Pneumonia Flashcards
Why is pneumonia important
- common disease with high rates of hospitalisation
- it kills
- expensive to treat
- treatable
Presents to all specialities
- GP
- A and E
- acute/general medicine
- respiratory medicine
- ITU
- surgeons
- Oncology
- HIV
- Radiology
- Paediatrics
- care the elderly
describe the epidemiology of pneumonia
• Incidence 5-11 cases/1000 adults
– 5-12% of respiratory infections presenting to GP’s
• Highest incidence in very young and very old
– BTS Audit – Mean age 71 (16-105) – 25% ≥85
• 22-42% require hospital admission in UK
• 5-7% need intensive care = 5% of ITU admissions – 50% Mortality
• 18.3% 30 day mortality
– 20% in first 24 hours – Median 5 days
• HAP affects 0.5-1% of inpatients
What is pneumonia
Symptoms and signs consistent with an acute lower respiratory tract infection associated with new radiographic shadowing for which there is no other explanation
What are the symptoms of pneumonia
Localised
- Cough and at least one other from:
- pleural pain
- dyspnoea
- tachypnoea
Systemic
- sweating, fevers, shivers, aches and pains and/or
- fever greater than 38 degrees
What are the signs of pneumonia
- new and focal chest signs
- new radiographic shadowing with no other explanation
How can you classify pneumonia
- aetiology
- patient factors
- clinical features
how do you classify pneumonia according to the aetiology
Organism
Source of infection
- community acquired
- health care associated - hospital acquired, ventilator associated, nursing home
How do you classify pneumonia according to patient factors
- underlying disease
- immunocompromise states
how do you classify pneumonia according to clinical features
- severity
- symptoms and signs
What organisms causes the most pneumonia
Strep Pneumoniae - greater than 50% of all cases
in approximately 50% of pneumonia cases there is…
no pathogen identified
what other factors can be used to help predict the organism that is causing the pneumonia
- Source of infection
- patient factors
- clinical features
How do you define hospital acquired pneumonia
- defined as someone who has developed pneumonia who has been in hospital for more than 48 hours or 10 days post discharge
What pathogens can cause hospital acquired pneumonia
Increased risk of
- aspiration
- H.influenzae
- Gram negative
- Staph aureus
What patient factors can help predict the most likely pathogen causing pneumonia
- Elderly are less likely to have M.pneumoniae and Legionella
- Diabetes - increase in bacteraemic pneumococcal pneumonia
- COPD - increase in H.influenzae and M. Catarrhalis
- Alcoholism - more likely to have all organisms - consider aspiration as more likely to aspirate and more likely to be infected with anaerobic bacteria
- Immunodeficiency - still the most common cause but more likely to be due to legionella, neutropenic sepsis and TB, PCP etc
clinical features cannot …
predict the likely pathogen
what pathogens do you need to cover in hospital acquired pneumonia
- Most commonly gram negative enterobacteria or staph Aureus
- pseudomonas
- Klebsiella
- bactericides
- clostridia
– Cover Gram Negatives
– No need to cover Legionella
what are the lung defence mechanisms
designed to treat a decrease in particle size as you go down the respiratory tract
- filtration/deposition in upper airways
- cough reflex
- mucociliary clearance
- alveolar macrophages
- humeral and cellular immunity
- oxidative metabolism of neutrophils
what can cause defects in the airway host defences
- filtration/deposition in upper airways = anatomical abnormalities
- cough reflex = aspiration e.g. post stroke
- mucociliary clearance = cystic fibrosis, bronchiectasis
- alveolar macrophages = alcoholism
- humeral and cellular immunity = HIV
- oxidative metabolism of neutrophils = chemotherapy
What has to happen in order for pneumonia to infect the body
Immune defence
- defect in host defence
- virulent organism
- overwhelming inoculum such as aspiration
What investigations are needed in pneumonia
- aid and confirm diagnosis
- stratify severity/risk
- target therapy
Aid/confirm diagnosis
- chest radiograph - within 4 hours
- FBC (WCC usually >15x109/l)/CRP (usually >100mg/l)
Stratify severity/Risk
- urea and electrolytes
- FBC/CRP/(LFT)
- Oxygen saturations
- ABG
Target therapy
- blood and sputum cultures – Pneumococcal urinary antigen
– Legionella urinary antigen +sputum culture
– Mycoplasma PCR (Sputum/Throat swab)
– Chlamydophilia PCR/Complement fixation
– Viral PCR(Nose/Throat swab)
What is the aim of microbiology
– Identify Pathogenic Bacteria
• Microscopy
– Test Sensitivity to Antibiotics
• Culture and Sensitivities
what cultures can be used to assess the microbiology of the pneumonia
- Blood and/or Sputum Cultures
- urinary antigens - only for pneumococcus and legionella
- PCR - nose or throat swab for viruses
what is urinary antigen test supposed to be for
- Pneumococcoal
- legionella – Only tests for Serogroup 1 (90% of European cases)
Describe urinary antigen tests
– Highly Sensitive (>80%) and Specific (>95%) – Rapid Result
– Remain Positive on Treatment
– No information on Antibiotic Sensitivities
– If positive → Specific sputum culture
When does staph aureus usually cause pneumonia
- winter
- 39% influenza symptoms
- 39% influenza virus - 50% of those admitted to ITU
What radiographic changes might you see in pneumonia
- Consolidation
- air bronchograms - highly suggestive on pneumonia
- shadowing
- collapse
- pleural effusion
- lymphadenopathy
What are air bronchograms
- dark lines going through a white area of lung
- air bronchi surrounded by the pus in the alveoli
How long does it take for pneumonia changes on a radiograph
- 73% at 6 weeks, slower in the elderly or multi lobar
When would you use CT scanning in pneumonia
- diagnostic doubt
- underlying cause such as cancer
How can you guide your treatment of pneumonia
CURB65
what is CURB65 made out of
- C - new confusion (AMTS less than or equal to 8)
- U - urea greater than 7mmol/l
- R - respiratory rate greater than 30/min
- B - blood pressure hypotensive
- 65 age over 65
What is the downside of CURB65
- requires a blood test result as you need to know the urea
- has binary cut offs
- young people blood pressure doesn’t decrease until they are severely ill
as CURB65 score increases….
mortality increases
How do you treat pneumonia according to the CURB65 score
– 0-1 – Treat at home • >50% of cost related to admission • ↓Mortality • ↓RiskofVTE • ↓ Risk of Hospital Acquired Infection
– 2 – Short admission, oral antibiotics
– 3+ – Admit + urgent senior review
– 4-5 – Admit + Critical Care (ITU/HDU) Review
What else should be used in the treatment of pneumonia
- Oxygen – Aim for target saturations
- i.v. Fluids, analgaesia & DVT prophylaxis
- Chest Physio/sitting out + Nutritional support
- Smoking cessation
What antibiotics are used in pneumonia
- Beta lactam in mild pneumonia with a macrolide added in moderate to severe pneumonia
What organisms are resistant to penicillin that can cause pneumonia
– Legionella & Mycoplasma
- but these are usually susceptible to macrolide
What is there route of antibiotics that should be given
Oral – Unless:
• CURB65 ≥3
• Unable to swallow
How long should the antibiotics be given for pneumonia
- Mild 5/7
- Moderate-Severe 7-10/7
- Atypicals 14-21/7
What can cause a failure to improve
Worried 3-4 days if not improving or getting worse
- repeat CXR/CRP at 3-4 days
Think about
– Incorrect diagnosis or complicating condition – Unexpected/resistant pathogen
– Impaired local or systemic immunity
– Local or distant complications of CAP
What should you consider if the CXR does not improve at 6 weeks
- consider bronchoscopy
- CT
Why do you not give everyone broad spectrum antibiotics
Individual
- adverse consequences of antibiotics - MRSA and clostridium difficile
Society
- antibiotic resistance
what are strategies for antibiotic stewardship
- Ensure diagnosis secure
- Discontinue if not appropriate
- Narrow spectrum if specific pathogen identified
- i.v. → oral switch
- Stop dates on drug charts
Who is give the influenza vaccine
- all greater than 65 years + 2-4
greater than 6 months in an at risk group:
- asthma
- COPD
- chronic respiratory, heart, kidney, liver or neurological disease
- diabetes
- immunosuppression
- pregnant women
- healthcare workers
What are the benefits of the influenza vaccine
51-67% protection
– ↓Bronchopneumonia
– ↓Hospital Admissions
– ↓Mortality
Who is given the pneumococcal vaccination
- all over 65s
Greater than 2 years in an at risk group:
- same as influenza
- asplenia/splenic dysfunction - give 4-6/52 prior to splenectomy if possible
- cochlear implants
- CSF leaks
Revaccinate every 5 years
- Asplenia/splenic dysfunction
- CKD
Who should you revaccinate with pneumococcoal vaccination
- Asplenia/splenic dysfunction
- CKD
describe what the pneumococcal vaccination does
- poorly protective
- reduces septicaemia
define atypical pneumonia
The term ‘atypical pneumonia’ has outgrown its historical usefulness and we do not recommend its continued use as it implies (incorrectly) a distinctive clinical pattern
what is atypical pathogens used to define
• “The term ‘atypical pathogens‘ is used to define infections caused by:
– Mycoplasma pneumoniae – Chlamidophila pneumoniae – Chlamidophila psittaci
– Coxiella burnetii
What do atypical pathogens all share
•Difficult to diagnose early in illness
• Resistant to β-lactams
• Replicate intracellularly
• Mixed reports regarding specific symptoms:
– Mycoplasma:
• ?Younger & less systemic features.
• Epidemics
– C.pneumoniae – ?Headaches, longer prodrome & older
– C.psittaci – Acquired from birds but only 20% have bird contact
– C.burnetii – Younger males, dry cough & high fever
What is legionella caused by
Inhalation of aerosol from infected water source e.g. air conditioning
How do you differentiate clinically legionella
– Men
– Healthy younger patients
– Smokers
– Neurological or GI symptoms – Less respiratory symptoms
Who do you need to inform in legionella outbreak
Inform HPU to perform source investigation
When do you do the follow up for pneumonia
- follow up is at 6 weeks
How do you treat low severity pneumonia CURB65=0-1
Home - amoxicillin 500mg tis orally or - Doxycycline 200mg loading dose then 100mg orally or - clarithromycin 500mg bd orally
How do you treat moderate severity pneumonia = CURB65=2
Hospital
- amoxicillin 500mg-1g tis orally plus clarithromycin 500mg bd orally
- if oral administration not possible amoxicillin 500mg tds IV or benzylpenicillin 1-2g QDS IV plus clarithromycin 500mg bd IV
or
- doxycycline 200mg daoding dose then 100mg orally
or
levofloxacin 500mg od orally or moxiflocaxin 400mg od orally
How do you treat high severity pneumonia CURB65=3-5
Hospital (consider critical care)
- antibiotics given as soon as possible
- Co-amoxiclav 1.2g tis IV plus clarithromycin 500mg bd IV
- if legionella strongly suspected consider adding levofloxacin
or
- benzylpencillin 1.2g qds IV plus either levofloxacin 500mg bd IV or ciprofloxacin 400mg bd IV
or - cefuroxime 1.5g tds IV or cefotaxime 1g tds IV or ceftriaxone 2g od IV, plus clarithromycin 500mg bd IV
What are the clinical signs in consolidation
- expansion is decreased on affected side
- percussion is dull
- tactile vocal remits is increased over the affected area
- breath sounds are bronchial over the affected area
- vocal resonance is increased over the affected area
What are the clinical signs of lung collapse
- mediastinum is shifters toward the abnormal side
- expansion is decreased on the affected side
- percussion is dull over the affected area
- breath sounds are reduced
What are the clinical signs of pleural effusion
- the mediastinum is shifted away from the abnormal side
- expansion is decreased on the affected side
- percussion is dull
- tactile vocal remits is decreased over the effect side
- breath sounds are reduced over the affected area
- vocal resonance is decreased over the affected area
What is the difference between low pitched and high pitched sounds in pleural effusion
- Low pitched sounds have poorer transmission through a pleural effusion than a normal lung
- high pitched sounds appear to have slightly higher auscultatory transmission through a pleural effusion than a normal lung
describe the clinical signs for a pneumothorax
- expansion is decreased on affected side
- percussion is resonant over the affected area
- tactile vocal fremitus is decreased over affected area
- breath sounds are reduced over the affected area
- vocal resonance is decreased over the affected area
What antibiotics are used against pneumococcal pneumonia
- Amoxicillin
- benzylpenicillin
- cephalosporin
What antibiotics is used against staphylococcal pneumonia
- flucloxacillin and rifampicin
What antibiotics is used against klebsillea pneumonia
- cefotaxime
- imipenem
What does the healing process of pneumonia look like
- 1 week – fever should have resolved
- 4 weeks – chest pain and sputum production should have reduced
- 6 weeks – cough and breathlessness should have reduced
- 3 months – most symptoms should have resolved but fatigue may still be present
- 6 months – people will feel back to normal