Pneumonia Flashcards
What is pneumonia?
Inflammation of the lung tissue, characterised by a loss of silhouette signs on CXR, indicating the location of infection.
What increases the risk of aspiration pneumonia?
Decreased gag reflex, coughing and swallowing reflex due to CNS diseases such as seizures and Parkinson’s disease, and CNS depression from alcohol, opiates, or anaesthetics.
Name three pathogens involved in aspiration pneumonia.
- Klebsiella pneumonia
- Anaerobic bacteria from the GI tract such as E.Coli, Lactobaccilus and bifidobacteria
- Staphylococcus aureus
What are common causes of inhalation pneumonia?
- Streptococcus pneumonia
- Mycoplasma pneumonia
- Chlamydia pneumonia
- Influenza pneumonia
- Legionella pneumonia
Which fungi are associated with pneumonia?
- Coccidioidomycosis
- Histoplasmosis
What conditions increase the risk of pneumonia?
Impaired mucociliary clearance with:
* Cystic fibrosis
* Primary ciliary dyskinesia
* Bronchiectasis
* COPD
* Smoking (destroys cilia)
* post-viral state
Which agent puts elderly and smokers at risk of pneumonia?
Leigonella pneumonia, a gram negative aerobic bacteria commonly found in hot tubs.
What is the most common cause of community-acquired pneumonia?
Streptococcus pneumonia.
It typically occurs when there is a defect in normal host defence mechanism or virulent pathogen overwhelms the immune response. Alveolar macrophages release cytokines like TNF-alpha and IL-8 and GCSF- which promotes neutrophil chemotaxis. Leakage of alveolar-capillary membrane causes decreased lung compliance and dyspnoea.
What are the features of streptococcus pneumonia?
Streptococcus pneumonia has a polysaccharide capsule which inhibits complement binding to cell surface and therefore inhibits phagocytosis. It contains virulent proteins such as neuraminidase, pneumolysins and autolysin to counteract the host immune response.
What are the features of bronchopneumonia?
Bronchopneumonia: descending infection from the upper respiratory tract which spreads locally into the lungs, creating patchy areas of consolidation where neutrophils have collected in the alveoli and bronchi
What are the features of ventilation pneumonia?
Ventilation pneumonia should be suspected in patinets with new onset dyspnoea, fall in oxygen saturation with same ventilator settings, fevers with chills. They should receive a CXR or CT scan if CXR is inconclusive with invasive sampling techqneus like broncho-alveolar lavage
What are the most common causes of pneumonia in patients with immunocompromisaiton (CKD, diabetes and HIV)
-> pseudomonas aeuroginoas
-> liegonella penumonia
-> pneumocystis jirovecci for patients with CD4 count less than 200
-> cytomegalovirus
What pathogens cause hospital-acquired pneumonia?
- MRSA
- Pseudomonas aeruginosa
What pathogens cause atypical pneumonia?
:MCL
mycoplasma pneumonia, chlamydia pneumonia and legionella pneumonia
What is the CURB-65 criteria used for?
To assess the severity of pneumonia and determine the need for hospitalization.
Confusion
->Uraemia over 20
->Rate of respiration over 30
->Blood pressure less than either 90 systolic or 60 diastolic
65 years old: likely to have other co-morbidities for higher risk, impaired kmucociliary clearance
What does a CURB-65 score of 0-1 indicate?
Managed as an outpatient.
What does a CURB-65 score of 2 indicate?
non ICU admission
What are the symptoms of atypical pneumonia?
It typically presents with upper respiratory tract infection symptoms such as:
* Headaches
* Nasal congestion
* Sore throat
* Ear aches
* Low-grade fever
* Rigors
What does a CURB-65 score of 3 indicate?
iCU admission
How does pneumonia cause a V/Q mismatch?
Pneumonia results in a V/Q mismatch due to consolidation of the lobes which reduces alvoeli available for gas exchange, resulting in respiratory failure in extreme cases of consolidation.
What is the presentation of pneumonia?
Patients typically have tachycardia, tachypnoea, hypoxaemia with fever and rigors?
There may be inflammation of the bronchioles, causing a productive cough. Inflammation of the lung parenchyma may occur, that may irritate the pleura and cause pleuritic type chest pain
What can excess inflammatory mediators in pneumonia result in?
Multi-organ failure.
What clinical signs indicate pneumonia due to consolidation?
- Bronchial breath sounds
- Dullness to percussion
- Enhanced vocal and tactile fremitus
- Chest crackles
- Hollow breath sounds which is harsh and unjoined up
What are constitutional symptoms of pneumonia?
Constitutional symptoms are non-specific symptoms which indicate generalised illness.
* Fatigue
* Headache
* Myalgia
* Arthralgia
These are more common with viral pneumonia, where there is watery or rarely mucopurulent sputum production. Bacterial penumonia can cause purulent or blood-tinged sputum.
