Pneumonia

Question 1

def

Answer 1

infection of distal lung parenchyma
several ways of categorization:
-community-acquired, hospital acquired, nosocomial
-aspiration pneumonia, pneumonia in immunocompromised
typical & atypical (mycoplasma, legionella)

Question 2

aetiology

Answer 2

community acquired
-streptococcus pneumonia (70%)
-haemophilus influenzae & moraxella catarrhalis (COPD)
-chlamydia pneumonia & chlamydia psittaci (contact with birds)
-mycoplasma pneumonia
-legionella (air conditioning)
-staphylococcus aureus (recent influenza infection, IV drug users)
hospital acquired
-gram negative enterobacteria (pseudomonas, klebsiella)
-anaerobes (aspiration pneumonia)
risk factors
-age
-smoking history
-alcohol
-pre-existing lung disease
-immunodeficiency
-contain with pneumonia

Question 3

epi

Answer 3

incidence 5-11/1000PA (higher in elderly)

CAP causes >60,000 deathsPA

Question 4

history

Answer 4

fever, rigors, sweating
cough
sputum (yellow, green or rusty)
SOB
pleuritic chest pain
confusion in severe cases, elderly, legionella)

Question 5

what does rusty sputum indicate about the cause of pneumonia

Answer 5

streptococcus pneumonia

Question 6

history of atypical pneumonia

Answer 6

headache
myalgia
diarrhoea/abdominal pain

Question 7

examination

Answer 7

on inspection
pyrexia, respiratory distress, tachypnoea, tachycardia, hypotension, cyanosis
on palpation, percussion, auscultation
-reduced chest expansion
-dullness to percussion
-increased tactile vocal fremitus
-bronchial breathing (inspiration phase lasts as long as expiration phase)
-coarse crepitations on affected side
clubbing

Question 8

investigations

Answer 8

1 bloods
-FBC (abnormal WCC)
-UEs (low na, especially with legionella)
-LFTs
-blood cultures
-ABG to assess pulmonary function
2 CXR
-lobar/patchy shadowing
-pleural effusion
-klebsiella often affects upper lobes
3 sputum/pleural fluid
-microscopy
-culture & sensitivity
4 urine
-pneumococcus antigens
-legionella antigens
5 bronchoscopy & bronchoalveolar lavage
-if pneumonia fails to resolve
-if there is clinical progression

Question 9

management

Answer 9

1 assess severity
-see prognosis
-if one or more features present manage in hospital
2 start empirical antibiotics
-oral amoxicillin with 0 markers
-oral/IV amoxicillin & erythromycin with 1 marker
-IV cefuroxime/cefotaxime/co-amoxiclav & erythromycin with >1 marker
-add metronidazole, if aspiration, empyema suspected
-switch to appropriate antibiotic as per sensitivity
3 supportive treatment
-oxygen (maintain PO2>8kpa, start with 28% in COPD to avoid hypercapnia)
-fluids for dehydration, shock, analgesia
-CPAP, BiPAP for respiratory failure
-surgical drainage for empyema/abscesses
4 discharge planning
-presence of two or more features of clinical instability (high temp, HR, RR, low BP, SaO2) indicate high likelihood of re-admission/mortality
5 prevention
-pneumococcal, H. influenzae type B vaccination in vulnerable groups (elderly, splenectomized)

Question 10

compiications

Answer 10

pleural effusion
empyema
septic shock
ARDS
acute renal failure

Question 11

complications of mycoplasma pneumonia

Answer 11

erythema multiforme
myocarditis
haemolytic anaemia
gullian barre syndrome

Question 12

what are the causes of non-resolving pneumonia

Answer 12

1 unusual pathogens (TB, aspergillus)
2 PE
3 malignancy (bronchial carcinoma, lymphoma)
4 inflammatory (vasculitis)
5 CCF

Question 13

prognosis

Answer 13

most resolve within 1-3wks

high mortality in severe pneumonia (CAP 5-10%, HAP 30%, ITU 50%)

Question 14

what is the system for markers of severe pneumonia

Answer 14

CURB-65

Confusion
Urea >7mmol/L
RR >30/min
BP <90SBP or <60DBP
Age >65yrs

other markers are hypoxia <8kpa, WCC<4 or >20

Question 15

what are clarithromycin + erythromycin

Answer 15

macrolides

erythromycin is given to those who are allergic to penicillin