Amiodarone-induced pulmonary inflammation. Correlation with drug dose and lung levels of drug, metabolite, and phospholipid

Myeloid bodies is not an uncommon ultrastructural finding

The presence of myeloid bodies (MBs) is classically associated with Fabry disease (FD). However, MBs are also identified in patients without clinical evidence of FD. We attempt to further understand the clinicopathologic significance of incidental MBs in those without FD. Among the 4400 renal biopsies accessioned at the University of Rochester Medical Center from 2010 to 2021, we identified 32 cases showing MBs, 6 of which had FD. Medications were compared between a non-FG and a control-group of randomly selected cases without MBs (non-MBs). Both Fabry-group (FG) and non-Fabry-group (non-FG) were predominantly middle-aged (mean 48 years vs 56, respectively). Non-FG had slight female predominance (1:4), while all in FG were female. The majority of both non-FG and non-MBs cohort were on the same medications reported to cause phospholipidosis except sertraline and hydralazine (p = .04), which were more frequent in non-FG. Ultrastructurally, non-FG tended to show focal MBs in predominantly podocytes, while FG showed more extensive MBs in not only podocytes but also parietal, tubular, endothelial, and myocyte cells (p = .03). In addition, half of FG had another superimposed renal disease including kappa-light chain deposition disease, thin-basement membrane nephropathy, and lithium-related changes. MBs are encountered not only in FD but in other settings including CADs, toxins, and other inheritable diseases. Although secondary causes of MBs typically show less extensive involvement compared to FD, these features overlap. Given the challenges in diagnosing female carriers, the finding of MBs, though not specific to FD, may be the only clue that leads to further work-up and timely diagnosis, underscoring the importance of considering FD among other etiologies in differential diagnosis.

Imaging drugs, metabolites and biomarkers in rodent lung: a DESI MS strategy for the evaluation of drug-induced lipidosis

Within drug development and pre-clinical trials, a common, significant and poorly understood event is the development of drug-induced lipidosis in tissues and cells. In this manuscript, we describe a mass spectrometry imaging strategy, involving repeated analysis of tissue sections by DESI MS, in positive and negative polarities, using MS and MS/MS modes. We present results of the detected distributions of the administered drug, drug metabolites, lipid molecules and a putative marker of lipidosis, di-docosahexaenoyl (22:6)-bis(monoacylglycerol) phosphate (di-22:6-BMP). A range of strategies have previously been reported for detection, isolation and identification of this compound, which is an isomer of di-docosahexaenoic (22:6 n-3) phosphatidylglycerol (di-22:6 PG), a commonly found lipid that acts as a surfactant in lung tissues. We show that MS imaging using MS/MS can be used to differentiate these compounds of identical mass, based upon the different distributions of abundant fragment ions. Registration of images of these fragments, and detected drugs and metabolites, is presented as a new method for studying drug-induced lipidosis in tissues. Graphical abstract.

Comparison of Oral, Intranasal and Aerosol Administration of Amiodarone in Rats as a Model of Pulmonary Phospholipidosis

‘Foamy’ alveolar macrophages (FAM) observed in nonclinical toxicology studies during inhaled drug development may indicate drug-induced phospholipidosis, but can also derive from adaptive non-adverse mechanisms. Orally administered amiodarone is currently used as a model of pulmonary phospholipidosis and it was hypothesized that aerosol administration would produce phospholipidosis-induced FAM that could be characterized and used in comparative inhalation toxicology. Han-Wistar rats were given amiodarone via (1) intranasal administration (6.25 mg/kg) on two days, (2) aerosol administration (3 mg/kg) on two days, (3) aerosol administration (10 mg/kg) followed by three days of 30 mg/kg or (4) oral administration (100 mg/kg) for 7 days. Alveolar macrophages in bronchoalveolar lavage were evaluated by differential cell counting and high content fluorescence imaging. Histopathology and mass-spectrometry imaging (MSI) were performed on lung slices. The higher dose aerosolised amiodarone caused transient pulmonary inflammation (p < 0.05), but only oral amiodarone resulted in FAM (p < 0.001). MSI of the lungs of orally treated rats revealed a homogenous distribution of amiodarone and a putative phospholipidosis marker, di-22:6 bis-monoacylglycerol, throughout lung tissue whereas aerosol administration resulted in localization of both compounds around the airway lumen. Thus, unlike oral administration, aerosolised amiodarone failed to produce the expected FAM responses.

Chronic Obstructive Pulmonary Disease and Cardiac Diseases. An Urgent Need for Integrated Care

Chronic obstructive pulmonary disease (COPD) is a global health issue with high social and economic costs. Concomitant chronic cardiac disorders are frequent in patients with COPD, likely owing to shared risk factors (e.g., aging, cigarette smoke, inactivity, persistent low-grade pulmonary and systemic inflammation) and add to the overall morbidity and mortality of patients with COPD. The prevalence and incidence of cardiac comorbidities are higher in patients with COPD than in matched control subjects, although estimates of prevalence vary widely. Furthermore, cardiac diseases contribute to disease severity in patients with COPD, being a common cause of hospitalization and a frequent cause of death. The differential diagnosis may be challenging, especially in older and smoking subjects complaining of unspecific symptoms, such as dyspnea and fatigue. The therapeutic management of patients with cardiac and pulmonary comorbidities may be similarly challenging: bronchodilators may have cardiac side effects, and, vice versa, some cardiac medications should be used with caution in patients with lung disease. The aim of this review is to summarize the evidence of the relationship between COPD and the three most frequent and important cardiac comorbidities in patients with COPD: ischemic heart disease, heart failure, and atrial fibrillation. We have chosen a practical approach, first summarizing relevant epidemiological and clinical data, then discussing the diagnostic and screening procedures, and finally evaluating the impact of lung-heart comorbidities on the therapeutic management of patients with COPD and heart diseases.

Drug-Induced Lung Toxicity

The number of blood-borne chemotherapeutic agents implicated in drug-induced lung toxicity continues to increase, although problems in detection remain. The initiation of drug-induced lung injury can have an immunologic or nonimmunologic basis. If endothelial cells are injured, interstitial pulmonary edema may result. Regardless of the source of injury, the progression of drug-induced lung toxicity is often quite similar, involving (1) parenchymal damage, (2) recruitment of inflammatory cells, and (3) progression of the inflammatory process. If the inflammatory reponse is sufficiently severe and disperse, increased collagen can be deposited in interstitial and intra-alveolar areas. The resulting attenuation of gas exchange can induce dyspnea and possibly death. Recent research suggests mediation of the fibrogenic process via cytokines such as transforming growth factor-β and tumor necrosis factor. Preliminary results demonstrating amelioration of cytokine mediated lung-induced fibrosis in animal models with appropriate antibodies suggest a possible future modality of therapy. Certain amphiphilic drugs are capable of eliciting a more specific form of lung toxicity. This class of drugs can interfere with phospholipid metabolism in pulmonary macrophages. In these cases, phospholipidosis results from phospholipid accumulation. The physiologic sequelae in human phospholipidosis is still uncertain.

Altered surfactant homeostasis and alveolar epithelial cell stress in amiodarone-induced lung fibrosis

Amiodarone (AD) is a highly efficient antiarrhythmic drug with potentially serious side effects. Severe pulmonary toxicity is reported in patients receiving AD even at low doses and may cause interstitial pneumonia as well as lung fibrosis. Apoptosis of alveolar epithelial type II cells (AECII) has been suggested to play an important role in this disease. In the current study, we aimed to establish a murine model of AD-induced lung fibrosis and analyze surfactant homeostasis, lysosomal, and endoplasmic reticulum (ER) stress in this model. AD/vehicle was instilled intratracheally into C57BL/6 mice, which were sacrificed on days 7, 14, 21, and 28. Extent of lung fibrosis development was assessed by trichrome staining and hydroxyproline measurement. Cytotoxicity was assessed by lactate dehydrogenase assay. Phospholipids (PLs) were analyzed by mass spectrometry. Surfactant proteins (SP) and markers for apoptosis, lysosomal, and ER stress were studied by Western blotting and immunohistochemistry. AECII morphology was evaluated by electron microscopy. Extensive lung fibrosis and AECII hyperplasia were observed in AD-treated mice already at day 7. Surfactant PL and SP accumulated in AECII over time. In parallel, induction of apoptosis, lysosomal, and ER stress was encountered in AECII of mice lungs and in MLE12 cells treated with AD. In vitro, siRNA-mediated knockdown of cathepsin D did not alter the AD-induced apoptotic response. Our data suggest that mice exposed to intratracheal AD develop severe pulmonary fibrosis, exhibit extensive surfactant alterations and cellular stress, but AD-induced AECII apoptosis is not mediated primarily via cathepsin D.

Drug-induced phospholipidosis: issues and future directions

Numerous drugs containing a cationic amphiphilic structure are capable of inducing phospholipidosis in cells under conditions of in vivo administration or ex vivo incubation. The principal characteristics of this condition include the reversible accumulation of polar phospholipids in association with the development of unicentric or multicentric lamellated bodies within cells. There is an abundance of data providing an understanding of potential mechanisms for the induction of phospholipidosis; however, the process is likely to be complex and may differ from one drug to another. The functional consequences of the presence of this condition on cellular or tissue function are not well understood. The general consensus is that the condition is an adaptive response rather than a toxicological manifestation; however, additional studies to examine this question are needed. Until this issue is resolved, concerns about phospholipidosis will continue to exist at regulatory agencies. Procedures for the screening of potential phospholipogenic candidate compounds are available. In contrast, a clear need exists for the identification of valid biomarkers to assess the development of phospholipidosis in preclinical and clinical studies.

Amiodarone pulmonary toxicity: a patient with three recurrences of pulmonary toxicity and consideration of the probable risk for relapse

A 44-year-old man was treated with amiodarone for dilated cardiomyopathy. After 53 months, he developed amiodarone-induced interstitial pneumonia. Amiodarone treatment was terminated, and the patient was given corticosteroids. These treatments were effective. However, pneumonitis recurred whenever prednisolone was reduced to less than 5 mg per day. Considering the patient's background characteristics, we considered his body mass index (BMI, kg/m(2)) and found his to be high. When four additional patients with amiodarone pulmonary toxicity were reviewed at our institute, a correlation between BMI and the duration of shadow disappearance was found (R(2)=0.8695). Because amiodarone is lipophilic, the patient's high BMI might have influenced the repeated appearance of pulmonary toxicity.

Susceptibility to amiodarone-induced pulmonary toxicity: relationship to the uptake of amiodarone by isolated lung cells

In previous studies, we showed that Fischer rats fed 175 mg/kg of amiodarone accumulated large amounts of drug and metabolite in the lung and developed pulmonary toxicity, whereas Wistar rats fed the same drug dose had significantly less amiodarone in the lung and did not develop pulmonary inflammation. The present study was designed to determine whether this difference in susceptibility between the strains was related to differences in uptake of amiodarone by lung cells. We found that isolated mixed lung cells of Fischer rats sequester significantly more drug than cells from Wistar rats. This difference in uptake cannot be due to drug metabolism because the lung is not capable of metabolizing amiodarone. We also found that the alveolar macrophage is one of the cell types in the mixed cell population that is partially responsible for the difference in drug uptake and that fibroblasts and type II pneumocytes are not involved. In addition, despite the fact that there was no difference in drug uptake, we found that fibroblasts isolated from Fischer rats were more susceptible to amiodarone-induced cytotoxicity than were Wistar fibroblasts. We conclude that genetic differences in lung drug sequestration and possibly the sensitivity to cytotoxicity may explain differences in susceptibility to amiodarone-induced pulmonary toxicity.

Intratracheal amiodarone administration to F344 rats directly damages lung airway and parenchymal cells

Amiodarone (AD) is gaining support as a first-line antiarrhythmic drug despite its potentially fatal pulmonary toxicity involving inflammation and fibrosis. We previously reported a model for this amiodarone-induced pulmonary toxicity (AIPT) in which F344 rats were intratracheally (i.t.) instilled with AD (6.25 mg/kg) in sterile water on days 0 and 2, which led to transient pulmonary inflammation and lung damage and subsequent fibrosis. The goals of this study were to determine the direct effect of the drug in the lung damage occurring after i.t. AD administration, to identify its location, and to examine its potential mechanisms. Using bronchoalveolar lavage and laser-scanning confocal microscopy, it was discovered that AD instillation produces rapid and massive damage to the alveolar-capillary barrier and damage or death to lung airway and parenchymal cells. While AD in solution was found to be capable of generating hydroxyl radicals, protection from AD-induced damage could not be obtained by incorporating water-soluble antioxidants in the drug solution. However, damage induced by free-radicals could still occur after AD partitions into lipid membranes. AD could also be directly disrupting cellular membranes via its amphiphilic structure. It is not known if the mechanism(s) of damage following i.t. AD treatment are similar to the mechanisms that underlie human AIPT. Therefore these data suggest that investigators should use caution in extrapolating results from animal studies that utilize i.t. administration of AD to human AIPT.

Estudo do efeito da amiodarona sobre o peso corpóreo e sobre determinantes morfológicos e citopatológicos do pulmão em ratos machos e fêmeas das linhagens Wistar, Wistar-Kyoto e SHR

Introdução: A maioria dos estudos experimentais sobre a toxicidade pulmonar induzida por amiodarona tem sido realizada em ratos machos da linhagem Fischer-344. Objetivos: Investigar o efeito da amiodarona sobre o peso corpóreo e sobre determinantes morfológicos e citopatológicos do pulmão em outras linhagens de ratos de ambos os sexos. Métodos: Grupos de ratos machos e de fêmeas das linhagens Wistar, Wistar-Kyoto (WKY) e espontaneamente hipertenso (SHR) receberam, por gavagem, durante quatro semanas, 175mg/kg/dia de amiodarona em suspensão salina. Os grupos controles receberam apenas salina. Foram estudados ganho de peso corpóreo, celularidade total e diferencial do lavado broncoalveolar (LBA) e histopatologia dos pulmões. Resultados: Mortalidade pela amiodarona foi observada nos ratos WKY tratados, sendo maior em machos. Animais SHR tratados de ambos os sexos apresentaram o menor ganho de peso entre as linhagens estudadas. Ratos machos Wistar e SHR tratados apresentaram maior ganho de peso do que as fêmeas das suas respectivas linhagens. O LBA de ratos SHR tratados de ambos os sexos era hemorrágico. A celularidade do LBA foi maior em machos tratados (WKY > Wistar > SHR). Entretanto, nos machos e fêmeas WKY a contagem diferencial mostrou o menor percentual de macrófagos e o maior de neutrófilos entre as três linhagens. Macrófagos do LBA de ratos Wistar tratados apresentavam fosfolipidose, enquanto a maioria dos macrófagos de ratos SHR tratados eram normais. No exame anatomopatológico dos pulmões, não houve diferenças entre os sexos e não foi observada pneumonite. Em ratos Wistar o exame foi caracterizado pela acentuada quantidade de macrófagos "espumosos" intra-alveolares, em ratos WKY, por inúmeros abscessos intraparenquimatosos e em ratos SHR, pela hemorragia alveolar. Conclusões: 1) a amiodarona induz em ratos Wistar maior quantidade de macrófagos espumosos do que nas linhagens WKY e SHR, embora no modelo utilizado eles não desenvolvam pneumonite; 2) a amiodarona tem maior efeito sobre os determinantes morfológicos e citopatológicos do pulmão em animais do sexo masculino.

Amiodarone-induced phospholipidosis: an in vivo [14C]-acetate uptake study in rat

Amiodarone (AD), a potent antiarrhythmic drug, is often associated with several adverse effects. It is shown to accumulate phospholipids in various tissues, and the impaired catabolism of phospholipids has been implicated in AD-induced phospholipidosis. The synthesis of phospholipids in tissues has not been dealt with. Hence, the incorporation of [14C]-acetate into phospholipids has been studied to understand the AD-induced phospholipidosis in lung and liver. A significant increase in lung and liver phospholipids was observed after 21 and 28 days of AD (175 mg/kg body weight/day) treatment. In the lung and liver, the incorporation of [14C]-acetate into all phospholipid fractions was elevated, while in the lung mitochondria phosphatidylcholine, phosphatidyl ethanolamine and the cardiolipin levels were significantly increased. The results indicate that, in addition to the impaired catabolism of phospholipid, AD treatment resulted in increased phospholipid synthesis.

Effect of amiodarone on the membrane bound enzymes of rat intestine

Amiodarone, a cationic amphiphile known for its clinical efficacy as an antiarrhythmic agent, unfortunately causes serious side effects. The present study was undertaken to investigate its intestinal toxicity, on oral administration, using a Wistar rat model. The relationship of drug dose and duration on intestinal toxicity was investigated. Optimum changes were observed after 21 days of AD administration at a dose of 175 mg/Kg body wt/day and this dosage was used for further studies. Histological studies revealed decreased villi and crypt size and reduction in the cellularity of lamina propria. Marked reduction in the activities of Ca(2+)-ATPase, alkaline phosphatase, disaccharidases and Na+, K(+)-ATPase was observed. The reduction in the uptake of 14C-glucose and 14C-glycine, in vivo, was correlated to the reduction in the activities of these enzymes. The reduction in the activities of the intestinal membrane bound enzymes may be attributed to altered morphology of the villi and crypts.

Amiodarone-induced pulmonary toxicity in Fischer rats: release of tumor necrosis factor alpha and transforming growth factor beta by pulmonary alveolar macrophages

Amiodarone is an antiarrhythmic drug with numerous side effects, the most serious being the development of pulmonary toxicity. We have previously reported that a single intratracheal instillation of amiodarone to Fischer 344 rats results in pulmonary fibrosis within 6 wk of treatment. Presently, the mechanism of amiodarone-induced pulmonary toxicity is unknown. Cytokines that stimulate fibroblast proliferation and/or collagen production may play a role in amiodarone-induced pulmonary toxicity. To investigate this possibility, female rats were given a single intratracheal instillation of amiodarone (6.25 mg/kg), its metabolite desethylamiodarone (5 mg/kg), or vehicle (sterile water). At 1, 2, 3, or 6 wk after treatment the lungs were lavaged and the recovered cells were counted and identified. The alveolar macrophages were isolated by attachment to plastic petri dishes, cultured overnight, and the spent media collected for tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) analyses. Desethylamiodarone treatment resulted in a neutrophilic alveolitis, but the levels of TNF-alpha and TGF-beta were not significantly different from control animals. In contrast, amiodarone treatment resulted in a lymphocytic alveolitis and significantly higher amounts of TNF-alpha were observed at 3 and 6 wk after treatment. A trend toward higher levels of TGF-beta was also noted in the amiodarone-treated group at wk 1-3 but the values were not significantly different from those of controls. In conclusion, the release of TNF-alpha may play a role in the development of amiodarone-induced pulmonary toxicity.

Amiodarone-induced pulmonary fibrosis in Fischer 344 rats

Amiodarone is a potent antiarrhythmic agent with a number of side-effects, the most serious being the development of pulmonary toxicity. The purpose of the study was to determine if a single intratracheal instillation of amiodarone would induce pulmonary fibrosis and associated functional changes in rats. Female Fischer 344 rats were given a single intratracheal instillation of 200 microliters containing 1.25 mg amiodarone (n = 9) while the control group received an equivalent volume of sterile water (n = 8). After 6 weeks, pulmonary function tests, lung hydroxyproline measurements and lung histology were performed. The amiodarone-treated animals showed a significant reduction in the coefficient of diffusion (kCO) and a significant increase in lung hydroxyproline levels as compared to the control group. The treated group had abnormal histology including areas of septal thickening with cellular infiltration of the interstitial and alveolar spaces, whereas the control group had normal histology. These observations suggest that the intratracheal instillation route of amiodarone treatment produces a fibrotic response in rats that can be measured physiologically, biochemically and histologically. This model may aid in the elucidation of the mechanism of amiodarone-induced pulmonary toxicity (AIPT)./ABS.

Comparative evaluation of amiodarone-induced phospholipidosis and drug accumulation in Fischer-344 and Sprague-Dawley rats

Amiodarone (AD) and its major metabolite, desethylamiodarone (desethylAD), are both phospholipogenic. The present study was undertaken to evaluate the comparative susceptibilities of male Fischer-344 and Sprague-Dawley rats to AD-induced phospholipidosis in alveolar macrophages (AMs), liver and kidney tissue and the concomitant accumulation of AD and desethylAD in these cells, tissues and plasma. Rats were administered AD (100 mg/kg/day, p.o.) for 1 week. Plasma concentrations of AD and desethylAD were approximately 4- and 12-fold higher, respectively, in Fischer-344s compared to Sprague-Dawleys 24 h after the last dose. AD and desethylAD levels in AMs were approximately 12- and 25-fold higher, respectively, in Fischer-344s than Sprague-Dawleys. In the liver and kidney, levels of both compounds were also significantly higher in Fischer-344s than Sprague-Dawleys. Ultrastructural features indicative of phospholipidosis were not observed consistently in any tissue except AMs from treated Fischer-344s. AM total phospholipid increased nearly 5-fold in Fischer-344s, while Sprague-Dawleys showed no increase over control. AMs from both strains incubated with 10 microM AD or desethylAD in vitro were not significantly different in their accumulation of the compounds. When incubated with AD or desethylAD, the lysosomal phospholipases A1 partially purified from AMs of both strains were equally sensitive to inhibition as measured by the drug concentration giving 50% inhibition in activity (IC50). The results of this study indicate that at the same administered dose, AD and desethylAD, accumulate to higher tissue levels and are more phospholipogenic in male Fischer-344 rats than in male Sprague-Dawley rats. The basis for the high susceptibility of Fischer-344 rats to AM-induced phospholipidosis is unknown at present but appears not to be related to biochemical or cellular features of the AMs.

Danger of amiodarone therapy and elevated inspired oxygen concentrations in mice

Our study showed a statistically significant incidence of pulmonary edema in mice receiving amiodarone and 100% oxygen. This finding, together with a variety of clinical reports, indicates that in patients receiving amiodarone therapy, FiO2 should be maintained at the lowest possible level, consistent with adequate oxygenation.

[Recurrent amiodarone lung toxicity after withdrawal of the drug and treatment with corticoids]

We present a case of recidivation in amiodarone-induced pulmonary toxicity 4 months after suspension of the drug, while treatment with corticoids was underway. Possible causes suggested are the persistence of high blood levels of amiodarone and the rapid decrease of corticoid dose.

Amiodarone pneumonitis: no safe dose

Pneumonitis is a serious adverse effect of amiodarone therapy, which is related to the average daily dose. A case of pneumonitis is described which developed after exposure to a low dose of amiodarone. This challenges the concept that low dose amiodarone therapy is safe.

Resistance of the hamster to amiodarone-induced pulmonary toxicity following repeated intraperitoneal administration

Amiodarone is an effective antidysrhythmic agent, restricted in use by the development of pulmonary toxicity. Several in vivo animal models have been used to study amiodarone-induced pulmonary toxicity. Intratracheal administration of amiodarone to the hamster has been used as a model for the critical amiodarone-induced pulmonary fibrosis (AIPF). In order to investigate the cellular mechanism of human AIPF, which occurs following oral or intravenous administration, an animal model of AIPF resulting from systemic administration of the drug would appear to be preferable. We have evaluated pulmonary toxicity following repeated intraperitoneal amiodarone administration to the hamster. Intraperitoneal treatment of hamsters for 1, 4, or 7 weeks with amiodarone (100 mg/kg/day) did not lead to pulmonary toxicity based on wet lung weight, hydroxyproline content, or histological examination. Furthermore, when comparing 1- and 7-week treatment groups, there was no pulmonary accumulation of either amiodarone or desethylamiodarone beyond levels found at 1 week. Therefore, failure to develop pulmonary toxicity may be due to an inability to accumulate sufficient amiodarone and/or desethylamiodarone. Intratracheal administration of amiodarone to rodents remains the only in vivo animal model for studying the mechanism(s) of AIPF.

Cytology of bronchoalveolar lavage in some rare pulmonary disorders: pulmonary alveolar proteinosis and amiodarone pulmonary toxicity

Cytological patterns of bronchoalveolar lavage (BAL) in pulmonary alveolar proteinosis (PAP) and amiodarone pulmonary toxicity (APT) are presented together with light and electron microscopy (EM). The differential cell count of BAL in both diseases is similar in that alveolar macrophages predominate. However, the cytology of PAP is characterized by scanty macrophages and alveolar epithelial cells in abundant periodic acid-Schiff (PAS)-positive extracellular material. The gross appearance of the BAL fluid is therefore opaque. In contrast, the cytology of APT is characterized by foamy alveolar macrophages with numerous lamellar bodies in their cytoplasm, and the BAL fluid is clear.

Amiodarone-associated hemoptysis

The manifestations of amiodarone pulmonary toxicity (APT) are generally nonspecific, and a diagnosis requires appropriate clinical history, laboratory testing consistent with toxicity, and exclusion of other disease entities. To our knowledge, hemoptysis associated with APT has not been described before; the following report describes such a case. We suggest that APT should be considered among the differential diagnosis of hemoptysis in a patient receiving amiodarone.

Amiodarone pulmonary toxicity in the rat is associated with increased lavage immunoglobulin and alveolar macrophages primed for increased interleukin-1 secretion

To determine whether a hypersensitivity reaction played a role in amiodarone-induced pulmonary inflammation and affected humoral immunity, we examined pulmonary immunoglobulin (Ig) levels, alveolar macrophage release of interleukin-1 (IL-1)-like activity, and the ability to generate both systemic and pulmonary humoral immune responses after immunization. Levels of IgG, IgM, and albumin in lavage fluid were measured by enzyme-linked immunosorbent assay (ELISA) in control rats and rats fed drug for 3, 8, 11, and 30 wk. Control rats showed no change in lavage Ig levels at any time point. However, drug-fed rats had a significant increase in IgG/albumin at 11 and 30 wk and IgM/albumin at 30 wk. To determine whether alveolar macrophages were in an activated state, the amount of IL-1-like activity released by cells from control rats was compared with drug-fed rats, using the standard C3H/HeJ thymocyte proliferation assay. We found no difference in the spontaneous release of IL-1 activity, but lipopolysaccharide-stimulated macrophages from the drug-fed rats produced significantly more IL-1 than did control macrophages. Finally, to examine antibody responses, control and drug-fed rats were immunized and boosted with 1 mg/ml of ovalbumin (OA) in adjuvant followed by an intratracheal immunization of OA. There was no difference in antibody titers measured by ELISA. In conclusion, although there is some suggestion of an immune-mediated component in amiodarone-induced pulmonary inflammation, the increase in lymphocytes and lavage Ig appears too late to be the sole cause.

Amiodarone pneumonitis. Bronchoalveolar lavage findings in 15 patients and review of the literature

Amiodarone (Am) pneumonitis is currently a common and potentially severe adverse reaction, the accurate diagnosis of which remains difficult to establish.

OBJECTIVES

To determine the contribution of bronchoalveolar lavage (BAL) in the diagnostic workup of patients suspected of having Am pneumonitis.

METHODS

Diagnosis of Am pneumonitis was established on the basis of (1) development of recent symptoms and pulmonary opacities while receiving the drug, (2) exclusion of other possible causes, and (3) improvement following cessation of Am and/or steroid therapy. (4) Confirmatory changes were obtained by histopathologic examination in eight cases. BAL was performed in each patient at the time of initial evaluation.

RESULTS

Am pneumonitis was diagnosed in 15 consecutive patients between 1985 and 1991. The disease was associated with significant morbidity and mortality. Six patients died; four died of Am pneumonitis. A neutrophilic BAL was found in nine patients (average PMN = 26.6 percent). A mixed pattern (lymphocytic + neutrophilic) was seen in four patients (average: Ly = 19.9 percent; PMN = 11.9 percent). Two patients had a normal BAL. No patient had a lymphocytic pattern. A low CD4+/CD8+ ratio was seen in two patients. A literature survey indicated 70 cases of Am pneumonitis with detailed information on BAL. The BAL pattern was mixed in 23 (33 percent), neutrophilic in 18 (26 percent), lymphocytic in 15 (21 percent), and normal in 14 (20 percent). No correlation was found between BAL pattern and prognosis. Also, BAL pattern was related neither to daily or total dose of Am nor to duration of treatment with Am.

CONCLUSION

The cellular profile of BAL in Am pneumonitis is highly variable, and no cellular pattern of BAL seems to be predictive of a detrimental outcome or of irreversible fibrosis. Aside from excluding other illnesses, and due to its extreme variability, the contribution of BAL differential in the initial workup of patients suspected of having Am pneumonitis is limited.

Amiodarone pulmonary toxicity

Amiodarone is an effective antiarrhythmic agent whose utility is limited by many side-effects, the most problematic being pneumonitis. The pulmonary toxicity of amiodarone is thought to result from direct injury related to the intracellular accumulation of phospholipid and T cell-mediated hypersensitivity pneumonitis. The clinical and radiographic features of amiodarone-induced pulmonary toxicity are characteristic but nonspecific. The diagnosis depends on exclusion of other entities, such as heart failure, infection, and malignancy. While withdrawal of amiodarone leads to clinical improvement in majority of cases, this is not always possible or advisable. Dose reduction or concomitant steroid therapy may have a role in selected patients.