Exogenous Lipoid Pneumonia Successfully Treated With Bronchoscopic Segmental Lavage Therapy

Case Report

A 65-y-old Japanese man was referred to the respiratory medicine department at our hospital because of abnormal radiologic findings. He had undergone a left hepatic lobectomy 13 y prior because of hepatocellular carcinoma. The patient had no respiratory symptoms. He reported a cigarette smoking habit of 1 pack/d for 45 y, and surprisingly, he had a habit of drinking 400–500 mL of milk and 400–800 mL of canned coffee with milk every day. His oxygen saturation was 96% on room air, and his body temperature was 35.6°C. His respiratory sounds were normal, and leg edema was not observed. An arterial blood gas analysis on room air revealed a pH of 7.43, P_aO2 or 82.5 mm Hg, and P_aCO2 of 36.5 mm Hg. His white blood cell count was 9.9 × 10³ cells/μL, C-reactive protein was 1.6 mg/dL, and the levels of serum Krebs von den Lungen-6 (KL-6) were elevated (1,255 U/mL). Pulmonary function tests demonstrated diffusion impairment as follows: vital capacity, 106.2% of predicted; FEV₁, 98.1% of predicted; diffusing capacity of the lung for carbon monoxide, 74.3% of predicted; and diffusing capacity/alveolar volume, 58.5% of predicted. The laboratory data and pulmonary function tests are shown in Table 1. Chest radiography revealed bilateral reticular shadows in both the mid and lower fields (Fig. 1A). High-resolution chest computed tomography scans revealed a geographic distribution of ground-glass opacities and associated thickening of the interlobular septa (crazy-paving patterns) in both lower lobes (Fig. 1, B and C). An examination of bronchoalveolar lavage fluid (BALF) from the left B8 bronchus showed a normal total cell count (2.5 × 10⁵ cells/mL), including 67% macrophages, 20% lymphocytes, 3% neutrophils, and 9% eosinophils. The CD4/CD8 ratio of lymphocyte subsets was 2.1. The BALF findings are shown in Table 2. The BALF appeared colorless and transparent and did not show a milky appearance. Cultures of the BALF were negative for bacterial, fungal, and mycobacterial pathogens. The BALF cytologic findings showed multiple lipid-laden macrophages (Oil Red O staining) (Fig. 2A). Lung specimens of the right B4 and B8 bronchi obtained by surgical lung biopsy showed airway-centered inflammatory lesions with foamy macrophages in the terminal air spaces (Fig. 2B). A swallowing function test revealed liquid dysphagia. Taken together, these findings revealed exogenous lipoid pneumonia.

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Fig. 1.

A: Chest radiography revealed bilateral reticular shadows in both mid and lower lung fields. B and C: High-resolution chest computed tomography scans revealed a geographic distribution of ground-glass opacities and associated thickening of the interlobular septa (crazy-paving patterns) in both lower lobes.

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Fig. 2.

A: Bronchoalveolar lavage fluid cytology showed multiple lipid-laden macrophages (Oil Red O staining). B: Lung specimens obtained by surgical lung biopsy showed airway-centered inflammatory lesions with foamy macrophages in the terminal air spaces (hematoxylin and eosin stain).

In addition, we performed an electrospray ionization mass spectrometry analysis of the BALF pellet and milk. Two specific peaks were observed in both the BALF pellet and milk samples (Fig. 3, arrows and circles), which were not observed in BALF pellets of normal volunteers (data not shown). It was believed that these peaks were caused by monoglycerides produced in the triglycerides' resolution processes from their molecular weights. These findings indicated the possibility of milk-induced or milk-containing drink-induced exogenous lipoid pneumonia.

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Fig. 3.

Electrospray ionization mass spectrometry analysis of the bronchoalveolar lavage fluid (BALF) pellet and milk at intensity 9,475 (A) and intensity 11,072 (B). Two specific peaks were observed in both the BALF pellet and milk (arrows and circles) that were not observed in BALF pellets of normal volunteers (data not shown). It was believed that these peaks resulted from monoglycerides produced in the triglycerides' resolution processes from their molecular weights.

This case received a follow-up examination because the patient had no respiratory symptoms. However, high-resolution computed tomography scans revealed extension of the ground-glass opacities and partial fibrosis after 10 months. Serum KL-6 levels were also elevated (2,300 U/mL). Pulmonary function tests revealed no remarkable changes. We performed bronchoscopic segmental lavage therapy 3 times in 15 d in the left lung, where radiologic findings had increased remarkably. For therapeutic purposes, 250-, 400-, and 250-mL volumes of warmed (37°C) sterile saline were instilled, and the recovery rates were 57%, 42%, and 76%, respectively. Chest percussion was not performed. The patient was given oral amoxicillin for a short duration to prevent infection after the bronchoscopy. He did not receive steroid therapy. We instructed the patient not to drink milk or milk-containing drinks at discharge.

Three months after the treatment, serum KL-6 levels decreased from 2,300 to 1,296 U/mL, and the radiologic findings improved in both lungs, including the right lung, where therapeutic BAL was not performed (Fig. 4). The patient has not experienced a recurrence of lipoid pneumonia in 2 y to date.

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Fig. 4.

We performed bronchoscopic segmental lavage therapy 3 times in 15 d in the left lung, where the radiologic findings had increased remarkably. For therapeutic purposes, 250-, 400-, and 250-mL volumes of warmed (37°C) sterile saline were instilled. After the treatment (arrows), the levels of serum Krebs von den Lungen-6 (KL-6) decreased, and the radiologic findings improved in both lungs.