1. Pneumonia Flashcards
Define pneumonia
Inflammatory consolidation of the lung parenchyma caused by the formation of intra-alveolar exudate from infection
What are the risk factors for pneumonia?
>65 Smoke Malnourished Immunocompromised Recurrent RTIs Medications Winter Virulence of organisms
What pathogens can cause pneumonia in the immunocompromised?
PCP
CMV
Mycobacteria
Toxoplasma
Which bacteria can cause pneumonia?
Strep pneumoniae Haemophilus influenzae Staph aureus Mycoplasma pneumonia Legionella pneumophilia
What viruses cause pneumonia?
Influenza pneumoniae
Respiratory synctial virus
COVID-19
What fungus can cause pneumonia?
PCP
Give the aetiology of pneumonia
Organisms get into alveoli
immune cells infiltrate and release CKs
Cause vasodilation and vascular permeability
Alveoli are filled with fluid: congestion
What causes SOB in pneumonia?
Reduced oxygen flow due to congestion
What causes a cough in pneumonia?
Bronchoconstriction and increased mucous secretion
What causes pleuritic chest pain in pneumonia?
Pain receptors on alveoli
What causes pyrexia in pneumonia?
CK release
What is lobar pneumonia?
Affects a section or lobe
Starts at bottom of lung and spreads up
What are the symptoms of lobar pneumonia?
SOB
Cough
Chest pain
Pyrexia
What are the signs of lobar pneumonia?
Decreased chest expansion
Dull on percussion
Bronchial breathing
Crackles
Give the stages of lobar pneumonia
Congestion
Red hepatisation
Grey hepatisation
Resolution/scarring
How does the lung appear during congestion?
Heavy and red due to vascular engorgement
What causes red hepatisation?
exudate with RBCs, neutrophils and fibrin in intra-alveolar spaces
How does red hepatisation appear?
Lobes are red, firm, airless like a liver
What causes grey hepatisation?
RBCs disintegrate and exudate remains
What is the difference between resolution and scarring?
Resolution: infection is cleared and enzymes digest exudate
Scarring: infiltration of fibroblasts and collagen deposition
What kind of population is lobar pneumonia associated with?
Neglect, alcoholics
Which pathogen most commonly causes lobar pneumonia?
Strep pneumoniae
How does bronchopneumonia appear on radiography?
Patchy
What are the symptoms of bronchopneumonia?
productive cough Pyrexia chest pain dyspnoea crackles
What population is associated with bronchopneumonia?
Extremes of age
What is a possible complication of bronchopneumonia?
Microabscess formation
What is atypical pneumonia also known as?
Interstitial pneumonia- no consolidation of alveoli
How does atypical pneumonia appear on a CXR?
Reticulonodular pattern ie. fluffy
How does the immune response to atypical pneumonia differ?
Causes lymphocyte infiltration rather than neutrophils
symptoms are milder and more insidious
What are the symptoms of atypical pneumonia?
Dry cough
Low grade pyrexia
Sore throat, myalgia, fatigue, diarrhoea
What are the signs of atypical pneumonia?
Rales
WCC is normal or only slightly elevated
Responsible pathogen has no gram stain or is a virus
What pathogens cause atypical pneumonia?
Mycoplasma Chlamydia Legionella Mycobacteria COVID-19
What are the risk factors for aspiration pneumonia?
Impaired cough Unconscious Pyloric stenosis Oesophageal obstruction Hiatus hernia
What kind of pneumonia is associated with aspiration?
Widespread bronchopneumonia
Can cause chemical pneumonitis with widespread inflammation and damage
What investigations should be done into pneumonia?
CXR
Blood tests
Blood, sputum, BAL for culture
What blood tests should be done if pneumonia is suspected?
FBC (high WCC) U&E (atypical pneumonia) LFTs Glucose CRP (used to monitor progressin)
What prognostic tools are used in pneumonia?
CURB-65
Pneumonia severity index
What complications can arise from pneumonia?
Parapneumonic effusion/empyema Abscess Delirium and sepsis ARDS Respiratory failure Organisms spread to other sites
What is an empyema?
Collection of pus within the pleural cavity resulting from a parapneumonic effusion
How should an empyema be investigated?
CXR
Aspirate pleural fluid (cytology and micro)
What is the treatment for an empyema?
Antibiotics
Chest drain
Surgical decortication if complex
What is a lung abscess also known as?
Necrotising pneumonia
What is a lung abscess?
Localised area of suppurative necrosis within parenchyma
Cavity formation
Caused by anaerobic bacteria
What are the causes of a lung abscess?
Aspiration
Complication of bacterial pneumonia
Bronchial obstruction
Septic embolus
What are the symptoms of a lung abscess?
Cough with lots of smelly sputum
Spiking fevers and malaise
Clubbing, weight loss, anaemia
Secondary amyloidosis
