a 52-year - old male , 30-pack - year current smoker , visited the emergency room complaining of severe chest pain and dyspnea .
a chest x - ray showed a large amount of pneumothorax in the right pleural cavity ( fig .
initial computed tomography showed diffuse lung emphysema , sequelae of tuberculosis in the right lung , and multiple bullae in the right upper and lower lobes .
surgery was required because of continuous air leakage through the chest drain for 4 days after a closed thoracostomy .
after multiple wedge resections of the right upper and lower lobes , the resection sites were covered with an absorbable polyglycolic acid sheet ( neoveil ; gunze ltd . ,
a mixture of 40 mg of viscum album extract ( european mistletoe , abnoba viscum f ; abnoba helmittel gmbh , pforzheim , germany ) with 50 ml of normal saline was administered into the pleural space by needle instillation upon the visceral and parietal pleura .
until the second postoperative day , the recovery was uneventful , with both lung fields clear on chest x - ray ( fig .
the patient started to complain of worsening dyspnea even at rest , and a follow - up chest x - ray showed loculated right pleural effusion and bilateral lung infiltration .
arterial blood gas analysis under 5 l of oxygen inhalation showed that arterial oxygen pressure ( pao2 ) was 42.0 mm hg and oxygen saturation was 78.9% .
after intubation and mechanical ventilator support , the follow - up arterial blood gas analysis showed a pao2 of 66.9 mm hg under with a fraction of inspired oxygen of 60% .
in addition , the follow - up complete blood cell count showed a white blood cell count of 10,940/mm , a neutrophil percentage of 88.0% , and a lymphocyte percentage of 10.0% .
bronchoscopy indicated that bronchial secretion was minimally purulent , and there were no abnormal findings suggesting the presence of bronchitis or pneumonia ( fig .
, the patient was diagnosed with acute respiratory distress syndrome ( ards ) resulting from insult and an immunologic response to viscum album .
methylprednisolone ( 50 mg / day ) was administered starting on the fourth postoperative day . though the initial signs suggested the development of ards , the clinical course after mechanical ventilator support was quite smooth , with good response to glucocorticoid therapy .
the lung infiltration on the chest x - ray rapidly resolved after 3 days of steroid administration .
the patient was discharged in good general condition on the 16th postoperative day ( fig .
3 ) . a follow - up chest x - ray 1 month after discharge showed no pleural effusion and no abnormal lung infiltration .
many therapeutic options have been used to treat uncontrolled air leaks from the lung or pleural effusion . among these , chemical pleurodesis using sclerosing agents , such as tetracycline , erythromycin , hydrophilic fumed silica , and talc powder , is one of the most important treatment modalities .
irritation of the pleura by instilled chemical agents promotes the sealing of the visceral pleural defect and prevents fluid accumulation .
however , chemical pleurodesis is also associated with many complications , such as high fever , severe chest wall pain , fibrothorax , empyema thoracis , and acute respiratory failure .
it is believed that transpleural absorption and intrapulmonary deposition of sclerosing agents occur via lymphatic stomata in the parietal pleura , resulting in the development of ards .
the instilled drugs induce diffuse inflammation , pleural coagulation , fibrinolytic imbalance , formation of fibrin adhesions , and recruitment and subsequent proliferation of fibroblasts and collagen production in the pleural space .
several new chemical agents are being investigated for their efficacy as pleurodesis agents with fewer complications , and viscum album extract is one of the most promising .
abnoba viscum f is an extract of viscum album ( european mistletoe ) , which grows on trees of the genus fraxinus .
this extract is one of the most frequently prescribed medications for the complementary treatment of cancer patients in a number of european countries .
it is known to stimulate the immune system , thereby enhancing quality of life and alleviating the side effects of chemotherapy and radiotherapy , which may improve survival .
in addition , viscum album instilled into the pleural cavity can induce diffuse inflammation and pleural coagulation / fibrinolytic imbalance , causing the formation of fibrin adhesions , recruitment and subsequent proliferation of fibroblast , and collagen production in the pleural space .
these reactions irritate the pleural surface , thus promoting the sealing of pleural defects and preventing fluid accumulation .
complications of viscum album pleurodesis have been reported and are mostly minor , including transient pleural effusion , a mild burning sensation , and mild fever episodes ; there have been no reports of serious complications .
viscum alum can also serve as an effective agent for chemical pleurodesis in the treatment of congenital chylothorax and pneumothorax with continuous air leak .
cho et al .   reported a case of viscum album - related ipsilateral acute pneumonitis after wedge resection for pneumothorax , and stated that it was self - limiting and had a benign clinical course .
however , in our case , the patient complained of progressive dyspnea with chest pain 2 days after wedge resection and chemical pleurodesis with viscum album .
the follow - up chest x - ray showed loculated pleural effusion and bilateral lung infiltration .
the blood gas analysis result and chest x - ray findings met the criteria of ards .
the materials used in surgery , such as neoveil and fibrin glue , are unlikely to be related to the development of ards , and we could not find any report of such an association .
in addition , the intraoperative course and postoperative course were similar to that of any other routine wedge resection , and otherwise uneventful .
furthermore , the pathophysiology of ards is thought to be related to immune reaction , which is the modality of action for viscum album as a pleurodesis and antitumor agent .
therefore , we assumed that the immune response to the viscum album extract was the cause of this episode of ards .
this is the first documented case of viscum album - related ards , to our knowledge .
respiratory deterioration was acute and progressive , which required placing the patient under intubation and mechanical ventilation .
fortunately , the response to steroid therapy was almost instantaneous and the patient showed almost full recovery without any notable sequelae or relapse after scheduled tapering down of the steroid . based on our experience , even though viscum album pleurodesis is considered to be a generally safe and effective procedure without serious complications , patients must be carefully monitored for signs of acute respiratory failure , which might be serious if appropriate treatment is not applied in time .
in addition , the pathophysiology of ards due to the immunologic response to viscum album extract must be investigated by scientific research , including animal studies .
 a 52-year - old male patient who underwent multiple wedge resections experienced postoperative acute respiratory distress syndrome in both lungs after viscum album pleurodesis . despite initial rapid deterioration in clinical condition and rapid progression of bilateral lung infiltration 
 , he exhibited a relatively smooth clinical recovery with marked response to glucocorticoid treatment . 
 our case report suggests that care must be taken to guard against the development of acute respiratory complications in the use of viscum album for pleurodesis . 
 however , in view of the clinically benign course , initial aggressive management of complications can prevent suffering and sequelae . 
Case report
Discussion