Larry w. Tsai
Chest Conference May 1, 2001
BRONCHOSCOPY
IN HYPERSENSITIVITY PNEUMONITIS
Diagnostic
criteria 4 Major, 2 Minor
1. Major
a. Symptoms compatible with HP- fever,
dyspnea, myalgia cough 2-9 hrs after exposure
b. Evidence of appropriate antigen
exposure by history, serum, or HAL antibodies
c. CT or CXR findings compatible with HP-
usually small centrilobular nodules .
d. BAL lymphocytosis
e. Histologic changes consistent with
HP f. Positive "natural challenge"
1. Minor
a. Bibasilar rales
b. Decreased diffusing capacity
c. Arterial hypoxemia at rest or with exercise
BAL
findings Supportive
1. Cell counts
a. Acute disease- neutrophils elevated (20-30%)
b. Chronic disease-lymphocytes elevated (60-
70%) with normal or decreased CD4:CD8 ratio
c. Lymphocytosis may persist after
symptoms have resolved but eventually seems to normalize
1. Immunoglobulin levels- IgG, IgM, IgA may
be elevated, antibodies to specific antigens may be detected
3. van den Hosch et al, 1986
a. 6 healthy volunteers, 10 sarcoid patients, 15
acute HP patients underwent BAL
b. HP patients had follow-up BALs over
subsequent 2 yrs
Table I. Yield, number and differentiation of cells in
BAL. performed in healthy volunteers ('normals'), palients with sarcoidosis and
patients with EAA on several occasions during the course of the disease (mean
+/- SEM values)
|
|
Normals |
Sarcoidosis |
EAA |
|
|
|
|
|
|
|
|
acute |
2-7days |
8-30
days |
2-12
mos |
12-24
mos |
|
Yield % |
67
+/- 4 |
61
+/1 3 |
41
+/- 4 |
46
+/1 4 |
50
+/- 5 |
52
+/- 4 |
59
+/- 9 |
|
Cells x 106 |
14
+/- 4 |
27
+/1 3 |
24
+/- 5 |
45
+/- 8 |
24
+/- 7 |
36
+/- 9 |
27
+/- 10 |
|
Macrophages % |
87
+/- 2 |
48
+/1 5 |
28
+/- 2 |
30
+/- 5 |
30
+/- 5 |
45
+/- 5 |
87
+/- 4 |
|
Lymphocytes % |
11
+/- 2 |
49
+/- 5 |
43
+/- 6 |
66
+/- 3 |
66
+/- 4 |
52
+/- 5 |
12
+/- 4 |
|
Neutrophils % |
<
1 |
2
+/- 1 |
26
+/- 6 |
3
+/- 1 |
1
+/- 0.2 |
2
+/- 0.3 |
<
1 |
|
Eosinophils % |
<
1 |
<
1 |
4
+/- 1 |
2
+/- 1 |
2+/-
1 |
1
+/- 1 |
<
1 |
|
Basophils % |
<
1 |
<
1 |
<
1 |
1
+/- 0.3 |
2
+/- 1 |
<
1 |
<
1 |
|
|
n=6 |
n=10 |
n=10 |
n=13 |
n=7 |
n=11 |
n=4 |
Pathology Open lung biopsy
1. Interstitial pneumonitis ( 100% )
a. patchy lymphocytic infiltrate of alveolar
walls
1. Granulomas (70%)
3. Unresolved pneumonia (65%)
a. neutrophilic, fibrinous infiltrate
of alveolar spaces
1. Interstitial fibrosis (65%)
5. Foam cells (65%)
6. Foreign body material (60%)
7. Edema (52%)
8. Bronchilitis obliterans (50%)
9. Pleural fibrosis (48%)
Transbronchial
biopsy Supportive
1. Due to small size of transbronchial biopsies,
generally only interstitial pneumonitis and granulomas are seen.
2. Descombes et al, 1997
a. 244 patients with diffuse chronic lung
infiltrates underwent transbronchial biopsy
b. Clinical/laboratory evaluation was
used as gold standard to determine diagnostic yield
c. Diagnostic yield for HP- 92%
|
Diagnosis |
Diagnostic yield |
|
Hypersenitivity pneumonitis |
92% |
|
Sarcoidosis Stage II-III Sarcoidosis Stage I |
75% 56% |
|
Lymphangitic carcinomatosis |
68% |
|
Pneumoconiosis |
54% |
|
Diffuse Tuberculosis |
38% |
|
Idiopathic fibrosis |
27% |
1. Lacasse et al, 1997
a. Transbronchial biopsies from 55
patients with acute farmer's lung were reviewed along with 50 control samples
including normals and a random distribution of diseases.
b. Interstitial pneumonitis and
granulomas were used as standardized criteria to develop a pathologic score,
"Probable, Possible, Nonspecific, or Alternate."
c. Likelihood ratios were calculated
based on the results:
Takehome
points:
1. The
diagnosis of HP depends on a constellation of historical, examination,
radiographic and laboratory findings.
2. BAL
and transbronchial biopsy are potentially useful diagnostic tools particularly
when other findings are equivocal.
REFERENCES
Descombes
E, Gariol D, Leuenberger P. Transbronchial lung biospy: an analysis of 530
cases with reference to the number of samples. Monaldi Archives for Chest Diseases. 1997; 52(4): 324-9.
Haitjema
T, van Velzen-Blad H, van den Bosch JMM. Extrinsic allergic alveolitis caused
by goose feathers in a duvet. Thorax. 1992;
47: 990-1
Lacasse
Y, Fraser RS, Fournier M, Cormier Y. Diagnostic Accuracy of Tranbronchial
Biopsy in Acute Farmer's Lung Disease. Chest.
1997; 112(6): 1459-65.
Schuyler
M, Cormier Y. The Diagnosis of Hypersensitivity Pneumonitis. Chest. 1997; 111(3): 534-6.
van
den Bosch JMM, Heye C, Wagenaar SS, van Velzen-Blad HCW. Bronchoalveolar Lavage
in Extrinsic Allergic Alveolitis. Respiration.
1986; 49: 45-51.