Pulmonary Flashcards
Allergic Bronchopulmonary Aspergillosis (ABPA)
Path
Prevalence
Path:
- Aspergillus fumigatus-> 80% of clinical infections
- Lung disease from hypersensitivity to aspergillus species caused by impaired mucociliary clearance, mucoid impaction, and airway obstruction
- Maybe due to increased use of antibiotics for infective exacerbations promoting the growth of fungal infections
Prevalence: 6-25% in CF patients; 1-8% in asthmatics Increased in: -Children >6y/o -Adolescents -Pts w/ decreased lung function -Chronic infection w/ (positive association of ABPA and P aeruginosa and S maltophilia) **P aeruginosa **Burkholderia cepacia **Stenotrophomonas **Candida albicans
Fungal pulmonary infection suspected for:
- CF, asthma
- Pre-existing lung cavities
- Severely immunocompromised
CF, asthma: Allergic bronchopulmonary aspergillosis
Pre-existing lung cavities:
- Aspergilloma
- Chronic necrotizing aspergillosis
Severely immunocompromised: Invasive aspergillosis
ABPA Sx and PE
Sx: worsening/new onset wheeze, dyspnea, fevers, chest pain, cough, hemoptysis, malaise, expectoration of brown/black mucous plugs, can be asx
High suspicion if pt fails to respond to IV abx for chest sx
PE: normal-non-specific: wheezes/crackles
ABPA Staging
Stage 1 (acute stage):
- acute wheeze, reversible airway obstruction
- markedly elevated IgE
- peripheral eosinophilia
- IgE and IgG to A fumigatus
- pulmonary infiltrates
Stage 2 (remission stage):
- decrease in IgE but NOT to normal
- Absence of eosinophilia
- Resolution of pulmonary infiltrates
Stage 3 (exacerbation stage): -Pts with known ABPA, similar to stage 1
Stage 4 (corticosteroid-dependent stage): -Steroid dependent, attempt to reduce/stop steroids leads to worsening ABPA w/ evidence of central bronchiectasis on CT
Stage 5 (fibrotic stage):
- Ends stage respiratory failure
- Serum IgE high/low
- Eosinophil count high/low
Screening for ABPA
High level of suspicion for ABPA in pts >6y/o
Measure serum IgE annually
- > 500 IU/ml: determine immediate cutaneous reactivity to A fumigatus and consider diagnosis
- 200-500 IU/ml: repeat IgE level and perform further diagnostic tests
ABPA Dx
Acute/subacute clinical deterioration
Serum total IgE > 1,000 IU/ml (major criteria for dx ABPA)
-RAST testing or Immediate cutaneous reactivity to A fumigatus >3mm or raised specific IgE to A fumigatus
Precipitating IgG antibodies to A fumigatus
Blood eosinophil count (Maybe present in CF due to chronic P aeruginosa infection rather than ABPA; may represent previous exposure rather than current disease)
New/recent changes on CXR/chest CT
`CXR:
-Transient-persistent pulmonary infiltrations in upper/mid lobes
-Clearing of infiltrates, partially/completely w/ oral steroids maybe suggestive of ABPA
Chest CT:
-Central bronchiectasis hallmark of ABPA (vs cylindrical bronchiectasis more common in CF)
-Varicose and cystic bronchiectasis typical in ABPA
-Single or multiple nodules with/without cavitation, patchy or segmental consolidation, peribronchial infiltrates with/without tree in bud patterns
Mere presence of A fumigatus isolated in sputum of CF is NOT associated with ABPA (seen in 9-57% of CF pts) or with worsening lung function
Marker used for ABPA exacerbation or measure response to therapy
A fumigatus serum total IgE
ABPA cutaneous reactivity testing False + False - Sensitivity Specificity
False +: Pts with severe eczema
False -: Taking antihistamines 24-48 hrs
High sensitivity-> absence of reaction reduces likelihood of ABPA (rule out ABPA)
Moderately low specificity (23-28% asthmatics; 29% CF)-> will have + skin test without ABPA (false positive)
RAST testing preferred over skin testing
ABPA Tx
Steroids (1st line)
- 2 weeks of daily oral prednisone (1-2mg/kg) followed by gradual tapering with duration of tx of at least 3 months
- Has been recommended for new ABPA infiltrates
Monitor serum IgE levels
- useful parameter of disease control
- Reduction of 30-50% is expected w/ commencement of therapy
Antifungal therapy
- Itraconazole (1st line), broad spectrum
- Voriconazole: newer drug, better tolerance and bioavailability
Obstructive disease Path: Dz: Flow Volume Loop: PFT:
Path: limits expiration
Dz:
- Asthma
- Bronchiectasis
- CF
Flow Volume Loop:
- Scooped flow volume loop
- Inc TLC, RV
- Dec/normal VC
PFT:
FEV1: Dec
FVC: Dec/normal
FEV1/FVC: Dec
Restrictive disease Path: Dz: Flow Volume Loop: PFT:
Path: limits inspiration
Dz:
- Neuromuscular disease
- Scoliosis
- Interstitial lung disease
- Obesity
Flow Volume Loop:
- Small
- Dec TLC, RV, and VC
PFT:
FEV1: Dec/normal
FVC: Dec
FEV1/FVC: Normal/Inc
Name the lung volumes
Inspiratory reserve volume (IRV)
Tidal volume (Vt)
Expiratory reserve volume (ERV)
Residual volume (RV)
Define vital capacity
Functional residual capacity
IRV + Vt + ERV
Total volume of air that can be exhaled after maximum inspiration
Define FRC
ERV + RV
Amount of air remaining in lungs after normal expiration
Define FVC
Forced vital capacity
Amount of air exhaled forcefully and quickly after maximum inspiration
