Lower respiratory tract infections Flashcards
Name the most common LRTIs
- Tracheitis
- Bronchitis
- Pneumonia
- Abscesses
- Bronchiolitis
What are predisposing factors to LRTIs? Give examples
- Loss os suppression of cough reflex/swallow= stroke, coma, ventilation
- Ciliary defects=PCD
- Mucus disorders=CF
- Pulmonary oedema=fluid flooding alveoli
- Immunodeficiency: congenital or acquired
- Macrophage function inhibition=smoking
What types of bacteria cause LRTIs?
- Strep pneumoniae
- Haem influenzae
- Staph aureus
- Klebsiella pneumonia
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae
- Legionella pneumophila
- Mycobacterium tuberculosis
What types of viruses cause LRTIs?
- Influenza
- Parainfluenza
- Adenovirus
- Respiratory syncytial virus
What types of fungi cause LRTIs?
- Aspergillus
- Candida
- Pneumocystitis jiroveci
Describe acute bronchitis
- Inflammation & oedema of trachea & bronchi
- Cough (dry)-associated with retrosternal pain, dyspnoea, tachypnoea
- Frequent in winter
- Children under 5yrs
- Viruses: rhino/corona/adenovirus, influenza
- Bacterial: less common m.pneumoniae, H.influenzae, B.pertussis
How is acute bronchitis diagnosed &treated?
D= vaccination? previous exposure, cultures of secretions, tests not indicated
T=Supportive, antibiotics if bacterial, Severely affected may require O2/resp support
Describe chronic bronchitis
- Productive cough on most days during at least 3mnths of 2 successive years
- Men & >40yrs
- Associated w/smoking, pollution, allergens
- Airflow obstruction present on spirometry=COPD
- Exogenous irritants= inflammation & oedema of airways
- Acute exacerbations= same pathogens as acute bronchitis
Describe Bronchiolitis
- Paeds: infants 2-10mnths
- Inflammation & oedema of bronchioles
- Acute onset, wheeze, cough, rest distress, nasal discharge
- Peak in winter
- RSV, parainfluenzae, adenovirus, influenza
How is Bronchiolitis diagnosed & treated?
D= CXR, full blood count, microbiological diagnosis
T=Supportive, O2, feeding assistance(NG?), antibiotics if complicated by bacterial infection
What is pneumonia and what are the 2 anatomical patterns shown by pneumonia?
- Infection affecting most distal airways, alveoli, formation of inflammatory exudate
1) Bronchopneumonia= Patchy distribution centred on inflamed bronchioles/bronchi, spread to surrounding alveoli
2) Lobar pneumonia= Affects part/entire lobe, S.pneumoniae
What are the types of pneumonia?
- Community acquired (CAP)
- Hospital acquired (HAP)= >48hrs after hospital admission, enterobacteriaceae & pseudomonas sp.
- Ventilator acquired (VAP)= subgroup of HAP, developing >48hrs after ET intubation/ ventilation
- Aspiration pneumonia= subgroup of HAP, abnormal entry of fluids into LRT, impaired swallowing mechanism
What are the ‘typical’ causative organisms of CAP?
- Strep pneumoniae
- Haem influenzae
- Moraxella catarrhalis
- Staph aureus
- Klebsiella pneumoniae
What are the ‘atypical’ causative organisms of CAP?
- Fail to respond to penicillin/sulpha drugs or no organism identified
- Mycoplasma pneumoniae
- Legionella pneumophilia
- Chlamydophila pneumoniae
- Chlamydophila psittaci
- Coxiella burnetii
What are the signs & symptoms of CAP?
- Rapid onset
- Fever/chills
- Productive cough
- Mucopurulent sputum-RUSTY
- Pleuritic chest pain
- General malaise/fatigue/anorexia
- Tachypnoea
- Tachycardia
- Hypotension
- Dull percussion
- Reduced air entry, bronchial breathing
What non-microbiological investigations can be done for suspected CAP? How is it treated
- Routine obs: pulse/BP/ox
- CXR
- Bloods: FBC/U&E/CRP?LFTs
- Amoxycillin
What is the clinical presentation of Mycoplasma pneumoniae?
- Autumn epidemics
- Children & young adults
- Cough
- Diagnosed by serology
- Rare complications: pericarditis, arthritis, Guillain-Barre, peripheral neuropathy
What is the clinical presentation of Legionella pneumophilia?
- Colonising water piping/ air con systems, showers
- High fever, rigors, dry cough becoming productive, dyspnoae, vomiting, confusion, diarrhoea
- Bloods: deranged LFTs, low sodium
What is the clinical presentation of Chlamydophilia pneumoniae?
- 3-10% CAP cases in adults
- Mild pneumonia/bronchitis in young adults/adolescents
- Elderly also affected
What is the clinical presentation of Chlamydophilia psittaci?
- Exposure to birds
- Pneumonia, splenomegaly, history of bird exposure
- Rash, hepatitis, haemolytic anaemia, reactive arthritis
What are the clinical presentations of:
- primary viral pneumonia
- Secondary bacterial pneumonia
- Primary= commonly in patients with pre-existing cardiac & lung disorders, cough, S.O.B, cyanosis
- Secondary= May develop after initial period of improvement: S. pneumonia, H. influenza, S.aureus
What microbiological investigations for inpatients with suspected CAP can be carried out?
- Sputum Gram stain & culture
- Blood culture
- Pneumococcal urinary antigen
- Legionella urinary antigen followed by..
- PCR or serology
On what organisms is PCR carried out?
- Viral pathogens= influenza
- Mycoplasma pneumoniae
- Chlamydophilia sp
How is the severity of CAP assessed?
- CURB65
- Confusion
- Urea: >7mmol/l
- Respiratory rate: >30
- Blood pressure: systolic: 65
