LOBAR PNEUMONIA Flashcards
What is pneumonia?
Acute inflammation with an intense infiltration of neutrophils in and around the terminal bronchioles. The affected bronchopulmonary segment or the entire lobe may be consolidated by the resulting inflammation and oedema.
What is CAP?
Pre-hospital or within 1st 24hrs
What is HAP?
More than 24hrs post-admission
What is the mortality rate?
21% in hospital
What age group is most affected?
Elderly. Only 30% are <65 years
What are the most common organisms?
S. pneumoniae, S. aureus, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae and respiratory viruses. Mixed pathogens occur up to 25% of the time.
Most common Aetiology of CAP?
may be primary or secondary to underlying disease
o Streptococcus pneumoniae is commonest cause
o Then H influenzae, Mycoplasma pneumonia
o Staph A, Legionella speciies, Moraxella catarrhalis and Chlamydia = rest of bacteria
o Gram -ve and anaerobes are rare
o Viruses only 15%
Aetiology of HAP?
o Acquired >48hrs after hospital admission
o Most commonly due to G -ve bacteria or Staph A
o Anaerobes
o Also Pseudomonas, Klebsiella, Bacteriodes, Clostridia
Aetiology of aspiration pneumonia?
o Usually due to vomit
o Occurs in those with stroke, myasthenia, bulbar palsies, decreased consciousness (drunk), oesophageal disease (achalasia, reflux), poor dental hygiene
o Staph pneumoniae and anaerobes
Aetiology in the immunocompromised patient
o Strep pneumoniae, H influenza, Staph A, M catarrhalis, M pneumoniae, G -ve bacilli, Pneumoncystic jiroveci (used to be named P carinii)
o Fungi
o Viruses
2 other aetiology’s of
- Radiotherapy
* Allergic mechanisms
What risk factors?
Age - elderly and very young
Lifestlye: smoking and alcohol
Prev. Viral infections: influenza or parainfluenza
Resp disease: asthma, COPD, malignancy, bronchiectasis, cystic fibrosis
Immunosuppresion: AIDS, cytotoxic therapy.
IV drug abuse (staph. Aureus infection)
Hospitalisation
Underlying comorbidities: DM, CV disease etc.
What symptoms?
Cough, purelent sputum (rust-coloured or blood-stained), breathlessness, fever, malaise.
Elderly: malaise, faitugie, anorexia and myalgia.
Young children: unspecific or abdominal pain
Cough, purulent sputum, fever, rigors, malaise, anorexia, dyspnoea. Heamoptysis, pleuritic pain
What signs?
Tachypneoa, bronchial breathing, crepitatoins, pleural rub, dullness with percussion.
Pyrexial, cyanosis
Confusion
Tachypnoea, tachycardia
Hypotension
Resp exam:
Reduced expansion. Dull to percussion. Increased tactile vocal fremitus. Bronchial breathing. Pleural rub. Bibasal crackles if pleural effusion
What is CURB-65?
- Confusion
- Urea >7mmol
- Resp rate 30/min+
- Systolic pressure below 90, or diastolic below 60
- Age > 65yrs
What does CURB-65 mean?
Score >2, admission to hospital. Less = treat at home. More = ?ICU
ABG/O2 sats of <8KPa/92%; co-morbidity; multilobar/bilateral involvement also indicate severe disease)
What investigations?
Pneumococcal and legionella urinary antigen tests.
CXR. (A follow-up CXR six weeks after recovery from pneumonia is recommended.) - consolidation
Sputum examination and culture.
Pulse oximetry or blood gases.
Aspiration of pleural fluid (for biochemistry and culture).
Bloods:
FBC with differential white cell count.
Raised CRP/ ESR - CRP (to aid diagnosis and as a baseline measure).
Blood cultures
Renal function and electrolytes.
LFTs.
Bronchoscopy/ bronchoalveolar lavage
What management?
Prevention: • Early antibiotic therapy • Influenza and pneumococcal vaccination • Targeted risk reduction i.e. Smoking cessation Not to smoke, rest and drink lots of fluids Oxygen for hypoxia Fluids for dehydrators Analgesics: NSAID's Nebuliser saline may help expectoration Chest physio therapy
What antibiotic treatment do you offer?
Mild - 5 day course of Amoxicillin (macrolide or tetracycline if allergic to penicillin). Add Flucloxicillin if Staph infection suspected
Moderate: 7-10 day course of antibiotics. Amoxicillin with a macrolide
Severe: a beta-lactamase stable beta-lactate and a macrolide
What is the progression of treatment?
Oral antibiotics – if not severe and not vomiting; amoxicillin/clarithromycin/doxycycline
IV antibiotics – if severe; co-amoxiclav/cephalosporin + clarithromycin
O2 - if low sats
IV fluids - if anorexia, shock or dehydration
Analgesia - if pleurisy
ITU - if shock, hypercapnia, uncorrected hypoxia; if CRP remains high or failure to improve then look for progression/complications
What is the best way of preventing it?
Pneumoccocal vaccine – offer to at risk groups i.e. >65yo, chronic heart, liver, kidney or lung failure/conditions, DM, immunosuppressed, small spleen, AIDS, chemotherapy
What are the differentials?
- Different organism responsible.
- Pulmonary oedema.
- Pleural effusion.
- Pneumothorax.
- Pulmonary embolus.
- Asthma.
- COPD.
- Bronchiectasis.
- Fibrosing alveolitis.
- Neoplasm.
- Sarcoidosis.
- Pneumonia complication - eg, empyema, lung abscess.
What are the complications?
- Pleural effusion that is usually sterile.
- Empyema: a reactive effusion can occur but is trivial. Empyema is potentially more serious and presents as the persistence of fever and leukocytosis after 4-5 days of appropriate antibiotic therapy.
- Lung abscess: can occur in disease due to S. pneumoniae and is classically seen in patients with klebsiella or staphylococcal pneumonia.
- Pneumatocele.
- Pneumothorax.
- Pyopneumothorax - eg, following rupture of a staphylococcal lung abscess in the pleural cavity.
- Deep vein thrombosis.
- Septicaemia, pericarditis, endocarditis, osteomyelitis, septic arthritis, cerebral abscess, meningitis (particularly in pneumococcal pneumonia).
- Postinfective bronchiectasis.
- Acute kidney injury.
What is the prognosis?
Mortality from CAP <1% of those well enough to be looked after in the community.
Hospital admissions: 5-10%
Incubated patients: 25%
ICU patients: 50%
Legionella has the most severe course and most significant morbidity
