Pneumonia Flashcards
what is pneumonia
inflammation of the lungs, usually caused by infection (invasion and overgrowth of pathogens in lung parenchyma resulting in intra-alveolar exudates and alveolar inflammation
what is pneumonitis
inflammation of the lungs, usually caused by chemical damage
pneumonia brief pathophysiology
infection of the lungs -> inflammatory response initiated -> alveolar oedema + exudate formation -> alveoli and respiratory bronchioles fill with serous exudate, blood cells, fibrin, bacteria etc. -> consolidation of lung tissue
what is a consolidation
fluid filling of lobular areas
what are the 3 types of pneumonia (classificaiton)
community acquired (CAP); hopsital acquired (HAP); immunocompromised
who does CAP affect
all ages; people who have recently been travelling; people with occupational exposure
typical CAP causing organisms
streptococcus pneumoniae
haemophilus influenza
Moraxella catarrhalis
when is pneumonia considered to be HAP
if occurs 3 days or more post admission
3 ways in which HAP can be acquired
from a ventilator; aspiration pneumonia (e.g. stroke pts.); environmental source
what organisms cause HAP
- pseudo. aeruginosa
- Acinetobacter. Species
depends on method of acquisition
examples of immunocompromised pts
HIV; transplant; cancer; primary immunodeficiency
what age groups does CAP affect the most
<5 and >65
what are the 3 different patterns on pneumonia (and what happens)
bronchopneumonia → filling with fluid and caused by inhalation (diffuse)
lobular pneumonia → entire lobule is filled with fluid (consolidation)
interstitial pneumonia → diseased intersitium without parenchymal disease (virus can survive due to mucus area)
how differentiate between bacterial and viral pneumonia (clinically)
bacterial - sudden onset, rapid progression, productive cough;
viral - slow onset, wheezing
what do the sputum colours indicate (which pathogens-which colours, 4)
rust coloured - S.pneumoniae;
green - Pseudomonas aeruginosa;
redcurrent jelly - Klebsiella;
bad smelling/tasting - anerobes
what does viral hijacking allow for?
bacteria to more easily enter the cells
what type of immunocompromised pts are particularly vulnerable to CAP
people with aspleenia (capsule is particularly infective);
what is empyema
pockets of pus that have collected inside a body cavity
how do coronaviruses attach to cells
viral protein envelope binds to glycoprotein receptors on cells
what is CURB 65
scoring system to assess whether a patient should be admitted to hospital (admit if over 2)
C - confusion
U - urea >7mmol/L
R -respiratory rate >25
B - BP <90/60mmHg
65 - over 65 yrs old
investigations for pneumonia (8)
-CRP/ESR
- CXR
- FBC, U&E, LFT
Microbe investigation
- Serology
- Sputum culture and gram stain
- Bronchoalveolar lavage
- PCR
- Urinary antigens (legionella and pneumococcus)
management for CAP
Depends on microbe! Generally immediate antibiotics are empirical and macrolide
Mild: Amoxicillin or doxycycline
Moderate: Amoxicillin + Doxycycline
Severe: Benzylpenicillin + clarithromycin
Very severe: clarithromycin + co-amoxiclav (or vancomyocin if allergy)
antiviral can be given if viral suspected (oseltamivir but only if started within 3-5 days)
management for HAP
empircal and macrolide antibiotics
Mild: Doxycycline
Severe: Co- amoxiclav or Vancomycin + ciprofloxacin
preventative measures for CAP (2)
smoking cessation; vaccines
risk factors for HAP
antibiotics; surgery; chronic lung disease; advanced age; immunosuppression; tracheal intubation; mechanical ventilation
examples of ventilator associated HAP organisms
P.aeruginosa; S.aureus (MRSA); E.coli; acinetobacter; haemophilus spp.
examples of aspiration pneumonia organisms
haemophilus spp.; Strep. pneumoniae; anerobes; mouth related streptococci
apsiration pneumonitis v aspiration pneumonia
Aspiration pneumonitis (Mendelson’s syndrome) - chemical injury caused by the inhalation of sterile gastric contents;
Aspiration pneumonia - infectious process caused by the inhalation of oropharyngeal secretions that are colonized by pathogenic bacteria (starts as pneumonitis and progresses to pneumonia)
what can a low CD4+ count leads to during infection
reactivation of virus (HIV); reactivation of dormant bacteria (TB); susceptible to intracellular bacteria; susceptible to fungi
what can poor phagocyte function lead to
susceptibility to pneumococcus
what causes Pneumocystis pneumonia (PCP)
the fungus Pneumocystis jirovecii
PCP CXR/CT findings
ground glass shadows (predominantly in perihilar or mid zones, though if on inhaled medications then may be in upper zones as these are the least ventilated); subpleural blebs; fine reticular interstitial changes
PCP managment
trimethoprin; sulfamethoxazole
what causes CMV pneumonitis
Human cytomegalovirus - opportunisitc pathogen so usually only affects those who are immunocomprimised
CMV pneumonitis treatment
Ganciclovir
what can cause neutropenia
chemotherapy; leukemia; bone marrow transplant; steroids
why might sputum samples not be reilable
poor quality - contaminated with other things e.g saliva, squamous cells
what staining is needed for mycobacteria
Ziehl-neelson stain (acid fast)
aspiration pneumonia treatment
amoxicillin + metronidazole (+gentamicin if severe)
