INTRODUCTION:Hypersensitivity pneumonitis (HP), also called extrinsic allergic alveolitis, is a complex syndrome of varying intensity, clinical presentation, and natural history, rather than a single uniform disease.
CASE PRESENTATION:59-year-old African-American female presented with persistent cough for three weeks, starting soon after influenza vaccination. Cough was non-productive, no diurnal or postural variation, no aggravating or relieving factors with no hemoptysis. There was associated chest tightness, wheezing, low-grade fever associated with chills and diaphoresis and unintentional weight loss of 30 pounds. Patient denied smoking, alcohol or recreational drug use. Patient lived in a basement apartment and worked as a cleaning lady. There was no known food, animal, drug or any seasonal allergies. Physical examination was normal except bilateral inspiratory crepitations at lung bases. Pulmonary Function Testing revealed moderate to severe restriction with moderately decreased DLCO. FVC was 1.24L (49%), FEV1 1.11L(54%), FEV1/FVC (89%) and DLCO 55%.CXR showed patchy mass-like densities bilaterally. HRCT Chest showed multiple bilateral lung masses of varying size and mild adenopathy suspicious of metastatic lung disease.Bronchoscopy was attempted but aborted due to severe bout of coughing which appeared to be possible due to airway hyperactivity. CT guided fine needle aspiration of right lung was done. Cytology showed clusters of fibrous stroma and bronchial epithelium, negative for malignancy, was considered non-diagnostic. Surgical pathology was suggestive of focal granuloma. Special stains were negative for viral, mycobacteria or fungi. The patient underwent right lung thoracotomy and wedge biopsies were taken from the right middle and lower lobes. Pathology showed ill formed granuloma, perivascular inflammatory cells, consistent with hypersensitivity pneumonitis with no organisms growing in the tissue culture. RAST (Radioallergosorbent test) was negative for specific precipitating antibodies to different antigens. Skin testing for various antigens was negative. Patient was started on steroids. Follow-up CXR and CT Chest three weeks after steroid treatment showed significant decrease in size and resolution of densities throughout both lungs fields.Followup PFT showed marked improvement in pulmonary function.
DISCUSSIONS:Radiographic manifestations of HP include, ground glass opacities or diffusely increased radiodensities in the acute phase of disease. As disease progress diffuse micronodules, ground-glass attenuation, focal air trapping, and fibrotic changes are observed. This case represents an unusual presentation of HP with pulmonary macronodular densities and masses. It is possible that cofactors are needed to render the patient hypersensitive to environmental antigens; recent studies suggest that a viral antigen could be such a trigger factor. Immunologically, HP is characterized by an early, neutrophil-type response and a later Th1-type granulomatous response to antigen. Studies have shown that a recent respiratory viral exposure can augment both of these inflammatory responses in HP. Our case report add important information to prior studies. It has been shown by evidence that a viral antigen exposure can augment the late granulomatous response in HP. Studies have shown a viral antigen can prime the lung for a greater early neutrophil-type response. These studies are consistent with clinical observations that suggest that in some patients, prior viral infections/exposure may enhance the clinical expression of HP. In our patient, it is possible that the development of lung masses was caused by the initial priming by influenza virus inoculated through vaccine.
CONCLUSION:The diagnosis of HP requires a constellation of clinical, radiographic, physiologic, pathologic, and immunologic criteria, each of which is rarely pathgnomonic alone. This may be the first reported case of HP after due to sensitization after influenza vaccination. Also Hypersensitivity pneumonitis presenting as pulmonary masses is extremely unusual.
DISCLOSURE:Javed Iqbal, No Financial Disclosure Information; No Product/Research Disclosure Information