Pneumonia + Lower Respiratory Tract Infections Flashcards
What is pneumonia?
Inflammation of the alveoli in which they fill up in fibrin rich fluid e.g. mucous + pus
Signs + symptoms of pneumonia
- cough: dry > mucous
- dyspnoea
- pleuritic chest pain
- pleurisy fever + chills
- tachycardia
- organ dysfunction e.g.mental dysfunction
- crackles
- bronchial breathing
- confusion
Clinical findings of pneumonia
- dull to percussion
- fine crackles
- decreased breath sounds
- bronchial breathing
- increased vocal resonance
Investigations of pneumonia
- chest X ray
- sputum sample
- blood culture
- nose + throat swab (for viruses)
- urine (legionella + strep pneumococcus)
- ABG
- C reactive protein
What four tests should you always do in a patient with suspected pneumonia?
Sputum
Blood culture
Nasal and throat swab
Urine antigens
Complications of pneumonia
Emphysema
Lung abscess
Bacteraemia
What is empyema?
Collection of pus in pleural cavity
What is bacteraemia?
Presence of bacteria in the blood
What are the types of pneumonia?
- community acquired pneumonia
- healthcare acquired pneumonia : > 48 hours post admission
- ventilated acquired pneumonia: > 48 hours post intubation
What is the gold standard for diagnosing pneumonia?
- presence of infiltrate + consolidations on imaging
- alongside symptoms + other findings
How does ventilator associated pneumonia occur?
- develops when a person is connected to a ventilator
- biofilm can cover the endotracheal tube + infect the lung
- person can’t cough + already ill so infection builds up > pneumonia
Common microbiota of the respiratory tract
Viridans streptococci
Neisseria
Anaerobes
Candida
Strep pneumoniae + pyogenes
Haemophilia influenzae
List lower respiratory infections
Acute bronchitits
Empyema
Lung abscess
Pneumonia
Bronchiectasis
What is acute bronchitits?
Inflammation of medium sized airways of the lungs (bronchi)
Normal chest X ray
What is bronchiolitits?
Viral infection of the bronchioles
Most commonly in children <12 months
What causes bronchiolitis?
Respiratory syncytial virus
What is a lung abscess?
- Localised collection of pus within the lung
- Leads to cavity formation with a thick wall
- due to microbial infection causing necrosis of lung parenchyma
What is seen on imaging of a patient with a lung abscess?
Presence air-fluid levels in cavity
What is an air fluid level?
Occurs when air rises above a fluid in a contained space (lungs) + there is a flat surface at the air fluid interface
Defences of the respiratory tract
- mucociliary clearance: nasal hairs + ciliated columnar epithelium of respiratory tract
- coughing + sneezing
- alveolar microbiota
- respiratory mucosal immune system: tonsils, alveolar macrophages, secretary IgA + IgG
Describe the responses to an infection in the lungs
- alveolar macrophages fails to stop the pathogen
- cytokines recruit more macrophages
- inflammation > increased permeability
- more WBCs to aid the macrophages
Describe the responses to a infection outside the lungs
- inflammatory mediators enter systemic circulation
- activates bone marrow,increases cardiac output + increases body temp
- dysregulation causes damage to surrounding tissues
What demographic are more at risk of lower respiratory tract infections?
- > 65 years old
- smoking (abnormal ciliary function)
- alcohol/drugs
- chronic lung diseases
- dysphagia
- immunocompromised
- malnutrition
- co-infection with viruses (abnormal ciliary function)
What are upper respiratory tract infections most commonly caused by?
Viruses
e.g. rhinovirus, coronavirus, influenza, RSV
Symptoms of community acquired pneumonia
- cough
- dyspnoea
- pleuritic chest pain
- mucopurulent sputum
- myalgia
- fever
What are 3 common causative organism of community acquire pneumonia?
- Streptococcus pneumoniae (most common)
- haemophilius influenzae
- moraxella catarrhalis
Treatment of community acquired pneumonia
Mild-moderate:
- Amoxicillin
- Or doxycycline or clarithromycin
Moderate-severe:
- hospital admission
- co-amoxiclav AND doxycycline/clarithromycin (to cover atypical organisms)
What is acute bronchitis most commonly caused by?
Viruses
Treatment of acute bronchitits
Bronchodilation
Physiotherapy
(Antibiotics if bacterial)
What atypical organisms may cause community acquired pneumonia?
- Mycoplasma pneumoniae (commonest): lacks peptidoglycan bacterial cell wall
- Chlamydia pneumoniae
- Legionella pneumophila (at contamined water sources)
- Chlamydophila psittaci (exposure to birds)
History suggestive of atypical cause of pneumonia
- contaminated water sources (travel)
- farm animals (>hepatitis)
- exposure birds (>rash, splenomegaly, haemolytic anaemia)
What is the significance of the lack of a peptidoglycan cell wall in the management of mycoplasma pneumoniae?
- Penicillins kill bacterial by inhibiting the synthesis of peptidoglycan cell wall
- no cell wall = no bacterial death
- penicillins are ineffective to mycoplasma pneumoniae
- macrolides are used instead e.g. erthyromycin, clarithromycin
How does atypical pneumonia present on a CXR?
Concentrated in perihilar region
What is hospital acquired pneumonia?
Infection of the lower respiratory tract in hospitalised patients > 48 hours after admission
What organisms cause hospital acquire pneumonia?
- staph aureus + MRSA
- E. coli
- pseudomonas aeruginosa
- Candida
First line treatment of hospital acquired pneumonia
Co-amoxiclav
Second line treatment of hospital acquired pneumonia
piperacilin/taxobactam or meropenem
What do you use to score the severity of pneumonia?
CURB-65
Outline CURB-65 score
One point for each:
- Confusion
- Urea: >7mmol/l
- Respiratory rate: >30
- Blood pressure: <90 systolic <60 diastolic
- >65 years old
Score 2 = mild, admit or mange
Score 2-5 = severe
What is the use of CURB-65?
- used to guide management + risk stratify
- ITU if CURB-65 score is high
Prevention of pneumonia
- Flu vaccine
- Pneumococcal vaccine
- covid 19 vaccine
- Chemoprophylaxis (oral penicillin/erythromycin)
- Smoking advice
Demographic of patients affected with aspiration pneumonia
- neurological dysphagia (stroke)
- epilepsy
- alcoholics
- drowning
Treatment of aspiration pneumonia
co-amoxiclav
Causes on non resolving pneumonia
CHAOS
- Complication: emypema, lung absess
- Host: immunocompromsied
- Antibiotic: inadequate dose, poor oral absorption
- Organism: resistant or unexpected organism non covered by antibiotics given
- Secondary diagnosis: PE, cancer
Pneumonia follow up
- repeat imaging
- follow up appointment in 6 weeks in clinic
- HIV test
- immunoglobulins
