Allergic bronchopulmonary aspergillosis - CHEST Publications ...

Radiologic Investigations: A wide spectrum of
radiographic appearances can occur in ABPA (Table
4). The chest radiographic findings of ABPA include
transient or fixed pulmonary opacities (Fig 3), tramline
shadows, finger-in-glove opacities, and toothpaste
shadows. 83–87 Findings noted on high-resolution
CT (HRCT) include central bronchiectasis, mucoid
impaction, mosaic attenuation, presence of centrilobular
nodules, and tree-in-bud opacities (Fig
4). 88,89 High-attenuation mucoid impaction (mucus
visually denser than the paraspinal muscle) is a
pathognomonic finding encountered in patients with
ABPA. 23,90–95 Central bronchiectasis with peripheral
tapering of bronchi on HRCT is believed to be a sine
qua non for the diagnosis of ABPA. Bronchiectasis
may not be present in all patients with ABPA, may be
present in patients with CF without ABPA, and
almost 40% of the bronchiectatic segments can also
Table 4—Radiologic Findings Encountered in Patients
With ABPA
1. Chest radiographic findings
Transient changes
Common
Patchy areas of consolidation
Radiologic infiltrates: toothpaste and gloved finger shadows
due to mucoid impaction in dilated bronchi
Collapse: lobar or segmental
Uncommon
Bronchial wall thickening: tramline shadows
Air-fluid levels from dilated central bronchi filled with fluid
Perihilar infiltrates simulating adenopathy
Massive consolidation: unilateral or bilateral
Small nodules
Pleural effusions
Permanent changes
Common
Parallel-line shadows representing bronchial widening
Ring-shadows 1–2 cm in diameter representing dilated
bronchi en face
Pulmonary fibrosis: fibrotic scarred upper lobes with
cavitation
Uncommon
Pleural thickening
Mycetoma formation
Linear scars
2. HRCT findings
Common
Central bronchiectasis
Mucus plugging with bronchoceles
Consolidation
Centrilobular nodules with tree-in-bud opacities
Bronchial wall thickening
Areas of atelectasis
Mosaic perfusion with air trapping on expiration
Uncommon
High-attenuation mucus (finding most helpful in differential
diagnosis)
Pleural involvement
Randomly scattered nodular opacities
have associated peripheral bronchiectasis. 22,96 Minimal
bronchiectasis can also be seen in asthma, 97,98
but the findings of bronchiectasis affecting three or
more lobes, centrilobular nodules, and mucoid impaction
are highly suggestive of ABPA. 99 The uncommon
radiologic manifestations of ABPA include
miliary nodular opacities, 100 perihilar opacities
simulating hilar lymphadenopathy, 84,101,102 pleural
effusions, 103–105 and pulmonary masses. 106–111
Serum Precipitins Against A fumigatus: The precipitating
IgG antibodies are elicited from crude
extracts of A fumigatus and can be demonstrated
using the double gel diffusion technique. 112,113 They
can also be present in other pulmonary disorders and
thus represent supportive not diagnostic evidence for
ABPA. 112–114
Peripheral Eosinophilia: A blood absolute eosinophil
count 1,000 cells/L is also a major criterion
for the diagnosis of ABPA. However, 53% of patients
in our series 22 had an absolute eosinophil count
1,000 cells/L, and thus a low eosinophil count
does not exclude the diagnosis of ABPA.
Sputum Cultures for A fumigatus: Culture of A
fumigatus in the sputum is supportive but not diagnostic
of ABPA. The fungus can also be grown in
patients with other pulmonary diseases due to the
ubiquitous nature of the fungi. We rarely perform
sputum cultures for the diagnosis of ABPA.
Pulmonary Function Tests: These tests help categorize
the severity of the lung disease but have no
diagnostic value in ABPA and need not constitute
the basis for screening. 22 The usual finding is an
obstructive defect of varying severity. 115–117
Role of Specific Aspergillus Antigens: Patients with
ABPA are evaluated with crude extracts from Aspergillus,
which lack reproducibility and consistency,
and they frequently cross-react with other antigens.
118 The advances in molecular techniques have
enabled detection and cloning of specific Aspergillus
antigens. The recombinant allergens Asp f1, Asp f2,
Asp f3, Asp f4, and Asp f6 have been evaluated for
their diagnostic performance in serologic studies in
asthmatic patients 119–122 and in patients with
CF 121,123–125 Preliminary data suggest a promising
role of these antigens in the diagnosis of ABPA.
Further studies are required before they can be
implemented in routine clinical practice.
Diagnosis and Diagnostic Criteria
The Rosenberg-Patterson criteria6,9 are most often
used for the diagnosis (Table 5). There are also a set
810 Global Medicine
Downloaded From: http://jupcvss.chestpubs.org/ on 08/01/2013