Pneumonia Flashcards
(91 cards)
What are the three main routes microorganisms gain access to the lower resp. Tract?
Inhalation as aerosolised particles
Enters lung via bloodstream from extrapulmonary site of infection
Aspiration of oropharyngeal contents
What is pneumonia ?
Inflammation of have lung parenchyma caused by an infective agent.
Usually bacterial, but can also be viral, fungal or parasitic.
Occurs when an infection agent gains access to the lower bronchial tree and alveoli host defences are impaired, or the organism is particularly virulent
What happens to aspirated microorganisms if the host immune system functions optimally?
Aspirated microorganisms are cleared from the region before infection can become established
What happens to aspirated microorganisms if the lung defences are impaired?
This can result in pneumonia.
How do viruses suppress the antibacterial activity of the lung in pneumonia?
Impairing alveolar macrophage function and mucociliary clearance. This sets the stage for secondary bacterial pneumonia,
What are some other factors that decrease mucociliary transport?
Also depressed by ethanol, narcotics and obstruction of a bronchus
What are the risk factors for pneumonia?
Age Certain diseases Smoking and alcohol abuse Hospitalisation in ICU Having COPd and using ICS >24 weeks Exposure to certain chemicals or pollutants Surgery or traumatic injury Ethnicity
How is age a risk factor for pneumonia?
> 65 years and children are more susceptible
How are certain diseases a risk factor for pneumonia?
HIV/AIDS,
neuromuscular diseases that affect breathing,
UTI migration of bacteria
How is smoking and alcohol abuse a risk factor for pneumonia?
Alcohol interferes with gag reflex of blood cells
Smoking causes paralysis of cilia
How is hospitalisation in an ICU a risk factor for pneumonia?
HAp is serious compared to other penumoniae and is acquired by patients who need mechanical intervention. Breathing tube bypasses normal defences and prevents coughing.
How is using an ICS >24 weeks a risk factor for pneumonia?
Makes the patient immunosuppressed, making entry of microorganisms easier
How is exposure to certain chemicals and pollutants a risk factor for pneumonia?
Working around agriculture, construction or around certain industrial chemicals or animals, air pollution or toxic fumes can contribute to lung inflammation which makes it harder for the lungs to clear themselves
How is surgery or traumatic injury a risk factor for pneumonia?
Makes coughing difficult
Lying down causes mucous to collect in the lungs
How is ethnicity a risk factor for pneumonia?
There are some possible ethnic driven factors e.g. Maori more prone to getting pneumonia.
What is the pathophysiology of pneumonia ?
Nominally, alveolar macrophages are huge main cells which respond to bacteria reaching lower airways.
If the microbial inoculum is too high or too virulent to be stopped by AM alone, polymorphonuclear neutrophils are recruited to the alveoli from the vascular compartment.
Cytokines secreted by AM (TNFα, IL-1β, IL-6, and IL-8) attracted PMN enhanced for phagocytosis to destroy the invading pathogens.
Excessive cytokine production also has deleterious effects such as sepsis leading to multi organ failure and death. Other cytokines (IL-10) balance this, by attenuating several inflammatory mechanisms
What is sepsis?
Systemic inflammatory response
What are the organisms responsible for community acquired pneumonia?
Streptococcus pneumoniae (gram +, most common)
Mycobacterium pneumoniae,
Legoniella,
C. pneumoniae,
Haemophilus influenzae,
Variety of viruses including influenza
What proportion of pneumonia is community acquired?
Up to 75%
What is community acquired pneumonia?
Infection of the alveoli, distal airways and interstitial of lungs which occurs outside hospital settings
What are the typical and frequent symptoms of CAP?
Typical:
Fever, cough (can be productive or non productive. Purulent sputum often coloured) pleuritic chest pain, chills and/or rigors, dysponea, increased respiration rate >20
Frequent: headache, nausea, vomiting, diarrhoea, fatigue, joint and muscle pain
What are the causative agents of hospital acquired pneumonia?
Staphylococcus aureus (MRSA) during outbreak
E. Coli
Clebsiella pneumoniae
Pseudomonas argeunosa
Which bacteria organisms is found in mechanical ventilation?
Pseudomonas argeunosa
What is the criteria for HAP?
Symptoms occur 48-72 hours post admission to hospital