Lower Respiratory Tract Infections And Pneumonia Flashcards
What types of microorganisms are microbiome of the upper respiratory tract?
Strep viridans Neisseria species Anaerobes Candida species (Strep pneumoniae) (Strep pyogenes) (Haemophilus influenzae)
Describe some of the first defences of the respiratory tract
Muco-ciliary clearance
Cough and sneezing reflex
Mucosal immune system - lymphoid follicles of pharynx and tonsils, alveolar macrophages, secretory IgA and IgG
Name some general types of problems that can compromise respiratory defences
Poor swallowing Abnormal ciliary function Abnormal mucus Dilated airways Defects in host immunity
Name some common upper respiratory tract infections
Rhinitis Pharyngitis Laryngitis Sinusitis Otitis media Epiglottitis Tracheitis
What are the most common viruses of the respiratory system?
Rhinovirus
Coronavirus
Influenza
Respiratory syncytial virus (RSV)
Bacterial super-infections in the respiratory tract can lead to …
Mastoiditis
Meningitis
Brain abscess
Name some common lower respiratory tract infections
Bronchitis Bronchiolitis Bronchiectasis Pneumonia Empyema Lung abscess
Describe acute bronchitis
Inflammation of the medium sized airways
Mainly in smokers
Cough, fever, increased sputum, shortness of breath
CXR = normal
What are the types of organisms causing acute bronchitis?
Viruses
Strep pneumoniae
H influenza
What is the treatment of acute bronchitis?
Bronchodilation
Physiotherapy
+/- antibiotics
What is pneumonia and its presentation?
Inflammation of lung alveoli Fever Cough (+/- sputum) Pleuritic chest pain Shortness of breath Rigors Malaise/nausea/vomiting Often localising signs and abnormal CXR
What are the different ways of classification of pneumonia?
By clinical setting (CAQ, HAQ) By presentation (acute, chronic) By organism (bacterial, viral, fungal) By lung pathology (lobar, broncho, interstitial)
What is pneumonitis?
Non-infective inflammatory disease
Describe the pathogenesis of pneumonia
Acute inflammatory response
Exudation of fibrin rich fluid
Neutrophil infiltration
Macrophage infiltration
What underlying factors predispose to pneumonia?
Pre-existing lung disease Immunocompromsied Geography, seasons, epidemics Travel Exposure to animals
What are the typical community causes of pneumonia?
Strep pneumoniae
H influenzae
What should you look for on examination of someone with pneumonia?
Pyrexia Tachycardia Tachypnoea Bronchial breathing Cyanosis Dullness to percussion Tactile vocal fremitus Crackles
What investigations should you do in someone with suspected pneumonia?
FBC Urea and electrolytes CXR CRP Arterial blood gases
What microbiological samples/investigations could you order in pneumonia?
Sputum culture Blood culture Broncho-alveolar lovage fluid (BAL) Nose and throat swabs Urine Serum (antibody test)
What does the CURB-65 score for pneumonia assess?
Confusion Urea > 7 mmol/L Resp rate >30 BP <90 s / <60 d > 65 years (Score of 2+ means admit to hospital)
What is the antibiotic treatment for mild-moderate pneumonia?
Amoxicillin
Doxycycline/erythromycin/clarithromycin
What is the antibiotic treatment for moderate to severe pneumonia?
Co-amoxicillin and clarithromycin/doxycycline
What are the possible outcomes of acute bacterial pneumonia?
Resolution with some organisation (fibrous scarring)
Lung abscess (liquefactive necrosis)
Bronchiectasis
Empyema
Which organisms cause atypical pneumonia?
Organisms without a cell wall Mycoplasma Legionella Chlamydia Coxiella
Why do we need different treatments for atypical pneumonia?
Cell wall active antibiotics don’t work eg. Penicillins
As the organisms don’t have cell walls
What Abx do we use for atypical pneumonia?
Macrolides (eg. Erythromycin/clarithromycin)
Tetracyclines (eg. Doxycycline)
Describe viral pneumonia
Damage to cells lining the airways/alveoli by virus and immune cells
Fluid filled air spaces - interferes with gas exchange
Can get severe necrosis
Patchy or diffuse ground glass opacity of CXR
Which viruses can cause viral pneumonia?
Influenza/parainfluenza
RSV
Adenovirus
Describe the causes the hospital acquired pneumonia
Staph aureus Enterobacteriaciae Pseudomonas species Haemophilus influenzae Fungi
What treatments do we use to treat HAQ pneumonia?
First line = co-amoxiclav
Second line = pipperacilin/tazobactam/meropenem
Describe aspiration pneumonia
Exogenous or endogenous material
Common in patients with neurological dysphagia, epilepsy, alcoholics and drowning
Mixed infection of strep viridans and anaerobes
Treat with co-amoxiclav
Describe some prevention methods for pneumonia
Flu vaccine
Pneumococcal vaccine
Chemoprophylaxis - oral penicillin/erythromycin
Stop smoking
