Pneumonia (RESP) Flashcards
Define pneumonia.
Respiratory infection characterised by inflammation of the alveolar space (with consolidation/interstitial lung infiltrates)
What are the different types of causative organisms for pneumonia? (3)
- bacterial pneumonia (most common, Streptococcus pneumoniae most common pathogen)
- viral pneumonia
- fungal pneumonia (e.g. Pneumocystis jiroveci)
What are some different types of pneumonia?
- community-acquired pneumonia (CAP)
- hospital-acquired pneumonia (HAP)
- viral pneumonia
- aspiration pneumonia
- atypical pneumonia
Define community-acquired pneumonia.
CAP is defined as pneumonia acquired outside hospital or healthcare facilities (majority of patients)
What are the two types of community-acquired pneumonia?
- typical
- Streptococcus pneumoniae
- Haemophilus influenzae
- Staphylococcus aureus
- Klebsiella pneumoniae
- atypical
- Mycoplasma pneumoniae
- Legionella pneumophilia
- Chlamydia psittaci
- Pneumocystis jirovecii
What organisms can cause typical CAP?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Staphylococcus aureus
- Klebsiella pneumoniae
What are the clinical features of Streptococcus pneumoniae typical CAP? (3)
- gram +ve encapsulated lancet shaped coccobacilli
- rusty sputum
- can reactivate HSV and cause cold sores
What are the features of Haemophilus influenzae typical CAP? (2)
- gram -ve coccobacilli
- especially in COPD patients (most common cause of exacerbation)
What are the features of Staphylococcus aureus typical CAP? (4)
- gram +ve cocci found in clusters
- common in IVDU
- also occurs after influenza
- causes cavitating (gas-filled) lesions on CXR
What are the features of Klebsiella pneumoniae typical CAP? (6)
- gram -ve non-motile encapsulated bacillus
- alcoholics and diabetics
- causes cavitating (gas-filled) lesions on CXR, typically upper lobe
- blood-stained sputum (red-currant jelly)
- commonly due to aspiration
- causes lung abscess formation and empyema (pus collection in lungs)
How is typical CAP treated?
Amoxicillin or Co-amoxiclav
What organisms can cause atypical CAP? (4)
- Mycoplasma pneumoniae
- Legionella pneumophilia
- Chlamydia psittaci
- Pneumocystis jirovecii
Which diseases is Mycoplasma pneumoniae associated with? (2)
- erythema multiforme (ring-shaped rash)
- autoimmune haemolytic anaemia (cold agglutins, IgM) –> RBC accumulation on blood smear
- diagnosed with serology and positive cold agglutination test
What can Legionella pneumophilia be caused by? (2)
- faulty air conditioning
- recent return from holiday
What are the clinical features of Legionella pneumophilia atypical CAP? (3)
Legionella = Low sodium, Liver derangement, Leukopenia
- hyponatraemia
- abnormal LFTs
- leukopenia
Diagnosed with urinary antigen
What is a risk factor for Chlamydia psittaci atypical CAP?
Associated with pet birds
Who does Pneumocystis jirovecii atypical CAP affect and how do we treat it?
HIV / immunocompromised individuals and causes desaturation on exercise –> treated with co-trimoxazole (trimethoprim + sulfamethoxazole)
How are atypical CAP treated?
Clarithromycin
What is idiopathic interstitial pneumonia?
- group of non-infective causes of pneumonia
- e.g. cryptogenic organising pneumonia –> a form of bronchiolitis that may develop as a complication of RA or amiodarone therapy
Define hospital-acquired pneumonia (HAP).
Pneumonia which has developed within hospitals occurring 48 hours or more after hospital admission and is not incubating at the time of admission
What organisms can cause hospital-acquired pneumonia? (2)
- gram -ve enterobacteria:
- Pseudomonas aeruginosa
- Klebsiella pneumoniae
- E. coli
- Acinetobacter spp
- Staphylococcus aureus
What does Pseudomonas aeruginosa cause in HAP? (2)
- CF
- bronchiectasis
What does S. aureus cause in HAP?
Cavitating (gas-filled) lesions on CXR
How is HAP treated?
Tazocin (piperacillin + tazobactam)
How is MRSA treated?
Vancomycin
What organisms can cause viral pneumonia? (3)
- influenza
- RSV
- parainfluenza
What is aspiration pneumonia?
- results from inhalation of oropharyngeal contents into lower airways –> chemical pneumonitis, lung injury, and resultant bacterial infection
- usually seen in patients with dysfunctional or unsafe swallow
- e.g. stroke, myasthenia gravis, bulbar palsies, alcoholics, reduced consciousness, oesophageal disease, neurological injury (–> aspiration of stomach contents)
What procedure puts patients at risk of aspiration pneumonia?
Intubation
Which lung is more commonly affected in aspiration pneumonia?
Right - since right bronchus is wider and more vertical than left
CXR = consolidation at right lung base
How do we treat aspiration pneumonia?
Amoxicillin and metronidazole
What are the features of a lung abscess? (5)
- chest pain
- subacute productive cough
- foul-smelling breath
- night sweats
- fever
How do we manage a lung asbcess?
IV Abx (rarely need to drain)
What are the symptoms of typical pneumonia? (8)
- productive cough with purulent sputum (yellow-green)
- dyspnoea (SOB) / tachypnoea
- pleuritic chest pain
- rigors or night sweats
- fever (and chills)
- confusion
- malaise
- red currant-jelly (bloody) sputum (Klebsiella pneumoniae)
What are the symptoms of atypical pneumonia? (7)
- slower onset
- non-productive cough
- headache
- low-grade fever
- myalgia and malaise
- diarrhoea
- SOB
Constitutional symptoms often predominate over respiratory findings, and there may be extrapulmonary manifestations
What is seen on examination in pneumonia? (7)
- crackles on auscultation (bronchial breathing)
- decreased breath sounds
- dullness on percussion
- increased tactile vocal fremitus
- coarse crepitations
- cyanosis
- chronic suppurative lung disease (empyema, abscess) –> clubbing
What are the extra clinical features of aspiration pneumonia? (6)
- Hx of vomiting
- foul-smelling breath
- frothy/purulent sputum
- delirium
- reduced appetite
- reduced mobility
What are the risk factors for pneumonia? (5)
- age <2 or >65
- smoking
- pre-existing chronic disease (COPD, bronchiectasis, HF)
- immunosuppression e.g. HIV
- crowded living conditions
What are the first-line investigations for pneumonia? (4)
- CXR
- pulse oximetry
- ABG
- U&Es
What do we see on CXR in pneumonia? (6)
- alveolar opacification
- air bronchograms
- consolidation
- lobar/multilobar shadowing (patchy)
- pleural effusion/cavitation (gas-filled)
- complications e.g. lung abscess
When do we redo CXR in pneumonia?
At 6 weeks after clinical resolution to rule out underlying malignancies that were hidden by original pneumonia consolidation
What might an pulse oximetry & ABG show in pneumonia?
Low arterial oxygen saturation (assess pulmonary function, can also find pre-existing respiratory disease e.g. COPD)
What might U&Es show in pneumonia?
- usually normal, elevated in patients with severe CAP
- urea>7mmol/L counts for 1 point in CURB-65 score to assess severity
What do we see on bloods in pneumonia? (4)
- FBC - neutrophilia in bacterial infection
- CRP - raised
- U&Es - dehydration (high urea)
- procalcitonin - increased in LRTIs
When do we do urinary antigen test for pneumonia? (2)
Rapid bedside test for diagnosis of:
- Legionella (atypical pneumonia)
- Streptococcus pneumoniae
What special investigation can we do for pneumonia?
Sputum MC&S
What lobes does Klebsiella pneumoniae tend to affect?
Upper lobes
What are some differential diagnoses for pneumonia? (12)
- COVID-19
- acute bronchitis
- congestive heart failure
- COPD exacerbation
- asthma exacerbation
- bronchiectasis exacerbation
- TB
- lung cancer/metastases
- empyema
- pulmonary embolism
- pneumothorax
- hypersensitivity pneumonitis
What are some differential diagnoses WITHIN pneumonia? (9)
- CAP
- HAP (>48h after admission; P. aeruginosa, S. aureus, Enterobacteria)
- aspiration pneumonia (unsafe swallow, right lung more common)
- Staphylococcal pneumonia (bilateral cavitating bronchopneumonia, IVDU, elderly, influenza)
- Klebsiella pneumonia (upper lobes, cavitating, red-currant sputum, complications e.g. empyema/abscess/pleural adhesions, weakened immune systems)
- Mycoplasma pneumonia (flu-like symptoms, younger patients, AIHA, erythema multiforme, complications e.g. SJS-TEN, GBS, meningoencephalitis)
- Legionella pneumonia (fever, myalgia, malaise –> dyspnoea, dry cough; poor hotel AC; hyponatraemia, deranged LFTs, leukopenia; antigen in urine)
- Chalmydophila psittaci (infected birds, lethargy, arthralgia, headache, anorexia and systemic symptoms)
- Pneumocystis pneumonia (immunosuppressed/HIV +ve)
What system do we use to assess severity of pneumonia?
CURB-65 (or CRB-65 in primary care):
- Confusion (abbreviated mental test <=8/10)
- Urea >7mmol/L
- Respiratory rate >/=30
- Blood pressure <90 systolic/<60 diastolic
- Age >/=65 years
What is the scoring for CURB-65 and CRB-65 for pneumonia?
CURB-65:
- 0-1 (low): outpatient - treat with amoxicillin
- 2 (moderate): hospitalisation - treat with amoxicillin and clarithromycin 7-10d
- 3-5 (high): ICU level of care - treat with IV co-amoxiclav and clarithromycin 7-10d
CRB-65 in primary care:
- 0 (low severity): treatment at home with oral amoxicillin 1st line
- 1/2 (moderate severity): hospital referral
- 3/4 (high severity): urgent hospital admission
What Abx do we give for CAP? (4)
- amoxicillin - typical
- clarithromycin - atypical/penicillin allergy
- erythromycin - pregnancy
- doxycycline - penicillin/macrolide allergy
When do we avoid clarithromycin?
Avoid in patients with long QT syndrome
What Abx do we give for HAP? (3)
- co-amoxiclav if within 5 days of admission
- side effect: cholestasis = high BR and ALP
- tazocin (piperacillin/tazobactam) if after 5 days of admission
- if severe: piperacillin/tazobactam, ceftriaxone, cefuroxime, levofloxacin
How do we manage pneumonia according to CURB-65 score?
- 0-1 (low severity): outpatient - empirical oral Abx –> amoxicillin
- 2 (moderate severity): hospitalisation - empirical oral/IV Abx –> amoxicillin + clarithromycin 7-10d (doxycycline if penicillin/macrolide allergy)
- 3-5 (high): ICU - broad spectrum IV Abx –> IV co-amoxiclav + clarithromycin 7-10d
- if penicillin-allergic, use cephalosporin (cefuroxime / cetriaxone) + macrolide
What Abx can we use in atypical pneumonia?
- Legionella: fluoroquinolone (levofloxacin) + rifampicin
- Chlamydophilia: tetracycline
- Pneumocystis jiroveci: high-dose co-trimoxazole
What supportive care can we give to patients with pneumonia? (5)
- oxygen - if hypoxemic (<94% / <88% at risk of hypercapnia)
- IV fluids - if hypotensive/signs of dehydration
- VTE prophylaxis with LMWH in immobile patients
- airway clearance
- analgesia (e.g. for pleuritic pain)
What do we prescribe on top of Abx for pneumonia patients with COPD?
Prednisolone, even if no sign of COPD exacerbation
How can we prevent pneumonia in high-risk groups? (2)
- Pneumococcal vaccine
- Haemophilus influenzae type B vaccine
What are some complications of pneumonia? (11)
- pleural effusion
- septic shock
- ARDS
- Abx-associated C. difficile colitis
- heart failure
- empyema
- lung abscess (swinging fever, persistent pneumonia, foul-smelling sputum, Klebsiella/S. aureus)
- ACS
- cardiac arrhythmias
- necrotising pneumonia
- pneumothorax
What are some specific complications of Mycoplasma pneumonia? (3)
- erythema multiforme
- autoimmune haemolytic anaemia
- myocarditis
Describe the prognosis of pneumonia.
- mortality increases with age and increasing CURB-65 score
- mortality of HAP>CAP
