pneumonia

Question 1

definition of pneumonia

Answer 1

Infection of distal lung parenchyma.

categorised as:

• community acquired/hospital acquired/nosocomial
• aspiration pneumonia, pneumonia in the immunocompromised
• typical and atypical (mycoplasma, chlamydia, legionella)

Question 2

pneumococcal pneumonia

Answer 2

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.

Question 3

staphylococcal pneumonia

Answer 3

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.

Question 4

klebsiella pneumonia

Answer 4

rare. Occurs in elderly, diabetics, and alcoholics.

Causes a cavitating pneumonia, particularly of the upper lobes, often drug resistant.

cefotaxime or imipenem.

Question 5

pseudomonas pneumonia

Answer 5

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.

Question 6

mycoplasma pneumonia

Answer 6

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).

Question 7

legionelaa pneumophilia

Answer 7

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

Question 8

chlamydophilia pneumoniae

Answer 8

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.

Question 9

chlamydophilia psittaci

Answer 9

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.

Question 10

viral pneumonia

Answer 10

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.

Question 11

pneumocystis pneumonia

Answer 11

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.

Question 12

aetiology of CAP

Answer 12

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

Question 13

aetiology of HAP

Answer 13

defined as >48hr after hospital admission

staph aureus or gram -ve enterobacter especially in COPD (Pseudomonas, klebsiella, bacteroides, clostridia)

anaerobes (aspiration pneumonia)

Question 14

aetiology of aspiration pneumonia

Answer 14

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.

Question 15

pneumonia aetiology in immunocompromised

Answer 15

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.

Question 16

RF for pneumonia

Answer 16

age - very young or very old

smoking

alcohol

pre-existing lung diseae

immunodeficiency

contact with pneumonia

Question 17

epidemiology of pneumonia

Answer 17

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.

Question 18

symptoms of pneumonia

Answer 18

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

Question 19

signs of pneumonia

Answer 19

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)

Question 20

investigations for pneumonia

Answer 20

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

Question 21

management of pneumonia

Answer 21

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.

Question 22

supportive treatment of pneumonia

Answer 22

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.

Question 23

discharge planning for pneumonia

Answer 23

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

Question 24

what do you do if there is non-resolving pneumonia

Answer 24

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

Question 25

prevention of pneumonia

Answer 25

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.

Question 26

how do you follow up pneumonia patients

Answer 26

6wk CXR

Question 27

complications of pneumonia

Answer 27

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

Question 28

pleural effusion from pneumonia

Answer 28

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

Question 29

empyema from pneumonia

Answer 29

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

Question 30

hypotension from pneumonia

Answer 30

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

Question 31

AF from pneumonia

Answer 31

common in elderly resolves with treatment of the pneumonia B blocker or digoxin may be needed to slow ventricular response short term

Question 32

resp failure with pneumonia

Answer 32

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.

Question 33

septacaemia from pneumonia

Answer 33

from bacterial spread from lung parenchyma into bloodstream may cause metastatic infection eg infective endocarditis, meningitis treat with IV AB

Question 34

complications from M pneumonia

Answer 34

erythema multiforme myocarditis haemolytic anaemia meningoencephalitis transverse myelitis Guillain-Barre syndrome

Question 35

prognosis of pneumonia

Answer 35

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

Question 36

CURB-65 score

Answer 36

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

Question 37

what suggests pneumonia compliocated by underlying pul disease

Answer 37

reduced lung vol on affected side suggests proximal lesion (most likely cancer), parapneumonic effusion/pleural empyema, or old disease

Question 38

treatment of pneumonia if penicillin allergy

Answer 38

* 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.**

Question 39

what does abscess formation suggest - pneumonia

Answer 39

Staphyloccus aureus or Klebsiella infection

Question 40

what do you do if suspect empyema

Answer 40

US - distinguish between solid and liquid

Question 41

treatment for Pneumocystis jirovecii pneumonia (also for toxoplasmosis and nocardiasis).

Answer 41

Co -trimoxazole (trimethoprim/ sulfamethoxazole; aka Septrin) is associated with rare but serious side effects and is therefore limited to this treatment

Question 42

use of gentamicin

Answer 42

serious gram -ve infections