Lung gangrene forms a spectrum of disease, which
includes necrotizing pneu-monia and lung abscess. So far less than 35
cases of pulmonary gangrene following bacterial pneumonia have been
reported(1-4), all in adults(5). We report pulmonary gangrene in two
pediatric patients.
Case Report
Case 1: An 18-month-old female was transferred
from a peripheral hospital with diagnosis of empyema. On examination,
there was high-grade fever, dyspnea and absence of air entry over left
lower zone. X-ray chest showed left sided effusion with
consolidation of the left lower lobe. A tube intercostal drain drained
50 mL of thick yellow pus. Though the condition of the child improved
after the drainage, she continued to have moderate degree of fever.
Daily pus drainage was about 25 -30 mL and it grew Klebsiella on
culture. One week after the tube thoracostomy, the child developed
broncho-pleural fistula. This patient could not afford a pre-operative
CT scan.
Case 2: A 4-year-old female was referred with
diagnosis of empyema and a left intercostal drainage tube in situ.
Clinical examination and X-ray revealed left pyothorax with
collapse and consolidation of the left lung. The tube-thoracostomy was
draining 30-40 mL of pus daily, which grew Klebsiella on the
culture. The child had no air leak. CT Scan of this patient showed hypo
density with multiple air pockets. There was bulging of the oblique
fissure, pleural thickening and rib crowding with reduced hemithorax
volume on the left side, suggestive of organized abscess in the left
lower lobe.
In both the cases inspite of antibiotics, the empyema
did not subside. Since the results of early decortication are
encouraging, we decided to do a decortication after 15 and 21 days of
conservative management respectively.
Bronchoscopy revealed no evidence of foreign body.
With one lung anesthesia, postero-lateral thoracotomy was performed.
Whole of the left lower lobe was black, avascular and friable. It could
be plucked in bits and piece without any bleeding. In the first case
granulation tissue was seen where the bronchus was opening and lobar
vessels could not be identified. The second patient showed intact lobar
vessels, which needed ligation and an intact but friable bronchus.
Because of the risk of mediastinitis, decision was
made not to disturb the hila. The bronchial openings were closed with
interrupted prolene stitches and thorough lavage was given. The
bronchial stumps were covered with lattisimus dorsi flap. Chest was
closed with a drain. Histopathology showed necrotic tissue and collapsed
areas. Micro-scopically, walls revealed inflammation, abscesses,
alveolar exudates, some viable tissue and loss of tissue integrity.
The first child made a good recovery and at 6 months
follow up is doing well. The second child being asymptomatic showed good
wound healing in her first follow-up.
Discussion
The pulmonary gangrene has been given various names
like spontaneous amputation, massive sequestration of the lung,
sponta-neous lobectomy, etc.(3). The term is actually applied to
lung sloughing in bacterial infections. But it is also described in
tuber-culosis, aspergellosis, mucormycosis and radiotherapy(3,6).
Most of the cases occur due to community acquired
pneumonia and are due to Klebsiella(7). Other organisms like
S. aureus, H. influenzae, pneumococci, and pseudo-monas(8)
have been described.
When whole of the lobe gets involved, the empyema
results due to the spread of the infection to the pleural space. But
when intrapulmonary portion of the pulmonary parenchyma necroses, it
forms a cavity with a gangrenous lung tissue floating inside the cavity.
A ‘crescent sign’ may be seen when the necrosed lung separates from the
viable lung(3,6). Such intrapulmonary cavities can be treated with tube
drainage(3).
When whole of a lobe or an entire lung is involved, a two-stage
procedure has been described. Initial diagnosis with pleuroscopy is
followed by pleural fenestration. All the non-viable tissues are excised
and for about a week, twice daily dressing of the pleural cavity is done
through this pleural ‘window’. Once the pleural cavity looks clean, a
formal thoracotomy can be done(2,4,9). Initial diagnosis with
thoracoscopy should be followed by surgery. Pre-operative diagnosis was
missed in our first case because of its rarity.
