Case presentation

 
          
       A 46 years old man, presented to the emergency room complaining of progressive dyspnea, wheezing, and productive cough for 10 days, years ago. He was a manual laborer with history of smoking one pack of cigarrettes a day for 13 years. A diagnosis of bronchial asthma was made 3 prior to admission.

      On examination he was anxious with mild respiratory distress without cyanosis. Pulse oxymetry reported O2 saturation 94% on room air. Chest examination revealed reduction of air entry on both sides, harsh vesicular breathing, prolonged expiratory phase, and expiratory wheezing were audible all over the chest bilaterally.

     ABG showed PH 7.42, PaO2 89.2, PaCO2 35.5, HCO3 23.1, and O2 sat 97%. Chest X-ray (CXR) reported multiple bullae bilaterally, with left sided “pneumothorax” (Figure 1). CT scan of the chest revealed multiple bilateral giant bullae (Figure 2).

     Based upon the CXR report in the emergency room, a left sided chest tube was inserted. The patient had minimal air leak, and follow up CXR showed no improvement in the supposed “pneumothorax”. He developed subcutaneous emphysema in the left aspect of the chest and neck.

    The patient was admitted to the hospital, and was started on treatment for bronchial asthma (consisting of bronchodilators, steroids, antibiotics, and theophyline). He continued to complain of dyspnea. Air leak in the chest tube remained active, and the subcutaneous emphysema persisted as well.

    One week after his admission to the hospital, there was no improvement in his clinical condition and surgical intervention was recommended. Review of his old CXR reports revealed that he had bilateral apical giant bullae at least 3 years prior to admission. Review of the CXR and the CT scan obtained during the current admission revealed the same bilateral apical giant bullae but there was no evidence of left penumothorax. CT Scan of the chest was repeated to evaluate the remaining lung tissue and parenchyma (Figures 3 A and B).

     The diagnosis was established as bilateral giant space occupying emphysematous bullae of the upper lobes, causing significant compression of fairly normal lung parenchyma, and affecting his lung function. The patient underwent surgical excision of the bilateral giant apical bullae through a median sternotomy incision.

    The patient improved with mild residual subcutaneous emphysema, and much less dyspnea. Air leak from left chest tube stopped on the 4th post-operative day, and it was removed. However, right side air leak persisted, and CXR showed right pneumothorax. A second right chest tube was inserted, nevertheless he continued to have increased air leak. Eventually, re-operation was performed, and the air leak site from the right lung was sutured. The patient did well postoperatively after maintaining good ventilation and the air leak stopped. The right chest tube was removed, and follow up CXR was free from pneumothorax. The patient was discharged in good general clinical condition. The importance of cessation of smoking and regular CXR follow up was emphasized to the patient. However, follow up was for a short period, and the patient returned back to his home country.

Fig.1: Initial Chest X-ray showing bilateral large apical radio-lucency, especially on the left side, mistaken for left pneumothorax. No subcutaneous emphysema.

 

Fig.2: Initial CT Scan of the chest showing bilateral apical giant bullae, larger on the left.

Comments


  
    When the patient was diagnosed to have bronchial asthma 3 years prior to his presentation, there was a chest X-ray report indicating the presence of bilateral giant apical bullae, however the patient was treated as bronchial asthma. Nevertheless the patient rarely used his asthma medications. The chest X-ray obtained in the Emergency Department during this admission also showed bilateral apical giant bullae, but an interpretation of left “penumothorax” led to the insertion of a left sided chest tube. This chest tube entered the thin walled giant bullae of the left lung with subsequent pneumothorax and subcutaneous emphysema. He remained symptomatic with dyspnea, and he could not be weaned off oxygen. The second right sided chest tube was inserted to eliminate the persistent postoperative pneumothorax, but the tube entered the emphysematous thin-walled right lung, and the patient required a second operation to stop the air leak and to repair the lung.
  
Discussion

Fig.3A: Repeated CT Scan of the chest showing persistent bilateral apical giant bullae with subcutaneous emphysema, and preserved lung parenchyma.

 

Fig.3B: Reconstructed coronal section CT scan of the chest clearly showing the location of the giant bullae and lung compression.

  
        A “bullus” is defined as an emphysematous space in the lung with a diameter of more than 1cm in the distended state. In current usage, it refers to a sub-pleural air cyst that forms as a result of dissolution of alveolar walls with enlargement of air spaces1,2 .

      Bullae may be single or multiple. They may be found as an isolated abnormality in an otherwise normal lung, or in association with emphysema. As an isolated abnormality, bullae are more common in the upper lobes. The size of the bullae may vary from 1cm in diameter to one that occupies the whole hemithorax1,2.

      Radiologically, bullae appear as avascular radiolucent area with thin curvilinear wall. The wall is usually less than 1mm in thickness. It may be visualized completely or segmentally, or it may even be invisible, making the detection of bullae difficult, and sometimes mistaken for pneumothorax, or give the appearance of vanishing lungs. It is well known that plain chest X-ray markedly underestimates the number and size of bullae. CT scan is more sensitive than chest X-ray to detect bullae. CT allows more accurate assessment of the number, size, and position of bullae, and it is particularly useful when bullae are obscured2.

      Bullae usually enlarge progressively at variable rates. They may compress the adjacent lung, particularly in progressive bullous emphysema, resulting in increasing respiratory embarrassment.
The main complications of bullae are pneumothorax, infection and haemorrhage. Spontaneous pneumothorax is a frequent and serious complication in patients with bullous disease. It occurs in about 15% of such patients2. Pneumothorax is a serious complication in patients with compromised lung function. Persistent air leak is common, since the visceral pleura overlying a bulla has inadequate underlying tissue support to seal the rupture. Therefore, one has to distinguish bullae carefully from pneumothorax to avoid iatrogenic pneumothorax in patients with bullous disease2.

        When bullae become infected they usually contain fluid and develop air-fluid level. Following infection, bullae often disappear. Haemorrhage into bullae is a less common complication and may be radiologically indistinguishable from infected bullae. Again bulla may disappear after a bleeding complication2.
    
       Apical giant bullae may precede, coincide or follow the complications of parenchymal pulmonary disease. However, it is an uncommon cause of respiratory compromise. Yet, when it compresses the lung tissues, it can significantly impair respiratory functions. Apical giant bullae are common in people with history of cigarette or cocaine smoking, in COPD patients, sarcoidosis, Marfan's syndrome, a1-antitrypsin deficiency, a1-antichynotrypsin deficiency, and Ehlers-Danlos syndrome2-4.

       Surgical resection of giant space-occupying emphysematous bullae allows the compressed lung to re-expand, permits better ventilation and perfusion, decreases dead space and residual volume, improves ventilation mechanics with remodeling of the diaphragm and the chest wall, and eventually treats complications, such as increased size or infection of bullae, recurrent pneumothorax, dyspnea, and respiratory failure. Nevertheless, the decision to operate and selecting patients who would benefit from the operation is challenging4-6.

      A wide variety of surgical procedures have been proposed in the management of bullous emphysema, such as intra-cavitary drainage, local excision of the bullae, plication, stapler resection, or lobectomy. The operation is usually accomplished through open approach, such as thoracotomy or sternotomy. The introduction of video-assisted thoracoscopy (VAT) has increased interest in using minimally invasive approach for many patients with severe emphysema who may not tolerate open thoracotomy operations very well4,6.¨ © Gulf Heart Association 2007.



References:

1. Spencer H. Pathology of the Lung. 4th Edition, 1984.

2. Greenberg JA, Singhal S, Kaiser LR. Giant bullous lung disease: evaluation, selection, techniques, and outcomes. Chest Surg Clin N Am 2003;13:631-49.

3. Van der Klooster JM, Grootendorst AF. Severe bullous emphysema associated with cocaine smoking. Thorax 2001;56:982-3.

4. Zar HJ, Cole RP. Bullous emphysema occurring in pulmonary sarcoidosis. Respiration 1995;62:290-3.

5. Vigneswaran WT, Townsend ER, Fountain SW. Surgery for bullous disease of the lung. Eur J Cardiothorac Surg 1992;6:427-30.

6. De Giacomo T, Rendina EA, Venuta F, et al. Bullectomy is comparable to lung volume reduction in patients with end-stage emphysema. Eur J Cardiothorac Surg 2002;22:357-62.