lecture 13 - Respiratory tract infection Flashcards
Is pharyngitis mostly viral or bacterial in origin?
Viral
What bacteria is the most common cause of bacterial pharyngitis?
Streptococcus pyogenes (GAS)
What are the symptoms of streptococcus pharyngitis?
sore throat, dysphasia, enlarged lymph nodes, pus on tonsils/pharynx, petechiae on palate, erythema
How can a Group A strep infection be diagnosed in the lab?
Gram stain, culture
What is the size and arrangement of group A streps?
Gram positive cocci in chains
What are the suppurative complications of GAS infections?
otitis media, sinusitis, tonsil abscesses, sepsis
What are non-supparative complications of GAS infections?
Immune-mediated disease - rheumatic fever/heart disease, acute glomerulonephritis
What antibiotic should be used to treat presentations of GAS pahryngitis?
Amoxicillin/penicillin
What bacteria is the most significant cause of otitis media?
Streptococcus pneumoniae
What anatomical feature increases the risk for otitis media in children, but doesn’t affect adults?
A shorter, horizontal auditory/Eustachian tube that makes drainage of the the ear more difficult
What is pneumonia?
Infection of the lung parenchyma (alveoli) with consolidation
What causes alveolar consolidation in pneumonia?
Inflammatory exudate is produced in alveoli in response to infection
What type of pathogen most commonly causes pneumonia?
Bacteria
What are the 3 key routes of infection of pneumonia?
Inhalation, aspiration, haemotagenous
What is the most common route of infection of pneumonia?
Aspiration - the swallowing of secretions into the lungs from the URT or GIT
What are the signs/symptoms of typical pneumonia?
Productive cough, yellow/bloody sputum, dyspnoea, fever, chest pain, nausea/vomiting
What are the histological findings for alveoli infected with pneumonia?
Fibrin rich inflammatory exudate, loss of alveolar spaces, neutrophil/macrophage infiltration
What are the 2 main types of typical pneumonia?
Lobar, bronco-
What bacteria most commonly causes lobar pneumonia?
Streptococcus pneumoniae
What bacteria most commonly causes bronchopneumonia?
Haemophilus
What lung is more commonly affected by lobar pneumonia?
Right lung
What is community-acquired pneomonia?
Infectious bacterial typical pneumonia (most commonly lobar) occurring in previously healthy individuals
What age groups are most likely to contract atypical pneumonia?
Children/adolescents, elderly (and immunocompromised)
What are some of the bacteria that most commonly cause atypical pneumonia?
Mycoplasma pneumoniae, legionella, chlamydia pneumoniae
What are some of the risk factors for developing pneumonia?
Intubation/mechanical ventilation, heart/lung disease, abdominal surgery, abnormal lung secretions (e.g. CF), immunosupression
What are the laboratory tests used to diagnose bacterial pneumonia?
Sputum culture and staining, PCR for atypical causes
What test is used to determine antimicrobial resistance before prescribing antibiotics for bacterial pneumonia?
AST - Antimicrobial sensitivity testing
