**8.4 Pulmonary gangrene**

A diabetic lady aged 40's complaining of severe abdominal and back pain visited an emergency suite. Diabetes mellitus had been poorly controlled. Mild obstructive dilatation of the bile duct and gallbladder were associated. Endoscopic retrograde biliary drainage was performed, but the patient soon died of septic shock. Autopsy demonstrated severe gangrenous and acalculous cholangitis and cholecystitis. Necrotic change with active growth of Gram-negative rods was proven in the biliary tree. Immunostaining using a monoclonal antibody disclosed the *Pseudomonas aeruginosa* antigen in the invasive bacilli (**Figure 24**). Neutrophilic reaction was relatively mild. The lower (intrapancreatic) part of the common bile duct remained

*Scanning electron microscopy of perforated enterococcal cholangitis. Numerous cocci, 0.7 μm in size, are*

intact. The association of diabetes mellitus was evident: the pancreatic islets revealed pronounced deposition of amyloid substances, and the kidney showed

*Acute* Pseudomonas *cholangitis (H&E and immunostain). Diabetes mellitus accelerated severe necrotizing (gangrenous) inflammation of the extrahepatic biliary tree. Neutrophilic reactions are limited. The rods are immunoreactive for a* Pseudomonas aeruginosa *antigen visualized with a monoclonal antibody. Acalculous*

diabetic glomerulosclerosis with nodular lesions.

*clustered at the site of perforation. Bar indicates 5 μm.*

**Figure 23.**

*Pathogenic Bacteria*

**Figure 24.**

**110**

*necrotizing cholecystitis was associated.*

Pulmonary gangrene is a rare form of acute and severe necrotizing pneumonia [55–57]. A necrotic process with cavity formation is observed in a pulmonary segment or lobe. The term pulmonary gangrene is applied when a large amount of lung tissue is sloughed off. The extent of necrosis is far extensive in pulmonary gangrene when compared with usual pulmonary abscess (**Figure 26**). The lesion is often located in the upper lobe of the lung. Thrombosis of large and small vessels plays a significant role in the ischemic pathogenesis. *Klebsiella pneumoniae* is often isolated from the gangrenous lesion. Infection of anaerobes should be the cause of foul smell. The anaerobes may secondarily infect the lung slough under the progressively anaerobic environment.
