pneumonia Flashcards
definition of pneumonia
Infection of distal lung parenchyma.
categorised as:
- community acquired/hospital acquired/nosocomial
- aspiration pneumonia, pneumonia in the immunocompromised
- typical and atypical (mycoplasma, chlamydia, legionella)
pneumococcal pneumonia
The commonest bacterial pneumonia.
Affects all ages, but is commoner in the elderly, alcoholics, post-splenectomy, immunosuppressed, and patients with chronic heart failure or pre-existing lung disease.
Fever, pleurisy, herpes labialis.
CXR shows lobar consolidation. If mod/severe check for urinary antigen.
amoxicillin, benzylpenicillin, or cephalosporin.
staphylococcal pneumonia
May complicate influenza infection or occur in the young, elderly, intravenous drug users, or patients with underlying disease, eg leukaemia, lymphoma, cystic fibrosis (CF).
It causes a bilateral cavitating bronchopneumonia.
flucloxacillin ±rifampicin, MRSA: contact lab; consider vancomycin.
klebsiella pneumonia
rare. Occurs in elderly, diabetics, and alcoholics.
Causes a cavitating pneumonia, particularly of the upper lobes, often drug resistant.
cefotaxime or imipenem.
pseudomonas pneumonia
A common pathogen in bronchiectasis and CF.
causes hospital-acquired infections, particularly on ITU or after surgery.
anti-pseudomonal penicillin, ceftazidime, meropenem, or ciprofloxacin + aminoglycoside. Consider dual therapy to minimize resistance.
mycoplasma pneumonia
Occurs in epidemics about every 4yrs
flu-like symptoms (headache, myalgia, arthralgia) followed by a dry cough
CXR: reticular-nodular shadowing or patchy consolidation often of one lower lobe, and worse than signs suggest.
PCR sputum or serology. Cold agglutinins may cause an autoimmune haemolytic anaemia.
Complications: Skin rash (erythema multiforme), Stevens–Johnson syndrome, meningoencephalitis or myelitis; Guillain–Barré syndrome.
Clarithromycin (500mg/12h) or doxycycline (200mg loading then 100mg OD) or a fluroquinolone (eg ciprofloxacin or norfloxacin).
legionelaa pneumophilia
Colonizes water tanks kept at <60°C (eg hotel air-conditioning and hot water systems) causing outbreaks.
Flu-like symptoms (fever, malaise, myalgia) precede a dry cough and dyspnoea. Extra-pulmonary features in-clude anorexia, D&V, hepatitis, renal failure, confusion, and coma.
CXR shows bi-basal consolidation. Blood tests may show lymphopenia, hyponatraemia, and deranged LFTS. Urinalysis may show haematuria.
diagnosis: urine ag/culture
fluoroquinolone for 2–3wks or clarithromycin
10% mortality
chlamydophilia pneumoniae
The commonest chlamydial infection. Person-to-person spread,
biphasic illness: pharyngitis, hoarseness, otitis, followed by pneumonia.
Diagnosis: Chlamydophila complement fixation test, PCR invasive samples.
Doxycycline or clarithromycin.
chlamydophilia psittaci
Causes psittacosis, an ornithosis acquired from infected birds (typically parrots).
headache, fever, dry cough, lethargy, arthralgia, anorexia, and D&V. Extra-pulmonary features are legion but rare, eg meningo-encephalitis, infective endocarditis, hepatitis, nephritis, rash, splenomegaly.
CXR shows patchy consolidation.
Diagnosis: Chlamydophila serology
doxycycline or clarithromycin.
viral pneumonia
Influenza commonest
but ‘swine flu’ (H1N1) is now considered seasonal and covered by the annual ‘flu vaccine. Others: measles, CMV, varicella zoster.
avian influenza
- if fever (>38°C), chest signs or consolidation on CXR, or life-threatening infection, and contact with poultry or others with similar symptoms
- D&V, abdominal pain, pleuritic pain, and bleeding from the nose and gums are reported to be an early feature in some patients
- H7N9 and H5N1
- diagnosis: Viral culture ± reverse transcriptase-PCR with H5 & N1 specific primers.
- Ventilatory support + O2 and antivirals may be needed. Most viruses are susceptible to oseltamivir, peramivir, and zanamivir.
- Nebulizers and high-air flow O2 masks are implicated in nosocomial spread.
pneumocystis pneumonia
in the immunosuppressed (eg HIV).
dry cough, exertional dyspnoea, low PaO2, fever, bilateral crepitations.
CXR may be normal or show bilateral perihilar interstitial shadowing.
Diagnosis: Visualization of the organism in induced sputum, bronchoalveolar lavage, or in a lung biopsy specimen.
High-dose co-trimoxazole, or pentamidine by slow IVI for 2–3 weeks. Steroids are beneficial if severe hypoxaemia.
Prophylaxis is indicated if the CD4 count is <200≈106/L or after the 1st attack.
aetiology of CAP
may be primary/secondary due to underlying lung disease
Streptococcus pneumoniae(70%),
Haemophilus influenzae and Moraxella catarrhalis(COPD) ,
Chlamydia pneumonia and Chlamydia psittaci (contactwith birds/parrots),
Mycoplasma pneumonia (periodic epidemics),
Legionella (anywhere with air conditioning),
Staphylococcus aureus (recent influenza infection, IV drug users),
Coxiella burnetii (Q fever, rare),
TB (may present as pneumonia).
Viruses including influenza account for up to 15%.
flu might be complicated by community-acquired MRSA pneumonia
aetiology of HAP
defined as >48hr after hospital admission
staph aureus or gram -ve enterobacter especially in COPD (Pseudomonas, klebsiella, bacteroides, clostridia)
anaerobes (aspiration pneumonia)
aetiology of aspiration pneumonia
Those with stroke, myasthenia, bulbar palsies, reduced consciousness (eg post-ictal or intoxicated), oesophageal disease (achalasia, reflux), or poor dental hygiene risk aspirating oropharyngeal anaerobes.
pneumonia aetiology in immunocompromised
Strep. pneumoniae, H. influenzae, Staph. aureus, M. catarrhalis, M. pneumoniae, Gram Ωve bacilli and Pneumocystis jirovecii (P carinii)
Other fungi, viruses (CMV, HSV), and mycobacteria.
RF for pneumonia
age - very young or very old
smoking
alcohol
pre-existing lung diseae
immunodeficiency
contact with pneumonia
epidemiology of pneumonia
Incidence 5–11 in 1000 (25–44 in 1000 in elderly).
Of these, 1–3 per 1000 will require hospitalization, and mortal-ity in those hospitalized is up to 14%.
Community-acquired causes>60000 deaths/year in the UK.
symptoms of pneumonia
fever
rigors
sweating
malaise
anorexia
productive cough (yellow, green or rusty in S pneumoniae)
breathlessness
pleuritic chest pain
haemoptysis
confusion (severe cases, elderly, legionella)
atypical pneumonia - headache, myalgia, diarrhoea/abdo pain
signs of pneumonia
consolidation
coarse crepitations on affected side - usually 1 lobe of 1 lung
pyrexia
resp distress
tachypnoea
tachycardia
hypotension
cyanosis
signs of consolidation:
- reduced chest expansion
- dullness to percussion
- increased tactile vocal fremitus
- bronchial breathing (inspiration phase lasts as long as expiration phase)
pleural rub
chronic supportive lung disease (empyema, abscess): clubbing
confusion - can be the only sign in the elderly
hypothermia
herpes labialis (pneumococcus)
investigations for pneumonia
oxygen sats
BP
blood
- FBC - abnormal WCC
- UE - reduced Na, especially legionella
- LFT
- CRP
- blood cultures - sensitivity 10-20%, if curb >/=2
- ABG - assess pul func if sats <92% or severe pneumonia
- blood film - RBC agglutination by Mycoplasma caused by cold agglutins
CXR
- GPs should consider a point of care CRP to guide antibiotic prescribing where LRTI is suspected
- lobar, multilobar infiltrates or patchy shadowing, may lag behind clinical signs
- pleural effusion
- cavitation
- klebsiella often affects the upper lobes
- repeat 6-8wks (if abnormal suspect underlying path eg lung cancer)
- may detect complications eg abscess - cavitation and air-fluid level
sputum (if CURB 3/more or 2/more w/o AB) /pleural fluid (if CURB-65≥2).
- microscopy
- culture and sensitivity
- acid-fast bacilli
urine
- pneumococcus (curb >=2) and legionella (if CURB-65≥3 or if clinical suspicion). ag
viral swabs
atypical viral serology
- raised Ab titres between acute and convalescent samples
- >2wks post-onset
- complement fixation tests acutely,
- PCR sputum/BAL
- paired serology
mycoplasma PCR/serolgy
bronchoscopy (and bronchoalveolar lavage)
- if pneumocystis carinii pneumonia is suspected,
- or when pneumonia fails to resolve
- or when there is clinical progression,
- or pt immunocompromised or on ICU
management of pneumonia
assess severity - if 1 or more marker of severity present = manage in hospital
start empirical AB (most who need AB can switch to oral within 3days):
- oral amoxicillin (0 markers)
- oral/IV amoxicillin and erythromycin (1 marker)
- IV cefuroxime/cefotaxime/co-amoxiclav (cover H influenxae) and erythromycin (>1 marker)
- add metronidazole, if aspiration, lung abscess or empyema suspected
- switch to appropriate AB as per sensitivity
- Levofloxacin and moxifloxacin can provide useful alternatives in selected hospitalized patients with community-acquired pneumonia.
supportive treatment of pneumonia
Oxygen (maintain PO2>8kPa, start with 28% O2in COPD to avoid hypercapnia)
parenteral fluids for dehydration or shock, analgesia, chest physiotherapy
CPAP, BiPAP or ITU care for respiratory failure, shock and hypercapnia. intubation
surgical drainage may be needed for empyema/abscesses.
discharge planning for pneumonia
presence of 2/more features of clinical instability (high temp, HR, RR and low BP, sats, mental status and oral intake)
= sig chance of re-admission or mortality
what do you do if there is non-resolving pneumonia
consider the other causes:
- Unusual pathogens, e.g. Chlamydia psittaci, C. burnetii, Mycobacterium tuberculosis, Nocardia, Actinomyces israelii, fungi (Aspergillus, histoplasmosis, coccidioidomycosis, blastomycosis)
- PE
- Malignancy: Bronchogenic carcinoma, bronchoalveolar cell carcinoma, lymphoma
- Inflammatory: Vasculitis, Wegener’s granulomatosis, sarcoidosis, systemic lupus erythematosus
- congestive HF
- drug toxicity
- diffuse alveolar haemorrhage
- bronchiolitis obliterans-organising pneumonia
- eosinophilic pneumonia
- acute interstitial pneumonia
- pulmonary alveolar proteinosis
prevention of pneumonia
Pneumococcal, H. influenzae type B vaccination every 5yr in vulnerable groups (e.g. elderly (>65), splenectomized, chronic heart liver lung or renal conditions, dm not controlled by diet, AIDS, chemo, prednisolone >20mg/d, cochlear implant, occupational risk eg welders, CSF fluid leaks).
CI to vaccine: Pregnancy, lactation, increased T°, previous anaphylaxis to vaccine or one of its components.
how do you follow up pneumonia patients
6wk
CXR
complications of pneumonia
pleural effusion
empyema - pus in the pleural cavity
localised suppuration -> lung abscess (especially staphylococcal, Klebsiella pneumonia, presenting with swinging fever, persistent pneumonia, copious/foul-smelling sputum),
(abscess may also be secondary to obstruction (e.g. malignancies), infarction or septic emboli (staphylococcal))
septic shock
hypotension
afib
ARDS
resp failure
septicaemia
pericarditis
myocarditis
cholestatic jaundice - due to sepsis/secondary AB therapy (flucloxacillin and co-amoxiclav)
acute renal failure
pleural effusion from pneumonia
Inflammation of the pleura by adjacent pneumonia may cause fluid exudation into the pleural space.
if accumulates faster than is reabsorbed = pleural effusion
if small - may be no consequence
If larger and patient symptomatic, or infected (empyema), drainage is required
empyema from pneumonia
suspected in ot with resolved pneumonia and a recurrent fever
CXR - pleural effusion
aspirated pleural fluid - yellow and turbid pH <7.2, low glucose, high LDH
should be drained with chest drain under radiological guidance
adhesions and loculation make this difficult
hypotension from pneumonia
due to a combination of dehydration and vasodilation due to sepsis
if systolic <90 give IV fluid challenge of 250mL colloid/crystalloid over 15min
if no rise - central line and IV fluids
if still <90 - ITU assessment for inotropic support
AF from pneumonia
common in elderly
resolves with treatment of the pneumonia
B blocker or digoxin may be needed to slow ventricular response short term
resp failure with pneumonia
T1 common ox <8Pa
treatment - high flow oxygen (60%) - caution in COPD
Transfer the patient to ITU if hypoxia does not improve with O2 therapy or PaCO2 rises to >6kPa.
consider elective ventilation if rising PaCO2 or worsening acidosis.
Aim to keep SaO2 at 94–98%, PaO2≥8kPa.
septacaemia from pneumonia
from bacterial spread from lung parenchyma into bloodstream
may cause metastatic infection eg infective endocarditis, meningitis
treat with IV AB
complications from M pneumonia
erythema multiforme
myocarditis
haemolytic anaemia
meningoencephalitis
transverse myelitis
Guillain-Barre syndrome
prognosis of pneumonia
most resolve with treatment (1-3wks)
high mortality of severe pneumonia: (community-acquired 5–10%; hospital-acquired 30%, 50% in those in ITU).
Markers of severe pneumonia CURB-65 score, hypoxia<8 kPa, WCC<4 or >20x10(9)/mm3, age>50 years, sats <92%, bilateral/multilobar
CURB-65 score
scoring mech for pneumonia - assess the severity
- Confusion
- Urea (>7mmol/L)
- RR (>30)
- BP (SBP<90 or DBP<60)
- >=65yrs
confusion and high RR may = resp failure/sepsis
what suggests pneumonia compliocated by underlying pul disease
reduced lung vol on affected side
suggests proximal lesion (most likely cancer), parapneumonic effusion/pleural empyema, or old disease
treatment of pneumonia if penicillin allergy
- Those with a mild penicillin allergy (rash only) may have a 2nd or 3rd generation cephalosporin instead of the co-amoxiclav, although patients with a history of severe allergy should avoid cephalosporins as there is a risk of crossover allergy
- clarithromycin is the drug of choice for penicillin-allergic patients with uncomplicated community-acquired pneumonia.
what does abscess formation suggest - pneumonia
Staphyloccus aureus or Klebsiella infection
what do you do if suspect empyema
US - distinguish between solid and liquid
treatment for Pneumocystis jirovecii pneumonia (also for toxoplasmosis and nocardiasis).
Co -trimoxazole (trimethoprim/ sulfamethoxazole; aka Septrin)
is associated with rare but serious side effects and is therefore limited to this treatment
use of gentamicin
serious gram -ve infections
