Infectious Disease 41 to 50
What are the other types of meningitis?
- Chronic (tuberculosis)
- Chemical/drug induced
- 3 out of 5 including bold
What organisms commonly cause bacterial meningitis in the different age groups?
- Neonates: Escherichia Coli and Group B Streptococcus
- Children: Streptococcus Pneumoniae, Haemophilus Influenzae (now less common)
- Adolescent/young adult: Neisseria meningiditis, Streptococcus Pneumoniae
- Older adults: Streptococcus Pneumoniae, Listeria
- 1 per age group
- Must mention bold
Name some common bacteria that cause wound infections.
- Staphylococcus aureus
- Streptococcus pyogenes
- Clostridium perfringens
- Aerobic Gram negative bacilli
- Pseudomonas aeruginosa
- Clostridium tetani
- Bold + 1 other
What diseases are cause by Staphylococcus aureus?
- Skin/soft tissue:
- Abscess (furuncle, carbuncle)
- Necrotising soft tissue infection
- Scalded skin syndrome
- 3 skin
- 3 non-skin infections
Describe the clinical features of Staph. Aureus toxic shock syndrome.
- Hypotension (shock)
- Renal failure
- Liver disease
- Respiratory failure
- Generalised erythematous rash
- Soft tissue necrosis at site of infection
- 4/7 (must have specific organs)
Outline the natural history and spectrum of TB.
Prompt: What can happen after primary infection?
- Primary infection.
- Primary complex (localised caseation) (Ghon complex is primary TB with mediastinal nodes).
- Primary complex may heal (organisms not viable) or lead to a latent infection (organisms viable).
- Latent period or progressive primary TB (latter of which may lead to miliary TB).
- Latent lesion reactivated leading to secondary TB (reinfection may also lead to secondary TB).
- Secondary TB occurs as localised (pulmonary or extra-pulmonary) caseating destructive lesions or progressive secondary TB.
- Progressive secondary TB may lead to miliary TB.
- 4/4 bold criteria to pass.
How is TB diagnosed?
- Clinical features in at risk patients (Hx and Examination) and apical lung consolidation/cavitation on CXR
- Microbiological confirmation:
- Acid fast smears and cultures (3-6 weeks solid agar media, 2 weeks liquid media)
- Other (e.g. Mantoux test)
- Must have bold criteria to pass.
How does Neisseria meningiditis cause infection?
- Common coloniser of the oropharynx – 10% of population at any one time can be carriers for months.
- Spread by respiratory droplets.
- Most people develop an immune response and clear it – they are then protected against future infection from this serotype (>13 serotypes).
- Invasive disease when a new serotype is encountered.
- Invades the respiratory epithelium, then invade the bloodstream.
- The capsule of the bacterium allows it to evade the immune system by prevention of opsonisation and complement destruction.
- Mortality is still approximately 10% despite antibiotic treatment.
- Need to have at least 4/7 to pass.
What are the clinical consequences of N. meningiditis infection?
- Generalised sepsis
- Necrotising vasculitis
- Sensorineural hearing loss
- Cognitive impairment
- Need to have at least 4 to pass.
Apart from N. meningiditis, what else can cause meningitis?
- Other bacteria:
- E. coli and Group B streptococcus (infants)
- Streptococcus pneumoniae
- Listeria monocytogenes
- Haemophilus influenzae
- Must have two specific bacteria plus viral as a group to pass.