Lymphoid hyperplasia and eosinophilic pneumonia as histologic manifestations of amiodarone-induced lung toxicity

Acute and chronic eosinophilic pneumonia: an overview

Acute and chronic eosinophilic pneumonia (AEP and CEP) include a group of rare interstitial lung diseases characterized by peripheral blood eosinophilia, increased eosinophils in bronchoalveolar lavage fluid, or eosinophilic infiltration of lung parenchyma. AEP is characterized by rapid onset, fast response to steroid treatment, and no relapse. CEP is characterized by marked tissue and peripheral blood eosinophilia, rapid response to steroid therapy, and tendency to disease recurrence. In addition, we briefly describe other eosinophilic lung diseases that must be considered in differential diagnosis of AEP and CEP. Eosinophilic pneumonias may be idiopathic or due to known causes such as medications or environmental exposure. At variance with previous reviews on this topic, a particular look in this overview was directed at pathological findings and radiological patterns.

Maximizing the Therapeutic Effect of Endothelin Receptor Antagonists in Pulmonary Fibrosis: A Paradigm for Treating the Disease

Using a lipopolysaccharide model of acute lung injury, we previously showed that endothelin-1 (ET-1), a potent mediator of vasoconstriction, may act as a "gatekeeper" for the influx of inflammatory cells into the lung. These studies provided a rationale for testing the effect of HJP272, an endothelin receptor antagonist (ERA), in hamster models of pulmonary fibrosis induced by intratracheal instillation of either bleomycin (BLM) or amiodarone (AM). To determine the temporal effects of blocking ET-1 activity, animals were given HJP272 either 1 h before initiation of lung injury or 24 h afterward. The results indicated that pretreatment with this agent caused significant reductions in various inflammatory parameters, whereas post-treatment was ineffective. This finding suggests that ERAs are only effective at a very early stage of pulmonary fibrosis and explains their lack of success in clinical trials involving patients with this disease. Nevertheless, ERAs could serve as prophylactic agents when combined with drugs that may induce pulmonary fibrosis. Furthermore, developing a biomarker for the initial changes in the lung extracellular matrix could increase the efficacy of ERAs and other therapeutic agents in preventing the progression of the disease. While no such biomarker currently exists, we propose the ratio of free to peptide-bound desmosine, a unique crosslink of elastin, as a potential candidate for detecting the earliest modifications in lung microarchitecture associated with pulmonary fibrosis.

Hesperidin Attenuates Hypothyroidism-Induced Lung Damage in Adult Albino Rats by Modulating Oxidative Stress, Nuclear Factor Kappa-B Pathway, Proliferating Cell Nuclear Antigen and Inflammatory Cytokines

The occurrence of worsening pulmonary function has been connected to hypothyroidism (HPO). Hesperidin (HES) was suggested to have antioxidant, anti-proliferative, and anti-inflammatory potential. Our study's objective was to determine whether HES could reduce carbimazole (CBZ)-induced lung injury more effectively than Eltroxin (ELT) in adult male albino rats or not. At random, 32 rats were distributed into four groups: Group I: normal control, to induce HPO, the remaining three groups were given CBZ (20 mg/kg/day) dissolved in distilled water for 1 week. They were then split up into three groups. Group II: orally administered CBZ (20 mg/kg b.w in water/day), Group III: HES (200 mg/kg/day) dissolved in 1% carboxymethyl-cellulose + CBZ treated, and Group IV: ELT (0.045 mg/kg/day) dissolved in distilled water + CBZ treated. All treatments were delivered for 12 weeks. Blood was collected to assess thyroid-stimulating hormone (TSH) and thyroid hormones (THs). Lung injury was evaluated based on the pulmonary content of interleukin (IL)-35, IL-6, and tumor necrosis factor-alpha (TNF-α), along with the estimation of lipid peroxidation, catalase, glutathione levels, superoxide dismutase, heme oxygenase-1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). The histological, ultrastructural, and immunohistochemical study of nuclear factor Kappa-B (NF-κB) and inducible nitric oxide synthase (iNOS), together with estimating the proliferation of cells using Antigen Ki-67 in lung tissue were performed. HES and ELT primarily suppressed variable lung damage mechanisms by suppressing TSH, the NF-κB/TNF-α pathway, iNOS, lipid peroxidation, Ki-67, and inflammatory mediators. On the other hand, they improved THs, antioxidant parameters, and the Nrf2/HO-1 pathway. HES and ELT exhibited an ameliorative effect that was reflected in the histopathological, immunohistochemical, and ultrastructural results. These results indicate that HES is a pneumoprotective agent that could be a promising treatment for oxidative stress, inflammation, and proliferation.

Lymphoid Interstitial Pneumonia (LIP) Revisited: A Critical Reappraisal of the Histologic Spectrum of "Radiologic" and "Pathologic" LIP in the Context of Diffuse Benign Lymphoid Proliferations of the Lung

The use of lymphoid interstitial pneumonia (LIP) as a diagnostic term has changed considerably since its introduction. Utilizing a multi-institutional collection of 201 cases from the last 20 years that demonstrate features associated with the LIP rubric, we compared cases meeting strict histologic criteria of LIP per American Thoracic Society (ATS)/European Respiratory Society (ERS) consensus ("pathologic LIP"; n=62) with cystic cases fulfilling radiologic ATS/ERS criteria ("radiologic LIP"; n=33) and with other diffuse benign lymphoid proliferations. "Pathologic LIP" was associated with immune dysregulation including autoimmune disorders and immune deficiency, whereas "radiologic LIP" was only seen with autoimmune disorders. No case of idiopathic LIP was found. On histology, "pathologic LIP" represented a subgroup of 70% (62/88) of cases with the distinctive pattern of diffuse expansile lymphoid infiltrates. In contrast, "radiologic LIP" demonstrated a broad spectrum of inflammatory patterns, airway-centered inflammation being most common (52%; 17/33). Only 5 cases with radiologic cysts also met consensus ATS/ERS criteria for "pathologic LIP." Overall, broad overlap was observed with the remaining study cases that failed to meet consensus criteria for "radiologic LIP" and/or "pathologic LIP." These data raise concerns about the practical use of the term LIP as currently defined. What radiologists and pathologist encounter as LIP differs remarkably, but neither "radiologic LIP" nor "pathologic LIP" present with sufficiently distinct findings to delineate such cases from other patterns of diffuse benign lymphoid proliferations. As a result of this study, we believe LIP should be abandoned as a pathologic and radiologic diagnosis.

Diffuse alveolar hemorrhage and acute eosinophilic pneumonia: A rare form of amiodarone pulmonary toxicity diagnosed by bronchoalveolar lavage

A 56-year-old man presented with fever, cough, and bloody sputum. He had undergone mitral valve replacement with mechanical prosthesis 14 months prior for mitral valve disease. Subsequently, the patient was taking warfarin and amiodarone. Chest imaging revealed dense, infiltrative shadows, and blood tests showed prolonged prothrombin time and eosinophilia. Warfarin was withdrawn, and antibiotics were started, but bloody sputum and respiratory failure persisted. Considering that eosinophilia was observed after the administration of amiodarone, the drug was discontinued, and bronchoalveolar lavage was performed. Cytology showed foam cells, eosinophils, and hemosiderin-laden macrophages; amiodarone-induced diffuse alveolar hemorrhage (DAH) and acute eosinophilic pneumonia (AEP) were diagnosed, and the patient was treated with corticosteroids. This report describes the first documented case of amiodarone-induced DAH and AEP. When a patient taking amiodarone presents with antibiotic-refractory pneumonia with bloody sputum and eosinophilia, amiodarone-induced DAH and AEP should be considered.

Learning objective

We report the first case of amiodarone-induced diffuse alveolar hemorrhage (DAH) and acute eosinophilic pneumonia (AEP) diagnosed by foam cells, eosinophils, and hemosiderin-laden macrophages on bronchoalveolar lavage cytology. When a patient taking amiodarone presents with antibiotic-refractory pneumonia with bloody sputum and eosinophilia, amiodarone-induced DAH and AEP should be considered.

A multicenter retrospective cohort study on predicting the risk for amiodarone pulmonary toxicity

BACKGROUND

Amiodarone is one of the most commonly used anti-arrhythmic agents. Amiodarone pulmonary toxicity is a potentially fatal adverse effect associated with amiodarone use. Previous studies on the epidemiology and risk factors for amiodarone pulmonary toxicity showed diverse results.

METHODS

A multicenter retrospective cohort study was conducted to identify clinic-epidemiologic markers associated with amiodarone pulmonary toxicity for development of a prediction rule. Patients taking amiodarone who were managed in 3 centres in Hong Kong from 2005 to 2015 were included in this study. Penalized logistic regression was used to model the outcome as it is rare.

RESULTS

A total of 34 cases with amiodarone pulmonary toxicity were identified among 1786 patients taking amiodarone for at least 90 days from 2005 to 2015. The incidence of amiodarone pulmonary toxicity was estimated to be 1.9%. The risk factors for amiodarone pulmonary toxicity included advanced age (OR 1.047, 95% CI 1.010-1.085, p = 0.013), ventricular arrhythmia (OR 2.703, 95% CI 1.053-6.935, p = 0.039), underlying lung disease (OR 2.511, 95% CI 1.146-5.501, p = 0.021) and cumulative dose of amiodarone (OR 4.762, 95% CI 1.310-17.309 p = 0.018).

CONCLUSIONS

The incidence of amiodarone pulmonary toxicity in Chinese patients in Hong Kong is estimated to be 1.9% in this study. Age, underlying lung disease, ventricular arrhythmia and cumulative dose of amiodarone are associated with the development of amiodarone pulmonary toxicity. A prediction rule was developed to inform the risk of developing amiodarone pulmonary toxicity.

Immune alveolitis in interstitial lung disease: an attractive cytological profile in immunocompromised patients

Background

Bronchoalveolar lavage (BAL) is a major diagnostic tool in interstitial lung disease (ILD). Its use remains largely quantitative, usually focused on cell differential ratio. However, cellular morphological features provide additional valuable information. The significance of the “immune alveolitis” cytological profile, characterized by lymphocytic alveolitis with activated lymphocytes and macrophages in epithelioid transformation or foamy macrophages desquamating in cohesive clusters with lymphocytes, remains unknown in ILD. Our objective was to describe patients’ characteristics and diagnoses associated with an immune alveolitis profile in undiagnosed ILD.

Methods

We performed a monocentric retrospective observational study. Eligible patients were adults undergoing diagnostic exploration for ILD and whose BAL fluid displayed an immune alveolitis profile. For each patient, we collected clinical, radiological and biological findings as well as the final etiology of ILD.

Results

Between January 2012 and December 2018, 249 patients were included. Mean age was 57 ± 16 years, 140 patients (56%) were men, and 65% of patients were immunocompromised. The main etiological diagnosis was Pneumocystis pneumonia (PCP) (24%), followed by drug-induced lung disease (DILD) (20%), viral pneumonia (14%) and hypersensitivity pneumonitis (HP) (10%). All PCP were diagnosed in immunocompromised patients while HP was found in only 8% of this subgroup. DILD and viral pneumonia were also commonly diagnosed in immunocompromised patients (94% and 80%, respectively).

Conclusion

Our study highlights the additional value of BAL qualitative description in ILD. We suggest incorporating the immune alveolitis profile for the diagnosis and management of ILD, especially in immunocompromised patients, since it guides towards specific diagnoses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01871-w.

Acute amiodarone pulmonary toxicity in the form of organizing pneumonia triggered by orthotopic heart transplantation

We report a case of a 60-year-old man who underwent orthotopic heart transplantation after short-term receipt of low-dose oral amiodarone for the management of ventricular tachycardia. Prior to transplant surgery, he had a normal chest radiograph and was free of supplemental oxygen. His initial postoperative chest radiograph showed subtle infiltrates, and thereafter his chest imaging continued to worsen. Although he was eventually able to wean off mechanical ventilation via a tracheostomy, he remained dyspneic and oxygen-dependent with persistently abnormal chest imaging as his post-transplant corticosteroid regimen was being tapered. In light of progressively worsening diffuse lung disease, he underwent bronchoscopy with transbronchial biopsies. Histology revealed foamy macrophages in association with foci of organizing pneumonia, a picture consistent with amiodarone pulmonary toxicity. Given these findings, corticosteroid dosing was increased for the clinical diagnosis of acute amiodarone pulmonary toxicity with subsequent normalization of oxygen saturation and chest radiography. Our case is the first to identify orthotopic heart transplantation as a potential trigger for acute amiodarone pulmonary toxicity. It is also only the second documented example of organizing pneumonia as the histological substrate of amiodarone pulmonary toxicity, which is an association that has therapeutic implications.

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Amiodarone pulmonary toxicity can present acutely, often precipitated by cardiothoracic interventions.

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Organizing pneumonia has only rarely been shown to underlie acute amiodarone pulmonary toxicity.

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Orthotopic heart transplantation surgery was the putative trigger in the present case, making this the first such description.

Crucial Role of PLGA Nanoparticles in Mitigating the Amiodarone-Induced Pulmonary Toxicity

BACKGROUND

Amiodarone (AMD) is a widely used anti-arrhythmic drug, but its administration could be associated with varying degrees of pulmonary toxicity. In attempting to circumvent this issue, AMD-loaded polymeric nanoparticles (AMD-loaded NPs) had been designed.

MATERIALS AND METHODS

AMD was loaded in NPs by the nanoprecipitation method using two stabilizers: bovine serum albumin and Kolliphor® P 188. The physicochemical properties of the AMD-loaded NPs were determined. Among the prepared NPs, two ones were selected for further investigation of spectral and thermal analysis as well as morphological properties. Additionally, in vitro release patterns were studied and kinetically analyzed at different pH values. In vitro cytotoxicity of an optimized formula (NP4) was quantified using A549 and Hep-2 cell lines. In vivo assessment of the pulmonary toxicity on Sprague Dawley rats via histopathological and immunohistochemical evaluations was applied.

RESULTS

The developed NPs achieved a size not more than 190 nm with an encapsulation efficiency of more than 88%. Satisfactory values of loading capacity and yield were also attained. The spectral and thermal analysis demonstrated homogeneous entrapment of AMD inside the polymeric matrix of NPs. Morphology revealed uniform, core-shell structured, and sphere-shaped particles with a smooth surface. Furthermore, the AMD-loaded NPs exhibited a pH-dependent and diffusion-controlled release over a significant period without an initial burst effect. NP4 demonstrated a superior cytoprotective efficiency by diminishing cell death and significantly increasing the IC50 by more than threefold above the pure AMD. Also, NP4 ameliorated AMD-induced pulmonary damage in rats. Significant downregulation of inflammatory mediators and free radicle production were noticed in the NP4-treated rats.

CONCLUSION

The AMD-loaded NPs could ameliorate the pulmonary injury induced by the pure drug moieties. Cytoprotective, anti-fibrotic, anti-inflammatory, and antioxidant properties were presented by the optimized NPs (NP4). Future studies may be built on these findings for diminishing AMD-induced off-target toxicities.

Eosinophilic pneumonia: A rare manifestation of amiodarone toxicity diagnosed using traditional bronchoscopy

Amiodarone is an antiarrhythmic agent used primarily to treat atrial and ventricular arrhythmias. However, the drug also has many adverse effects, including pulmonary toxicity, and a wide range of pulmonary diseases have been reported. Amiodarone-induced eosinophilic pneumonia is a relatively rare adverse effect with an incidence ranging between 5 and 13% [1]. The majority of cases have been diagnosed with lung biopsy, with only one prior reported case diagnosed by bronchoalveolar lavage (BAL) [2]. This report describes the second documented case of amiodarone-induced eosinophilic pneumonia diagnosed by eosinophilia on BAL cytology. In this case, complete cessation of symptoms occurred after discontinuation of amiodarone and treatment with corticosteroids. An updated review of the literature of amiodarone-induced eosinophilic pneumonia is also detailed.

The role of mast cells and macrophages in amiodarone induced pulmonary fibrosis and the possible attenuating role of atorvastatin

Amiodarone (AM) is an effective anti-arrhythmic drug. We investigated the role of mast cells and macrophages on AM induced pulmonary fibrosis and the action of atorvastatin on this fibrosis. Rats were allocated into four groups; negative control (1), positive control (2), 30 mg/kg body weight/day AM (3) and AM + 10 mg/kg/day atorvastatin (4). Lungs were harvested and prepared for histology and immunohistochemistry. Hematoxylin and eosin stained sections of group 3 exhibited disorganized lung architecture. We found cellular debris in the lumen of both intrapulmonary bronchi and bronchioles with partial disruption of the thickened epithelial lining and mononuclear cellular infiltration into the lamina propria. We also observed thickening of the epithelial lining and the smooth muscle layer. Congested, dilated and thickened blood capillaries and thickened inter-alveolar septa were observed with mononuclear cellular infiltrates in the lung of group 3. Most alveoli were collapsed, but some dilated ones were detected. In some alveoli, type ІІ pneumocytes were increased, while type I cells were decreased. We observed significant increases in the amount of collagen in the thickened inter-alveolar septa, around bronchioles and around blood capillaries in sections from group 3. We found a significant increase in mast cells and alveolar macrophages in group 3 compared to group 1. Mast cells and macrophages appear to play important roles in AM induced pulmonary fibrosis. Atorvastatin appears to attenuate this condition.

Minocycline-induced acute eosinophilic pneumonia: A case report and review of the literature

Acute eosinophilic pneumonia (AEP) can be a challenging diagnosis and is often initially misdiagnosed as one of the more common pneumonia syndromes such as acute respiratory distress syndrome. Early bronchoalveolar lavage (BAL) is critical in distinguishing the diagnosis to initiate proper management. The etiology of AEP is unknown, though many drugs have been implicated, including minocycline. Minocycline is commonly used for pneumonia, acute bronchitis, urinary tract infections, and acne and is likely the cause of AEP in our patient. There are 26 case reports of minocycline-induced AEP. In most cases, outcomes were favorable and symptoms rapidly resolved upon discontinuation of minocycline, with 11 cases employing steroids, one case twelve hours of CPAP and another 5 days of intubation. None resulted in mortality. Although it is difficult to evaluate without further studies, steroids should be recommended for minocycline-induced AEP, especially for those with severe or persistent symptoms.

Amiodarone-Induced Lung Injury With Bilateral Lung Pneumonitis and Peripheral Eosinophilia

Amiodarone is a widely used antiarrhythmic that is used in the management of a variety of atrial and ventricular arrhythmias. Amiodarone-induced lung injury is an adverse effect in 5% of patients taking amiodarone, usually within 12 months of commencing therapy. Different mechanisms of injury and histopathological changes have been proposed and described. Eosinophilic pneumonia is one uncommon presentation of amiodarone-induced lung injury. The following is a case report of a 62-year-old woman who, after taking 400 mg of amiodarone twice daily for 8 months, developed bilateral interstitial pneumonitis with peripheral eosinophilia. After cessation of amiodarone, she had significant improvement in terms of her clinical symptoms and partial regression of pulmonary infiltrates on radiological imaging. The case underlies the importance of vigilance monitoring patients who are taking potentially pneumotoxic drugs as well as describing a classic example of drug-induced pneumonitis.

Comparative Study between Intravenous and Intraperitoneal Stem Cell Therapy in Amiodarone Induced Lung Injury in Rat

Background and Objectives:

The fibrosing form of lung injury (occupational, environmental, infective or drug induced) is associated with significant morbidity and mortality. Amiodarone (AM), often prescribed for control of arrhythmias is considered a potential cause. No effective treatment was confirmed, except lung transplantation. Intravenous (IV) stem cell therapy may produce pulmonary emboli or infarctions. Despite being commonly used in clinical practice, the intraperitoneal (IP.) route has been rarely used for cell delivery. The present study aimed at investigating and comparing the possible effect of IP stem cell therapy (SCT) on pulmonary toxicity versus the intravenous route in a rat model of amiodarone induced lung damage.

Methods and Results:

36 adult male albino rats were divided into 4 groups. Rats of AM group were given 30 mg/kg daily orally for 4 weeks. Rats of IV SCT group were injected with stem cells in the tail vein. Rats of IP SCT group received IP cell therapy. Histological, histochemical, immunohistochemical and morphometric studies were performed. Obstructed bronchioles, overdistended alveoli, reduced type I pneumocytes, increased thickness of alveolar septa and vessels wall besides increased area% of collagen fibers regressed in response to IV and IP SCT. The improvement was more obvious in IV group. The area% of Prussion blue +ve and CD105 +ve cells was significantly higher in IV group.

Conclusions:

Cord blood MSC therapy proved definite amelioration of lung injury ending in fibrosis. The effect of IP SCT was slightly inferior to that of IV SCT, which may be overwhelmed by repeated IP injection.

ECMO for pulmonary rescue in an adult with amiodarone-induced toxicity

Amiodarone is a highly effective antiarrhythmic agent. Unfortunately amiodarone-induced pulmonary toxicity is described for medium-long term therapy. We describe a case of a 65-year-old man admitted to our department for breathlessness and with a history of recurrent episodes of atrial fibrillation for which he had been receiving amiodarone (200 mg/day) since 2008. Despite diuretic therapy, along with aspirin, statins and antibiotics the patient continued to complain of severe dyspnea and had a moderate fever. Thus, diagnostic hypotheses different from acute cardiac failure were considered, in particular non-cardiogenic causes of pulmonary infiltrates. Following suspicion of amiodarone-induced pulmonary toxicity, the drug was discontinued and corticosteroid therapy was initiated. Due to the deterioration of the clinical picture, we proceeded to intubation. After few hours from intubation we were forced to institute a veno-venous extracorporeal membrane oxygenation due to the worsening of pulmonary function. The patient’s clinical condition improved which allowed us to remove the ECMO after 15 days of treatment. Indications for use of ECMO have expanded considerably. To our knowledge this is the first successful, reported article of a veno-venous ECMO used to treat amiodarone-induced toxicity in an adult. In patients with severe but potentially reversible pulmonary toxicity caused by amiodarone, extracorporeal life support can maintain pulmonary function and vital organ perfusion at the expense of low morbidity, while allowing time for drug clearance.