Secondary Organizing Pneumonia Research Articles

Secondary organizing pneumonia after coronavirus disease (literature review)

New coronavirus disease (COVID-19) is a life-threatening infection that can lead to the development of persisting symptoms. Clinical, radiological and histopathological characteristics of post-coronavirus pneumonia are similar to secondary organizing pneumonia (SOP). This type of pneumonia is considered to be a complication of COVID-19, which correlates with the severity of the disease and increases patient mortality rates.It should be noted that radiological signs of pneumonia are can be observed in recovered individuals in 67% of cases. Moreover, fibrosis, complicated by symptoms of respiratory failure, may develop in 5-8% of the cases despite the fact that SOP resolves independently in 25% of individuals, and, in most cases, can be easily treated.Currently there are no methods of treating SOP induced by COVID-19; the first-line therapy involves the use of glucocorticosteroids (GCs). Despite the effectiveness of GCs, the treatment lasts for more than six months, and the disease has a high probability of relapse upon treatment discontinuation. Clinical trials have been registered to determine the optimal treatment duration and dosages of GCs in SOP treatment after COVID-19, however, the lack of consensus remains, keeping this issue open. This review provides data regarding organizing pneumonia, SOP induced by COVID-19, its radiological signs and treatment options within the framework of ongoing clinical trials.

Resolution of an insidious and migratory Mycobacterium tuberculosis-associated secondary organizing pneumonia: a case report and literature review

BackgroundOrganizing pneumonia (OP) is a rare interstitial lung disease. Secondary organizing pneumonia (SOP) caused by Mycobacterium tuberculosis (MTB) is extremely rare. Migratory MTB-associated SOP is more deceptive and dangerous. When insidious tuberculosis (TB) is not recognized, SOP would be misdiagnosed as cryptogenic organizing pneumonia (COP). Use of steroid hormone alone leads to the progression of TB foci or even death. Clues of distinguishing atypical TB at the background of OP is urgently needed.Case presentationA 56-year-old female patient was hospitalized into the local hospital because of cough and expectoration for more than half a month. Her medical history and family history showed no relation to TB or other lung diseases. Community-acquired pneumonia was diagnosed and anti-infection therapy was initialized but invalid. The patient suffered from continuous weigh loss. More puzzling, the lesions were migratory based on the chest computed tomography (CT) images. The patient was then transferred to our hospital. The immunological indexes of infection in blood and pathogenic tests in sputum and the bronchoalveolar lavage fluid were negative. The percutaneous lung puncture biopsy and pathological observation confirmed OP, but without granulomatous lesions. Additionally, pathogen detection of the punctured lung tissues by metagenomics next generation sequencing test (mNGS) were all negative. COP was highly suspected. Fortunately, the targeted next-generation sequencing (tNGS) detected MTB in the punctured lung tissues and MTB-associated SOP was definitely diagnosed. The combined therapy of anti-TB and prednisone was administrated. After treatment for 10 days, the partial lesions were significantly resorbed and the patient was discharged. In the follow-up of half a year, the patient was healthy.ConclusionsIt is difficult to distinguish SOP from COP in clinical practice. Diagnosis of COP must be very cautious. Transient small nodules and cavities in the early lung image are a clue to consider TB, even though all pathogen tests are negative. tNGS is also a powerful tool to detect pathogen, ensuring prompt diagnosis of TB-related SOP. For clinicians in TB high burden countries, we encourage them to keep TB in mind before making a final diagnosis of COP.

P204 Secondary organizing pneumonia caused by Aspergillus flavus in immunocompromised patients

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PMIntroductionFungal pneumonia is a known complication in immunocompromised patients. However fungal infection leading to organizing pneumonia (OP) is a rare entity. Here we present two cases of co-occurrence of OP with Aspergillus lung infectionCase 1: A 33-year-old male with a history of recurrent oral-genital ulcerations and low-grade fever for the last 3 months presented with shortness of breath and high-grade fever for 10 days. On presentation he was hypotensive, tachycardic, and tachypneic, examination revealed bilateral crackles. His initial investigations were hemoglobin (Hb) 8.8, total leucocyte counts (TLC) 13 000, platelet 190 000, liver function test (LFT), and kidney function test (KFT) were normal. High-resolution commuted tomography (HRCT) revealed multifocal areas of interlobular septal thickening with ground glass opacity and patchy areas of consolidation seen in bilateral lung fields (Fig. 1). He was initially managed with broad-spectrum antibiotics and oxygen support by a high flow nasal cannula (HFNC); as the condition deteriorated, he was mechanically ventilated. Fibreoptic bronchoscopy with bronchoalveolar lavage (BAL) was performed. Investigations for tuberculosis, nocardia, pneumocystis carinii, and bacterial infection in BAL was negative. Galactomannan index (GMI) in BAL was 3.15 and grew Aspergillus flavus. Transbronchial biopsy revealed features consistent with organizing pneumonia. He was started on voriconazole and steroids. He was diagnosed with undifferentiated connective tissue disorder. As the patient's condition improved in due course of time, he was extubated and discharged in stable condition on voriconazole and steroids and is currently doing fine.Case 2: A 56-year-old male known case of mantle cell lymphoma on consolidation therapy, presented with 15 days history of shortness of breath and high-grade fever. Chest examination revealed decreased breath sounds bilaterally in the lower lung zones with lower zone crackles. Initial investigations showed Hb 10.9, TLC 3.90, platelet 150000, KFT and LFT were normal. HRCT scan revealed multilobular areas of consolidation showing air bronchogram with ground glass opacities in bilateral lung (Fig. 1). Bronchoalveolar lavage fluid (BALF) revealed the growth of Aspergillus flavus and was GMI 1.97. Investigations for tuberculosis, nocardia, pneumocystis carinii and bacterial infection was negative. Transbronchial biopsy revealed features consistent with organizing pneumonia. He was started on combination therapy with voriconazole and micafungin along with steroids. Initially, he was managed with oxygen support but his oxygenation gradually worsened, he was mechanically ventilated, and received multiple pruning sessions. Patient had refractory organizing pneumonia, did not show any improvement even after 1 month, and left against medical advice.ConclusionBacterial and viral infections are the common causes of secondary OP. Fungal infections implicated in secondary OP are rarely described, of which there are reports of Pneumocystis jiroveci (PJP) and Penicillium infection leading to secondary OP. Aspergillus flavus is a ubiquitous fungal agent and is considered as pathogenic in immunocompromised settings can lead to secondary organizing pneumonia. High index of suspicious for OP is always to be kept in mind while treating Aspergillus flavus pneumonia.

The many faces of cryptogenic organizing pneumonia (COP).

Organizing pneumonia (OP) is interstitial pneumonia with an acute or subacute clinical course and a histological pattern compatible with acute lung injury. It usually arises after a recent infection of the peripheral bronchial system, whereby is called secondary OP. However, often OP arises with no recognizable cause for which it is called cryptogenic organizing pneumonia (COP). From a radiological standpoint, COP exhibits different imaging appearances and this review makes radiologists and clinicians familiar with the entire spectrum of expected disease findings. Successful interpretation of imaging is pertinent for a rapid diagnosis of COP and knowledge of the entire spectrum of imaging findings in COP is mandatory.

ORGANIZING PNEUMONIA AS A SIDE EFFECT OF COVID-19 VACCINE

TYPE: Case Report TOPIC: Diffuse Lung Disease INTRODUCTION: Comprehensive side effects of Coronavirus disease 2019 (COVID-19) vaccine are still unknown. Here we report the case of organizing pneumonia (OP) post COVID-19 vaccination. CASE PRESENTATION: A 73-year-old male with past medical history of hypertension presents with shortness of breath, cough, low-grade fever, generalized weakness and decreased appetite for one week. Patient had received second dose of COVID-19 vaccination 2 months prior. Physical examination revealed bilateral crepitations. Patient was hypoxic requiring supplemental oxygen. COVID-19 PCR and rapid antigen test (x 2) were negative. Computed tomography showed extensive bilateral ground glass infiltrates and some interstitial septal thickening with nodular infiltrates. Patient was started on broad spectrum antibiotics. Multiple transbronchial biopsies collected from different sites showed findings consistent with typical organizing pneumonia. Further infectious, immunologic, rheumatologic and vasculitis work-up to look for underlying cause of OP was negative. DISCUSSION: OP is a histopathological condition in which bronchioles, alveoli and walls of small bronchi become inflamed and get occupied with buds of granulation tissue progressing from fibrin exudates to loose collagen containing fibroblasts. It has varied radiologic manifestations. In addition to cryptogenic organizing pneumonia, it can be seen in vasculitis, bronchocentric granulomatosis, chronic eosinophilic pneumonia, hypersensitivity pneumonia, diffuse alveolar damage, non-specific pneumonia, lung abscess, pulmonary infarct and cancers. Secondary OP can be caused secondary to heart-lung transplantation, bone-marrow transplantation, infections, acute respiratory distress syndrome, drug use, radiotherapy, connective tissue diseases and aspiration pneumonia. CONCLUSIONS: As this being the first reported case of post COVID-19 vaccine related OP, further studies and data is required to establish causative relationship. DISCLOSURE: Nothing to declare. KEYWORD: Coronavirus disease 2019 vaccine

MAC CALLING THE COP: ORGANIZING PNEUMONIA SECONDARY TO MYCOBACTERIUM AVIUM COMPLEX INFECTION

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Organizing pneumonia (OP) is an inflammatory lung disease involving the distal bronchioles, respiratory bronchioles, bronchiolar ducts & alveoli. OP may be cryptogenic (COP) or secondary to several factors such as drugs, infections, radiation therapy, malignancy or CTD.Mycobacterium Avium Complex (MAC) pulmonary infection is a challenging entity & diagnosis relies on the integration of clinical, radiological, microbiological & pathological results. The clinical course is heterogenous, ranging from asymptomatic cases to patients with refractory disease associated with considerable morbidity and mortality. CASE PRESENTATION: A 44-year-old female with history of COPD, DM 2, alcoholic cirrhosis, tobacco & opioid use disorder presented with worsening SOB & dry cough for a week. She was treated a year ago with 3 months of steroid therapy for COP with complete clinical and physiologic improvement and normalization of the chest film.She endorsed subjective fever & myalgias but denied hemoptysis, night sweats, weight loss, rashes, joint swelling or pain, sick contacts, recent travel & occupational exposure. Vitals were significant for fever, hypoxia, tachypnea & tachycardia. Physical exam revealed crackles in bilateral mid to lower lung fields. Laboratory results showed leukocytosis & thrombocytopenia. Serum chemistry was notable for elevated lactate but normal procalcitonin, cardiac enzymes & BNP. COVID19 PCR nasal swabs x 2 were negative. CTA showed patchy bilateral consolidations with surrounding ground glass opacities throughout lung fields & no evidence of PE. Patient was started on broad spectrum antibiotics. Infectious & Rheumatological work up turned out to be negative. Given negligible improvement & previous history of COP, she underwent VATS with wedge biopsy & histopathology confirmed florid organizing pneumonia. Glucocorticoid therapy was initiated. At 8 weeks, her tissue culture revealed the presence of MAC. Due to unfavorable clinical response to steroid therapy alone, it was decided to start Rifabutin, Ethambutol & Azithromycin to treat MAC pulmonary infection causing secondary OP. Patient showed clinical improvement & glucocorticoids were gradually tapered. Patient was referred to respiratory rehabilitation & scheduled for follow up at outpatient clinic. DISCUSSION: MAC pulmonary infection & secondary OP association has been rarely reported in the literature. OP is believed to be a consequence of alveolar epithelial injury. Both MAC pulmonary infection & OP have increased cytokine production leading to the inflammation suggesting a common pathway. Therefore, it may be possible for MAC to trigger an OP reaction. CONCLUSIONS: We recommend a systematic assessment of potential etiological agents triggering, what is considered to be COP. Further studies are warranted to establish a causal relationship between MAC & OP thus representing another manifestation of NTM-PD. REFERENCE #1: Cordier J-F. Cryptogenic organising pneumonia. Eur Respir J 2006;28:422–46 REFERENCE #2: Griffith DE, Aksamit T, Brown-Elliott BA, et al. An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases. Am J Respir Crit Care Med 2007;175:367–416 REFERENCE #3: Carre PC, King TE, Mortensen R, et al. Cryptogenic organizing pneumonia: increased expression of interleukin-8 and fibronectin genes by alveolar macrophages. Am J Respir Cell Mol Biol 1994;10:100–5 DISCLOSURES: No relevant relationships by Muhammad Ahsan, source=Web Response No relevant relationships by Kristin Fless, source=Web Response No relevant relationships by Thomas Ng, source=Web Response No relevant relationships by ARCHANA SREEKANTAN NAIR, source=Web Response

Radiological progression of COVID-19 organizing pneumonia.

Key messageIt has recently been recognized that the clinical course of coronavirus disease 2019 (COVID‐19) and secondary organizing pneumonia (OP) tend to follow a subacute progression of respiratory illness. We present images of radiological progression of COVID‐19 pneumonia and secondary OP.

Analysis of the clinical characteristics of 176 patients with pathologically confirmed cryptogenic organizing pneumonia.

BackgroundCryptogenic organizing pneumonia (COP), is a form of idiopathic interstitial pneumonia (IIP) and is diagnosed by clinical-radiologic-pathologic (CRP) diagnosis. To summarize the clinical, imaging, pathological, and prognostic characteristics of 176 patients with confirmed COP.MethodsPatients who were diagnosed with organizing pneumonia (OP) by lung biopsy between January 1, 2000, and December 31, 2013, in our hospital were retrospectively analyzed and followed up until 12/31/2017. COP was confirmed by CRP diagnosis.ResultsA total of 1,346 OP cases were identified including 1,170 (86.9%) secondary OP cases (31 cases were originally misdiagnosed as COP but later confirmed as secondary OP during follow-up) and 176 (13.1%) cases of COP. The 176 patients with COP presented with no specific clinical symptoms and chest CT revealed diverse imaging features, such as patchy ground-glass opacity (112/176, 63.6%), consolidation (100/176, 56.8%), nodules (70/176, 39.8%), and fibrous stripes (69/176, 39.2%). The majority of patients (65.3%, 115/176) presented mixed patterns, and 12 (6.8%) showed a reversed halo sign. Of the 176 patients, 83 patients had unilateral lesions (ULs) and did not undergo glucocorticoid therapy. Of the 93 patients with bilateral lesions (BLs), 3 underwent complete resection and were radically cured. The other 90 patients underwent partial resection; of these patients, 37 cases achieved spontaneous remission, and 53 were treated with glucocorticoid therapy. After steroid therapy was reduced or stopped, 35 (66%) patients experienced recurrence. Overall, the 5-year survival rate for the COP patients in our study was 98.3%.ConclusionsOur study showed that the majority of the patients pathologically diagnosed as OP had secondary OP (86.9%), with COP accounting for only 13.9% of cases. CRP diagnosis and continuous follow-up may be the key for the accurate diagnosis of COP.

Cryptogenic and Secondary Organizing Pneumonia: Clinical Presentation, Radiological and Laboratory Findings, Treatment, and Prognosis in 56 Cases.

Organizing pneumonia is an important disease that is associated with non-specific clinical findings and radiographic appearance. Our aim was to examine the clinical and radiological features, laboratory findings, diagnostic approach, and response to therapy in subjects with cryptogenic (COP) and secondary organizing pneumonia (SOP). Patients' medical records were retrospectively reviewed between 2010 and 2016 in our hospital. We analyzed the symptoms, radiological features, pulmonary function tests, laboratory data, bronchoalveolar lavage findings, treatment, and prognosis. Thirty-seven patients were diagnosed with COP and 19 patients with SOP. The most common causes of SOP were determined as rheumatologic diseases. The most common symptoms were cough (71.4%) and dyspnea (66.1%). Bilateral symmetrical consolidations were the most prominent radiological appearance in both COP and SOP. The general radiographic findings were not different in COP and SOP. However, pulmonary lesions were located rather in the central (p=0.023) and middle (p=0.001) zones in patients with SOP. Corticosteroid (CS) therapy was administered to 34 (60.7%) patients. Two patients showed deterioration despite CS therapy. The clinical and radiographic findings, treatment response, prognosis were similar in patients with COP and SOP.

Pathology-radiology correlation of common and uncommon computed tomographic patterns of organizing pneumonia

Organizing pneumonia (OP) is a common pattern of lung injury that can be associated with a wide range of etiologies. Typical and not-so-typical imaging features of OP occur, as both common and rare lung pathologies can mimic the same imaging pattern as that of OP. This article will attempt to describe the difference between confusing terminologies that have been used in the past for OP and existence of primary versus secondary OP. The role of a multidisciplinary approach as an essential component to correctly diagnose and effectively manage challenging cases of OP will be highlighted. Additionally, we will discuss the limitation of transbronchial and importance of open lung biopsy to make the correct diagnosis. One example of an emerging diagnosis in the spectrum of OP and diffuse alveolar damage is acute fibrinous and organizing pneumonia. Ultimately, the reader should feel comfortable recognizing the many variable presentations of OP and be able to participate knowledgeably in a multidisciplinary team after reading this article. OP is a disease entity with variable radiographic and distinct histological characteristics that requires a multidisciplinary approach to correctly diagnose cryptogenic OP. Classic radiologic findings of OP occur in as low as 60% of cases. Secondary causes include infections, neoplasms, inflammatory disorders, and iatrogenic. Acute fibrinous and organizing pneumonia can appear similarly, but miliary nodules are a clue to diagnosis.

Secondary organizing pneumonia following viral pneumonia caused by severe influenza B: a case report and literature reviews

BackgroundSome reported that organizing pneumonia (OP) may occur after influenza A infections including swine-origin influenza A (H1N1). However, OP associated with influenza B infection has never been reported. We report the first case of secondary OP associated with viral pneumonia caused by influenza B.Case presentationA 23-year old woman was diagnosed as viral pneumonia caused by type B influenza. Despite of antiviral therapy, abnormal chest shadows were not improved. Bronchoscopy and transbronchial lung biopsy showed organizing pneumonia due to viral pneumonia caused by influenza B. Corticosteroid therapy was started at 30 mg daily (0.5 mg/kg), and the dose was reduced to 25, 20, 15 or 10 mg per day every month with symptomatic and radiological resolution. Even after corticosteroid therapy was discontinued, we did not confirm disease recurrence.ConclusionsPhysicians should be aware of the possibility for SOP and severe viral pneumonia even in case of type B as well as type A influenza infections.

Organizing Pneumonia as a Histopathological Term.

Organizing pneumonia (OP) is an interstitial lung disease characterized by granulation tissue buds in alveoli and alveolar ductus, possibly accompanied by bronchiolar involvement. Histopathologically, OP may signify a primary disease and be observed as a contiguous disease or as a minor component of other diseases. In this study, the clinical significance of histopathological OP lesions and clinical and radiological features of patients with primary OP were examined. Between January 2011 and January 2015, of 6,346 lung pathology reports, 138 patients with OP lesions were retrospectively evaluated. According to the final diagnoses, patients were grouped as reactive OP (those with final diagnosis other than OP) and primary OP (those with OP). Patients with primary OP were classified according to etiology as cryptogenic and secondary OP. Radiological evaluation was conducted within a categorization of "typical," "focal," and "infiltrative." Of 138 patients, 25% were males and the mean age was 54±14 years. Pathologically, 61% of patients had reactive OP and 39% had primary OP. All reactive OP lesions were reported using surgical specimens, and the most frequent primary diagnoses were malignancy (65%), infection (15%), interstitial lung diseases other than OP (7%), and bronchiectasis (5%). Other diagnoses included bullae, foreign body, hamartoma, bronchogenic cyst, and bronchopleural fistula. Of all the primary OP patients, 48 had cryptogenic OP and six had secondary OP. Radiological involvement was consistent with typical OP in 30%, focal OP in 63%, and infiltrative OP in 7% of the patients. All focal OP lesions were defined using surgical resections. Positron emission computed tomography (PET-CT) was recorded in 28 patients. In 11 patients, lymphadenomegaly was comorbid. The mean widest diameter of focal opacity was 2.7±1.2 (1.2-4.9) cm, and the mean the maximum standardized uptake value (SUVmax was 6.1±3.9 (1.7-16.7). OP lesions generally present as a minor component of other diseases. In patients with OP, cryptogenic OP and radiological focal OP is more frequently observed. Most focal OP lesions are detected using surgical resections because of malignant prediagnosis owing to elevated SUVmax.

Organize pnömonili olguların retrospektif değerlendirilmesi: Kriptojenik organize pnömoni sekonder organize pnömoniden farklı mıdır?

Organizing pneumonia (OP) is an uncommon clinic opathological situation among lung diseases. If no underlying cause can be detected, it is named as cryptogenic OP (COP). In this study, the etiologic and clinical characteristics of patients diagnosed as OP in our hospital in the last ten years were evaluated retrospectively. It was also aimed to make a comparison between COP and secondary OP patients. One hundred sixty-five patients diagnosed as OP pathologically in the 10 year period from August 2003 to August 2013 were included into that study. Patients' data were evaluated retrospectively from the medical records. One hundred sixty five patients pathologically diagnosed as OP were included. Diagnostic methods were trans-thoracic fine-needle biopsy (TTFNB) in 89 (53.9%) patients, open lung biopsy (lobectomy, wedge resection, segmentectomy) in 52 (31.5%) patients and transbronchial biyopsy (TBB) in 24 (14.5%) patients. One hundred (60.6%) of the patients were defined as COP and 65 (39.4%) as secondary OP. Cough, fatigue and dyspnea were the most common symptoms on admission. We detected OP cases secondary to anthracosis and cyst hydatic besides other well known etiologies. In 61 patients, the main radiologic manifestation was multiple bilateral patchy consolidation typical for OP. In 76 patients focal lesions (solid mass, cavitating mass lesion) and in 6 patients infiltrative opacities were detected radiologically. There is no difference between properties of OP from clinical, laboratory and radiologic finding sin the criptogenic and seconder form of OP. Although it is not asserted, cyst hidatic and anthracosis could be kept in mind for the list of underlying ethiologies for secondary OP.

Factors associated with the relapse of cryptogenic and secondary organizing pneumonia.

Organizing pneumonia (OP) is a histopathological response pattern to lung inflammation. It is clinically classified into cryptogenic OP and secondary OP, which is associated with various clinical conditions. Rapid resolution with corticosteroids and frequent relapses are common in OP. However, few studies have investigated the factors associated with OP relapse. The medical records of 75 patients with biopsy-proven OP, diagnosed between January 2010 and August 2015, who underwent corticosteroid therapy were retrospectively reviewed. Initially, the patients were all treated successfully; however, 31 patients experienced relapse thereafter (R group), whereas the others did not (NR group; 44 patients). The clinical, radiological, and pathological characteristics and administered corticosteroid doses were compared between the two groups. The neutrophil percentage in the bronchoalveolar lavage (BAL) fluid and the level of fibrin deposition in lung biopsy specimens were higher in the R group than in the NR group (P=0.01 and P=0.002, respectively). The multivariate analysis demonstrated that both factors were statistically significant predictors of OP relapse. A high neutrophil percentage in the BAL and the level of fibrin deposition in lung biopsy specimens are considered predictive factors of OP relapse during the tapering or after the cessation of steroid therapy. Patients without these findings may be treated with low-dose corticosteroids.

Is there any superiority among diagnostic methods in organizing pneumonia in terms of clinical features of the patients?

BackgroundOrganizing pneumonia (OP) can be idiopathic or secondary to some clinical situations. If an etiological cause is not present, this phenomenon is called cryptogenic OP. Secondary OP is associated with various diseases that are known to induce the OP.ObjectivesThe aim of this study was to evaluate the clinical features of the cases with OP and compare the patients diagnosed by bronchoscopic transbronchial biopsy with patients diagnosed by surgical lung biopsy.Patients and methodsMedical records of 41 patients diagnosed with OP between 2004 and 2014 were reviewed retrospectively.ResultsTotally, 41 patients with OP were identified. In all, 39.02% of the cases were diagnosed by bronchoscopic methods, and 60.97% of the cases were diagnosed by surgical procedures. Although the frequency of ground glass opacities, consolidations, and micronodules was higher in the group diagnosed by bronchoscopy, mass-like lesions were more common in the cases diagnosed by surgery. Bronchoscopy, performed in 30 patients totally, had a diagnostic efficacy of 53.33%. Diagnostic value of bronchoscopy was significantly higher in cryptogenic OPs. Although diffuse radiological pattern was more common in “successful bronchoscopy” group, frequency of focal pattern was higher in “failed bronchoscopy” group. Ground glass opacity in successful bronchoscopy group and mass-like lesions in failed bronchoscopy group reached significant differences.ConclusionThere were significant differences between the diagnostic procedures in terms of radiological patterns. This is the first study about the relationship between the diagnostic methods and the characteristics of OP.

Cryptogenic and Secondary Organizing Pneumonia: Clinical Presentation, Radiographic Findings, Treatment Response, and Prognosis

Organizing pneumonia (OP) is a distinct clinical and pathologic entity. This condition can be cryptogenic (COP) or secondary to other known causes (secondary OP). In the present study, we reviewed the features associated with COP and secondary OP in patients from two teaching hospitals. The medical records of 61 patients with biopsy-proven OP were retrospectively reviewed. Forty patients were diagnosed with COP and 21 patients with secondary OP. The clinical presentation, radiographic studies, pulmonary function tests (PFTs), laboratory data, BAL findings, treatment, and outcome were analyzed. The mean age at presentation was 60.46 ± 13.57 years. Malaise, cough, fever, dyspnea, bilateral alveolar infiltrates, and a restrictive pattern were the most common symptoms and findings. BAL lymphocytosis was observed in 43.8% of patients with OP. The relapse rate and mortality rate after 1 year of follow-up were 37.8% and 9.4%, respectively. The in-hospital mortality was 5.7%. The clinical presentation and radiographic findings did not differ significantly between patients with COP and secondary OP. A mixed PFT pattern (obstructive and restrictive physiology) and lower blood levels of serum sodium, serum potassium, platelets, albumin, protein, and pH were observed among patients with secondary OP. Higher blood levels of creatinine, bilirubin, Paco₂, and BAL lymphocytes were also more common among patients with secondary OP. There were no differences in the relapse rate or mortality between patients with COP and secondary OP. The 1-year mortality correlated with an elevated erythrocyte sedimentation rate, low albumin, and low hemoglobin levels. The clinical and radiographic findings in patients with COP and secondary OP are similar and nonspecific. Although certain laboratory abnormalities are more common in secondary OP and can be associated with worse prognosis, they are likely due to the underlying disease. COP and secondary OP have similar treatment response, relapse rates, and mortality.

Intraluminal plugs in idiopathic and secondary organizing pneumonia: repair or remodelling?

Organizing pneumonia (OP) is an inflammatory lung disease characterized histologically by intraluminal plugs involving alveolar ducts and alveoli. The aim was to examine extracellular matrix repair and remodelling in 12 cases of idiopathic OP and compare these with 11 cases of secondary OP. Collagen/elastic fibre density, myofibroblast proliferation, microvascular density and endothelial activity in the intraluminal plugs were evaluated by histochemistry, immunohistochemistry and morphometry. The density of the collagen system fibres was greater in plugs of idiopathic OP when compared with secondary OP (P < 0.001). Quantification of myofibroblastic cells confirmed differences observed in patterns of immunoexpression; when compared with secondary OP, idiopathic OP contained fewer myofibroblastic cells in intraluminal plugs (P = 0.01). Microvascular density (CD34) and endothelial activity (vascular cell adhesion molecule-1 and E-selectin) were significantly greater in secondary OP (P < 0.05). Idiopathic and secondary OP show significant variation in morphological features that may represent different responses to injury. Increased collagen synthesis, low myofibroblast proliferation, poor microvascularization and minimal endothelial activity found in idiopathic OP may be more of a remodelling process than secondary OP repair.

The Organizing Pneumonias

In this comprehensive review, two very closely related interstitial pneumonias are discussed: the cryptogenic form of organizing pneumonia (COP); and secondary forms of organizing pneumonia (OP), which occur in association with identifiable medical conditions. Some newer and lesser known of these associated conditions are described, most importantly post-radiation OP.Rapidly progressive, corticosteroid-resistant and poor prognostic forms of OP have been described. These types purportedly occur more frequently in secondary OP. However, OPs frequently coexist with other interstitial pneumonias, especially when associated with connective tissue diseases. Therefore, tissue sampling error or an incorrect morphologic diagnosis can be the basis for the occurrence of clinically aggressive OPs. By using the 2002 American Thoracic Society/European Respiratory Society diagnostic criteria, some pre-2002 cases reported as OP would be re-classified today.Although COP is considered to have a good prognosis and to be corticosteroid responsive, approximately 70% of patients, treated with corticosteroids, relapse even during initial treatment. Multiple and late relapses occur in about one-third of the patients. We performed a meta-analysis of second-line treatment options for corticosteroid-refractory forms of OP. Three alternative nonsteroid agents - cyclophosphamide, azathioprine, and cyclosporin - have been used in combination with corticosteroids. On careful review, in a number of cases reported as secondary OP, other histologic interstitial patterns besides OP were described. The need for second-line therapy in these patients might have been dictated by the non-organizing pneumonic component. Most of the scant number of reports come from outside the US. World experience with these is limited, but good clinical outcomes have been noted, even in patients with interstitial patterns in addition to OP.The initiation of the OP tissue response in the bronchiolar and sub-bronchiolar location may be due to the presence of bronchiolar-associated lymphoid tissue found at the bifurcations of the bronchioles. Inhaled antigens stimulate granulocyte colony stimulating factor-mediated airway inflammation, followed later by CD44-mediated clearance. Repair requires intrabronchiolar formation of granulation tissue and a favorable ratio of matrix metalloproteinase to tissue inhibitors of metalloproteinase (MMP : TIMP) within the stroma. This reparative milieu allows extracellular matrix degradation and re-synthesis to occur. MMP-expressing fibroblasts then phagocytose the collagen fibrils and microfibrils produced earlier in repair, reversing the initial fibrosis.

Organizing pneumonia. Features and prognosis of cryptogenic, secondary, and focal variants.

Organizing pneumonia (OP) is a non-specific response to many types of lung injury. Clinicians frequently encounter pathology reports of OP in patients with no underlying condition (cryptogenic OP, also known as BOOP or bronchiolitis obliterans OP) or in association with drugs or nonpulmonary disease. The goals of this study are to describe the clinical course and outcomes in patients with 3 clinical variants of OP. A retrospective study of patients with OP seen at the Mayo Clinic, Rochester, Minn, from January 1, 1984, through June 30, 1994, was conducted. Initial features were obtained from medical records. Chest radiographs and pathology specimens were reviewed for this study. Resolution, relapse, and survival were obtained from medical records and a follow-up patient questionnaire. Seventy-four patients had pathologically confirmed OP. Organizing pneumonia was classified into 3 clinical groups: symptomatic cryptogenic OP; symptomatic OP related to underlying hematologic malignant neoplasm, collagen vascular disease, or drugs (secondary OP); and asymptomatic OP presenting as a focal nodule (focal OP). Thirty-seven patients (50%) had cryptogenic OP and 27 patients (36%) had secondary OP. No difference was found between cryptogenic and secondary OP in type or severity of symptoms, signs, laboratory and pulmonary function tests, or radiologic or pathologic findings. Corticosteroids were given at a similar initial dose (prednisone, about 50 mg/d). Resolution of symptoms was more frequent in patients with cryptogenic OP than those with secondary OP. Relapse was infrequent in both of these groups. Five-year survival was higher in patients with cryptogenic OP (73%) than in secondary OP (44%), and respiratory-related deaths were more frequent in patients with secondary OP. Organizing pneumonia was an asymptomatic focal rounded opacity in 10 patients (14%), most often detected on chest radiograph and diagnosed on lung biopsy done for suspicion of lung cancer. Patients with focal OP required no treatment and had no relapse or respiratory-related deaths. Clinical classification of OP is useful to predict clinical course and outcome. Cryptogenic OP most often was a symptomatic bilateral lung process that had an overall favorable prognosis with prolonged corticosteroid therapy. Patients with secondary OP had a high mortality rate when the disease was associated with predisposing conditions or drugs. Patients with asymptomatic focal OP had an excellent prognosis.