Acute respiratory infection and pneumonia Flashcards
What does the term ‘opportunistic pathogens’ mean?
Opportunistic pathogens are a group of microorganisms that do not usually infect healthy hosts but produce infections in hospitals, to immunosuppressed persons or those patients presenting underlying diseases as cystic fibrosis, which favours infection
What does the term ‘commensal micro-organisms’ mean?
Commensals are those type of microbes that reside on either surface of the body or at mucosa without harming human health.
The microbes living in harmony with human mostly consist of bacteria, also known as commensal bacteria, which are 10 times more than the cells present in our body.
Give some examples of opportunistic pathogens found within the URT? Incl. where they are found
- S.aureus in the nasal cavity
- S.aureus, Strep.pneumoniae, H.influenzae, Neisseria meningitidis in the pharynx
- There is minimal bacterial colonisation in the LRT
What is colonisation?
Presence of organisms not causing infection
Give some infectious causes of pneumonia? (Viral, fungal, mycobacterial and parasitic)
- Viral
- Influenza A, B
- Respiratory syncytial virus (RSV) - Fungal
- Aspergillus sp. - Mycobacterial
- Mycobacterium tuberculosis - Parasitic
- Pneumocystis jirovecii
- Ascaris lumbricoides
Give examples of different URT infections and common symptoms
- Tonsilitis, pharyngitis, laryngitis, sinusitis, common cold, otitis media
- Nasal congestion
- Runny nose
- Sore throat
- Cough
- Sneezing
- Headache
- Facial pain
- Fever
Give examples of different LRT infections
- Bronchitis
- Pneumonia
- Lung abscesses
What are the main aetiological agents for bronchitis?
Viruses such as:
- Influenza
- Adenovirus
- Rhinovirus/coronavirus
What is the most common form of pneumonia?
Bronchopneumonia
Who is most susceptible to bronchopneumonia?
Infants and elderly
Lobar pneumonia is caused by which organisms?
Streptococcus pneumoniae
Klebsiella spp.
Generalised interstitial changes are seen with which pneumonia subtypes?
Viral pneumonia
- Pneumocystic jirovecii pneumonia
Cavitating pneumonia is not very common, which organisms can it be caused by?
S.aureus
Klebsiella spp
Mycobacterial pneumonias
Risk factors for pneumonia
- Mainly due to impairment of host defences
1. Alterations in host consciousness e.g. stroke, seizures (compromise epiglottic closure - aspiration of oropharyngeal flora)
- Cigarette smoking
- Affects immunity and defence mechanisms of mucus production and mucociliary escalator - Alcohol
- General sepsis
- Immunosuppression
- Iatrogenic manipulation e.g. intubation
- Drugs e.g. aspirin, PPI
- Congenital e.g. Kartagener’s syndrome
Main symptoms of pneumonia
- Systemic
- Fever
- Chills - Central
- Headaches
- Loss of appetite
- Mood swings - Skin
- Clamminess
- Cyanosis - Lungs
- Cough with sputum or phlegm
- SoB
- Pleuritic chest pain
- Haemoptysis - Muscular
- Fatigue
- Aches - Vascular
- Low BP - Heart
- High HR - Gastric
- Nausea
- Vomiting - Joints
- Pain
How is pneumonia diagnosed?
- Blood tests: RBC, WCC, CRP
- CXR
- Microbiological tests - cultures, serological tests
- Throat swab or tracheal secretions for virology - PCR or immunofluoresence
- Urine - pneumococcal antigen or legionella antigen detection