Download CSIM2.1: case launch

CSIM2.1: CASE LAUNCH – THE BOY WHO STOPPED BREATHING
19/01/09
CASE OVERVIEW
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2-year-old boy presents with fever (body temperature 40˚C), drooling and stridor
o No significant medial history
o Had not been vaccinated
On examination appears anxious and breathes noisily then suddenly turns blue and collapses
o Nurse originally suspects tonsillitis but tonsils appear normal
o Epiglottis appears inflamed confirming a diagnosis of epiglottitis
Bloom cultures reveal the presence of Haemophilus influenzae type B (HiB)
o Intubated and given 10 days of intravenous cefotaxime – broad-spectrum cephalosporin
o Makes full recovery
LEARNING OUTCOMES
Describe the major features of an acute bacterial infection using Haemophilus influenzae as an example
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Acute bacterial infection can present with a variety of non-specific, often flu-like symptoms including:
o Inflammation
o Pyrexia
o Pain / generalised discomfort
In the case of Haemophilus influenzae causing a respiratory tract infection, symptoms may include:
o Difficulty breathing
o Chest pain
o Nasal congestion
Describe some of the different infections due to Haemophilus species
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Haemophilus influenzae is a non-motile gram-negative bacterium
o Encapsulated strains are coccobacilli – in between the two forms – and more virulent
 Type B strains can cause septic arthritis, meningitis, epiglottitis and bacteraemia
o Non-encapsulated strains are pleomorphic but often filamentous
 Present as part of the normal flora of up to 75% of the population
 Can cause otitis media, sinusitis and pneumonia
o Infections tend to affect children under 5 years of age – very low rates in adults
o Does not produce exotoxins and role of endotoxins is unclear
Explain the difference between pathogenic and non-pathogenic bacteria
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Pathogenic bacteria are those capable of causing disease which largely depends on virulence factors
Explain why some Haemophilus species are more pathogenic than others
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The more pathogenic Haemophilus species have more virulence factors, e.g. type B is encapsulated