Respiratory (pneumonia, acute bronchitis, asthma) Flashcards
when to give oxygen
Always give oxygen to an acutely ill hypoxic patient, regardless of if they have COPD or not:
- Any critically ill patient should initially have oxygen via a reservoir mask at 15L/min
- Hypoxia is more dangerous than hypercapnic respiratory failure in acute scenarios
Oxygen saturation targets for acutely ill patients are
94-98%
Oxygen saturation targets for COPD
Patients with COPD and other risk factors for hypercapnia who develop critical illness should have the same initial target saturations as other critically ill patients pending the results of blood gas results after which these patients may need controlled oxygen therapy with target range 88–92% or supported ventilation if there is severe hypoxaemia and/or hypercapnia with respiratory acidosis.”
oxygen management in COPD
1st-line: prior to blood gas results: 28% Venturi mask at 4 L/min + aim for SpO2 88-92%
Once blood gas results are available:
- If pH and PCO2 are normal on blood gas: aim for 94-98%
- If pH is normal but pCO2 and bicarbonate raised: aim for 88-92%
This is because if the pCO2 is raised, and so is the bicarbonate, it is likely that the patient has longstanding hypercapnia - If pH is 7.25-7.35 and pCO2 is raised: use non-invasive ventilation (NIV)
FEV1
The forced expiratory volume in one second (FEV1) is the volume of air exhaled in the first second of a forced expiration:
This is usually reduced in both obstructive and restrictive disease
FVC
The forced vital capacity (FVC) is the maximum amount of air forcibly exhaled after taking in the deepest breath possible:
This may be reduced in obstructive and restrictive disease
In obstructive disease, the FEV1/FVC ratio is generally
<0.7
In restrictive disease, the FEV1/FVC ratio may be
normal or raised (i.e. ≥0.7)
Example obstructive conditions may be:
Asthma
COPD
Bronchiectasis
Cystic fibrosis
Lung tumours
Example of restrictive conditions may be:
Pulmonary fibrosis
Asbestosis
Kyphosis/scoliosis
Neuromuscular disorders
Severe obesity
pneumonia classification
- Community-acquired pneumonia (CAP): developed outside of hospital and most common
- Hospital-acquired pneumonia (HAP): developed in hospital (>48 hours after hospital admission)
Community-Acquired Pneumonia
Typical bacteria:
- Streptococcus pneumoniae – most common cause
- Haemophilus influenzae
- Staphylococcus aureus (following an influenza infection)
atypical bacteria
- Mycoplasma pneumoniae
- Legionella peumophila (air-conditionig, hotels, hyponatraemia)
- Klebseilla pneumonia (alcoholics and diabetics, aspiration)
- Chlamydia psottaci (parrots)
Fungal
* Pneumocystis jirovecii
* Usually clear chest and dry cough
* Desaturations with exertion may be seen
Hospital-Acquired Pneumonia
bacteria
Early-onset HAP (<5 days after hospital admission): Streptococcus pneumoniae
- Late-onset HAP (>5 days after hospital admission): Methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa
presentation of pneumonia
- Cough with or without sputum
- Dyspnoea
- Chest pain which may be pleuritic
- Fever
- Tachycardia
- Reduced oxygen saturations
- Coarse crackles on auscultation
- Reduced breath sounds on auscultation
presentation of atypical pneumonia : mycoplasma pneumoniae
- Flu-like symptoms (fever/malaise/myalgia) precede a dry cough
- There may be erythema multiforme or erythema nodosum
presentation of atypical pneumonia : legionella pneumoniae
- Classically spread by air-conditioning systems and in-building water systems
- Dry cough
- Diarrhoea
- Encephalopathy
- Hyponatraemia
- Reduced lymphocytes
- Deranged LFTs
- Elevated creatine kinase
presentation of atypical pneumonia : Klebsiella pneumoniae
- More common in alcoholics and diabetics
- May happen after aspiration
- “Red-currant” sputum may be present
pneumoni assessment in primary care
CURB-65
CURB-65
- Confusion
- Urea
- RR- >30
- Blood pressure - systolic <90 mmHg, diastolic <60mmHg
- Age - >65
CURB-65 intepretation
- 0 (low risk, mortality <1%): consider treating the patient at home - amoxicillin or doxycyline (clarithromycin)
- 1-2 (moderate risk, mortality 1-10%): consider hospital referral for assessment and treatment - amoxicillin + doxycycline (clarithromycin)
- ≥3 (high risk, mortality >10%): admit to hospital immediately - co-amoxiclav or meropenem
pneumonia investigations
- Chest x-ray
- FBC- WCC
- CRP
- Blood cultures
- sputum cultures and gram stain
- Legionella urinary antigen
- Pneumococcal urinary antigen
- PCR
follow up after pneumonia
CXR after 6 weeks
complications of pneumonia
Complications
- Pleural effusion
- Sepsis
- Empyema
- Lung abscess
- Pneumothorax
- Acute kidney injury
- Post-infective bronchiectasis
Acute bronchitis
Acute bronchitis describes the inflammation of the bronchi, usually caused by a viral or bacterial infection.
causes of acute bronchitis
Viral
* Rhinovirus
* Enterovirus
* Influenza
* Parainfluenza
* Adenovirus
* Respiratory syncytial virus
Bacterial
* Streptococcus pneumoniae
* Haemophilus influenzae
* Moraxella catarrhalis
Acute bronchitis vs pneumonia.
- May or may not have sputum/wheeze/breathlessness
- Substernal/chest wall pain may be present during coughing
- Patients generally appear mildly ill
- A wheeze is often present
- Crackles are unlikely but may be present and improve with coughing
- There is often no shortness of breath
- Although not routinely performed for bronchitis, chest X-rays are normal
management of acute bronchitis
If stable: self-care advice + simple analgesia (paracetamol +/- NSAIDs)
Offer antibiotics immediately if:
* The patient is systemically very unwell
* They have comorbidities such as heart/lung/kidney/liver/neuromuscular disease, immunosuppression, or cystic fibrosis
* CRP >100mg/L (offer delayed prescription if 20-100mg/L)
antibiotics for acute bronchitis
1st-line: doxycycline (vs amoxicillin in pneumonia) – contraindicated in children/pregnancy
Consider amoxicillin or if penicillin-allergic, clarithromycin or erythromycin if pregnant
asthma risk factors
- Family history
- Family and/or personal history of atopy e.g. eczema/food allergy/hayfever
- Male sex – for pre-pubertal asthma
- Female sex – for the persistence of asthma from childhood to adulthood
- Respiratory infections in infancy
- Prematurity
- Obesity
- Occupational triggers (e.g. isocyanates)
asthma presentation
- Wheeze
- Cough – usually dry
- Shortness of breath
- Chest tightness
The pattern of these symptoms can help make a diagnosis of asthma more likely compared to other conditions such as chronic obstructive pulmonary disease (COPD). Features suggesting asthma are:
- Episodic symptoms – they are usually diurnal (worse at night/early morning)
- Symptoms may be triggered by exercise/chest infections/cold air exposure/allergens e.g. pollen, animal dander
- Symptoms may worsen with aspirin and beta-blockers.
- Beta-blockers are contraindicated in asthma
- An expiratory polyphonic (multiple pitches and tones) wheeze is heard throughout the chest on auscultation
- There may be a family or personal history of other atopic conditions
investigations for asthma : >17
- spirometry with bronchodilator
- FeNO
spirometry for asthma
- Reduced FEV1
- Normal FVC
- FEV1/FVC ratio: <0.7
Reversibility testing involves giving a bronchodilator and observing changes in spirometry findings:
* Adults: improvement in FEV1 of ≥12% and a volume of ≥200 ml is positive
* Children: improvement in FEV1 of ≥12% is positive
Nitric oxide (NO) and asthma
is released by eosinophils during inflammatory reactions. In asthma, FeNO levels are raised:
* Adults: ≥40 ppb is raised
* Children: ≥35 ppb is raised
investigations for asthma : : 5-16 years
- Spirometry with BDR testing
- Offer FeNO if spirometry is normal or spirometry shows an obstructive picture with a negative BDR test
investigating asthma :<5
Diagnosis is made clinically
management of asthma: >17 years old
First line:
- SABA e.g. salbutamol
Second line:
- SABA + low dose inhaled ICS e.g. beclometasone
Third line:
- SABA + low dose ICS + LTRA
Fourth line
- SABA + low-dose ICS + long-acting beta-agonist (LABA e.g. salmeterol) +/- LTRA (depending on response)
Fifth line
- ABA + maintenance and reliever therapy (MART) that includes a low-dose ICS +/- LTRA
- MART is a single inhaler containing ICS and LABA which can be used for relief of symptoms and maintenance therapy
Sixth line
- SABA + medium-dose MART +/- LTRA or SABA + moderate-dose ICS + LABA
Seventh line
SABA +/- LTRA and one of:
- Fixed high-dose ICS (i.e. not as a MART)
- Trial adding long-acting muscarinic receptor antagonist (LAMA) or theophylline
- Refer to specialist
asthma patients 5-16 years
Management is very similar to adults:
- 1st-line: SABA
- 2nd-line: SABA + paediatric low-dose ICS
- 3rd-line: SABA + paediatric low-dose ICS + LTRA
- 4th-line: SABA + paediatric low-dose ICS + LABA (stop LTRA if it has not helped)
- 5th-line: SABA + MART that includes paediatric low-dose ICS
- 6th-line: SABA + paediatric moderate-dose ICS MART or SABA + moderate-dose ICS + LABA
- 7th-line: SABA and one of:
- High-dose paediatric ICS as fixed-dose or part of a MART
- Trial adding theophylline
- Refer to specialist
all asthma patients should have an annual
influenza jab
stepping down treatment of asthma
Consider stepping down asthma treatment every 3 months if the patient is stable and treatment is sufficient. This involves reducing the dose of ICS by 25-50% at a time.
acute asthma exacerbation risk factors
- Previous near-fatal asthma
- Previous admission for asthma, particularly if in the last year
- Frequent emergency attendance for asthma, particularly in the last year
- Asthma requiring 3 or more medications to manage
- Increasing use of beta2-agonists
- Having brittle asthma – this is asthma that is difficult to control and may unpredictably lead to life-threatening attacks
- NSAID sensitivity
- Smoking or passive smoking
- Exposure to triggers/allergens such as animal fur
- Pregnancy
- Inadequately treated disease
classification of asthma exacerbation
Moderate asthma
- Peak expiratory flow rate (PEFR): 50-75% best (or predicted if best unknown)
- Respiratory rate <25 /min
- Pulse <100 bpm
Severe asthma
- PEFR 33-50% best (or predicted if unknown)
- Respiratory rate >25 /min
- Pulse >110 bpm
Life-threatening asthma
- PEFR <33% best (or predicted if unknown)
- Oxygen saturations <92%
- Signs of exhaustion:
- PaO2 <8kPa
- Normal PaCO2
- Cyanosis
- Silent chest
- Poor respiratory effort
- Arrhythmia
- Hypotension
- Exhaustion
- Altered consciousness
Near-fatal asthma
- PaCO2 raised
Investigations asthma exacerbation
In the community and hospital
- Peak flow measurements – to help gauge severity
- Pulse oximetry – to help gauge the severity
In hospital
- Arterial blood gases – if patients show signs of life-threatening asthma
- Consider a chest x-ray if there is suspicion of another condition such as pneumothorax
management of acute asthma exacerbation
All patients
- 15L oxygen via non-rebreathe mask (aim for SpO2 94-98%) + short-acting beta2-agonists (SABA) + corticosteroids:
* If patients have moderate/severe asthma, SABAs can be given through pressurised metered-dose inhalers (pMDI)
* If patients have life-threatening/near-fatal asthma, nebulised SABAs are used
* The corticosteroid should be continued for at least 5 days following the attack - Nebulised ipratropium bromide:
* If patients have not responded to SABA + corticosteroid treatment or have a severe/life-threatening attack - IV magnesium sulfate
* This is often given for severe/life-threatening asthma - IV aminophylline – must be started under specialist guidance
- Escalate to intensive care and consider intubation and ventilation or extracorporeal membrane oxygenation (ECMO)
Discharging asthma patients from hospital
Patients should only be discharged following treatment provided all of the following apply:
- They have been stable on their medication they are to be discharged with
- Their inhaler technique has been checked and recorded
- They have been given a personal asthma action plan
- Their PEFR is >75% of their best (or predicted if best unknown)
Occupational asthma
should be suspected in all adults with new-onset asthma. This is a form of asthma caused by the workplace triggered by stimuli that may or may not be allergenic. It may be helpful to ask the following:
Are symptoms better on days away from work?
Are symptoms better on holiday?
occupational asthma causes
Causes
- Isocyanates (used in making foams/fibres/paints etc.)
- Flour and grains
- Adhesives
- Metals
- Resins
- Animal exposure
investigations for occupational asthma
Serial peak flow measurements at work and away from work
lung abscess
An abscess is a localised collection of pus within the lung leading to the formation of a cavity.
This differs from an empyema, where the collection of pus occurs in a pre-existing normal anatomical cavity.
Causes of lung abscess
Bacterial infection:
* Staphylococcus aureus
* Klebsiella pneumoniae
* Pseudomonas aeruginosa
* Tuberculosis
MOA
* Aspiration (e.g. inhalation of a foreign body)
* Haematogenous (e.g. secondary to infective endocarditis)
* Extension of a hepatic abscess
* Lung cancer
* Severe or incompletely-treated pneumonia
* Trauma
Risk Factors lung abscess
- Risk factors for gastric aspiration (e.g. strokes leading to dysphagia)
- Pneumonia
- Diabetes mellitus
- Immunodeficiency
- Severe dental disease
- Excess alcohol consumption
- Drug misuse
- Underlying respiratory diseases e.g. COPD, bronchiectasis
presentation of lung abscess
Often develop over weeks
- Fever (swinging)
- Productive cough – often copious amounts of foul-smelling sputum are produced
- Pleuritic chest pain
- Constitutional symptoms – weight loss, night sweats, malaise
- Dyspnoea
- Some patients may have haemoptysis
- Finger clubbing may be seen in chronic cases
investigations for lung abscess
Chest x-ray:
* Shows focal consolidation with central cavitation and an air-fluid level
Blood cultures:
* May show causative organism and should ideally be taken before antibiotics are given, but do not delay treatment
Sputum cultures:
May show causative organism
management of lung abscess
1st-line: IV antibiotics and sepsis six if necessary
Drainage may be necessary or surgery
