Respiratory tract infections Flashcards
What are the 3 main routes of transmission for respiratory tract infections ?
- Contact (touch)
- Airborne
- Droplet
Define what acute cough/ acute bronchitis is
It is an infection of the the bronchi - the large airways.
What is acute bronchitis caused by ?
- It is usually due to viral infection
- Less commonly it may be caused by bacterial infection
What are the main causative organisms of bacterial acute bronchitis ?
H.influenzae, S.pneumoniae, M.catarrhalis.
What are the main clinical features of acute bronchitis ?
- The key symptom is a productive cough
- May have a transient wheeze
- You may also develop a fever, headache, cold symptoms and aches and pains.
- Symptoms typically peak after 2-3 days and then gradually clear. However, it commonly takes 2-3 weeks for the cough to go completely after the other symptoms have gone.
In someone with acute bronchitis would you expect their chest exammination and CXR to be normal ?
Yes
What is the mainstay of the treatment of acute bronchitis ?
It is usually self-limiting in the average joe so treatment is supportive:
- Analgesia – paracetamol and ibuprofen
- Hydration.
- Time.
When may antibiotics be used in the treatment of acute bronchitis ?
- When the patient is systemically very unwell
- When the patient has symptoms and signs of serious complications
- When the patient is at high risk of serious complications due to serious co-morbidity
- When the patient is aged 65 or older
- Where community acquired pneumonia is suspected, antibiotic treatment should be commenced without delay, and assessment of the CRB-65 score is essential
When antibiotics are indicated for treatment of acute bronchitis what should be given?
- 1st line = Amoxicillin
- 2nd line = Doxycyline if penicillin allergy
Define what bronchiolitis is
Bronchiolitis is an acute viral infection of the lower respiratory tract that occurs primarily in the very young.
Who is most commonly affected by bronchiolitis ?
Most common cause of a serious lower respiratory tract infection in < 1yr olds (90% are 1-9 months)
During what part of the year do most cases of bronchiolitis occur ?
Winter
What are the causes of bronchiolitis ?
- Respiratory syncytial virus (RSV) is the principle cause
- Others include; Mycoplasma, parainfluenza and adenoviruses
What are the typical clinical features of bronchiolitis ?
Coryzal symptoms (including mild fever) precede:
- Dry cough
- Increasing breathlessness
- Wheezing & fine inspiratory crackles (not always present)
- Intercostal recession
- Cyanosis
- Feeding difficulties
What are the main reasons for admitting someone with bronchiolitis ?
- Poor feeding
- RR > 50
- Apnoea
- Central cyanosis
- Persistent O2 sats < 92%
- Dehydration
- Severe respiratory distress, for example grunting, marked chest recession
- Patient or parental exhuastion
How is bronchiolitis diagnosed ?
By PCR on throat or pernasal swabs
What is the treatment of bronchiolitis ?
Supportive - give O2
Define what bronchiectasis is
This is where there is permanent fixed dilatation of the bronchi & bronchioles secondary to chronic infection or inflammation
List the causes of bronchiectasis
- Post-infective: tuberculosis, measles, pertussis, pneumonia
- Cystic fibrosis
- Bronchial obstruction e.g. lung cancer/foreign body
- Immune deficiency: selective IgA, hypogammaglobulinaemia
- Allergic bronchopulmonary aspergillosis (ABPA)
- Ciliary dyskinetic syndromes: Kartagener’s syndrome, Young’s syndrome
- Yellow nail syndrome
What are the signs/symptoms of bronchiectasis ?
- Persistent cough - with copious amounts of purulent sputum & intermittent haemoptysis
- SOB
- Finger clubbing
- Coarse inspiratory crackles
- Wheeze
- Chest pain, usually non-pleuritic
- Large airway rhonchi (low-pitched snore-like sounds)
What additional parts to a history might make you think more of bronchiectasis ?
- Young age at presentation.
- History of symptoms over many years.
- Recurrent “chest infections” and Abx prescriptions but with no response or short lived to the antibiotics
- Absence of smoking history.
What initial investigations should be done in someone with suspected bronchiectasis ?
- Sputum culture — to identify colonizing pathogens
- Chest X-ray — to exclude other pathology and to help confirm the diagnosis where disease is severe.
- Post-bronchodilator spirometry — to assess the severity of airflow obstruction.
What CXR features are suggestive of bronchiectasis?
Signet rings & tramlines
What is the gold standard test done to diagnose bronchiectasis ?
High-resolution computed tomography (HRCT)
What additional investigations are done to determine the cause of bronchiectasis following definitive diagnosis with HRCT ?
- Testing for cystic fibrosis (such as sweat chloride or gene testing)
- Screening for gross antibody deficiency (serum immunoglobulin G [IgG], IgA, IgM and serum electrophoresis)
- Serum total immunoglobulin IgE and specific IgE or skin prick test to Aspergillus – to exclude allergic bronchopulmonary aspergillosis
- Specific antibody levels against capsular polysaccharides of Streptococcus pneumoniae
- Tests of ciliary function — for children where no other cause for bronchiectasis is identified and if there is a history of continuous rhinitis, neonatal respiratory distress, and/or dextrocardia; and for adults if there is a history of upper respiratory tract problems or otitis media.
- Bronchoscopy — for children with suspected foreign body aspiration or to exclude an endobronchial lesion in adults.
- Gastrointestinal investigations (such as 24-hour pH monitoring) — for adults and children suspected of having bronchiectasis secondary to gastro-oesophageal reflux and aspiration.
What is the general management of bronchiectasis ?
- Physical training e.g. inspiratory muscle training
- Postural drainage (x2 daily) - chest physio may aid sputum expectoration & mucous drainage
- Antibiotics for exacerbations
- Bronchodilators may be useful in patients with asthma, COPD, CF & ABPA
- Corticosteroids for ABPA
- Stop smoking
- Vaccinations - influenza & pneumococcal
- Surgery may be indicated for localised disease or to control severe haemoptysis
Describe what an acute exacerbation of bronchiectasis is
An acute exacerbation of bronchiectasis is a sustained worsening of symptoms from a person’s stable state.People with bronchiectasis should be educated so they know how to recognise an acute exacerbation. Signs to look out for include:
- Acute deterioration over a few days.
- Worsening cough.
- Increased sputum volume, viscosity or purulence.
- Increased wheeze, breathlessness or haemoptysis.
- Feeling systemically unwell.
What organism commonly causes chest infections/pneumonia in young patients bronchiectasis ?
Haemophilus influenzae
Describe what chronic bronchial sepsis is
This is when there are all the hallmarks of bronchiectasis but with no evidence of it on HRCT
What is the management of an acute exacerbation of bronchiectasis ?
- Send a sputum sample for culture and susceptibility testing.
- Offer an initial antibiotic based on the severity of symptoms, previous exacerbation and hospital admissions, the risk of developing complications, and previous sputum culture and susceptibility results.
- First-choice oral antibiotics for empirical treatment are clarithromycin or azithromycin
Define what influenza ‘flu’ is
- Flu (influenza) is caused by the influenza virus. However, many other viruses can cause an illness similar to flu.
- It is often difficult to say exactly which virus is causing the illness, so doctors often diagnose a flu-like illness.
What are the causes of influenza ‘flu’?
There are three types of influenza virus - A, B and C. Influenza A and B cause most of the cases of flu. Each winter a different type of influenza virus causes an outbreak of flu which affects many people. This is called seasonal flu. If you get a flu-like illness during an outbreak of seasonal flu, it is likely to be caused by the prevailing influenza virus.
When do most cases of infleuza ‘flu’ occur?
In a period of six to eight weeks during the winter.
What is the cause of the winter epidemics of influenza?
Minor mutations in the surface proteins of the virus - antigenic drift
What are some of the causes of flu-like illnesses?
Parainfluenza viruses & many others
What is swine flu?
Swine flu is caused by a particular strain of influenza A virus which is called H1N1v. It seems to affect children and young adults more commonly than those over the age of 60 years. Most people with this type of flu have a mild flu-like illness. You are more likely to have sickness and/or diarrhoea with this type of flu.
How is influenza transmitted ?
By droplets when someone coughs or sneezes, or through direct contact with respiratory secretions of someone with the infection
What are the symptoms of influenza ‘flu’?
- Fever (upto 40 degrees) & sweats
- Headache
- Malaise
- Myalgia (muscle ache quite marked) & arthralgia
- Prostration (state of being exstremly weak)
- Dry cough
- Sneezing
- Sore throat
Appreciate this:
The illness caused by the influenza virus tends to be worse than illnesses caused by other viruses which cause a flu-like illness. Even if you are young and fit, flu can make you ill enough to need to go to bed.
Typically how long does symptoms of influneza last?
- Typically, symptoms are at their worst after 1-2 days. Then they usually gradually ease over several days.
- Most people completely recover within 2-7 days
How is influenza ‘flu’ usually diagnosed ?
Diagnosis is usually made using clinical features alone when it is known to be circulating in the community
When a definitive diagnosis of influenza is required what is done ?
PCR of nasopharyngeal swabs, throat swabs or of other respiratory samples
What may indicate that someone has developed complications of influenza?
- Signs and symptoms that require hospital admission.
- Symptoms of LRTI (hypoxaemia, dyspnoea, lung infiltrate).
- Central nervous system involvement.
- Significant exacerbation of an underlying medical condition.
What are some of the complications which can develop as a result of influenza?
- Bronchitis
- Penumonia - most commonly this is a secondary pneumonia caused by bacterial infection with H. influenza. Or this may be a primary influenzal pneumonia
- Sinusitis
- Ottitis media
- Encephalitis
- Pericarditis
- Reyes syndrome (coma, Increased LFTs)
- Influenza during pregnancy - associated with perinatal mortality, prematurity, smaller neonatal size & LBW
List the people who are considered at risk groups for suffering a worse prognosis from influenza
‘At risk group’ includes people aged over 65 years, children aged under 6 months, pregnant women (at any stage of pregnancy, or women up to two weeks post partum), and people with any of the following conditions:
- Asplenia or dysfunction of the spleen
- Chronic respiratory disease
- Chronic heart disease
- Chronic kidney disease
- Chronic liver disease
- Chronic neurological conditions
- Diabetes mellitus
- Immunosuppression - people undergoing chemo or radiotherapy, bone marrow transplants, HIV, treated with systemic steroids for > 1 month, multiple myeolma & genetic disorders affecting the immune system
- Morbid obesity (body mass index of 40 or more).
What is the treatment of inflenza ‘flu’?
For uncomplicated influenza in previously healthy people tx = supportive (no antivirals needed) with hydration, paracetamol & ibuprofen)
For complicated influenza or uncomplicated in at risk groups (including pregnant women):
- 1st line = oseltamivir
- 2nd line = zanamivir
When is post-exposure prophylaxis for influenza done ?
Prescribe either oseltamivir (upto 48hrs after exposure) or zanamivir (upto 36hrs after exposure) if all the following apply:
- The national surveillance scheme indicates that influenza is circulating.
- The person has been exposed to a person (in the same household) with an influenza-like illness
- The person is either immunocomprimised or in an at risk group of having a worse prognosis of influenza
Note - this is not done in at-risk groups who have been vaccinated against seasonal influenza at least 14 days before exposure.
Who is influenza vaccines recommended for ?
- All people older than 65 years, and those older than 6 months if they at in an at risk group (mentioned in previous flashcard)
- health and social care staff directly involved in patient care (e.g. NHS staff)
- carers of the elderly or disabled person whose welfare may be at risk if the carer becomes ill (at the GP’s discretion)
- All children aged two-five years (not yet at school)
- All primary school aged children (primary one to primary seven) at school.
What are the signs/symptoms of pnuemonia ?
Symptoms:
- Cough
- Purulent suptum +/- haemoptysis
- Dysponea/SOB
- Chest pain (pleuritic)
- Fever
Signs:
- Fever, rigors, sweats
- Tachypnoea & tachycardia
- Decreased O2 sats, cyanosis
- Signs of consolidation = dullness to percussion, decreased chest expansion, decreased breath sounds, bronchial breathing
- Confusion
- Pleural rub
- Crackles
- Herpes labialis reactivation of HSV due to aleration of immune system)
Appreicate this
Shows the severity of pneumonia based on sputum colour
What is the initial management and assessment of someone with pneumonia ?
What further assessment should be done in someone with pneumonia ?
How is pnuemonia diagnosed ?
- Initially measure FBC, Us & Es & CRP - this allows you to calculate severity based on CURB65
- Take blood & suptum cultures + viral PCR & pneumococcal & legionella antigen tests (legionella one can now be done with the viral PCR of sputum)
- Atypical serology - Mycoplasma IgM, ( already done Legionella urinary antigen), Respiratory Viruses, Chylamidia serology, Other specific tests
- Also do ABG’s if low O2 sats or patient has pre-exisiting resp disease e.g. COPD
(basically do the initial ones and if severity worse enough do the diagnostic tests for the organisms)
What additional tx do patients alongside Abx’s for pneumonia recieve ?
What review do patients how have had pneumonia require?
