LUNG - Organising Legionnaires disease

Hemisected left lung. There is pronounced anthracosis. This is most marked in the subpleural region. Patchy areas of organising consolidation are seen predominantly in the lower part of the upper lobe and the posterior segment of the lower lobe. There is a small multiloculated abscess containing purulent material. Histological examination of this specimen shows an organising pneumonia with early interstitial fibrosis. Legionnaires disease is an acute bacterial pneumonia. It gained notoriety in 1976 when a small epidemic was reported in the United States. The disease has, however, been known for some years prior to this. The causative agent Legionnella pneumophilia is best detected using a silver stain.
The patient, a 73 year old female, presented with a short history of depression. She was admitted to Porirua Hospital in August 1983 and readmitted in November 1983 for ECT. There was little improvement clinically. In late December she was noted to become increasingly dyspnoeic with obvious cyanosis. She was transferred to Wellington Hospital. Chest xray on admission showed interstitial pneumonitis. She developed respiratory failure despite erythromycin and gentamycin therapy and was transferred to the Intensive Care Unit for ventilation. Legionella titres taken on admission were 1:64 and had risen to 1:512 ten days later. She failed to make any clinical progress and died in respiratory failure. At post mortem examination the right lung weighed 1040 g. and the left lung weighed 900 g. Both lungs were firm, congested and oedematous.