Self-assessment Questions

5 Acute infections

• 1. Are antibiotics useful for treating tissue spreading infections?

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  Correct answer:

  Antibiotics are invaluable when the infection is spreading through the tissues (e.g. cellulitis, peritonitis, pneumonia), but drainage is essential when abscess formation has occurred.

• 2. What is the most common causative organism of cellulitis? Why is this so invasive?

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  Correct answer:

  β−haemolytic Streptococcus. The invasiveness of this organism is due to the production of hyaluronidase and streptokinase, which respectively dissolve the intercellular matrix and fibrin inflammatory barrier.

• 3. Which organism produces streptokinase?

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  Correct answer:

  β−haemolytic Streptococcus.

• 4. What is an abscess?

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  An abscess is a localized collection of pus, usually, but not invariably, produced by pyogenic organisms. Occasionally, a sterile abscess results from the injection of irritants into soft tissues (e.g. thiopentone). An abscess commences as a hard, red, painful swelling, which then softens and becomes fluctuant. If not drained, it may discharge spontaneously onto the surface or into an adjacent viscus or body cavity. There are the associated features of bacterial infection, namely a swinging fever, malaise, anorexia and sweating with a polymorph leucocytosis.

• 5. What is the causative organism of a boil?

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  Correct answer:

  Staphylococcus.

• 6. What is hidradenitis suppurativa?

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  Correct answer:

  Multiple infected foci in the axillae or groins, due to infection of the apocrine sweat glands of these regions, are usually misdiagnosed as boils. They do not respond to antimicrobial therapy and can only be treated effectively by excision of the affected skin. If this is extensive, the defect may require grafting.

• 7. How would you manage a patient with a furuncle?

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  Correct answer:

  When pus is visible, the boil should be incised. Recurrent crops of boils should be treated by improving the general hygiene of the patient, and by use of ultraviolet light and hexachlorophene baths, but systemic antibiotic therapy is seldom indicated.

• 8. What is a carbuncle?

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  Correct answer:

  A carbuncle is an area of subcutaneous necrosis that discharges onto the surface through multiple sinuses. It is usually staphylococcal in origin. The subcutaneous tissues become honeycombed by small abscesses separated by fibrous strands. The condition is often associated with general debility, and diabetes, in particular, must be considered.

• 9. What systemic disease should you consider in a patient who gets a carbuncle?

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  Correct answer:

  It is often associated with general debility and diabetes.

• 10. How would you manage a patient with a carbuncle?

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  Correct answer:

  Surgery is rarely indicated initially. Antibiotic therapy is given and the carbuncle merely protected with sterile dressings. Occasionally, a large sloughing area eventually requires excision and a skin graft. Diabetes, if present, should be controlled.

• 11. Is tetanus common? Why?

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  Correct answer:

  Tetanus is now a rare disease in the Western world, thanks to a comprehensive immunization policy. In the developing world it remains prevalent with a mortality of up to 60%.

• 12.Which organism causes tetanus?

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  Correct answer:

  Clostridium tetani.

• 13.What type of organism is Clostridium tetani?

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  Correct answer:

  An anaerobic, exotoxin-secreting, Gram-positive bacillus.