Current Respiratory Medicine Reviews - Volume 8, Issue 4, 2012

Descending necrotizing mediastinitis is an acute, polymicrobial infection. Originating in the pharynx or neck, this necrotizing process descends into the chest producing widespread tissue necrosis. Despite the introduction of modern antimicrobial therapy and computed tomographic imaging, this form of mediastinitis has continued to produce reported mortality rates of 25% to 40%. This review discusses the pathophysiology, diagnosis and treatment of descending necrotizing mediastinitis with recommendations for treating physicians based on the modern literature.

Hemothorax is most commonly seen following trauma or iatrogenic injury, but can be related to underlying medical issues. The primary issue to be determine dis whether or not the patient is stable and/or has ongoing hemorrhage. Simple tube thoracostomy usually suffices to manage the problem, but specific subsets of patients are at increased risk of complications, notably empyema. The role, type and timing of surgical intervention depends upon patient stability, underlying etiology and co-existing medical variables.

Formal resectional surgery for benign and malignant diseases of the lungs was one of the last frontiers to be explored and mastered within the broad specialty of surgery. This was the result of the unique physiological properties of the pleural space and the mechanics of respiration. Additional obstacles included the requirement for refined anesthesia, surgical techniques and equipment in order to allow successful control of the airway and vasculature. Despite impressive and ongoing improvement in operative technique, anesthetic management, patient selection and perioperative care, the complexities unique to the airway, pleural space and rigid chest wall continue to make pulmonary resection a challenging undertaking. Post-resection bronchopleural fistula and post-resection empyema, while relatively uncommon, remain perhaps the most morbid and difficult complications encountered in thoracic surgery. Understanding of and adherence to basic principles of management as well as the thoughtful application of innovative therapies have resulted in improved outcomes when these dreaded complications occur.

Prolonged air leak (PAL) is one of the most common complications after pulmonary resection. PAL is associated with longer hospital stay, increased morbidity, and increased cost. PAL can be defined in various ways, but the most commonly accepted definition is an air leak which prolongs the hospital stay. Patients with decreased lung function and emphysema are at the highest risk for PAL, as are patients with intrapleural adhesions. PAL is also associated with various risk factors for poor wound healing (e.g. steroids and malnutrition). PAL is more common after lobectomy, especially upper lobectomy. Fissureless techniques and VATS surgery have been associated with a decreased risk of PAL, as have buttressed staple lines, chemical sealants, and various measures to reduce the volume of the pleural cavity (such as creation of an apical tent or iatrogenic pneumoperitoneum). These techniques may be used routinely, but are usually employed only in high-risk patients or patients with an intraoperative air leak. Early use of water seal has been consistently demonstrated to reduce the incidence of PAL, except when a patient develops an expanding pneumothorax or worsening symptoms on water seal. Patients with PAL who tolerate water seal drainage can be discharged with a chest tube still in place attached to a one-way valve or portable drainage system. For recalcitrant PAL, sclerosants and endobronchial valves have both shown some success. Reoperation is required for <2% of patients with PAL.

The management of spontaneous pneumothorax in the non-ventilated patient is determined by whether or not there is marked underlying lung pathology (secondary) or not (primary). Primary pneumothorax is generally managed initially by simple tube drainage, although the success of operative approaches suggests that earlier intervention may be beneficial. In contrast, patients with severe underlying lung disease have both increased operative risk, as well as failure of both operative and non-operative management. In either setting, early surgical consultation is ideal and particularly in the setting of secondary pneumothorax a multi-modality approach is optimal.

The management of empyema varies according to etiology and chronicity. Empyema most commonly arises in the setting of pneumonia. In general, early surgical drainage, using thoracoscopic approaches, are favored as they appear to be associated with quicker resolution and lower complication rates. However, anatomic and physiologic issues may affect outcomes and approaches, notably the presence or absence of thick visceral peel and/or other causes of a persistent space. In these settings, combined catheter based, medical and more aggressive surgical approaches may be required.

Malignant pleural mesothelioma (MPM) is an aggressive malignancy. It most frequently develops following occupational exposure to asbestos, a highly flame-retardant material used in construction. The delay between exposure and development of MPM ranges from 25-50 years and therefore most patients present in the 5th to 7th decade of life. MPM can present like many other common pleural diseases therefore diagnosis requires clinical acumen. Tissue sampling is required with best results from directed pleural biopsy. Once a diagnosis of MPM has been made, treatment depends upon the stage of disease, histological diagnosis and performance status of the patient. Palliation is reserved for patients with multiple comorbidities that are unlikely to withstand aggressive treatment or patients with advanced disease involving the peritoneum or contralateral hemithorax. Those presenting with epithelial histology, earlier stage and good performance status are candidates for multimodality therapy. Case series report long term survival in patients treated with a trimodality approach involving chemotherapy, surgery and radiation. Our approach is to carefully select patients by thoroughly evaluating patient's physiological status and clinical stage of disease before embarking on induction chemotherapy, extrapleural pneumonectomy and postoperative radiotherapy. By utilizing this paradigm we report outcomes similar to other expert groups treating this aggressive malignancy. In order to improve upon outcomes, novel chemotherapeutic targets need to be identified. Molecular biological techniques are uncovering potential mediators in the carcinogenesis of MPM.

Malignant pleural effusion represents advanced disease. Management is determined by the patient's performance status, symptoms and degree of lung re expansion after pleural fluid drainage. The goal of management is control of patient symptoms, with minimum morbidity and maximum patient independence. Pleural fluid evacuation and long term palliation can be achieved by either chemical pleurodesis or patient controlled drainage with a tunneled pleural catheter. Thoughtful patient evaluation is critical to choosing the appropriate palliative option for each individual with malignant pleural effusion.

Chylothorax is a rare condition that results from thoracic duct damage with chyle leakage from the lymphatic system into the pleural space, usually on the right side. It first manifests as a pleural effusion, and although can have multiple causes, a chyle leak usually is a result of injury at the time of surgery. Definitive diagnosis involves cholesterol and triglyceride measurement in the pleural fluid. Complications include malnutrition, immunosuppression and respiratory distress. Treatment may be either conservative or aggressive depending on the clinical scenario. In this review, we discuss the etiologies, diagnostic methods, and treatment modalities of chylothorax.

Biological agents such as monoclonal antibodies, soluble receptors and molecular mimetics, offer the potential to enhance or replace conventional therapies in the treatment of autoimmune diseases, multiple sclerosis, solid tumors and hematological diseases. As tumor necrosis factor (TNF) plays an essential role in host defense, anti-TNF therapies have increased the risk of serious infections, including mycobacterial and opportunistic infections. The increase in bacterial, fungal and parasitic or viral infections has been well-documented. Lung involvement is expected in 20% of the serious bacterial infections. Diagnosis of lung infections associated with biological agents can prove very difficult due to atypical clinical and pathological features. Patients and physicians should be alerted on the importance of early symptom recognition to avoid the delay in diagnosis. Pulmonary involvement presentation may often be dramatic with acute respiratory failure and bilateral infiltrates. Vigilance is needed for rapid diagnosis with the institution of computer assisted tomography and fiberoptic bronchoscopy. In this review we summarize epidemiology, offending pathogens, and diagnostics of pulmonary infections associated with the use of biological therapies. Measures that can be used for prophylaxis, such as vaccinations and latent infections therapy, will also be reviewed.