Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN.
Department of Radiology, Mayo Clinic, Rochester, MN.
Chest. 2021 Aug;160(2):624-632. doi: 10.1016/j.chest.2021.02.037. Epub 2021 Feb 26.
Exogenous lipoid pneumonia (ELP) develops when lipid-containing substances enter the airways through aspiration or inhalation and incite an inflammatory response. The diagnosis of ELP often is difficult because findings may be nonspecific. The clinical course of ELP has not been well characterized.
What are the presenting clinicoradiologic features of ELP, its causative agents, and clinical course?
We searched the Mayo Clinic electronic medical records for patients diagnosed with ELP between 1998 and 2020. Inclusion diagnostic criteria were: (1) lipoid pneumonia (LP) on histopathologic examination, (2) lipid-laden macrophages in BAL fluid, or (3) fatty attenuation of parenchymal opacities on chest CT imaging. Additionally, all patients were required to have a clinician diagnosis of LP in the absence of conditions known to cause endogenous LP.
Thirty-four patients were identified. Mean age was 71 years, with no sex predominance; one-half were asymptomatic. The diagnosis was confirmed by lung biopsy (including three lobectomies for suspected malignancy) in 71% of patients, CT scan in 24% of patients, and BAL in 5% of patients. Most patients manifested bilateral parenchymal opacities that commonly involved the lower lobes; fatty attenuation was identifiable in only 41% of patients. A causative substance was identified in 79% of patients, in most cases after the diagnosis was established. Over a median follow-up of 1.2 years, only 20% of patients with chronic respiratory symptoms improved, whereas 50% worsened. Over a median follow-up interval of 1 year, CT scan abnormalities improved or resolved in 33% of patients and progressed in 39% of patients. Patients who deteriorated were older, with a higher prevalence of GI disorders than those who remained stable or improved.
ELP often is asymptomatic and may not manifest fatty attenuation on chest CT imaging. Clinical and radiologic abnormalities persist or worsen in most affected patients, even when the causative agent is discontinued.
外源性类脂性肺炎（ELP）是由于含脂物质通过吸入或吸入进入气道并引发炎症反应而发展起来的。由于其发现可能不具有特异性，因此 ELP 的诊断通常很困难。ELP 的临床病程尚未得到很好的描述。
ELP 的临床表现、其病因和临床病程有哪些？
我们在梅奥诊所的电子病历中搜索了 1998 年至 2020 年间诊断为 ELP 的患者。纳入的诊断标准为：（1）组织病理学检查为类脂性肺炎（LP），（2）BAL 液中含脂巨噬细胞，或（3）胸部 CT 成像显示实质混浊呈脂肪衰减。此外，所有患者均需在无已知引起内源性 LP 的情况下由临床医生诊断为 LP。
共确定了 34 名患者。平均年龄为 71 岁，无明显性别差异；有一半的患者无症状。71%的患者通过肺活检（包括 3 例怀疑为恶性肿瘤的肺叶切除术）、24%的患者通过 CT 扫描和 5%的患者通过 BAL 来确诊。大多数患者表现为双侧肺实质混浊，常见于下叶；仅 41%的患者可识别出脂肪衰减。在 79%的患者中确定了一种致病物质，大多数情况下是在诊断确立后。在中位数为 1.2 年的中位随访期间，仅有 20%的慢性呼吸系统症状患者得到改善，而 50%的患者则恶化。在中位数为 1 年的随访间隔内，33%的患者 CT 扫描异常改善或消退，39%的患者进展。恶化的患者年龄较大，胃肠道疾病的患病率高于稳定或改善的患者。
ELP 通常无症状，胸部 CT 成像可能不会显示脂肪衰减。在大多数受影响的患者中，临床和影像学异常持续存在或恶化，即使停用了致病物质也是如此。
