Pneumonia Flashcards
What patterns can be seen on a chest X-ray?
- consolidation
- interstitial
- nodule or mass
- atelectasis
Whats a consolidation?
any pathologic process that fills the alveoli with fluid, pus, blood, cell (including tumor cells) or other substances resulting in lobar, diffuse or multifocal ill-defined opacities
What is an interstitial pattern?
involvement of the supporting tissue of the lung parenchyma resulting in fine or coarse reticular opacities or small nodules
What is a nodule or mass pattern on a chest x-ray?
any space occupying lesion either solitary or multiple
What is atelectasis?
the collapse of a part of the lung due to a decrease in the amount of air in the alveoli resulting in volume loss and increased density
What is pneumonia?
acute inflammatory process of the pulmonary parenchyma
Types of pneumonia?
- nosocomial pneumonia
- community acquired penumonia
Types of nosocomial pneumonia?
- hopital acquired pneumonia
- ventilator associated pneumonia
- healthcare associated pneumonia
Causes of community acquired pneumonia according to pathogens?
- bacterial
- viral
- fungal
- parasitic
- eosinophilic
Types of community acquired pneumonia according to part of lung affected?
- lobar pneumonia
- bronchopneumonia
- interstitial pneumonia
- diffuse pneumonia
How long does it take for you to acquire hospital acquired pneumonia?
in hospital for >48 hours
How long does it take to get ventilator acquired pneumonia?
on ventilator for >48 hours
Bacterial pathogens - typical?
- streptoccocus pneumoniae - 20-60%
- haemophilus influenza - 3-10%
- s. aureus
- gram negatives - 80% of nosocomial infections
- mycobacteria tuberculosis
Causes of nosocomial infections?
gram negatives
1. E. coli
2. klebsiella
3. pseudomonas
4. acinetobacter
Bacterial causes of pneumonia - atypical?
have no cell wall
1. mycoplasma pneumoniae
2. chlamydophila pneumoniae
3. legionella pneumophila
Viral causes of pneumonia?
- respiratory syncytial virus - RSV
- SARS-COV-2
- rhinovirus
- adenovirus
Fungal causes of pneumonia?
- histoplasma capsulatum
- cryptococcus neuformans
- aspergillus
- PCP
What questions to ask in background medical history for pneumonia?
What can make you susceptible to acquiring pneumonia?
- HIV/malignancy/immunosuppressant drugs?
- Structural lung diseases/cystic fibrosis
- High aspiration risk?—GNRs, anaerobes if poor dentition
- Recent hospitalization or on a ventilator
- End stage renal disease(ESRD)/ Intravenous drug use - staph aureus
Questions to ask on occupational hsitory?
- Animal exposures
- Recent hotel stay or cruise ship trip/ long haul flights - legionella from air conditioners
The purpose of investigations?
- establish diagnosis
- identify the pathogen
- assess the severity
Routine blood investigations?
- CBC - with differential
- BUN/Cr
- electrolytes
- glucose
- liver enzymes
- blood culture
Microbiological tests?
- sputum gram stain
- sputum for culture
- sputum for Ziehl Heelsen stain
- sputum cytology
- sputum for gene xpert MTB/RIF
Imaging studies?
- x-ray chest P/A and lateral view
- compute tomography
Serological tests?
- pneumococcal antigen test
- legionella antigen test
Oxygen tests?
- pulse oximetry
- arterial oxygen saturation
Miscellaneous tests?
- HIV test
- nasopharyngeal/oral swab
What is the CURB 65 score used for?
scoring system used as guidance on the likely risk of fatal outcomes for community acquired pneumonia
What is CURB 65 score criteria?
C - confusion
U - urea level in plasma > 7mmol/L (19mg/dl)
R - respiratory rate > or = 30/min
B - blood pressure (systolic < 90mmHg, diastolic < 60mmHg)
65 - age > 65
What is the CURB 65 scoring system?
0-1 : treat as outpatient
2 : admit into hospital
3 and above : indication of severe pneumonia (often require ICU care)
Pathogenesis of pnemonia?
- aspiration of secretions from the mouth and nasopharynx into the lungs - most common route of entry
- direct inhalation
- hematogenous route
- contiguous extension
Pathophysiology of pneumonia?
- bacteria enter the lungs - from the throat, nose, airborne droplets or blood
- bacteria may invade the spaces between cells and between alveoli
- the macrophages and neutrophils inactivate the bacteria and the neutrophils also release cytokines
- this cause general activation of the immune system
- leading to the fever, chills and fatigue
- the neutrophils, bacteria and fluid fill the alveoli
- resulting in the consolidation seen on the chest x-ray
Pathological evolution of lobar pneumonia?
- oedema
- red hepatization
- grey hepatization
- resolution
Describe oedema pathology?
1st - 2nd day = 2 days
1. onset is sudden with fever and rigors
2. the affected lung lobe experienced usual early changes of acute inflammation
- the alveolar capillaries are engorged and contain an increased number of polymorphs
3. the affected lung lobe appeared to be dark red, frothy and contained blood-stained fluid rich with causative bacteria
Describe red heaptization?
2nd - 4th day = 3 days
1. there is pain upon breathing due to the pleural exudate and productive cough with brown sputum
2. the affected lung lobe is dry, solid, red, granular and contains no air
3. there are presence of massive confluent exudation with neutrophils, red cells and fibrin filling the alveolar spaces of the affected lung lobe
4. some fibrin is also found on the pleural surface
Describe grey hepatization?
4th - 8th day = 5 days
- due to the development of antibodies towards the causative bacteria
- the affected lung lobe is even more solid and is dry, granular and has grayish white color appearance upon cut section
- gray color is due to the presence of increased amount of exudate within the alveolar of the affected lung lobe
- the alveolar exudate contained high concentration of neutrophils and dense fibrin
- the pleural surface is covered by a confluent fibrinous exudate
Describe resolution?
8th - 9th = days
- the inflammatory process subsides due to the elimination of causative bacteria
- the consolidated exudate within the alveolar spaces undergoes progressive enzymatic digestion to produce granular, semi-fluid debris that will be resorbed, ingested by macrophages, expectorated or organized by fibroblasts growing into it
- this is enzymatic digestion is catalyzed by proteolytic enzymes possibly produced in part by the neutrophils
Symptoms of pneumonia?
- pleuritic pain
- hemoptysis - coughing out blood or blood-stained sputum
- purulent sputum
- fever
- cough
- dyspnea
- anorexia
- malasie
- rigor
Signs of pneumonia on physical exam?
- tachypnea
- tachycardia
- hypotension
- fever
- cyanosis
- signs of lung consolidation
- pleural rub
What are the signs of lung consolidation?
- diminished lung expansion
- dull percussion note
- increased tactile vocal fremitus
- increased vocal resonance
- bronchial breathing
Differential diagnosis of pneumonia?
- pulmonary TB
- pulmonary edema
- pulmonary infarction
- acute respiratory distress syndrome
- pulmonary hemorrhage
- lung cancer or metastatic cancer
- atelactasis
- radiation pneumonitis
- drug reactions involving the lung
- extrinsic allergic alveolitis
- pulmonary vasculitis
- pulmonary eosinophilia
- bronchiolitis obliterans and organizing penumonia
General complications of pneumonia?
- respiratory failure
- sepsis - multisytem failure
- haemolytic anaemia
- cardiac dysfunction
Local complications of pneumonia?
- pleural effusion/parapneumonic effusion
- empyema
- lung abscess
- DVT and pulmonary embolus
- pneumothorax
- adult respiratory distress syndrome
What is empyema? Clinical signs and symptoms?
definition - collection of purulent fluid in the pleural space
signs + symptoms - ongoing fever, persistently elevated inflammatory markers despite appropriate antibiotic therapy
Principles of management?
- oxygen supply
- intravenous fluid
- analgesia
- empirical antibiotic treatment for pneumonia
- management of complications
Oxygen therapy?
- Supplemental oxygen should be maintained at oxygen saturations between 94% - 98%
- In COPD patient, the oxygen saturation should be maintained in between 88% - 92%.
Intravenous fluid management?
When to give it?
Maybe required if the patient has
1. anorexia
2. dehydration
3. shock
Analgesia management?
If there is presence of pleuritic pain / pleurisy,youcan use simple analgesia like:
1. paracetamol
2. non-steroidal anti-inflammatory drugs (NSAIDs)
Benefits of treating the pain?
- reduces the risk of further complications
e.g. sputum retention, atelectasis [incomplete expansion of lung / airlessness in a previously air-filled space] - reduces risk of secondary infection
- due to restricted breathing that is caused by pleuritic pain
Treatment for pneumocystis jirovecii pneumonia?
- cotrimoxazole (sulphamethoxazole) 100mg/kg/day
- trimethoprim 20mg/kg/day)
- for 21 days - add prednisolone start 40 mg bd 5/7, 40mg od 5/7, then 20mg od x 11/7 days
(If severe with hypoxia or respiratory distress)
