Tuberculosis and Lung Abscess COPY

Question 1

Tuberculosis

Answer 1

-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

Question 2

primary pulmonary tuberculosis: AKA Primary TB disease

Answer 2

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

Question 3

Primary tuberculosis: AKA TB infection

Answer 3

-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

Question 4

secondary or reactivation (or postprimary tuberculosis) + which segment of lungs

Answer 4

-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)

Question 5

postprimary disease/reactivation - bad TB

Answer 5

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)

Question 6

clinical feature of active TB

Answer 6

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

Question 7

approach to TB diagnosis

Answer 7

-clinical suspicion for disease -> risk factors, compatible H and P

1. order chest radiograph -> if imaging suggest TB…
2. 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
3. TST or interferon-gamma release assay (IGRA)

Question 8

TB: Definitive diagnosis:

Answer 8

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

Question 9

drug susceptibility testing of culture isolates is routine to tailor tx for MDR

Answer 9

-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

Question 10

resolution of active TB CXR

Answer 10

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

Question 11

reactivation tuberculosis: radiographic manifestations

Answer 11

Fibrocavitary apical disease
Nodules, and pneumonic infiltrates
Findings typically in apical or posterior segment of upper lobes

Question 12

tuberculin skin test + criteria

Answer 12

TST: Tuberculin Skin Test
Diagnosis of TB by diameter of induration
Does not distinguish Active vs Latent

Question 13

QuantiFERON-TB hold in-tube (QFT-GIT) assay

Answer 13

Preferred over TST
- High sensitivity (> 95% for active and 80% for latent)
- Recommended for those who received the BCG vaccine

Question 14

treatment of tuberculosis in HIV neg person: for primary or reactivation

Answer 14

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)

Question 15

treatment of tuberculosis in HIV + pts

Answer 15

Longer duration of therapy
Must account for drug interactions between rifamycin derivatives
Directly Observed Therapy should be used

Question 16

tx of drug resistant tuberculosis

Answer 16

-Need expert
-Some experts recommend at least 18– 24 months of a three-drug regimen

Question 17

tx of extrapulmonary tuberculosis

Answer 17

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

Question 18

before and during tx of TB

Answer 18

-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

Question 19

tx of latent tuberculosis

Answer 19

-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)

Question 20

lung abscess description

Answer 20

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

Question 21

lung abscess risk factors

Answer 21

-Aspiration MC**
-Periodontal disease
-Alcoholism- no gag reflex when passed out

Question 22

lung abscess presentation + symptoms

Answer 22

-Anaerobic infection: insidious
-Aerobic bacteria: acute and abrupt

Sx:
-Cough, purulent sputum, pleuritic chest pain, fever, and hemoptysis
-bad breath, poor dentition

Question 23

lung abscess imaging

Answer 23

-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

Question 24

lung abscess dx

Answer 24

-clinical symptoms
-identification of predisposing condition
-chest radiograph/CT findings

Question 25

lung abscess tx

Answer 25

IV Therapy, then switch to oral
Augmentin OR Clindamycin x several months

Surgery indications:
-Refractory hemoptysis
-Inadequate response to medical therapy

Question 26

lung abscess prognosis

Answer 26

Higher mortality rates (up to 75% mortality rate):
-Immunocompromised
-Significant comorbidities
-Infection with P. aeruginosa, S. aureus, and K. pneumoniae