Rare Complication Of Blunt Chest Trauma: Pulmonary Pseudocyst
S Gezer, S Y?ld?z, A K?l?çgün
Keywords
blunt chest trauma, lung cyst, pulmonary contusion, traumatic pulmonary pseudocyst
Citation
S Gezer, S Y?ld?z, A K?l?çgün. Rare Complication Of Blunt Chest Trauma: Pulmonary Pseudocyst. The Internet Journal of Thoracic and Cardiovascular Surgery. 2008 Volume 13 Number 1.
Abstract
Traumatic pulmonary pseudocyst is an infrequent complication of blunt chest trauma.
A 40 year-old male patient was hospitalized after a blunt chest trauma. Twenty hours after the accident, two air filled cysts with a surrounding consolidation area, in the upper lobe of left lung were detected radiologically. The patient did not give any previous lung disease history. The cysts of the lung were firstly accepted as traumatic pulmonary pseudocyst and followed-up with conservative management. During the follow-up, pseudocysts began to shrink after the 17th day and compeletely resolved on the 51st day of the accident.
This rare entity is most often seen in children and young adults. Traumatic pulmonary pseudocysts do not include epithelium or bronchial wall elements as it is in a true cyst. The treatment is generally conservative since they usually resolve spontaneously. Surgery should be considered in case of failed conservative treatment and development of complications.
Introduction
Blunt chest trauma frequently causes pulmonary contusions, hematomas or effusions; but rarely leads to the formation of a cystic lesion (1). This rare lesion -named “traumatic pulmonary pseudocyst” (TPP)- is an infrequently talked about subject, especially, among surgeons (2). The majority of the patients with TPP are children or young adults with a mean age of 20 (3). We report the case of a 40 year old patient who sustained TPP with hemopneumothorax due to a blunt chest trauma.
Case Presentation
A 40 year old male patient admitted due to complaints, including chest pain and dyspnea, after an industrial accident (being compressed between a truck and a wall). In his physical examination, the unique pathological finding was the sensation of pain with palpation of chest wall lateral to left mammary gland. A chest x-ray (CXR) displayed a partial left sided pneumothorax and fracture of the 5 th left rib. Tube thoracostomy of the left hemithorax was performed. The control CXR, 20 hours after the accident, presented an air cyst like cavity in the upper zone of left hemithorax (figure) and a thoracic computed tomography (CT) was performed. It displayed two air filled cysts ( first one is 8x4,5x3,5 cm and the other is 2x1,7x1 cm in dimensions) with a surrounding consolidation area, in the upper lobe of left lung and a left sided hemopneumothorax (figure).
Figure 1
The patient did not give any previous lung disease history. Also, investigation of tuberculosis –which is not rare in our country- were negative in sputum for three consecutive days. So, the cysts were firstly accepted as “traumatic pulmonary pseudocyst” and were decided to be followed-up conservatively. The neumothorax of the patient got well and chest tube was removed on the 6 th day. The TPP lesions did not complicate further and the patient was discharged on the 10 th day. The patient was followed-up with CXR every week, in outpatient clinic. The TPP lesions began to shrink after the 17 th day of the accident and a second thoracic CT on the 51 st day of the accident displayed the complete resolution of TPP lesions.
Discussion
Traumatic pulmonary pseudocysts are rare lesions; Kato and coworkers reported the TPP formation in 0,34% of chest injuries (4). The mechanism of TPP development was explained: Tear and shear injuries in the pulmonary interstitial tissue at the time of the trauma initiate the development of the pseudocyst (5). Centrifugal forces in the surrounding pulmonary tissue or the possitive pressure created within the torn or sheared area cause the pseudocyst to grow (5). These lesions are named as “pseudocysts” since they do not include epithelium or bronchial wall elements as it is in a true cyst (1). They should not be confused with preexisting pulmonary lesions such as congenital pulmonary cysts, post-pneumonia pneumatocele, tuberculosis cavity, abscess, mycotic cavity or carcinomas (3). Our patient did not give any previous lung disease history and tuberculosis investigations were negative. Furthermore, resolution of the cavities during the follow-up confirmed our TPP diagnosis.
TPPs are most often seen in children and young adults, in whom the thorax is elastic, the visceral pleura intact and the parenchyma easily injured (1). It is believed that the more elastic and pliable chest wall of young people and children permits the transmission of kinetic energy more efficiently to the underlying lung parenchyma (6). Our patient was 40 year old and was a little far from the mean age group of TPP patients (3).
Presentations of TPP are hemoptysis, chest pain, cough, dyspnea, mild fever, and leukocytosis. All of those findings are attributable to chest trauma and parenchymal injury, and not specific for TPP. Chest pain and dyspnea were the symptoms, our patient complained.
CXR and thoracic CT are the radiological methods of choice in TPP diagnosis. TPPs are seen as air filled cavities, usually with air-fluid level, and surrounding lung often shows consolidation due to pulmonary contusion on CXR (4). But, they detected by chest radiographies alone in only 50% (4). Thoracic CT can more precisely define the location and size of the cyst and provide early detection and differential diagnosis (1).
Since the TPPs usually resolve spontaneously within 4 months, unless it is complicated by a blood-filling cavity, treatment of TPP is generally conservative (2). The indications for surgery are failed conservative treatment, development of complications such as respiratory deterioration, an increase in size of the pseudocyst, or a failure of the pseudocyst to become progressively smaller (3,7). Secondary infection is another serious complication of TPP that may be lethal (8). Gincherman et al. suggested 3 steps of treatment protocol in case of secondary infection and septic course; 1 st step: antibiotic treatment according to sputum culture antibiograms; 2 nd step: if clinical improvement is not apparent, early CT-guided catheter drainage should be considered; 3 rd step: thoracotomy or thoracoscopy should be considered if clinical improvement is not observed despite catheter drainage (8). In our patient, there were other complications of blunt chest trauma including pneumothorax and rib fracture, but we did not observe any complication of TPP and used antibiotics only during tube thoracostomy period. Also, with conservative treatment, TPP lesions completely resolved in 7 weeks.
As a conclusion, TPP is a rare complication of blunt chest trauma. Initially, differential diagnosis between pulmonary pseudocyst and preexisting pulmonary lesions such as congenital pulmonary cysts, post-pneumonia pneumatocele, tuberculosis cavity, abscess, mycotic cavity or carcinomas may be difficult. But, the patients history and follow-up should help to the clinician. Usually, conservative management is the choice of treatment and TPP resolves spontaneously. Surgery should be considered in case of complications or failure of conservative treatment.
Correspondence to
Dr. Suat Gezer Düzce Üniversitesi, T?p Fakültesi, Göğüs Cerrahisi Kliniği 81620 Konuralp/Düzce/TÜRKIYE e-mail address: Suatdr@hotmail.com Tel no: 00 90 380 5414110 Fax no: 00 90 380 5414105