[Exogenous lipoid pneumonia induced by long-term usage of compound menthol nasal drops: a case report]

Here we reported a case of exogenous lipoid pneumonia from Peking University Third Hospital. A 62-year-old male presented with chronic cough and expectoration for 8 years, without chest pain, hemoptysis or short of breath. He was an ex-smoker. In his past medical history, the patient reported chronic rhinitis sicca for 20 years. Chest computed tomography (CT) showed patchy ground glass opacities in his bilateral lower lobe. In recent 3 years, his symptoms showed slowly deteriorative changes, as did his chest CT findings. No improvement of the patient's symptoms was observed, although he had been treated with many antibiotics. Then he was referred to our hospital for a detailed investigation for interstitial lung disease. On admission, the physical examination showed no abnormal findings except for inspiratory fine crackles in his bilateral lower lung field on auscultation. The results of the laboratory analysis, including complete blood cell count, biochemistry, arterial blood gas, urinalysis, antinuclear antibody (ANA), antineutrophil cytoplasmic antibody (ANCA) and tumor markers were all within normal ranges. To exclude the possibility of infectious or malignant conditions, bronchoscopy was performed. Secretions from the left lower lobe bronchus were collected for bacterial, fungal and fast-acid cultures, which were all negative. A bronchoalveolar lavage (BAL) was performed in the left lower lobe with a 30% recovery. The total cell count of the BAL fluid was 6.5×10⁴/mL, and the cellularity differential revealed increased neutrophils (20%) and lymphocytes (17%). The cytological examination in the BAL fluid showed no malignant cells. All the clinical data above did not reveal any conclusive information. However, the pathological findings of his transbronchial lung biopsy (TBLB) were highlighted with lipid-laden macrophages engulfed by large vacuoles occupying almost completely the cytoplasm of the cells, which were consistent with those of exogenous lipoid pneumonia. Given these findings, it emerged that the patient was taking twice daily inhalations of a compound menthol nasal drops (essential oil of camphor, menthol and liquid paraffin) for his chronic rhinitis sicca for at least 10 years. Then he discontinued oil nasal sprays and showed gradual improvement 3 months later without intensive treatment. The presenting case report emphasizes the fact that chronic inhalation of nasal sprays and decongestants containing mineral oils was a cause of exogenous lipoid pneumonia, and clinicians should bear it in mind.