Pneumonia Flashcards
What is pneumonia?
An infection of the lung tissue. It causes inflammation of the lung tissue and sputum filling the airways and alveoli. Pneumonia can be seen as consolidation on a chest xray.
How does pneumonia present?
Consolidation on CXR
How can pneumonia be classified?
- “community acquired pneumonia”.
- If it develops more than 48h after hospital admission it is labelled “hospital acquired pneumonia”.
- If it develops as a result of aspiration, meaning after inhaling foreign material such as food, then it is labelled “aspiration pneumonia”.
How does pneumonia present?
- Shortness of breath
- Cough productive of sputum
- Fever
- Haemoptysis (coughing up blood)
- Pleuritic chest pain (sharp chest pain worse on inspiration)
- Delirium (acute confusion associated with infection)
- Sepsis
What are the signs of pneumonia?
There may be a derangement in basic observations. These can indicate sepsis secondary to the pneumonia:
Tachypnoea (raised respiratory rate) Tachycardia (raised heart rate) Hypoxia (low oxygen) Hypotension (shock) Fever Confusion
What are the characteristic chest signs of pneumonia?
There are characteristic chest signs of pneumonia:
- Bronchial breath sounds. These are harsh breath sounds equally loud on inspiration and expiration.
- These are caused by consolidation of the lung tissue around the airway.
Focal coarse crackles. These are air passing through sputum in the airways similar to using a straw to blow in to a drink. - Dullness to percussion due to lung tissue collapse and/or consolidation.
How is the severity of pneumonia assessed?
NICE recommend using the scoring system CRB-65 out of hospital and CURB-65 in hospital.
C – Confusion (new disorientation in person, place or time)
U – Urea > 7
R – Respiratory rate ≥ 30
B – Blood pressure < 90 systolic or ≤ 60 diastolic.
65 – Age ≥ 65
What does the CURB-65 score show?
The CURB 65 score predicts mortality (score 1 = under 5%, score 3 = 15%, score 4/5 = over 25%). The scoring system is there to help guide whether to admit the patient to hospital:
Score 0/1: Consider treatment at home
Score ≥ 2: Consider hospital admission
Score ≥ 3: Consider intensive care assessment
What are the common causes of pneumonia?
Streptococcus pneumoniae (50%) Haemophilus influenzae (20%)
What are the less common organisms causing pneumonia?
- Moraxella catarrhalis in immunocompromised patients or those with chronic pulmonary disease
- Pseudomonas aeruginosa in patients with cystic fibrosis or bronchiectasis
- Staphylococcus aureus in patients with cystic fibrosis
What is atypical pneumonia?
The definition of atypical pneumonia is pneumonia caused by an organism that cannot be cultured in the normal way or detected using a gram stain. They don’t respond to penicillins and can be treated with macrolides (e.g. clarithomycin), fluoroquinolones (e.g. levofloxacin) or tetracyclines (e.g. doxycycline).
Give examples of atypical pneumonia causing organisms?
- Legionella pneumophilia
- Mycoplasma pneumoniae
- Chaymdophilia pneumoniae
- Coxiella burnetti
- Chlamydia psittaci
Legionella pneumophilia
Legionella pneumophila (Legionnaires’ disease). This is typically caused by infected water supplies or air conditioning units. It can cause hyponatraemia (low sodium) by causing an SIADH. The typical exam patient has recently had a cheap hotel holiday and presents with hyponatraemia.
Mycoplasma pneumoniae
Mycoplasma pneumoniae. This causes a milder pneumonia and can cause a rash called erythema multiforme characterised by varying sized “target lesions” formed by pink rings with pale centres. It can also cause neurological symptoms in young patient in the exams.
Chlamydophila pneumoniae.
Chlamydophila pneumoniae. The presentation might be a school aged child with a mild to moderate chronic pneumonia and wheeze. Be cautious though as this presentation is very common without chlamydophilia pneumoniae infection.
