【病例】肺泡蛋白沉积症1例CT影像表现

12 3月

History: A 15-year-old girl presents with a persistent cough. There is a clinical concern for atypical pneumonia. The patient did not improve with antibiotics, and radiographs were repeated.

病史:15岁女孩持续咳嗽,临床怀疑为非典型肺炎,使用抗生素后无好转,拍胸片复查。

A previous chest radiograph from 2016 and a current (2017) radiograph are shown below. 前后两次胸部平片如下所示。

【病例】肺泡蛋白沉积症1例CT影像表现

【病例】肺泡蛋白沉积症1例CT影像表现

CT images and additional information

A chest CT scan was performed. Lung function test showed forced vital capacity (FVC) of 49%, forced expiratory volume in one second (FEV1) of 42%, and FEV1/FVC ratio of 80. Blood workup showed positive antigranulocyte-macrophage colony-stimulating factor (anti-GM-CSF). Additional labs were unremarkable.

行胸部CT扫描,肺功能测试显示最大肺活量为49%,1秒用力呼气量为42%,FEV1/FVC比为80。血液检查:抗粒细胞异型巨噬细胞集落刺激因子阳性;其它实验室检查无特殊。

【病例】肺泡蛋白沉积症1例CT影像表现

【病例】肺泡蛋白沉积症1例CT影像表现

Findings

  • Radiograph 2016: Radiograph shows bibasilar predominant diffuse airspace and some interstitial opacities, left worse than right. Normal cardiomediastinal silhouette is seen.
  • Radiograph 2017: Radiograph shows progression of the basilar predominant diffuse airspace and interstitial opacities. No pneumothorax or pleural effusion is seen. The cardiomediastinal silhouette is obscured by airspace opacities but is grossly stable.
  • Chest CT: CT demonstrates geographic bilateral diffuse ground-glass opacities with thickened interlobular and intralobular septa — “crazy paving pattern.”

影像表现:

  • 2016胸片:双肺野基底部弥漫性肺泡及间质的密度增高影,左侧为著,心影纵隔影正常;
  • 2017胸片:下部为著的肺泡及间质阴影较前进展,未见气胸或胸腔积液。心影纵隔影边缘模糊,但大体正常;
  • 胸部CT:地图样分布的双侧弥漫性磨玻璃影,小叶内及小叶间间隔增厚,呈“铺路石征”。

Differential diagnosis

  • Pulmonary alveolar proteinosis
  • Diffuse alveolar hemorrhage
  • Acute interstitial pneumonia
  • Pulmonary edema
  • Eosinophilic pneumonia
  • Bronchiolitis obliterans
  • Diffuse alveolar damage
  • Atypical pneumonias
  • Nonspecific interstitial pneumonitis
  • Organizing pneumonia

鉴别诊断:

  • 肺泡蛋白沉积症(PAP)
  • 弥漫性肺泡出血
  • 急性间质性肺炎
  • 肺水肿
  • 嗜酸性粒细胞性肺炎
  • 闭塞性细支气管炎
  • 弥漫性肺泡损伤
  • 非典型性肺炎
  • 非特异性间质性肺炎
  • 机化性肺炎

Diagnosis: Pulmonary alveolar proteinosis

诊断:肺泡蛋白沉积症

Key points

Pulmonary alveolar proteinosis (PAP)

Epidemiology 流行病学

  • Pulmonary alveolar proteinosis is a broad group of rare diseases caused by the accumulation of pulmonary surfactants in the alveolar space. PAP是一组罕见疾病,由于肺泡内肺表面活性物质沉积所致。
  • It is a rare entity, with an estimated prevalence of about 0.1 to 0.37 per 100,000 individuals. 该病罕见,发生率约为十万分之0.1-0.37。

Pathophysiology 病理生理学

The etiology of pulmonary alveolar proteinosis is variable, with known causes including the following: PAP的病因不同,已知的包括以下几个方面:

  • Autoimmune: 自身免疫性的

Impaired GM-CSF signal, which is critical for the regulation of surfactant and lung homeostasis. Usually caused by GM-CSF antibodies or GM-CSF deficiency. 受损的GM-CSF信号对调节表面活性物质和肺体内平衡至关重要;通常由GM-CSF抗体或GM-CSF缺陷引起。

It is the most common adolescent-adult form. 这最常见于青少年及成人。

Additional autoimmune causes with positive antinuclear antibodies (ANAs), antineutrophil cytoplasmic antibodies (ANCAs), antidouble-stranded DNA (anti-ds-DNA), anti-Ro, anti-La, or factor rheumatoid. 其他自身免疫病因:抗核抗体(ANAs)、抗中性粒细胞胞质抗体(ANCA)、抗双链DNA(抗ds-DNA)、抗Ro/La抗体或类风湿因子阳性。

  • Hereditary: 遗传性的

Surfactant dysfunction syndromes is caused by genetic mutations that increase the production of surfactant or the removal. 由于基因突变导致的表面活性物质功能障碍综合征,表面活性产物增加。

It is the most common neonatal form.  主要见于新生儿。

  • Secondary: 继发性的

Hematologic disorders and malignancies 血液系统疾病及恶性肿瘤

Systemic diseases, such as systemic lupus erythematosus (SLE) or stem cell bone marrow transplantation 系统性疾病,例如:系统性红斑狼疮(SLE)、干细胞骨髓移植

Atypical infections 非典型感染

Drugs 药物

Secondary to altered surfactant production, removal, or both. 继发于表面活性剂产物的变化、消失,或两者同时发生。

The alveoli are filled with eosinophilic, acellular, and finely granular material. Interstitial space is mostly normal.

肺泡充满嗜酸性的,无细胞的,细粒状物质。 间质部分大多正常。

Clinical presentation 临床表现

  • Patients present with slowly increasing dyspnea and dry cough. 患者表现为缓慢加重的呼吸困难及干咳。
  • Depending on the age of onset, the etiology is suggested. 根据发病年龄的不同,可推断其病因。
  • Additional important diagnostic labs include restrictive pattern with decreased lung volumes in lung function tests, hypoxemia, and increased lactate dehydrogenase. 重要的实验室检查包括:肺功能测试中肺容量减少,低氧血症和乳酸脱氢酶增加。
  • Bronchoalveolar lavage may show cellular debris, acellular globules, and foamy macrophages. 支气管肺泡灌洗可显示细胞碎片,无细胞球和泡沫巨噬细胞。
  • In some cases, biopsies may be needed for diagnosis. 有些病例,可能需要借助活检来诊断。

【病例】肺泡蛋白沉积症1例CT影像表现

Imaging features

Radiographs:

  • Radiographs will show persistent diffuse bilateral mostly symmetrical alveolar opacities, usually with air bronchograms.
  • Usually, the perihilar regions are more affected than the periphery.
  • Rarely, can have pneumothorax with subpleural cysts rupture.

CT:

  • Crazy paving pattern, which combines ground-glass opacities and superimposed reticular pattern (thickened interlobular and intralobular septa), will be seen. Most common in autoimmune PAP.
  • Ground-glass pattern can be geographic and perihilar in autoimmune PAP and diffuse in secondary PAP.
  • Slow progression without treatment. Progression includes traction bronchiectasis, honeycombing, and lung cysts.

影像表现:

平片:

  • X线片会显示持续弥漫性双侧肺泡阴影,大部分双侧对称,通常伴有支气管充气征
  • 通常情况下,病灶分布在肺门周围区域比肺外周更显著。
  • 很少会有胸膜下囊肿破裂导致的气胸。

CT:

  • 可见铺路石征,结合磨玻璃影和叠加的网状影(增厚的小叶内和小叶间间隔),最常见于自身免疫性PAP。
  • 在自身免疫性PAP中磨玻璃影可呈地图样分布及在肺门周围分布,而在继发性PAP多弥漫分布。
  • 未治疗时病程缓慢进展,包括出现:牵拉性支气管扩张,蜂窝状和肺囊肿。

Treatment and prognosis

  • Treatments include whole-lung lavages, rituximab, plasmapheresis, and lung transplantation.
  • In patients with GM-CSF deficiency, subcutaneous and inhaled GM-CSF supplementation results in a response in 50% of cases.

治疗及预后

  • 治疗包括:全肺灌洗,利妥昔单抗,血浆置换和肺移植。
  • 在GM-CSF缺乏的患者中,皮下和吸入GM-CSF补充剂在50%的病例中有效。

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