRTB should have sputum cultures monthly during the entire course of treatment -> check resistance, see if its working
tx of latent tuberculosis
-Essential to controlling and eliminating TB
-Reduces risk it will progress to active disease
-Testing targets high risk groups who stand to benefit from tx of latent infection
-Undergo a careful assessment to exclude active disease
Tx: Rifampin (RIF) daily for 4 months*** (just know this)
lung abscess description
parenchymal necrosis and cavitation secondary to infection
Cause:
-High microorganism burden = MC is anaerobes
-Inadequate microbial clearance from the airways
Aerobic bacteria and opportunistic pathogens MC if immunocompromised
lung abscess risk factors
-Aspiration MC**
-Periodontal disease
-Alcoholism- no gag reflex when passed out
lung abscess presentation + symptoms
-Anaerobic infection: insidious
-Aerobic bacteria: acute and abrupt
Sx:
-Cough, purulent sputum, pleuritic chest pain, fever, and hemoptysis
-bad breath, poor dentition
lung abscess imaging
-Chest radiograph:
-MC: posterior segment of upper lobes and superior segments of lower lobes
-Air-fluid level common:
-laying down aspiration- upper lobe
-standing aspiration- lower lobe
-right lung MC- anatomy
CT of chest:
-Size and location of the abscess
-Evaluate for additional cavities, empyema, infarction pleural disease
-Blood, sputum cultures, +/- pleural fluid cultures
lung abscess dx
-clinical symptoms
-identification of predisposing condition
-chest radiograph/CT findings
lung abscess tx
IV Therapy, then switch to oral
Augmentin OR Clindamycin x several months
Surgery indications:
-Refractory hemoptysis
-Inadequate response to medical therapy
lung abscess prognosis
Higher mortality rates (up to 75% mortality rate):
-Immunocompromised
-Significant comorbidities
-Infection with P. aeruginosa, S. aureus, and K. pneumoniae
