Bacteria, fungi and protozoa infections Flashcards
Describe the structure of a bacteria
- 0.2-2 um diameter
- Single, circular chromosome
- No nucleus
- No organelles
- Divide by binary fission
Describe the structure of eukaryotes
10-100um diameter Multiple, linear chromosomes Membrane bound nucleus Membrane bound organelles Divide by mitosis
How do infections cause morbitity and mortality
Toxins from the organism
Immunopathology from host
What are exotoxins
Proteins secreted by the pathogen
What are the symptoms of diphtheria
Sore throat, fever
What are the effects of diphtheria on the heart
Myocarditis
Hearat block
What does the diphtheria toxin do
Inhibits protein synthesis
What is an endotoxin
Part of outer membrane of gram negative bacteria
Released during lysis of the organism and leads to macrophage activation
Describe the pathogenesis of menigococcal disease
- Activation of inflammatory cascade
- IL-6 and TNF- alpha released
- This leads to myocardial depression, endothelial dysfunction and coagulopathy
- Capillary leak and shock
What anatomical differences are there in children
Thinner skin, shorter airways, anatomy of Eustachian tube (otitis media)
Define fever
temp >37.8
Name 3 organisms that cause septicaemia and meningitis
Streptococccus pneumoniae
Neisseria meningitidis
Haemophilus influenzae B
Which organism causes septicaemia and meningitis in students
Neisseria meningitidis
How do you recognise septicaemia
Tachycardia Tachypnoea Prolonged capillary refill Low BP Rash
What are the top 3 organisms that infect young infants
Group B strep
E Coli
Listeria
What drugs are given to older children with meningitis
Ceftriaxone
What drugs are given to younger children with meningitis
Cefotaxime or ceftriaxone
Is streptococcus pneumoniae gram positive and negative
Positive
What immune defects predispose one to pneumococcal infection
Absent/ non functional spleen
Hypogammaglobulinaemia
HIV infection
Why may there be an absent or non functional spleen
Congenital asplenia
Traumatic removal
Hyposplenism
How can empyema be managed
Chest drain
Video assisted thoracoscopic surgery
Describe how childhood exposure leads to late reactivation of pulmonary disease
Childhoos exposure Primary pulmonary infection Successful immune response Well adult Late reactivation of pulmonary disease
Describe how childhood exposure leads to immediate disease
Exposure Primary pulmonary infection Inadequate immune response Progressive pulmonary disease Lymph/ haematogenous spread Miliary extra-pulmonary disease Death
What gram positive bacillus causes tetanus
Clostridium tetani
