IPLab:Lab 4:Septic Emboli

Clinical Summary

This 4-year-old female sustained second and third degree burns involving approximately forty percent of the body surface. Subsequently, she developed septicemia secondary to skin infection and died in septic shock on the 10th hospital day. Antemortem blood cultures were positive for Enterobacter aerogenes and Staphylococcus aureus.

Autopsy Findings

Postmortem findings included (1) multiple abscesses diffusely distributed throughout the parenchyma of the lung and heart, (2) lobular pneumonia, and (3) visceral congestion.

Images

• 
  This gross photograph of lung demonstrates microabscesses due to septic embolization. Note the small 2 to 3-mm lesions scattered throughout this lung tissue (arrows).
• 
  This is a gross photograph of myocardium with multiple embolic lesions scattered throughout the left and right ventricles.
• 
  This low-power photomicrograph shows a section of lung on the left and myocardium on the right. Both pieces of tissue have multiple embolic lesions seen as blue staining areas with massive infiltration of inflammatory cells (arrows).
• 
  This is a higher-power photomicrograph of the focal lesions in the lung produced by the septic emboli. Note these are clearly demarcated from the relatively normal surrounding lung tissue.
• 
  This is a higher-power photomicrograph of one of these septic abscesses illustrating the colonies of bacteria within necrotic cellular debris (arrows). This is typical of an abscess.
• 
  This is a low-power photomicrograph of myocardium with septic abscesses (arrows).
• 
  This is a higher-power photomicrograph of the abscess within the myocardium illustrating colonies of bacteria as the dark blue-staining material (arrow).
• 
  This is a high-powered photomicrograph of a myocardial abscess stained with a special tissue Gram stain (Brown & Brenn) to illustrate the colonies of bacteria in this myocardial tissue (arrows).

Virtual Microscopy

<peir-vm>IPLab4SepticEmboli</peir-vm>

Study Questions

• <spoiler text="What is the most common cause of septicemia in burn patients?">Pseudomona aeruginosa.</spoiler>
• <spoiler text="What factors dictate the location of the abscesses formed by septic emboli?">Distribution of blood flow downstream from the source of septic emboli.</spoiler>

Additional Resources

Reference

• eMedicine Medical Library: Septic Shock
• eMedicine Medical Library: Bacterial Sepsis
• eMedicine Medical Library: Multisystem Organ Failure of Sepsis
• Merck Manual: Sepsis and Septic Shock
• Merck Manual: Bacteremia

Journal Articles

• Hiorns MP, Screaton NJ, Müller NL. Acute lung disease in the immunocompromised host. Radiol Clin North Am 2001 Nov;39(6):1137-51, vi.

Images

• PEIR Digital Library: Vasculitis Due to Septic Embolus Images
• WebPath: Pulmonary Thromboembolus
• WebPath: Atherosclerosis and Thrombosis

Related IPLab Cases

• Lab 3: Lung: Lobar Pneumonia
• Lab 4: Lung: Thromboembolus

Sepsis is the presence and persistence of pathogenic microorganisms and their toxins in the blood.

An abscess is a collection of pus (white blood cells) within a cavity formed by disintegrated tissue.

In alcoholics, aspiration pneumonia is common--bacteria enter the lung via aspiration of gastric contents.

Plural of embolus. An embolus is something that blocks the blood flow in a blood vessel. It may be a gas bubble, a blood clot, a fat globule, a mass of bacteria, or other foreign body. It usually forms somewhere else and travels through the circulatory system until it gets stuck.

An abscess is a collection of pus (white blood cells) within a cavity formed by disintegrated tissue.