BULLOUS EMPHYSEMA


are defined as dilated airspace in the lung parenchyma measuring more than 1cm4


by Burke in 1937 and appeared in texts under the term ‘vanishing lung syndrome’6


. Bullous emphysema was originally described , the term has been largely


superseded by ‘bullous emphysema’.


CLINICAL PRESENTATION A 49 year male self-presented to an urgent care centre complaining of severe right sided chest pain with signs of respiratory distress. His pulse was elevated and his oxygen saturation was reduced. However, his temperature and blood pressure were both within the normal range. On examination there was reduced air entry on the right side. A chest radiograph was requested and undertaken, see Figure 2. The staff managing the patient were concerned by


his presentation, particularly by the chest radiograph appearances. A large pneumothorax or tension pneumothorax was considered the most likely diagnosis. The ambulance service was then contacted with a view to transfer to the nearest emergency department (ED). Due to mounting concern by the ambulance service, during transfer, a needle decompression was performed. This was considered the most appropriate pre-hospital management in a tension or large pneumothorax in this instance, as a full intercostal drain and appropriate medical support was not available during transfer. A needle decompression involves inserting a large bore cannula in the second intercostal space7


. An escape of air


from the pleural space was heard on insertion. A CT scan of the chest was performed following arrival at the ED in which large bullae and a pneumothorax measuring 4cm at its maximum depth were observed (Figure 4). The previous history of COPD, emphysema and large bullae was then discovered after further discussion with the patient and examining his radiology history. The patient was admitted and monitored and was initially doing well. His condition then deteriorated as a result of the pneumothorax, so a chest drain was inserted. He then improved, the drain was removed and he was discharged. Following further examination of his history, it was clear that a diagnosis of severe bullous emphysema had previously been made. This was attributed to many years of combined cigarette and cannabis smoking. In recent years, the patient had suffered a number of acute respiratory episodes and presented to emergency care several times. He had also been seen and managed by the respiratory team as an out-patient over a number of years. After this acute episode, the patient was seen again by


the respiratory physicians in an out-patient clinic. Despite his severe underlying chronic bullous emphysema, he continued to gradually improve from this acute presentation.


AETIOLOGY Bullous emphysema is a disease process characterised by the presence of bullae with surrounding emphysematous lung tissue. Bullae are defined as airspaces greater than 1cm with a wall thickness less than 1mm8,9


. The


American Thoracic Society and European Respiratory Society define emphysema as abnormal permanent enlargement of airspaces distal to the terminal bronchiole, accompanied by destruction of alveolar septa without a fibrotic component8


Lung bullae can occur in various disease processes and . Bullous disease can be


divided into bullous emphysema and primitive bullous disease5


 Figure 4: A CT scan of chest showing extensive bullous disease and a right sided apical pneumothorax measuring 4cm in maximum depth. Smaller green vertical arrow – apical pneumothorax. Larger red horizontal arrow – area of bullous disease.


presence of bullae, but the absence of emphysematous lung tissue10


. The initial chest radiograph had shown


large areas of absence of normal lung markings and therefore this presented a management dilemma, particularly given the concerning symptoms. Unknowingly, the diagnosis of bullous emphysema had been made in the past using a combined approach of chest radiography, CT and respiratory function tests. The link between cigarette smoking and emphysema is well established1,11,12


. The progression of COPD is


closely associated with the total tobacco dose; the age of starting smoking, passive smoking exposure, depth of inhalation and the total number of cigarettes smoked, are important indicators in establishing total tobacco dose1


.


An estimated 90% of people with COPD either smoke or have previously smoked; while other environmental factors contribute, smoking is considered the highest risk factor11


.


Recent evidence suggests an emerging link between cannabis smoking and bullous emphysema9,13,14


. The


study of the specific effects of cannabis smoking and how they might differ from the effects of cigarettes is in its infancy. Much of the data originates from case series’, rather than larger higher quality studies. The investigation into the effects of a drug that is illegal in the United Kingdom is not without its methodological challenges. However, some potentially useful and indeed concerning information is emerging. Hii et al14 looked at ten patients who regularly smoked cannabis and found the effects presented approximately 20 years earlier than those of cigarettes. They also speculated over the effects of the higher temperatures of cannabis smoking compared to cigarettes. Golwala13


investigating


a number of the effects of cannabis suggested that three to four ‘joints’ per day gave equivalent symptoms to 24 cigarettes. Beshay at al15


proposing the term ‘joint year’ as . Combined bullous


disease in the presence of emphysema needs to be distinguished from either disease process that occurs separately. Bullous lung disease is characterised by the


JUNE 2017


a description similar to the cigarette exposure equivalent ‘pack years’, suggested one ‘joint’ was equivalent to 24 cigarettes. A number of researchers have suggested that differences in the way cannabis is smoked compared to cigarettes is important. Smoking techniques, considered to increase the psychoactive effect on the individual, can involve a 70% increase in volume on each inhalation and often involve a longer breath hold9 has also been linked with barotrauma16


. This effect . The direct


pharmacological differences between cigarettes and 7


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