PNEUMONIA - Community Acquired Pneumonia Flashcards
what is pneumonia?
= inflammation of the substance of the lungs
what typically causes pneumonia?
- bacteria most commonly
- but also viruses and fungi
what is the hallmark of pneumonia both clinically and on the chest X-ray?
CONSOLIDATION.
= region of lung tissue that has filled with something other than air, e.g. liquid, pus, blood.
how is pneumonia classified?
it is classified by the setting in which the person contracted the infection.
1) Community acquired
2) hospital acquired
3) Pneumonia in immunocompromised hosts.
- through either a genetic defect, immunosuppressive mediation, acquired immunodeficiency e.g. HIV.
what organism is the commonest cause of community acquired pneumonia?
streptococcus pneumonias 70%
- however, in 30-50% of cases no organism is identifiable
- in 20% of cases more than one organism is present
- haemophilus influenza 5%
- staphylococcus aureus 4%
Where are the 2 sites of community acquired pneumonia?
1) lobar pneumonia
= infection is localised, affecting whole of one or more lobes
2) bronchopneumonia
= widespread small patches of consolidation in both lungs, mainly the lobules of the lungs are affected
- caused by infection centred in the bronchi or bronchioles
how is pneumonia spread?
it is spread by respiratory droplets
what are the clinical features of pneumonia?
1) cough
- dry or productive
- haemoptysis
2) breathlessness
- alveoli become filled with pus & debris impairing gas exchange
- coarse crackles are heard of auscultation, due to consolidation of lung parenchyma
3) fever
- presence of fevers often indicates empyema
4) extra-pulmonary features;
- myalgia, arthralgia & malaise
= common in infections caused by Legionella & mycoplasma
- myocarditis & pericarditis
= most common in mycoplasma pneumonia - headache
= common in legionella pneumonia - abdominal pain, diarrhoea & vomiting
- labial herpes simplex
= common in pneumoccal pneumonia - skin rashes
5) other features
- in elderly, confusion or current falls
in pneumococcal pneumonia what colour is the sputum?
characteristically a rust colour.
What does the CURB-65 score stand for?
C = confusion U = urea level > 7 R = respiratory rate > 30 B = systolic blood pressure < 90mmHg; diastolic < 60mmHg 65 = age > 65
1 point for each of the above
Score 0-1 = outpatient
Score 2 = admit to hospital
Score 3 = ICU
if symptoms have been present for several weeks of have failed to respond to antibiotics, what diagnosis could be ruled out?
Tuberculosis
what would you find on examination of the patient?
- reduced expansion
- dullness to percussion
- coarse crepitations
- bronchial breathing (occasionally)
- pleural rub
what investigations should be done?
1) chest X-ray
2) blood tests
- full blood counts
- electrolytes
- urea
- biochemistry
- C reactive proteins a
3) sputum culture & gram sain
4) blood culture
5) pulse oximetry & arterial blood gas analysis
6) HIV test
what would the typical white cell count of strep pneumonia be?
- white cell count would be >15 x 10^9
what would the typical white cell count be for mycoplasma?
white cell count would be normal
what would the blood tests show for legionella?
- lymphopenia without marked leucocytosis, hyponatraemia, hypoalbuminaemia & high serum levels of liver aminotransferases
describe the gram stain for strep pnneumoniae, staph aureus, H influenza and M catarrhallis?
Strep pneumonia;
- Gram positive
- diplococci
Staph aureus
- gram positive
- clusters (like bunch of grapes)
Diagnostic infections caused by Staph Aureus, H. influenzae, M catarrhalis and gram negative organisms.
what oxygen saturation warrants pulse oximetry and arterial blood gas analysis to be done?
if the oxygen saturation is < 94%.
why should an HIV test be done?
because pneumonia is a common initiation presenting illness in patients with previously undiagnosed HIV infection.
how would you manage somebody with community acquired pneumonia?
1) oxygen
2) intravenous fluids
3) antibiotics
4) thrombo-prophylaxis
5) physiotherapy
6) nutritional supplementation
7) analgesia
when supplemental oxygen is given, what % are you trying to keep saturation between?
- between 94-98% (provided the patient is not at risk of CO2 retention)
- in patients with known COPD, oxygen sats should be maintained between 88% & 92%
how many hours of presentation of symptoms should you given in a hospital before administering antibiotics?
4 hours.
what link is there with some antibiotics, such as cephalosporins, to illness?
these antibiotics can cause an increase incidence of clostridium difficile associated diarrhoea (CDAD).
give examples of what analgesias could be used?
how analgesias help?
examples;
- paracetamol
- NSAIDS
- they help treat pleuritic pain thereby reducing the risk of further complications due to restricted breathing due to pain
what are 3 complications of community acquired pneumonia?
1) lung abscess
2) para-pneumonic effusion
3) empyema
what can pleural effusions develop into?
may develop into an empyema
what are early indications of an empyema?
- fever
- rising or persistently elevated inflammatory markers
what does the pH of an exudative effusion with pleural fluid need to be to suggest an empyema?
pH < 7.2
what is a lung abscess?
severe localised suppuration within the lung associated with cavity formation.
name some causes of a lung abscess?
1) aspiration pneumonia
2) TB
3) pneumonia caused by certain species
4) septic emboli containing staphylococci
5) inadequately treated CAP
6) spread from amoebic liver abscess
7) bronchial obstruction by an endolumial cancer
8) foreign body inhalation
what are the clinical features of a lung abscess?
- persisting or worsening pneumonia
- production of large amounts of sputum
- foul smelling sputum
- fever
- weight loss
- malaise
