IPLab:Lab 1:Lung Abscess
This 67-year-old male with advanced colon cancer developed obstruction of the bowel and underwent palliative surgeryPalliative surgery provides alleviation but is not curative. to remove an 8-cm portion of colon containing the obstruction. During the surgery the patient had several episodes of hypotension. After surgery he did not regain consciousness and required ventilator support. Four days after surgery, the patient developed a fever and his white blood cell count was found to be 15,256 cells/mm³A normal white blood cell count is 4000-11,000 cells/mm³.. Thus, he was started on broad-spectrum antibiotics. A chest x-ray demonstrated infiltratesAn infiltrate is an accumulation of cells in the lung parenchyma--this is a sign of pneumonia. in both lungs, which worsened over the next several days. His overall condition continued to deteriorate and he died 12 days after surgery.
At autopsy, metastatic colon cancer was found throughout the abdominal cavity and invading into the liver. The lungs were markedly consolidatedConsolidation is the filling of lung air spaces with exudate--this is a sign of pneumonia. and had several focal abscessesAn abscess is a collection of pus (white blood cells) within a cavity formed by disintegrated tissue. that were 2 to 4 cm in diameter. Liquefied material poured out from inside these abscessesAn abscess is a collection of pus (white blood cells) within a cavity formed by disintegrated tissue. when the lungs were sliced.
This higher-power photomicrograph of lung demonstrates the edge of the abscess. Note the loss of material from the center of the abscess (1) and loose necrotic material that has not been expelled (2). This material is made up of inflammatory cells (primarily dead white blood cells) and necrotic lung tissue.
The patient had terminal cancer, had undergone a major surgery, and was on a ventilator. Any of these factors could have predisposed the patient to pneumoniaIn alcoholics, aspiration pneumonia is common--bacteria enter the lung via aspiration of gastric contents.. Also, being a patient in the hospital is itself a risk factor due to nosocomial infections.
The proteolytic enzymes released by white blood cells digest the tissue and cause it to liquefy. The presence of bacteria accentuates the inflammatory response and the bacteria themselves can also release enzymes that digest the tissue.
If the patient had lived, the body could have eventually removed all of the necrotic and liquefied material. However, since there was loss of tissue and disruption of the basement membranes, many of the lesions would heal by scar tissue. So, the lung would never return to its original normal morphology and function.
- Brandenburg JA et al. Clinical presentation, processes and outcomes of care for patients with Pneumococcal pneumonia. J Gen Intern Med 2000 September; 15(9): 638–646.
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