Diagnosis
Case 95
【Progress】
She received steroid pulse treatment, getting respiratory data improved and leading to discharge without respiratory disorder.
【Discussion】
The definition of acute respiratory distress syndrome (ARDS) described (1, 2) in Case 94, is ; the onset is over one week or less; CT reveals bilateral opacities with pulmonary edema with no existence of cardiac failure and fluid overload: PF ratio (pulmonary oxygen pressure / fraction of inspiratory oxygen) < 300 mm Hg. In our case, PF ratio was 64.1 mmHg and CT showed bilateral opacities in bilateral lungs with no evidence of cardiac failure and fluid overload, which meet the definition of ARDS. Meanwhile, acute interstitial pneumonia (AIP) is the same as Hamman-Rich syndrome classically termed and causes acute respiratory failure with unknown causes (3). In these days, natural killer T cells and interleukin 18 and 2 are considered to play an important role for the occurrence of AIP (4). Histological findings revealed organizing diffuse alveolar damages (DAD) associated with those of cryptogenic organizing pneumonia (COP) and non-specific interstitial pneumonia (NSIP). Namely, collapsed air spaces with fibroblasts infiltration, alveolar septal edema and/or fibrosis, hyperplasia and proliferation of type II pneumocytes, thrombotic small arteries are microscopically found (3). Although lung biopsy was not conducted in our case, laboratory data revealed normal range of the number of leukocytes but elevation of the values of KL6 and D dimmer. KL6 is sialylated carbohydrate antigen and produced by Type II pneumocytes which function to secret surfactant and to restore alveolar damages (5 - 8). The values of KL6 elevate in cases with alveolar wall damages such as interstitial pneumonia (8, 9). D dimer can be elevated not only in pulmonary embolism but also in AIP since histologically thrombotic small arteries are found in AIP (3). Based on bilateral diffuse opacity in chest CT and elevation of KL6 values and absence of other diseases causing ARDS, diagnosis of AIP was eventually made in our case. AIP is an idiopathic version of the ARDS.
As CT findings, ground glass opacity, air space consolidation, crazy paving pattern (melon skin appearance) and traction bronchiectasis are characteristic of AIP (10, 11). AIP is categorized into early (exudate) phase and late (proliferative) phase. Traction bronchiectasia is found mainly in the late phase. When marked honey comb pattern is found, it should be considered the worsening of usual interstitial pneumonia (3). In our case, ground glass opacity, crazy paving pattern and traction bronchiectasis were found in chest CT but not honey comb pattern, indicative of proliferative phase of AIP.
Prognosis of AIP is poor, mortality rate is known to 60% or greater (3). Steroid therapy whether to be effective or not, is controversial. It was recently reported that early aggressive diagnostic approach, lung-protective mechanical ventilation, and the early immunosuppressive therapy induced the higher survival rate (12). In our case, steroid pulse therapy was effective, leading to discharge without respiratory disorder.
【Summary】
We present a ninety three-year-old female suffering from general fatigue and motion difficulty. She had experienced some difficulty in breathing in these days. Laboratory test revealed PF ratio 64.1 and no evidence of bacterial infection. Chest CT showed ground glass opacity, air space consolidation, crazy paving pattern and traction bronchiectasis. Based on elevation of KL 6 and radiological findings, clinical diagnosis of AIP was made. We should keep in mind that AIP is an idiopathic pattern of ARDS. KL 6 which is secreted by alveolar cell type II, elevates in interstitial pneumonia. As radiological findings of AIP, ground glass opacity, crazing paving pattern and traction of bronchiectasis are crucial to get acquainted. The early diagnosis and speedy lung-protective mechanical ventilation and immunosuppressive therapy might improve the prognosis.
【References】
1.Wheeler AP, Bernard GR. "Acute lung injury and the acute respiratory distress syndrome: a clinical review." Lancet. 2007 May 5;369(9572):1553-64. Review. PMID 17482987
2.Ferguson ND, Fan E, Camporota L et-al. The Berlin definition of ARDS: an expanded rationale, justification, and supplementary material. Intensive Care Med. 2012;38 (10): 1573-82. doi:10.1007/s00134-012-2682-1 - Pubmed citation
3.Vourlekis JS, et al. Acute interstitial pneumonitis. Case series and review of the literature. Medicine (Baltimore). 2000;79 (6): 369-78.
4.Okamoto M, et al. Interleukin 18 (Il-18) in synergy with Il-2 induces lethal lung injury in mice: a potential role for cytokines, chemokines, and natural killer cells in the pathogenesis of interstitial pneumonia. Blood. 2002;99(4):1289–1298.
5.Ward HE,et al. Alveolar type I and type II cells. Aust N Z J Med. 1984 Oct;14(5 Suppl 3):731-4.
6.Tanaka S, et al (2011). Krebs von den Lungen-6 (KL-6) is a prognostic biomarker in patients with surgically resected nonsmall cell lung cancer. International Journal of Cancer 130 (2): 377-87. PMID 21351094.
7.Castranova V, et al. The alveolar type II epithelial cell: a multifunctional pneumocyte. Toxicol Appl Pharmacol. 1988 May;93(3):472-83.
8.Ohnishi H, et al. Comparative study of KL-6, surfactant protein-A, surfactant protein-D, and monocyte chemoattractant protein-1 as serum markers for interstitial lung diseases. Am. J. Respir. Crit. Care. Med. 165 (3): 378-81. PMID 11818324.
9.Okada F, et al. Comparison of pulmonary CT findings and serum KL-6 levels in patients with cryptogenic organizing pneumonia. Br J Radiol.2009;82: 212-218
10.Ichikado K, et al. Acute interstitial pneumonia: comparison of high-resolution computed tomography findings between survivors and nonsurvivors. Am J Respir Crit Care Med. 2002 Jun 1. 165(11):1551-6. [Medline].
11.Johkoh T, et al. Acute interstitial pneumonia: thin-section CT findings in 36 patients. Radiology. 1999;211 (3): 859-63.
12.Avnon LS, Pikovsky O, Sion-Vardy N, Almog Y. Acute interstitial pneumonia Hamman-Rich syndrome: clinical characteristics and diagnostic and therapeutic considerations. Anesthesia and Analgesia. 2009;108(1):232–237
2018.3.7