A 59-year-old woman complained of productive cough without fever since April 2018. She is a housewife and has no history of diabetes and smoking. She had undergone routine blood examinations in another hospital, which showed no significant abnormality. The initial diagnosis was a pulmonary infection. Her cough and sputum production, although attenuated, persisted despite receiving 15 days of treatment with ceftriaxone and tazobactam. The patient then received combined administration of amoxicillin and metronidazole for 4 weeks, after which the chest computed tomography (CT) showed that reticulations were superimposed on lobar ground-glass opacities (GGOs), accompanied by small patchy consolidation in the right middle lobe (RML) (Figure 1A). Since then, she had not received any treatment, despite suffering from occasional coughing.
The patient was admitted to our department in November 2018 because of a worsening cough. She was afebrile with a respiratory rate of 20 breaths per minute, heart rate of 72 beats per minute, blood pressure of 135/84 mmHg, oxygen saturation of 97% on room air, and BMI of 23 kg/m2. The breath sounds were clear, and no rales were heard during the auscultation of both lungs. No heart murmur was heard. Laboratory test results were all normal, including routine blood, urine and stool examinations and serum CRP, fasting blood glucose, PCT, tumour markers and HIV test. The opacities in RML were almost unchanged in comparison to previous imaging. Smears and cultures of sputum, blood and bronchoalveolar lavage fluid (BALF) for bacteria, fungi and acid-fast bacillus were all negative. Histopathology of the specimens obtained by transbronchial lung biopsy (TBLB) showed a large number of foamy cells and cholesterol clefts in alveolar spaces with scattered multinucleated giant cells, and multifocal lymphocyte infiltration with fibrotic proliferation in the interstitial space (Figure 1B). Upon further questioning, the patient admitted that she used household spray and hair spray frequently. Collectively, the patient's clinical history, imaging features, laboratory test results, histopathology as well as the lack of evidence for pulmonary infection led to the presumptive diagnosis of ExLP. The patient was instructed to stop using household spray and hair spray (withdrawal from lipid exposure) and treated with oral prednisone at a dose of 30 mg/day for 15 days, after which the dose was reduced to 15 mg/day for 7 days, and tapered to discontinuation within the following 6 days. Her symptoms improved progressively, so she was discharged and followed up in our outpatient clinic.
In early April 2019, she presented to our hospital again because of rough coughing accompanied by a lot of yellow sticky sputum. Chest CT showed that GGOs had progressed into lobar consolidation with air bronchogram in RML (Figure 1C). Routine blood, urine and stool examinations, liver and kidney function tests, serum PCT tests and coagulation function studies did not show abnormalities. The interferon-gamma release assay test was negative. Serum high-sensitivity C-reactive protein (hs-CRP) concentration and erythrocyte sedimentation rate (ESR) were both elevated at 12.32mg/L and 71mm/h, respectively. The pathogenic examinations were all negative, including sputum and BALF smears for acid-fast bacilli; sputum, BALF and blood cultures for bacteria and fungi; (1,3)-beta-D-glucan (G test) and Galactomannan (GM test) tests of BALF. Through next-generation sequencing of blood and BALF for pathogen discovery, no clinically significant pathogenic microorganisms were found. Histopathology of the specimens obtained by TBLB still revealed a large number of foamy cells filled in alveoli, accompanied by granulomatous lesions scattered in the interstitial space (Figure 1D and E), no caseous necrosis was found. The tissue samples obtained by TBLB were cultured for bacteria, fungi, and acid-fast bacilli. Fortunately, the presence of MTB was confirmed on the 25th day of lung tissue culture.
Then she was transferred to a specialized TB hospital and received quadruple therapy with isoniazid, rifampin, pyrazinamide and ethambutol for 3 months, followed by isoniazid and rifampicin. Her symptoms gradually relieved as treatment progressed. After 4 months of treatment, chest CT showed that the lung opacities had been absorbed almost completely (Figure 1F). The patient returned to her normal lifestyle and no longer suffered from symptoms associated with the use of household spray/hair spray. Satisfactory therapeutic results have been achieved, which confirmed a diagnosis of MTB infection.