LRTI and Pneumonias Flashcards
What common microbiota are found in the respiratory tract?
Viridans streptococci, Neisseria species, Candida species
What defences does the respiratory tract have against pathogens?
Mucociliary clearance mechanisms,
Cough and sneeze reflex,
Respiratory mucosal secretion of IgA and IgG,
Alveolar commensal microorganisms.
What virulence factors are presented by mycoplasma pneumoniae?
Shear off cilia to prevent action of the mucociliary elevator
What virulence factors allow streptococcus pneumoniae and neisseria meningitides to colonise the lower respiratory tract?
Able to split IgA and as such impair the mucosal immune response.
What risk factors are common for lower respiratory tract infections?
Smoking, Age >65, Chronic lung disease eg COPD, Cystic fibrosis, Aspiration.
What drugs may increase the risk of lower respiratory tract infection?
PPI - pneumonia,
H2 antagonists - myelosuporession,
Antipsychotics,
Glucocorticoids.
What are the most common causes of acute bronchitis?
Viruses,
Streptococcus pneumoniae,
Haemophilus influenzae.
How is acute bronchitis treated?
Bronchodilators and physiotherapist +- antibiotics.
What is the difference between lobar pneumonia and bronchopneumonia?
Lobar pneumonia affects an entire lobe, whereas bronchopneumonia shows diffuse patches of damage to the lung.
What are the most common causative organisms of typical pneumonia?
Streptococcus pneumoniae,
Haemophilus influenzae,
Viruses such as RSV and Rhinovirus.
What are the most common causative organisms of atypical pneumonia?
What are the associations common in the presenting patients history?
Mycoplasma (crowded places such as prisons or boarding schools),
Legionella (contaminated water).
What might be heard on auscultation and percussion of chest in a patient with pneumonia?
Crackles, bubbles and dull percussion, all related to fluid within the lungs.
What abnormalities are seen on X-ray with pneumonia?
Consolidations, infiltrates and cavitations. May see fluid lines.
What is CURB 65 score?
Used to asses severity of pneumonia.
Confusion? Urea above 7mmol/L, resp rate above 30, BP below 90/60, above 65 years. If score over 2, manage as severe pneumonia
What investigations may be carried out for pneumonia?
FBC, UandE, CRP, Arterial blood gas, CXR, sputum and blood culture
What tests would best confirm a viral cause of pneumonia?
What about legionella and pneumococcus?
Nose and throat swabs.
Urine antigen tests.
What are some differential diagnoses for pneumonia?
Heart failure with pulmonary oedema,
Pulmonary embolism,
Atelectasis,
Lung cancer.
How is pneumonia managed in UHL?
Moderate: Amoxicillin first line or doxycyline/clarithromycin if allergic for 5-7 days.
Severe: admit with coamoxiclav + clarithromycin/doxycyline for 7-10 days.
What complications may be seen in pneumonia?
Empyema (infection spreads to pleural space), lung abscesses, bacteraemia and sepsis.
What are the most common causes of hospital acquired pneumonia?
Staphylococcus aureus, MRSA, Pseudomonas species.
How is hospital acquired pneumonia managed differently?
Coamoxiclav first line, piperacillin/tazobactam/meropenem second line
Where is aspiration pneumonia commonly seen?
Epileptics, drowning, nursing home residents.
What atypical organisms might cause pneumonia in the immune suppressed?
HIV - Pneumocystis Jirovecci, TB.
Neutropenia - Aspergillus species.
Splenectomy - encapsulated bacteria such as streptococcus pneumoniae
What prevention options are there for pneumonia?
Flu vaccine annually for high risk patients,
Pneumococcal vaccines every 5 years,
Chemoprophylaxis for very high risk eg splenectomy.
