Immune Checkpoint Inhibitor Therapy-related Pneumonitis: Patterns and Management.

In recent years, the use of immune checkpoint inhibitor (ICI) therapy has rapidly grown, with increasing U.S. Food and Drug Administration approvals of a variety of agents used as first- and second-line treatments of various malignancies. ICIs act through a unique mechanism of action when compared with those of conventional chemotherapeutic agents. ICIs target the cell surface receptors cytotoxic T-lymphocyte antigen-4, programmed cell death protein 1, or programmed cell death ligand 1, which result in immune system-mediated destruction of tumor cells. Immune-related adverse events are an increasingly recognized set of complications of ICI therapy that may affect any organ system. ICI therapy-related pneumonitis is an uncommon but important complication of ICI therapy, with potential for significant morbidity and mortality. As the clinical manifestation is often nonspecific, CT plays an important role in diagnosis and triage. Several distinct radiographic patterns of pneumonitis have been observed: (a) organizing pneumonia, (b) nonspecific interstitial pneumonia, (c) hypersensitivity pneumonitis, (d) acute interstitial pneumonia-acute respiratory distress syndrome, (e) bronchiolitis, and (f) radiation recall pneumonitis. Published guidelines outline the treatment of ICI therapy-related pneumonitis based on the severity of symptoms. Treatment is often effective, although recurrence is possible. This article reviews the mechanism of ICIs and ICI therapy complications, with subsequent management techniques and illustrations of the various radiologic patterns of ICI-therapy related pneumonitis.©RSNA, 2019.

Organizing pneumonia secondary to cetuximab in a patient with colorectal cancer.

Organizing pneumonia (OP) may be idiopathic or secondary to a variety of causes including drugs. OP and other forms of pulmonary toxicity secondary to cetuximab, however, have been described rarely. It is paramount to recognize and differentiate OP from other common conditions that cancer patients are prone to such as infection and pulmonary embolism. A 69-year-old man with colorectal cancer received ten cycles of palliative chemotherapy [FOLFIRI (5-Fluorouracil, Leucovorin, Irinotecan) and cetuximab] with clinical and radiological response. He developed dyspnea following cycle 4, then 6 weeks later presented with cough, fever, tachypnea, hypoxia, bilateral crackles and diffuse pulmonary shadows. He was started on antibiotics but his condition deteriorated further. Cultures, including blood and bronchioalveolar lavage, grew no pathogens and molecular analysis and cytology for bacteria viruses were negative. Trans-bronchial biopsy was consistent with organizing pneumonia. Treatment with corticosteroids resulted in dramatic clinical and radiological resolution with normalization of gas exchange and pulmonary function. Corticosteroids were stopped and he was restarted on FOLFIRI and remained well with no relapse over a year of follow up. Although pulmonary toxicity secondary to cetuximab is uncommon, it is important to recognize, as it may be associated with poor prognosis. To the best of our knowledge, this is the first report of OP attributed to cetuximab with histopathological evidence.

Secondary organizing pneumonia (bronchiolitis obliterans with organizing pneumonia) associated with adalimumab for treatment of chronic plaque psoriasis.

Organizing pneumonia is defined histopathologically by intra-alveolar buds of granulation tissue, consisting of intermixed myofibroblasts and connective tissue. The pathological pattern of organizing pneumonia may be idiopathic or related to a determined cause, termed secondary organizing pneumonia. We report a 68-year-old woman with a longstanding history of chronic plaque psoriasis, treated with the tumor necrosis factor (TNF) inhibitor, adalimumab. After 8 years of treatment, she developed a gradual-onset, non-productive cough with associated generalized fatigue and mild dyspnea. Radiological investigations demonstrated ground-glass opacities in the left lower lobe and bronchoscopy revealed a fibroinflammatory process consistent with organizing pneumonia. Her biologic treatment was ceased and corticosteroid treatment commenced, with resolution of both her symptoms and the radiological findings. Given the increasing incidence of biologic treatment in the management of dermatological conditions, clinicians should be aware of secondary organizing pneumonia as a possible side effect of TNF inhibitor therapy.

Nivolumab-induced organizing pneumonia in a melanoma patient.

We report the case of a 70-year-old woman with vaginal melanoma and multiple metastases in the lung. After the third dose of nivolumab, decreased room-air resting arterial oxygen saturation with bilateral basal fine crackles on auscultation developed despite the absence of respiratory symptoms. Computed tomography showed ground-glass opacities with airspace consolidations scattered with a peculiar distribution, and most were observed around the existing metastatic tumors in the lung. From the 42nd day to the 56th day after the last administration of nivolumab, she received dexamethasone 1-2 mg/body for the prevention of adverse events after stereotactic radiation for brain metastasis. At 3 months after the last administration of nivolumab, a computed tomography scan revealed improvement of the pneumonia and a decreased size and number of metastatic lesions in the lung, although some lesions showed enlargement. Further examination is needed to clarify the relationship between the pattern of pneumonia after Nivo therapy and clinical effects.

Lung disease and ulcerative colitis--mesalazine-induced bronchiolitis obliterans with organizing pneumonia or pulmonary manifestation of inflammatory bowel disease?

Ulcerative colitis can be associated with numerous extraintestinal organ manifestations. Pulmonary disease in inflammatory bowel disease (IBD) is supposed to be a rare entity and has to be distinguished from infectious complications and side-effects of medications used in the treatment of IBD. We present the case of a 20-year-old male patient with ulcerative colitis and a 4-week history of respiratory symptoms, malaise, fever and respiratory insufficiency under a medication with mesalazine. Computed tomography showed bilateral subpleural consolidations, bronchoscopy revealed signs of acute bronchitis. The diagnostic work-up ruled out an infectious cause. Under the tentative diagnosis of a mesalazine-induced bronchiolitis obliterans with organizing pneumonia (BOOP) the medication with mesalazine was withdrawn and the patient received a corticosteroid trial. The symptoms quickly improved and prednisone was tapered and stopped after 6 months. Unexpectedly, lung function after complete resolution of respiratory symptoms revealed a residual obstructive ventilatory defect that might be due to an asymptomatic pulmonary manifestation of ulcerative colitis. A review of the literature shows that pulmonary manifestations in IBD as well as pulmonary toxicity of mesalazine might not be as rare as expected and should be included as differential diagnoses in the work-up of respiratory symptoms in patients with IBD. A pragmatic therapeutic approach is reasonable in critically ill patients as it is not always easy to distinguish both entities.

Bronchiolitis obliterans organizing pneumonia following nitric acid fume exposure.

We describe a patient with clinical, radiological and pathological features of bronchiolitis obliterans organizing pneumonia. Investigation showed that this was likely to have been a delayed consequence of inhalation of nitric acid fumes (containing nitrogen dioxide) after a fire. This case shows that thorough investigation of the aetiology is important not only in clinical management but also in ensuring patients benefit from appropriate work injury compensation.

Cryptogenic organizing pneumonia after withdrawal of systemic corticosteroids for chronic eosinophilic pneumonia and severe asthma under benralizumab treatment.

A 79-year-old woman with severe asthma developed chronic eosinophilic pneumonia (CEP). After CEP resolved with oral prednisolone at 30 mg/day, prednisolone was tapered and discontinued under introduction of benralizumab for her severe asthma. However, 8 weeks later, symptoms and bilateral patchy infiltrates on chest radiography appeared. Lymphocytosis without eosinophilia was seen in bronchoalveolar lavage fluids, and transbronchial biopsy indicated organizing pneumonia. Cryptogenic organizing pneumonia (COP) was diagnosed and resolved with prednisolone at 30 mg/day. Prednisolone was tapered to 3 mg/day without relapse of CEP or COP. This case suggests the overlap and similar pathogenesis of CEP and COP.

Pulmonary complications of treatment with pegylated interferon for hepatitis C infection-two case reports.

Pegylated interferon (Peg-IFN) in combination with ribavirin is the standard of care in the treatment of chronic hepatitis C (HCV). Peg-IFN is known to have a number of side effects but severe respiratory complications are uncommon. We report two cases, one of Peg-IFN induced interstitial pneumonitis (IP) and the other of bronchiolitis obliterans organising pneumonia (BOOP) in patients with chronic hepatitis C infection. In general, respiratory complications of Peg-IFN are mild and resolve with withdrawal of Peg-IFN. However, as illustrated in our first case fatal interstitial pneumonitis can occur. We present a review of the available literature on Peg-IFN induced lung toxicity. In conclusion, pulmonary toxicity with Peg-IFN is rare but fatality can occur. We highlight the importance of maintaining a high index of suspicion for early diagnosis and prompt treatment, which includes withdrawal of Peg-IFN and consideration of corticosteroid treatment.

Minimal effective dose of maintenance steroid therapy for relapse of cryptogenic organizing pneumonia.

BACKGROUND: Long-term maintenance steroid therapy (MST) is frequently required for repeated relapses of cryptogenic organizing pneumonia (COP); however, the optimal minimal dose has not been clarified. Therefore, this study evaluated the minimal MST dose required to prevent repeated relapses and identify relapse predictors. METHODS: We retrospectively reviewed the medical records of patients with steroid-treated COP and compared background factors between the non-relapse and relapse groups. We also reviewed the treatment course in the relapse group and determined the minimal effective steroid dose based on the MST dose at relapse events and the current relapse prevention dose. RESULTS: In total, 48 patients were identified, including 27 (56%) in the non-relapse group and 21 (44%) in the relapse group. Receiver operating characteristic curve analysis identified prednisolone at 5 mg/day as the optimal cut-off value in the relapse group. Relapse-free time in patients with relapsed COP was significantly longer in the MST dose ≥5 mg/day group than in the <5 mg/day group (log-rank P = 0.003; hazard ratio, 0.19; 95% confidence interval [CI], 0.04-0.60). Multivariate logistic regression analysis demonstrated that a high eosinophil percentage and CD4/CD8 ratio in bronchoalveolar lavage fluid (BALF) were predictors of relapse (odds ratio [OR], 1.12; 95% CI, 1.02-1.23; P = 0.008 and OR, 3.87; 95% CI, 1.29-11.6; P = 0.008, respectively). CONCLUSIONS: Our results indicate that 5 mg/day of prednisolone may be the minimal effective dose for preventing repeated relapses, and a high BALF eosinophil percentage and CD4/CD8 ratio are independent predictors of relapse.

Etanercept induced organizing pneumonia in a patient with rheumatoid arthritis.

TNF inhibitors are being used in a rapidly expanding number of rheumatoid arthritis (RA) patients due to their effectiveness and acceptable safety profiles. To date, concerns regarding the adverse effects of TNF inhibitors have focused on infections, hematologic malignancies, and demyelinating disorders. Recently, the development of autoantibodies and other autoimmunity has been increasingly reported. Here, we describe a 36-year-old RA patient in whom organizing pneumonia and systemic lupus erythematosus were detected during etanercept treatment.

Temozolomide-associated bronchiolitis obliterans organizing pneumonia successfully treated with high-dose corticosteroid.

Temozolomide is an oral alkylating agent with clinical activity against glioblastoma multiforme (GM). It is generally well-tolerated and has few pulmonary side effects. We report a case of temozolomide-associated brochiolitis obliterans organizing pneumonia (BOOP) requiring very high-dose corticosteroid treatment. A 56-yr-old woman presented with a 2-week history of exertional dyspnea. For the treatment of GM diagnosed 4 months previously, she had undergone surgery followed by chemoradiotherapy, and then planned adjuvant chemotherapy with temozolomide. After the 1st cycle, progressive dyspnea was gradually developed. Chest radiograph showed diffuse patchy peribronchovascular ground-glass opacities in both lungs. Conventional dose of methylprednisolone (1 mg/kg/day) was begun for the possibility of BOOP. Although transbronchial lung biopsy findings were compatible with BOOP, the patient's clinical course was more aggravated until hospital day 5. After the dose of methylprednisolone was increased (500 mg/day for 5 days) radiologic findings were improved dramatically.

Chronic exposure to particles caused bronchioloalveolar carcinoma in a patient with cryptogenic organizing pneumonia evaluated by elemental analysis.

An 81-year-old Japanese man had organizing pneumonia (OP), and he had worked as a painter and had a history of exposure of various paints over 20 years. The major features on computed tomography (CT) in patients were cryptogenic organizing pneumonia (COP) showing airspace consolidation, and air bronchograms were consistent finding in consolidation in right lung of S¹°. Such parenchymal abnormalities were clinically and pathologically diagnosed COP and the lesion was improved by corticosteroid therapy. About 1.5 years later, similar shadows emerged in new locations of right S4 and left S8, and these were bronchioloalveolar carcinoma (BAC) classified as adenocarcinoma. BAC causes similar X-ray changes to COP and inflammation accompanying BAC can also respond to corticosteroids, which may lead to delay in the diagnosis of BAC associated with COP. These radiological features lead to difficulty in making a diagnosis of new parenchymal diseases. The present patient had been painter, and metals of carcinogens were proven in both tissue of COP and BAC. Here, we reported a painter with COP and new-onset BAC who had been exposed to particles proven by elemental analysis. The combination of COP with BAC is considered uncommon, but the risk of BAC may increase when there is a history of particle inhalation.

Disease-modifying antirheumatic drugs and organising pneumonia.

Organising pneumonia (OP) in rheumatoid arthritis (RA) may be part of pulmonary manifestation (disease related) or disease-modifying antirheumatic drugs (DMARDs) related. We report a case series of RA patients with DMARDs related OP. A 65-year-old woman developed OP 3 weeks after initiation of methotrexate (MTX). High-resolution CT (HRCT) scan of the thorax revealed bilateral consolidations in the lung bases. She had complete radiological resolution 6 months after corticosteroid therapy with cessation of MTX. The second case was of a 60-year-old woman on MTX with recent addition of leflunomide due to flare of RA. She developed worsening cough 4 months later and HRCT scan revealed consolidation in the left upper lobe with biopsy proven OP. She responded within 6 months of corticosteroid therapy with clinical and radiological resolution. This case series highlights that OP may developed with low-dose MTX (as early as 3 weeks) and leflunomide and the diagnosis requires a high index of suspicion.