CSIM1.62 Bacterial And Fungal Respi Tract Infections Flashcards
Describe the defence mechanisms of the lung
Hair in nose
Mucus in URT trap dirt
Ciliated columnar cells in airways trap and remove dirt
Lysozyme, IgA and complement in mucus kill organisms
Immune cells like neutrophils, macrophages in mucus
Common infections of URTI?
Pharyngitis, tonsillits, laryngitis, sinusitis, ENT infections
Common cause of pharyngitis?
Group A strep
Virulence characteristics of Group A strep
M protein which neutralises complement, prevents opsonisation and evades immune system
Also makes streptokinase, DNAses and exotoxins such as streptolysins and superantigens.
Clinical features of group A streptococcus URTI infection
Scarlet fever - strawberry tongue and rash due to erythrogenic toxin -> induce T cell activation and capillary membrane damage
Rheumatic fever
Sore throat, fever, headache, tonsillar enlargeent, exudative tonsils, cervical lymphadenopathy, N&V,
What causes diphteria?
Cornyebacterium diptheriae
Features of diptheria?
Membrane on tonsils causing difficulty swallowing, breathing and swallowing
Other non-specific symptoms include fever, chills, fatigue, cyanosis, store throat
Features of acute laryngitis?
Hoarsness of voice, dry cough.
Causative organisms of otitis media?
H influenzae, s pneumoniae
Common illnesses causerd by LRTI infections
Epiglottitis, laryngotracheobronchitis, whooping cough, acute bronchitis, acute pneumonia,
Common causes of pneumonia?
Strep pneumoniae H influenzae S aureus Legionella Mycobacterium tuberuclosis
Example of fungal respiratory tract infections
Aspergilliosis
Candidiasis
What patients are more likely to get fungal respiratory tract infections?
Immunocompromised, HIV AIDS
What fungal infection can be contracted from pigeon droppings?
Cryptococcus neoformans
Describe aspergilliosis
Inhaled spores, goes to lung, forms aspergillioma.
Can spread systemically causing sepsis and organ failure.
