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Chest InfectionsChest Infections

Lawrence PikeLawrence Pike

Chest InfectionsChest Infections

• Acute bronchitisAcute bronchitis

• Acute exacerbation of chronic Acute exacerbation of chronic bronchitisbronchitis

• Community acquired pneumonia Community acquired pneumonia

Acute bronchitisAcute bronchitis

• Acute bronchitis is typically self-limiting Acute bronchitis is typically self-limiting lasting 7 to 14 days. lasting 7 to 14 days.

• Usually caused by adenovirus, rhinovirus or Usually caused by adenovirus, rhinovirus or influenza virus. influenza virus.

• Bacteria rarely cause acute bronchitis, Bacteria rarely cause acute bronchitis, however, they may act as secondary however, they may act as secondary invaders following a viral infection. Bacteria invaders following a viral infection. Bacteria implicated include Streptococcus implicated include Streptococcus pneumoniae, Haemophilus influenzae, pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and occasionally Moraxella catarrhalis and occasionally Staphylococcus aureus (especially during Staphylococcus aureus (especially during influenza epidemics).influenza epidemics).

Acute exacerbation of chronic Acute exacerbation of chronic bronchitisbronchitis

• Increased purulent sputum, Increased purulent sputum, worsening cough, pyrexia and worsening cough, pyrexia and increased breathlessness. increased breathlessness.

• Haemophilus influenzae, Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pneumoniae and Moraxella catarrhalis are commonly Moraxella catarrhalis are commonly grown from sputum samples.grown from sputum samples.

Community acquired Community acquired pneumonia pneumonia • An acute lower respiratory tract infection with An acute lower respiratory tract infection with

purulent sputum, cough, fever, breathlessness purulent sputum, cough, fever, breathlessness combined with signs on examination and changes combined with signs on examination and changes on chest x-ray. on chest x-ray.

• Usual bacteria implicated Usual bacteria implicated – include Streptococcus pneumoniae (most common), include Streptococcus pneumoniae (most common),

Haemophilus influenzae, Moraxella catarrhalis and Haemophilus influenzae, Moraxella catarrhalis and occasionally Staphylococcus aureus (especially during occasionally Staphylococcus aureus (especially during influenza epidemics). influenza epidemics).

• Atypical infections Atypical infections – include those caused by Mycoplasma pneumoniae, include those caused by Mycoplasma pneumoniae,

Chlamydia pneumoniae, Chlamydia psittaci and Chlamydia pneumoniae, Chlamydia psittaci and Legionella pneumoniae. Legionella pneumoniae.

IncidenceIncidence

• 17% of all 'acute' consultations are for 17% of all 'acute' consultations are for acute respiratory infectionsacute respiratory infections

• In previously healthy subjects acute In previously healthy subjects acute bronchitis is usually self-limiting in nature. bronchitis is usually self-limiting in nature. However, around 5% are pneumonias However, around 5% are pneumonias

• Acute exacerbation of chronic bronchitis is Acute exacerbation of chronic bronchitis is associated with viral infections in 50% of associated with viral infections in 50% of cases. cases.

• Mycoplasma pneumoniae occurs in Mycoplasma pneumoniae occurs in epidemics with a 4-year cycle. It is most epidemics with a 4-year cycle. It is most common in children common in children

Symptoms and SignsSymptoms and Signs

• Clinical presentations range from cough without Clinical presentations range from cough without sputum or chest signs, to an illness characterised sputum or chest signs, to an illness characterised by expectoration of mucopurulent sputum, fever, by expectoration of mucopurulent sputum, fever, dyspnoea, pleuritic chest pain and diffuse or focal dyspnoea, pleuritic chest pain and diffuse or focal signs in the chest. signs in the chest.

• Consider pneumonia in any patient, of any age, Consider pneumonia in any patient, of any age, with cough and dyspnoea, tachypnoea and with cough and dyspnoea, tachypnoea and pleuritic chest pain; and/or focal signs in the pleuritic chest pain; and/or focal signs in the chest, especially if they are systemically unwell. chest, especially if they are systemically unwell.

• Legionella pneumonia should be considered if risk Legionella pneumonia should be considered if risk factors such as recent travel or recent repair of factors such as recent travel or recent repair of plumbing are present. plumbing are present.

Differential DiagnosisDifferential Diagnosis

• Influenza Influenza • Congestive cardiac failure Congestive cardiac failure • Chronic obstructive airways disease Chronic obstructive airways disease • Pulmonary embolism Pulmonary embolism • Acute pulmonary oedema Acute pulmonary oedema • Chest infection with underlying malignancy Chest infection with underlying malignancy • Subdiaphragmatic pathology: e.g. Subdiaphragmatic pathology: e.g.

cholecystitis, pancreatitis, perforated cholecystitis, pancreatitis, perforated duodenal ulcer, subphrenic/hepatic abscessduodenal ulcer, subphrenic/hepatic abscess

Should I use an antibiotic ?Should I use an antibiotic ?

• Cough may persist for 2 to 3 weeks after Cough may persist for 2 to 3 weeks after presentation and is unlikely to resolve or improve presentation and is unlikely to resolve or improve more quickly as a result of antibiotic therapy. more quickly as a result of antibiotic therapy.

• Unnecessary use of an antibiotic may cause Unnecessary use of an antibiotic may cause resistance of organisms to the drug and increased resistance of organisms to the drug and increased patient expectations of antibiotics for future patient expectations of antibiotics for future minor illness. Antibiotics may also cause side-minor illness. Antibiotics may also cause side-effects. effects.

• Resistance of Streptococcus pneumoniae to Resistance of Streptococcus pneumoniae to penicillin V has increased from 0.3% in 1989 to penicillin V has increased from 0.3% in 1989 to 7.5% in 1996; and to erythromycin has increased 7.5% in 1996; and to erythromycin has increased from 3.3% in 1989 to 11.8% in 1996. from 3.3% in 1989 to 11.8% in 1996.


• To minimise resistance, it is important to To minimise resistance, it is important to prescribe only when appropriate and prescribe only when appropriate and necessary. necessary.

• Antibiotics may be of benefit if two or Antibiotics may be of benefit if two or preferably three of the following are present: preferably three of the following are present: – increased sputum volumeincreased sputum volume– purulent sputumpurulent sputum– dyspnoea. dyspnoea.

In childrenIn children thethe probability of a viral cause is probability of a viral cause is higher than in adults.higher than in adults.


• Antibiotic therapy should be Antibiotic therapy should be considered for the following groups:considered for the following groups:1. Reduced resistance to infection.1. Reduced resistance to infection.2. Co-existing illness, diabetes, 2. Co-existing illness, diabetes, congestive cardiac failure, asthma.congestive cardiac failure, asthma.3. History of previous persistent 3. History of previous persistent mucopurulent cough.mucopurulent cough.4. Clinical deterioration. 4. Clinical deterioration.

Which Antibiotic?Which Antibiotic?

• Most cases of bacterial chest infection in the Most cases of bacterial chest infection in the community remain sensitive to amoxycillin community remain sensitive to amoxycillin

If treatment with amoxycillin shows no If treatment with amoxycillin shows no improvement within 48 hours, erythromycin improvement within 48 hours, erythromycin should be substituted. should be substituted.

Erythromycin is first choice if an atypical Erythromycin is first choice if an atypical organism is suspected. However, organism is suspected. However, azithromycin or clarithromycin may be more azithromycin or clarithromycin may be more active than erythromycin against active than erythromycin against Haemophilus influenzae and also have less GI Haemophilus influenzae and also have less GI upset. upset.


For exacerbations of chronic bronchitisFor exacerbations of chronic bronchitis Amoxycillin or a Tetracycline (and Amoxycillin or a Tetracycline (and

erythromycin in pencillin allergy) are erythromycin in pencillin allergy) are appropriate first choices if any antibiotic appropriate first choices if any antibiotic is to be used. is to be used. 5% of Streptococcus pneumoniae and 5% of 5% of Streptococcus pneumoniae and 5% of

Haemophilus influenza strains are Haemophilus influenza strains are tetracycline-resistant. 15% H. influenza strains tetracycline-resistant. 15% H. influenza strains are amoxycillin-resistant. are amoxycillin-resistant.


• Pneumonia in a previously healthy chest - amoxycillin is still Pneumonia in a previously healthy chest - amoxycillin is still the first choice antibiotic. the first choice antibiotic.

• If Staphylococcus aureus is suspected e.g. after influenza or If Staphylococcus aureus is suspected e.g. after influenza or measles - add flucloxacillin. Staphylococcal pneumonia measles - add flucloxacillin. Staphylococcal pneumonia requires treatment for 2 to 3 weeks, then, if symptoms requires treatment for 2 to 3 weeks, then, if symptoms persist, seek advice from a specialist. persist, seek advice from a specialist.

• If Mycoplasma pneumoniae (consider this during an If Mycoplasma pneumoniae (consider this during an outbreak) or Legionella infection suspected (e.g. recent outbreak) or Legionella infection suspected (e.g. recent travel), use erythromycin. Legionella pneumonia, will travel), use erythromycin. Legionella pneumonia, will require a prolonged course of antibiotic until proven require a prolonged course of antibiotic until proven resolution, and admission should be strongly considered or resolution, and admission should be strongly considered or specialist advice sought in all cases. Erythromycin is the specialist advice sought in all cases. Erythromycin is the historical drug of choice, although the newer macrolides historical drug of choice, although the newer macrolides may be an alternative. may be an alternative.


• Chlamydia infections- use a tetracycline or Chlamydia infections- use a tetracycline or erythromycin for 10 to 14 days. erythromycin for 10 to 14 days.

• Quinolones (Ciprofloxacin, Ofloxacin) have poor Quinolones (Ciprofloxacin, Ofloxacin) have poor activity against Streptococcus pneumoniae and activity against Streptococcus pneumoniae and should not be used as single agents in "blind should not be used as single agents in "blind therapy" of chest infections. therapy" of chest infections.

• First generation cephalosporins, e.g. cephalexin, First generation cephalosporins, e.g. cephalexin, are not an appropriate choice for lower are not an appropriate choice for lower respiratory infections. respiratory infections.

• Co-amoxiclav should be considered if B-Co-amoxiclav should be considered if B-lactamase resistant strains are locally a problem - lactamase resistant strains are locally a problem - consult local protocols - or for treatment of consult local protocols - or for treatment of pneumonia during influenza epidemics. pneumonia during influenza epidemics.

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