Pneumonia & other lower respiratory tract infections Flashcards
What scoring system is used for people with pneumonia to determine severity?
CURB-65 = Confusion, Urea, Respiratory rate, Blood pressure
Urea > 7mmol/l
Respiratory rate>30
BP systolic<90mmHg or diastolic<60mmHg
Age>65
Each feature scores 1 if present
What are general tests to order for pneumonia cases?
FBC
CRP
Blood cultures
Sputum MCS
CXR
HIV
Urine
What is consolidation in an xray?
Fluid in the lung e.g. pus, blood, water instead of air
What are signs and symptoms of pneumonia?
Malaise/confusion
Fever/chills
Rigor
Tachycardia
Tachypnoea/dyspnoea
Cough (productive)
Vomiting
Diarrhoea
What are risk factors of pneumonia?
Older than 65
Smoker
Malnourished
Underlying lung disease
Immunocompromised
Certain medications
Recent resp infection
What are some pulmonary defences?
Cough reflex
Mucus secretion
Alveolar macrophages
IgA antibody
Microflora
Nose hairs
What are some causative bacterial organisms?
Strep. pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
Staphylococcus aureus
Legionella spp
Mycoplasma pneumoniae
Mycobacterium tuberculosis
What are some causative viral organisms?
Influenza
Parainfluenza
Respiratory syncytial virus
Human metapneumovirus
Rhinovirus
Coronaviruses
What are some causative fungi organisms?
Pneumocystis jirovecii
Asperillus sp
Histoplasma sp
Cryptococcus sp
How can pneumonia be classified?
Community acquired
Hospital acquired
Ventilator associated
Aspiration
Describe community acquired pneumonia
No hospitalisation within month prior to presentation
Strep pneumoniae, viruses, H.influenzae, Mycoplasma
Describe hospital acquired pneumoniae
Acquired after at least 2 days of hospitalisation
E.coli, Klebsiella, Enterobacter, viruses
Describe ventilatory associated pneumonia?
Occurring more than 48h after intubation
Staph aureus, pseudomonas, stenotrophomonas, acinetobacter
Describe aspiration pneumonia
Occurring as a result of inhalation of stomach contents
Chemical pneumonitis, oral anaerobes, alpha-haem strep
What antibiotics should be given to someone with pneumonia with a CURB score of 0-1?
Doxycycline
Erythromycin
Amoxicillin 3-5 days
What antibiotics should be given to someone with pneumonia with a CURB score of 2-5?
IV benzylpenicillin and doxycycline/erythromycin
Oral amoxicillin +/- doxycycline/erythromycin OR levofloxacin
What is legionellosis?
Outbreaks associated with water systems, cooling towers, water features, showers
Caused by Legionella sp
Describe Legionella sp
Environmental
Survive in protozoa
Aerobic gram negative flagellated bacteria
Fastidious (difficult to culture)
Can be detected by urine antigen test
What are the 2 species of Legionella sp?
L.pneumophilia (water)
L.longbeachae (soil, compost)
What is the pathophysiology of Legionella?
Inhalation of micro-aerosis
Survives and replicates in macrophages - toxin, enzyme production
Pontiac fever 4-6h
What are antibiotics used to treat legionellosis?
1st line = levofloxacin 750mg IV/oral
2nd line = doxycycline 200mg oral, 7-10 days
Why are organisms that cause VAP different to CAP?
Microaspiration of oropharyngeal/GI colonisers
Contaminated ventilation devices
Immune suppression
Inhalation of infectious aerosols
Hospital acquired MDR organisms
What antibiotics are given to treat HAP?
co-amoxiclav IV/ oral 5-7 dayd OR levofloxacin
What antibiotics are given to treat VAP?
piperacillin-tazobactam IV and amikacin (or meropenem) + vancomycin and rifampicin if MRSA
What are risk factors of aspiration pneumonia?
Reduced consciousness
Neurological deficit (dysphagia)
UGIT disorder (GORD)
Mechanical disruption (scope/intubation)
Vomiting
Poor dental hygiene
Describe aspiration pneumonia
Chemical pneumonitis - acidic stomach contents
Oedema
Peribroncheal haemorrhage
Damage to bronchial epithelial cells
What can occur, but very rarely, as a result of aspiration pneumonia?
Bacterial super-infection (13-26%) by S.aureus, pseudomonsa, aerobic falcultative gram-negative bacilli
Anaerobes - peptostreprococcus, fusobacterium, prevotella, bacteroides
What are fungi that cause pneumonia in immunosuppressed individuals?
Pneumocystis jirovecii
Aspergillus sp.
Cryptococcus
Histoplasma
Mycobacteria that cause pneumonia in immunosuppressed?
M. Tb
NTM - non-tuberculosis mycobacteria
Viruses that cause pneumonia in immunosuppressed?
CMV
VZV
SARS-CoV2
How can the causative organism be identified?
Nose/throat swab - PCR, lateral flow
Sputum/BAL - microscopy, culture, PCR
Blood - culture, PCR, biomarkers, serology
Urine - antigen agglutination tests
What agar is used for strep pneumoniae?
Horse blood agar
Draft shape colonies
What agar is used for H. influenzae?
Chocolate agar
What agar is used for aspergillus?
Sabaroud dextrose agar
What agar is used for pseudomonas?
CLED - cysteine lactose electrolyte deficient
What are the gram positive bacteria causing pneumonia?
Staph aureus
Strep pneumoniae
What are the gram negative bacteria that cause pneumonia?
E.coli
Klebsiella
Pseudomonas
Haemophilus
Moraxella
What bacteria are urine antigen tests used for?
Strep pneumoniae
Legionella pneumophila
