S9) Lower Respiratory Tract Infections and Pneumonia ❌❌❌❌ Flashcards
Identify 4 common microbial flora of the upper respiratory tract
- Viridans streptococci
- Neisseria sp
- Anaerobes
- Candida sp
Identify 5 less common microbial flora of the upper respiratory tract
- Streptococcus pneumoniae
- Streptococcus pyogenes
- Haemophillus influenzae
- Other: Pseudomonas, Escherichia coli
Identify three defences of the respiratory tract
- Muco-ciliary clearance mechanisms (nasal hairs, ciliated columnar epithelium)
- Cough & the sneezing reflex
- Mucosal immune system (lymphoid follicles, alveolar macrophages, IgA, IgG)
Identify 5 ways in which the respiratory defences can be compromised
- Poor swallowing (muscle weakness, alcohol)
- Abnormal ciliary function (smoking, viral infection)
- Abnormal mucus (cystic fibrosis)
- Dilated airways (bronchiectasis)
- Defects in host immunity (HIV, Immunosuppression)
Identify 5 common upper respiratory tract infections
- Rhinitis
- Pharyngitis
- Laryngitis
- Sinusitis
- Otitis media
Respiratory tract infections are most commonly caused by viruses.
Identify 5 of these
- Rhinovirus
- Coronavirus
- Influenza
- Respiratory syncytial virus (RSV)
When are bacteria common causes for respiratory tract infections?
Bacterial super-infection common with sinusitis and otitis media – can lead to mastoiditis, meningitis, brain abscess
Identify 5 common lower respiratory tract infections
- Bronchitis
- Pneumonia
- Empyema
- Lung abscess
- Bronchiectasis
What is acute bronchitis?
Acute bronchitis is the short-term inflammation of medium-sized airways
Identify 5 typical presentations of acute bronchitis
- Cough
- Fever
- Increased sputum production
- Increased shortness of breath
- Normal CXR
Identify 2 causative organisms of acute bronchitis
- S. pneumoniae
- H. influenzae
How is acute bronchitis treated?
- Bronchodilation
- Physiotherapy
- ± Antibiotics
What is pneumonia?
Pneumonia is a condition resulting from the inflammation of the lung parenchyma (alveoli) and the accumulation of fluid in the air spaces
Identify and describe the four different ways of classifying pneumonia?
- By clinical setting (community acquired, hospital acquired)
- By presentation (acute and chronic)
- By organism (bacterial, viral, fungal)
- By lung pathology (lobar, interstitial or bronchopneumonia)
Describe the pathology of pneumonia
- Acute inflammatory response
- Fibrinous exudate
- Neutrophil infiltration
- Macrophage infiltration
Identify the 5 main causative organisms for Community Acquired Pneumonia (CAP)
- Streptococcus pneumoniae (most common)
- Haemophilus influenzae (common)
- Moraxella catarrhalis
- Staphylococcus aureus
- Klebsiella pneumoniae
Identify 5 symptoms of pneumonia (besides being explictly unwell)
- Fever
- Cough (± sputum)
- Pleuritic chest pain
- Shortness of breath
- Nausea & vomiting
Identify 6 signs of pneumonia seen on examination
- Pyrexia
- Tachycardia
- Tachypnoea
- Cyanosis
- Dullness to percussion (tactile vocal fremitus)
- Crackles
Identify 5 investigations commonly requested for pneumonia
- Full Blood Count
- Urea & Electrolytes
- C Reactive Protein
- Arterial Blood Gases
- Chest X Ray (abnormal)
Which microbiological samples and investigations are requested for pneumonia?
- Sputum / induced sputum
- Blood culture
- Broncho alveolar lavage fluid (BAL)
- Nose & Throat swabs
The CURB-65 score is used to determine the severity of pneumonia.
Which 5 measurements are involved?
- Confusion
- Urea > 7 mmol/l
- RR > 30
- BP <90/60
- Age > 65 years
Score 2-5 = manage as severe
Which 4 considerations are made when determining whether or not a patient needs antibiotic treatment for pneumonia?
- Community vs hospital acquired?
- Severity of illness?
- Personal risk factors
- Ventilator associated?
Community acquired pneumonia is treated with empiric therapy.
Outline this treament for mild-moderate and moderate-severe pneumonia
- Mild-moderate: amoxicillin or doxycycline/erythromycin/clarithromycin
- Moderate-severe: co-amoxiclav and clarithromycin/doxycycline
Describe the outcome of acute bacterial pneumonia in terms of resolution and complications
- Resolution – organisation (fibrous scarring)
- Complications – lung abscess, bronchiectasis, empyema
Identify 5 possible reasons for the failure of antibiotic treatment for pneumonia
- Empyema / abscess
- Proximal obstruction (tumour)
- Resistant organism (incl. Tb)
- Not receiving / absorbing antibiotics
- Immunosuppression
Identify 4 atypical organisms which do not respond to penicillins (cell-wall active antibiotics)
Organisms without a cell wall:
- Mycoplasma
- Legionella
- Chlamydia
- Coxiella
Which antibiotics can be used for pneumonia caused by atypical organisms?
Agents that work on protein synthesis:
- Macrolides (clarithromycin / erythromycin)
- Tetracyclines (doxycyline)
Identify 2 extra-pulmonary features of pneumonia caused by atypical organisms
- Hepatitis
- Hyponatraemia
Viral pneumonia accounts for 10% of pneumonia cases.
Identify 3 effects of viral pneumonia (and arising immune cells)
- Damage to cells lining the airways / alveoli
- Fluid filled air spaces interferes with gas exchange
- Severe viral pneumonia necrosis / haemorrhage into the lung parenchyma
How does viral pneumonia present on a chest X-ray?
Abnormal – patchy or diffused ground glass opacity
Identify 4 causes of viral pneumonia
- Influenza
- Parainfluenza
- Respiratory Syncytial virus (RSV)
- Adenovirus
When does hospital acquired pneumonia commonly occur?
- > 48 hours in hospital
- Often previous antibiotics
- ± Ventilator
Identify 5 causative organisms of hospital acquired pneumonia
- Staphylococcus aureus
- Enterobacteriaciae
- Pseudomonas spp
- Haemophilus influenzae
- Fungi (Candida sp.)
Outline the treatment of hospital acquired pneumonia
- First line: Co-amoxiclav
- Second line/ITU: Pipperacilin / Tazobactam / Meropenem
When is aspiration pneumonia commonly seen?
Aspiration of exogenous material or endogenous secretions into the respiratory tract
Which patient groups commonly present with aspiration pneumonia?
- Neurological dysphagia (strokes)
- Epilepsy
- Alcoholics
- Drowning
Which causative organisms are at play in aspiration pneumonia?
Mixed infection – viridans streptococci & anaerobes
How is aspiration pneumonia treated?
Co-amoxiclav
Identify 4 immunosuppresion patient groups who are vulnerable to pneumonia and other lower respiratory tract infections
- HIV (PCP, TB, atypical mycobacteria)
- Neutropenia (fungi e.g. Aspergillus spp)
- Bone marrow transplant (CMV)
- Splenectomy (encapsulated organisms)
Identify and describe three ways in which pneumonia can be prevented
- Vaccination – flu vaccine and pneumococcal vaccine (high risk patients)
- Chemoprophylaxis – oral penicillin / erythromycin (high risk patients)
- Stop smoking
what is a course of a typical infection indside and outside the lungs?
INSIDE:
- alveoli macrophages fail to stop pathogen
- cytokines recruit more macrophages
- inflammation → increased permeability
- more WBC + proteins
OUTSIDE:
- inflammatory mediators into systemic circulation
- physiological response → activates bone marrow, more CO, raised body temp
- dysregulation → signs of tissue or organ injury
chalmydia pneumonia virulence factor
ciliostatic factor
mycoplasma pneumonia virulence factor
shear of cilia
influenza virulence factor
slows mucus velocity
pneumococcus virulence factor
inhibits phagocytosis
what are some drugs that can increase risk of pneumonia
- antacids (PPI/H2 antagonist)
- antipsychotics
- ACE inhibitors
- glucocorticosteroids
