Lobar Pneumonia Flashcards
What is pneumonia?
Acute lower respiratory tract infection
Pneumonia is usually classified by the setting in which the patient contacts the infection.
What are the 5 classes of pneumonias acquired from different setting?
- Community acquired pneumonia
- Hospital acquired pneumonia
- Aspiration pneumonia
- Pneumonia in immunocompromised
- Ventilator acquired pneumonia
Community acquired pneumonia may be primary or secondary to underlying disease. 20% of patients have more than one organism present, whilst 30-50% have no identifiable organisms.
Which typical and non-typical organisms cause community acquired pneumonia?
Which is the most common organism?
- Streptococcus pneumoniae (most common cause)
- Haemophillus influenzae
- Moraxella catarrhalis
Atypical:
- Mycoplasma pneumoniae
- Staphylococcus aureus
- Legionella species
- Chlamydia
* Virus account for up to 15% of the cases.
What is the difference between lobar and diffuse pneumonia?
Lobar pneumonia: when one or more lobes is affected commonly seen in strep. pneumoniae, klebsiella and legionella pneumonias
Diffuse pneumonia: when the lobules of the lung are mainly affected due to infection on the bronchi/bronchioles (bronchopneumonia) commonly seen in mycoplasma, chlamydia, staph. pseudomonas pneumonias.
What are the signs and symptoms seen in community acquired pneumonia?
*Note: community acquired pneumonia should always be considered in sick elderly patients as they tend to have atypical presentation i.e. confusion, recurrent falls
Symptoms:
Dry or productive cough (purulent sputum)
Haemoptysis
Dyspnoea
Fever , rigors
Anorexia , malaise
Pleuritic chest pain
Signs:
Pyrexia
Cyanosis
Confusion (esp in elderly)
Tachypnoea & tachycardia
Hypotension
Signs of consolidation i.e. reduced expansion, dull percussions, increased tactile fremitus/vocal resonance, bronchial breathing, pleural rub
What are the risk factors of community acquired pneumonia?
Age <16 or >65 years
Co-morbidities i.e. HIV, diabetes, CKD, malnutrition, recent viral respiratory infection
Other respiratory conditions i.e. cystic fibrosis, bronchiectasis, COPD, obstructing lesion
Lifestyle: cigarette smoking, excess alcohol, IV drug use
Iatrogenic: immunosuppressant therapy inc. prolonged use of corticosteroids
What are the extra pulmonary features of community acquired pneumonia?
Myalgia, arthralgia and malaise common esp. in Legionella and Mycoplasma
Myocarditis and pericarditis seen in mycoplasma pneumonia
Headache common in legionella
Abdominal pain, diarrhoea and vomiting common in legionella
Labial herpes simplex reactivation in pneumococcal pneumonia
Erythema multiforme and erythema nodosum (skin rashes) seen in mycoplasma pneumonia
What initial investigations do you carry out to assess the severity of the community acquired pneumonia and which severity score system is used?
CURB-65 score => 1 point for each
Confusion - abbreviated mental test <8/10
Urea >7mmol/L
Respiratory rate >30 breaths/min
Blood pressure <90/60mmHg
Age >65 years old
Score 0-1 => treat as outpatient
Score 2 => treat at hospital
Score 3+ => intensive care unit => mortality rate increases with increasing score
Which further investigation is needed for community acquired pneumonia?
Blood tests: FBC, U&E, LFT, CRP
Strep. pneumoniae : increased WCC, ESR, CRP
ABG if O2 <92% or severe pneumonia
Chest X-ray: lobar/multi-lobar infiltrates, cavitation or pleural effusion
[*Normal chest x-ray on presentation should be repeated 2/3 days later if community acquired pneumonia suspected clinically.
*Repeated again 6 weeks later to rule out underlying bronchial malignancy causing pneumonia due to bronchial obstruction]
Sputum for microscopy & culture
Urine: check for legionella/pneumococcal urinary antigen
What is the management for mild pneumonia (CURB-65 score 0-1) caused by streptococcus pneumoniae or haemophilus influenzae?
Treated at home with standard antibiotic i.e. amoxicillin or clarithromycin if penicillin allergy
What is the management for severe pneumonia?
Antibiotics: 1st dose administered within 1hr if high risk & treatment should not be delayed whilst investigations are awaited. IV antibiotics switched to oral once temperature settled for at least 24h.
Maintain O2 >94%
IV fluids if hypotensive, shock, dehydrated
VTE prophylaxis in admitted to hospital >12h (subcutaneous LMWH & TED stockings)
Analgesia (paracetamol or NSAID) if pleurisy
ITU if in shock, hypercapnia or hypoxic
Follow-up at 6 weeks ± CXR
What are the complications of community acquired pneumonia?
Type 1 respiratory failure => treat with high-flow O2 ; ITU if not recovering
Hypotension => IV fluids 250ml over 15 mins
Sepsis
Pleural effusion (common 1/3 - 1/2 cases)
Empyema => suspected if patient resolving from pneumonia develops a fever
Lung abscess => supportive infection
Atrial fibrillation Pericarditis Myocarditis Cholestatic jaundice Brain abscess
*Repeat CRP and CXR in patients not improving to look for progression/complications
What are the prevention measures for community acquired pneumonia?
- Cigarette smoking cessation
- Vaccination against influenza for high risk groups
- Pneumococcal vaccine => all patients >65yrs admitted in hospital who haven’t had the vaccine before
Who are the at risk groups to receive the pneumococcal vaccine?
Adults >65 years
Chronic heart, liver, renal or lung conditions
Diabetes not controlled by diet
Immunosuppression e.g. decreased spleen function, AIDS or chemotherapy
How do you manage a patient with community acquired pneumonia with a CURB-65 score of 2 (9% mortality) caused by streptococcus pneumoniae, haemophilus influenzae or mycoplasma pneumoniae?
Investigations:
Blood culture ; sputum (if not started antibiotics) ; urine pneumococcal antigen if suspected clinically
Treatment:
Amoxicillin + clarithromycin orally
Penicillin allergy => doxycycline
