Respiratory Tract infections Flashcards
what are the approaches to respiratory tract infections
anatomical - upper vs lower respiratory tract infections microbiological - virus, bacteria, fungus, parasite - atypical vs typical pneumonia
what is the healthy ‘normal’ state of the lungs
URT - is not sterile, some microorganisms are present in healthy individuals (normal flora) LRT- tract is normally sterile defence mechanisms include: - cilia - mucous production -cough - cough and swallow mechanisms - immunoglobulins - IgA
problems with lung defence mechanisms
- ciliopathy - Kartageners
- mucus pathology - CF
- immunodeficiency states
history taking
symptoms: cough, nature of sputum, haemoptysis, pleuritic pain, fever, night sweats, coryxam symptoms (nasal discharge/facial pain, muscle aches and pains, lethargy)
history of travel
employment - animal exposure, weather, air conditoning, student, occupational exposures
birds? - pets
underlying predisposing illness
unwell contacts
URTI - facts
common short lived and rarely serious usually viral aetiology only require antibiotics if: - bacterial aetilogy known or suspected - systemically unwell - features high risk complications
URTI - features
coryzal features
- nasal discharge, sneezing and cough
pharyngeal involvement - sore throat
laryngeal involvement - hoarse/lost voice
can be complicated by - tracheitis/bronchitis = wheeze
nasal congestions, facial pain/pressure should raise the possibility of sinusitis - if persisits consider Ab
URTI - causative organisms
location and common pathogens
nasopharynx - rhinovirus, coronavirus, S. aureus
oropharynx - Group A strep, corynebacterium, diptheriaw, EBV, adenovirus
Epiglottis - Haemophilis influenzae
Larynx , trachea - parainfluenza, S aureus
What bacteria causes epiglottitis
Haemophilus influenza type B - nearly completely disappeared due to vaccine
- acute onset of fever
- sore throat
- must avoid manipulation of the throat - call for help ENT
What bacteria causes sinusitis
Inflammation of the lining of the sinuses
S. Aureus
H. Influenzae
Anaerobes
What bacteria causes pharyngitis - sore throats
Streptococcus pyogenes - group A strep most common bacterial cause causing 30% Characterised by: - inflammation - exudate - fever - tender cervical lymph nodes Complications - scarlet fever -red rash all over the body - rheumatic fever - post strep glomerulonephritis
Whooping cough
Bordetella pertussis bacteria Contagious - notifiable Symptoms: - mild cold like - develop into coughing fits - BARKING cough can persist from weeks to months Transmission person to person coughs etc Young children most at risk Vaccination programme
Important viruses in respiratory tract infection
Influenza/parainfluenza
RSV
Novel Coronavirus
Influenza facts
3 types A, B, C Type A and B most disease burden Influenza virus is antigenically unstable Drift and shift Seasonal epidemics and pandemics Vaccinations - risk groups offered, components aim to cover circling strain Diagnosis - throat swab - Suspect flu clinically - isolate
What does RSV stand for and how is it transmitted
Respiratory syncytial virus - droplets and secretions
Symptoms mild - children <6months severe - bronchiolitis and pneumonia
60% of children are infected prior to 1yo
Disease in childhood does not given life long protections
What are novel coronaviruses
Cause infection of differing severity in humans and animals
SARS - severe acute respiratory syndrome
- identified 2002
MERS-CoV - Middle East respiratory syndrome coronavirus
2012 identified
Types of lower resp tract infections
Pneumonia - infection of lung tissues
Acute bronchitis/bronchiolotis - inflammation of bronchi
Difference pneumonia shows radiological changes on CXR
Types of pneumonia
Acute and chronic
Acute: community and hospital acquired
Community - typical and atypical
Chronic: pulmonary TB and fungal pneumonia
Predisposing conditions to pneumonia
Condition and the organism
Alcoholic - s. Pneumoniae, h. Influenzae, k. Pneumoniae
COPD- h. Influenzae, s. Pneumoniae
Cystic fibrosis - pseudomonas, staphylococci
Post influenza - staphylococci, H. Influenzae
Mechanical ventilation- klebsiella, MRSA, P. Aeruginosa, enterobacter
When are community acquired pneumonias most common
Winter
What are the causes of community acquired pneumonia
Variety typical and atypical
Signs and symptoms of community acquired pneumonia
Typical -fever, chest pain, purulent sputum
Atypical - dyspnoea, cough, minimal sputum production, more systemic upset
Chest radiograph signs in community acquired pneumonia
Can be lobar, multilobar, segmental - one or more lung lobes affected
Bronchopneumonia- diffuse/patchy, bilateral, assymetric, usually affects both lower lobes
Most common cause of community acquired pneumonia
Stereptococcus pneumoniae - aka pneumococcus
It is a normal inhabitant of URT
Associated with - resp tract infection, otitis media, sinusitis
How to prevent pneumococcal pneumonia
Polyvalent pneumococcal vaccine Offered to only those at risk -elderly - splenectomised patients - alcoholics - COPD
COPD exacerbation
Not always due to infection - characterised by colour of the sputum, increased production, fever
H. Influenzae
Streptococcus pneumoniae
Moraxella catarrhalis
Types atypical pneumonia bacteria
Legionella pneumophila Mycoplasma pneumoniae Chlamydia psittaci Chlamydia pneumoniae Coxiella burnetti
Facts about legionella pneumophilia
Gram neg rod
Responsible for large outbreaks
Associated with environmental water sources
- taps in hospitals
- water systems - air conditioning
Symptoms - mild fluid like to sever pneumonia
Lab diagnosis - urine legionella antigen test
Facts about chlamydia psittaci
Obligate intracellular bacteria
Usually causes infection in birds - parrots and budgies
Transmission to humans is by inhalation of dried bird faeces
Symptoms - flu like illness, pneumonia
Prevention - treat infected birds
Mycoplasma pneumoniae facts
Small gram neg organism
Transmission- resp droplets
Infection most common in children5-14 and adults 30-39
Epidemics occur every 4 years
Range of symptoms from ill resp illness to pneumonia
Difficult to diagnose and grow
How is hospital acquired pneumonia defined
Presenting 2 or more days after hospital admission
Patient from nursing home or long term residential care facility/having haemodialysis and has spent less than 2 days in hospital in the last 90 days a
- health care associated pneumonia
Risk factors of hospital acquired pneumonia
Endotrachial intubatiin
Ventitlation - VAP
Immunocompromised
Post surgery
Common organisms of hospital acquired pneumonia
Gram. E.g. E. coli Klebsiella Serratia Pseudomonas MRSA S pneumoniae
How do antimicirobial therapies differ in hospital acquired pneumonia
Differs between late onset after 5 days and early onset before 5 days
Why does the patient not improve
Wrong bug
Wrong drug
Complications
Diagnosing approach to pneumonia
History and exam
Blood culture (if considering IV antibiotics take a BC)
Sputum cultures and throats swab of appropriate
Send urine
CXR
Routine blood - inc LFTs - atypical pneumonias and systemic viral infections can affect them
Pleural aspiration if evidence required
How to assess the severity of community acquired pneumonia
CURB 65 Confusion of new onset U rea greater than 7mmol/l Resp rate greater than 30 Blood pressure less than 90mmHg systolic or less than 60 diastolic Age 65+
Treatment approach to pneumonia
Start smart then focus
Broad empirical antibiotics based on most likely infection presentation - all trusts have guidelines
Narrow spectrum when further microbiological clinical evidence emerges
When prescribing initially 4 things that are considered
Reason
Route
Dose
Duration
After 48hours of antibiotic treatment what is considered
Whether to continue
Cancer
Or
Concert to oral
