A 52-year-old woman was referred to a chest physician with a six-month history of dyspnoea associated with a non-productive cough, intermittent fever and night sweats. At the onset of the illness her symptoms were intermittent, usually worse in the evenings, but over the past few weeks they had become more persistent. The patient also complained of reduced appetite and loss of weight. She had worked on a farm with her husband for the past four years. She smoked ten cigarettes per day. There was no previous history of breathlessness. On examination she was thin. There was evidence of peripheral cyanosis but no clubbing. Auscultation of the
lungs was normal. The chest X-ray showed reticulonodular shadowing affecting the upper and mid zones.
What is the most probable diagnosis?
a. Cryptogenic fibrosing alveolitis.
b. Chronic bronchitis.
c. Tuberculosis.
d. Extrinsic allergic alveolitis.
e. Allergic bronchopulmonary aspergillosis
Answer:
d. Extrinsic allergic alveolitis.
The patient is a farmer’s wife and her original symptoms were consistent with an allergic (hypersensitivity) pneumonitis; however, more recently she has developed persistent breathlessness, suggesting advanced paren chymal lung disease. Repeated episodes of pneumonitis
progress to pulmonary fibrosis. The CXR in the acute and subacute forms of the disorder may reveal fleeting micronodular interstitial shadows affecting the upper, mid and lower zones. It is important to note that the CXR may be normal in a few cases. In more chronic cases the CXR is similar to that seen in cryptogenic fibrosing alveolitis except that in EAA fibrosis is usually more pronounced in the upper zones.
Diagnostic features of EAA: 1. Evidence of exposure to a recognized antigen 2. Compatible clinical radiographic and physiological features (i.e. cough, wheeze, fever, micronodular shadows in upper, mid or lower zones, restrictive lung defect) 3. Bronchoalveolar lavage with lymphocytosis (with low CD4 to CD8 ratio) 4. Positive inhalation challenge test 5. Compatible histopathological changes