Lower respiratory tract infections Flashcards
List some lower respiratory tract infections
Acute bronchitis Exacerbation of COPD Pneumonia Empyema Lung abscess Bronchiectasis
What are the symptoms of pneumonia?
Malaise fever pleuritic chest pain cough purulent sputum - rusty Dyspnoea headache
What are the signs of pneumonia?
pyrexia tachypnoea central cyanosis dullness on percussion of affected lobe bronchial breathing inspiratory crepitations increased vocal resonance
What are the investigations for pneumonia?
FBC CXR - opacities Blood cultures Throat swab Urinary legionella sample Sputum culture
List some microbiological causes of pneumonia
Strep pneumoniae Haemophilus influenzae Legionella Staph aureus Mycoplasma pneumoniae Chlamydia psittaci Viruses
What organism is mostly associated in pneumonia in younger people with a sub-acute course with non-respiratory complications such as haemolytic anaemia?
Mycoplasma pneumoniae
How do you score severity of pneumonia?
CURB 65 C - confusion U - blood urea >7 R - resp rate >30 B - diastolic pressure <60 65 - age >65yo
CURB score 0-1: home care
CURB score 2: hospital care
CURB score 3-5: ITU
How do you treat CURB 0-1 pneumonia?
Amoxycilin or clarithromycin or doxycycline
How do you treat CURB 2 pneumonia?
Amoxycillin and clarithromycin/levofloxacin
How do you treat CURB 3-5 pneumonia?
Co-amoxiclav and clarithromycin/levofloxacin
When is levofloxacin used?
In penicillin allergic individuals
What supportive treatments are given alongside antibiotics for pneumonia?
O2
Fluids
CPAP
Intubation and ventilation
What are some complications of pneumonia?
Septicaemia and shock Acute kidney injury Empyema Lung abscess Haemolytic anaemia (mycoplasma) ARDS
How can you distinguish TB from pneumonia?
TB often in upper lobes of the lungs and often has a much more chronic course
What are some differential diagnoses of pneumonia?
TB Lung cancer Pulmonary embolism Cardiac failure Pulmonary vasculitis
What is empyema?
Collection of pus in a cavity of the body, particularly in pleural cavity
What often causes empyema?
Streptococcus (52%)
Staph Aureus (11%)
Anaerobes (20%)
What are the symptoms and signs of empyema?
Chest pain
Cloudy pus
Absence of cough
High swinging fever
How do you diagnose empyema?
Pleural aspiration
CT
Pleural ultrasound
How do you treat empyema?
Chest drain IV antibiotics Intrapleural t-PA to degrade clots DNase Surgery if they don't improve
Describe a lung abscess
Type of liquefactive necrosis of lung tissue and formation of cavities >2cm containing necrotic debris or fluid, caused by microbial infections
What organisms usually cause lung abscesses?
Staph Aureus
Pseudomonas
Anaerobes
What are the symptoms of lung abscess?
lethargy
weight loss
swinging fever
How do you treat lung abscesses?
Prolonged antibiotics
Must check its not TB
What can cause bronchiectasis?
Idiopathic Immotile cilia syndrome CF Childhood infections e.g. measles Hypogammaglobulinaemia Allergic bronchopulmonary aspergillosis
What can cause hypogammaglobulinaemia?
Acquired Drug related GI or kidney related haematological disorders cancer
What are the symptoms of bronchiectasis?
Chronic cough Daily sputum, half cup or more Wheeze Dyspnoea Chronic fatigue Fitting chest pain Haemoptysis
What are the signs of bronchiectasis?
Clubbing
Crepitations on auscultation
Signet ring appearance on CT
Positive sputum culture
How do you treat bronchiectasis?
Chest physiotherapy
Long term antibiotics
Inhaled beta 2 agonists and corticosteroids
What are some diagnostic techniques for LRTIs?
Microscopy and culture of sputum and blood
Antigen detection methods
Nucleic acid amplification - PCR
Serology (antibody measurement)
What are the 3 major respiratory pathogens?
Strep pneumoniae
Haemophilis influenzae
Moraxella catarrhalis
What staining technique is used only for TB?
ZN or auramine phenol stain
Appear as red bacilli that resist decolorisation by alcohol or acid (AAFB)
How long do you have to culture mycobacterium in TB?
6-12 weeks
What is broncho-alveolar lavage?
Lower airway sample collected during bronchoscopy - squirts fluid into the lungs then collects it for examination
What organisms are not easily cultured?
Legionella pneumophilia
Mycoplasma pneumoniae
Chlamydia psittaci
Coxiella burnetti
What are some techniques used for antigen detection?
Latex agglutination
EIA/ELISA
PCR
Immunofluorescence
In what body fluid can you find legionella and pneumococcal antigens?
Urine
Describe the PCR technique
Denaturation at 94-98C
Annealing of primers at 50-65C
Elongation at 75C
What respiratory viruses are tested for on a multiplex assay?
Influenza A and B Adenovirus RSV Parainfluenza Metapneumovirus Coronavirus Rhinovirus
What is a marker of primary infection?
IgM
What is a marker of secondary infections?
IgG
