Pneumonia Flashcards
What are some common flora of the respiratory tract?
Viridans streptococci
Neisseria spp
Anaerobes
Candida spp
What are the natural defences of the respiratory tract?
Muco-ciliary clearance mechanisms
- nasal hair
- ciliated columnar epithelium
Cough and sneezing reflex
Respiratory mucosal immune system
- lymphoid follicles of pharynx
- alveolar macrophage
- secretory IgA and IgG
Less common flora of the respiratory tract?
Streptococcus pneumoniae Streptococcus pyogenes Haemophillus influenza Pseudomonas E. coli
What are the main infections of the upper respiratory tract?
Rhinitis Pharyngitis Epiglottis Laryngitis Tranchesitis Sinusitis Otitis media
What are the main pathogens that cause upper resp tract infection?
Viruses
- rhinovirus
- coronavirus
- influenza
- parainfluenza
- respiratory syncytial virus
What is pneumonia?
Inflammation of pulmonary parenchyma with consolidation, usually due to an infection.
What is inflammation of the pulmonary parenchyma due to from a cause other than infection? What can these causes be?
Pneumonitis
Physical or chemical
In pneumonia, what causes the consolidation?
Accumulation of inflammatory exudate in the alveoli and adjoining ducts
Alveolar space contains liquid instead of gas
What is lobar pneumonia?
Confluent consolidation involving a complete lung lobe.
What is lobar pneumonia usually caused by?
Streptococcus pneumoniae
Community acquired
Acute onset
Pathology of lobar pneumonia?
Typical acute inflammatory response
Exudation of fibrin-rich fluid
Get neutrophil and macrophage infiltration
How does the immune system help in the clearance of lobar pneumonia?
Antibodies lead to opsonisation and phagocytosis of bacteria
What is broncho-pneumonia?
Infection starting in the airways and spreading to adjacent alveoli and lung tissue
When is broncho-pneumonia normally seen?
In the context of a pre-existing disease
What is broncho-pneumonia normally caused by?
Streptococcus pneumoniae Haemophilus influenzae Staph aureus Anaerobes Coliforms
How does bronchopneumonia appear on an X ray?
Diffuse and patchy
Who is aspiration pneumonia common in?
Patients with neurological dysphagia - strokes
Epilepsy
Alcoholics
Drowning
Patients with a lower level of consciousness eg anaesthesia
What can be aspired to cause aspiration pneumonia?
Food
Drink
Saliva
Vomit
What organisms can cause aspiration pneumonia?
Oral flora
Anaerobes
What is interstitial pneumonia?
Inflammation of the interstitium of the lungs Includes -alveolar epithelium -pulmonary capillary endothelium -basement membrane -perivascular and perilymphatic tissue
What is chronic pneumonia?
Inflammation of lungs that persists for an extended period of time
Common causative organisms of community-acquired pneumonia?
Streptococcus pneumoniae
Haemophilus influenzae
Klebsiella pneumoniae
Rare:
Chlamydia pneumophilia
Mycoplasma pneumoniae
Legionella pneumophilia
Causative organisms of hospital acquired pneumonia?
Gram negative bacilli Staphylococcus aureus Pseudomonas MRSA Drug resistant organisms are more common
What would make you suspect that pneumonia is caused by Streptococcus pneumoniae?
Community acquired More common in elderly Commonly preceded by viral infection Rapid temperature - 39.5*C Pleuritic pain Dry cough becoming increasingly productive Rust-coloured sputum Breathing becomes more rapid and shallow with decreased chest expansion on side of infection
What would make you suspect the organism is H influenzae?
Common in elderly
COPD patients
Community acquired
What would make you suspect Legionella pneumophilia the causative organism?
Recent travel
Young person or a smoker
Illness
Multi-system involvement
What would make you suspect Mycoplasma pneumoniae as the causative organism?
Young people
Prior antibiotics
Extra-pulmonary involvement - haemolysis, skin and joints
What would make you suspect Staph aureus as the most common causative pathogen of pneumonia?
IV drug user
Occurred after influenza
What would make you suspect Chlamydia pneumophilia to be the causative organism of pneumonia?
Contact with birds
What would make you suspect coxiella to be the causative organism of pneumonia?
Animal contact - sheep
What would make you suspect S milleri to be the causative organism of pneumonia?
Dental infection
Abdominal source
Aspiration
Presentation of pneumonia?
Almost always
- malaise
- fever
- productive cough
- sputum may be purulent/rust coloured/stained with lots of blood
- fever, chills, sweats, rigors
- cough, dry in infants and elderly
- vomiting
- headache
- loss of appetite
- haemoptysis
- pleuritic chest pain
- upper abdominal tenderness
What might you find on examination of a patient with pneumonia?
Signs of consolidation
- bronchial breath sounds
- crackles
- wheeze
- dullness to percussion
- reduced vocal resonance
- seen on CXR
Tachypnoea
Tachycardia
Diarrhoea
When is pneumonia classed as hospital acquired?
48hrs after hospital admission
Very common, 15% of hospital acquired infections
Who is hospital acquired pneumonia common in?
Ventilated and post-surgical patients
What is the scoring system used to assess chance of mortality from pneumonia?
C - confusion U - urea >7mmol/L R - resp rate >30/min B - blood pressure, systolic <60 65 - aged over 65
What specimens can be used for lab diagnosis of pneumonia?
Sputum Nose and throat swabs Endotracheal aspirates Bronchoalveolar lavage fluid Open lung biopsy Blood culture Urine - detects legionella and pneumococcus antigens Serum - antibody detection
Microbiological investigations for pneumonia?
Microscopy - Gram staining and acid fast Culture bacteria and viruses PCR of respiratory viruses Antigen detection for legionella Serology - Antibody detection
Common pathogens which cause pneumonia in the immunosuppressed?
Cytomegalovirus (CMV)
Mycobacterium avium intracellulare
Aspergillus, candida, pneumocystis, jiroveci
Crytosporidia, toxoplasma
Supportive treatment of pneumonia
Fluids (oral/IV)
Anti-pyretic drugs - reduce fever and malaise
Strong analgesics for pleural pain
Oxygen if cyanosed
Antibiotics for community acquired pneumonia?
Target organism is normally pneumococcus
Penicillin - amoxycillin
Antibiotics for hospital-acquired pneumonia?
More likely to be Gram negative
IV co-amoxiclav
Treatment of legionella pneumonia?
Levofloxacin
Antibiotics for atypical pathogens of pneumonia?
Tetracyclines
Macrolides
Possible outcomes of pneumonia?
Resolution Organisation (scarring) Complications -lung abscess -bronchiectasis -empyema -respiratory failure -hypotension -septicaemia
How to prevent pneumonia?
Flu vaccine for high risk patients
Pneumococcal vaccine
Chemoprophylaxis
-oral penicillin/erythromycin
When is chemoprophylaxis for pneumonia given?
Asplenic patients
Immunosuppressed
