Management of specific respiratory tract infections

Published in MedicineWise News

Date published: About this date

Clinical content may change after this date. This information is not intended as a substitute for medical advice from a qualified health professional. Health professionals should rely on their own expertise and enquiries when providing medical advice or treatment.

Key messages

  • Antibiotics are only appropriate in acute cough if a chest X-ray suggests pneumonia or in exacerbations of COPD with sputum purulence plus increased sputum volume and/or dyspnoea
  • Antibiotics are only appropriate in sore throat if all 4 diagnostic criteria (fever, exudate, lymphadenopathy & absence of cough) for streptococcal infection are present
  • Use penicillin V for 10 days in uncomplicated sore throat that appears to be streptococcal
  • Reserve macrolides when treating respiratory tract infections for those with pertussis or those hypersensitive to penicillin
  • Cough and cold medicines have limited efficacy
  • Provide advice to patients on appropriate symptomatic relief

Antibiotics are not usually indicated for acute cough

Acute bronchitis is usually viral

Acute bronchitis has a non-bacterial cause in > 90% of cases1 and there are no indications for prescribing antibiotics for immunocompetent patients. Despite this, 66% of patients diagnosed with acute bronchitis are prescribed an antibiotic.2

Acute cough may persist for 3–4 weeks.3 Encourage smokers to quit. If the cough is persistent or particularly troublesome, consider investigations for asthma, pertussis, COPD or subacute or chronic pneumonias including pneumonia due to pulmonary tuberculosis.1,4

Confirm pneumonia with a chest X-ray before treating with antibiotics

Patients with an acute cough and new focal chest signs, dyspnoea, tachypnoea or fever lasting more than 4 days should be suspected of having pneumonia.5 Patients with 2 of the following – fever, rigors, new-onset cough, change in sputum colour (if there is chronic cough), pleuritic chest pain, dyspnoea – may also have pneumonia.6 Perform or request a chest X-ray if pneumonia is suspected to confirm the diagnosis.5

Treat confirmed non-severe pneumonia with antibiotics

Standard therapy for community-acquired pneumonia is empirical, as identifying the causative organism is often not feasible.4 Streptococcus pneumoniae is the most common organism.4 In X-ray confirmed non-severe cases of pneumonia use:

  • amoxycillin 1 g orally, 8-hourly for 7 days.4

Mycoplasma pneumoniae and Chlamydophila (Chlamydia) pneumoniae are also common in non-severe pneumonia. The efficacy of using antibiotics to treat these –atypical– causes of pneumonia is uncertain.7,8 If you decide to cover these organisms, add:

  • doxycycline 200 mg orally, for the first dose, then 100 mg daily for a further 5 days, OR
  • clarithromycin 250 mg orally, 12-hourly for 7 days, OR
  • roxithromycin 300 mg orally, daily for 5 days.4

In patients hypersensitive to penicillin replace amoxycillin with:

  • cefuroxime 500 mg orally, 12-hourly for 7 days, OR
  • moxifloxacinA 400 mg orally, daily for 7 days in those with immediate penicillin hypersensitivity.4

When to use antibiotics in acute exacerbations of COPD

Bacteria are implicated in acute exacerbations of COPD in about 50% of cases.9 Use antibiotics only if there is sputum purulence plus increased sputum volume and/or dyspnoea.4,5
Prescribe amoxycillin (500 mg orally, 8-hourly) or doxycycline (100 mg orally, twice daily) for 5 days.4,9

A response to antibiotics should be seen within 3–5 days.9 If response is unsatisfactory use amoxycillin+clavulanic acid.9

Antibiotics for cough may be considered in vulnerable populations

Consensus guidelines suggest that antibiotics may be considered in people with acute cough who are systemically very unwell, are immunocompromised or have significant co-morbidities – particularly if they are older.3,5,9
A. Moxifloxacin is not PBS-subsidised.

Antibiotics may be an option for confirmed or suspected streptococcal sore throat

Acute sore throat is usually viral but may also be due to infection by group A Streptococcus. Antibiotics are an option for people with confirmed or suspected group A Streptococcus.4
Four diagnostic criteria identify those most likely to have streptococcal sore throat
People with all 4 of the following signs and symptoms are most likely to have group A Streptococcus infections. These are:

  • fever > 38°C
  • exudate on the tonsils
  • tender cervical lymphadenopathy
  • absence of cough.3,4

Children aged 3–12 years and those in close contact with someone who has had streptococcal sore throat are also more likely to be infected with group A Streptococcus.10,11 Infection with Epstein-Barr virus (EBV) may cause severe pharyngitis and should be suspected in adolescents and young adults. Antibiotics are not indicated for the treatment of glandular fever.4

Symptoms often resolve without antibiotics

The natural history of symptoms in untreated people with sore throat is similar for those who have a positive swab for group A Streptococcus and those who are untested or have a negative swab; most no longer have any symptoms within a week.12

Prescribe antibiotics to Aboriginal and Torres Strait Islander children with streptococcal sore throat, from remote communities4

The main rationale for treating streptococcal sore throat with antibiotics is to prevent rheumatic fever. Remote Aboriginal and Torres Strait Islander communities have a much higher incidence of rheumatic fever than the rest of Australia. In 2002, the incidence of acute rheumatic fever in the Northern Territory was 346 per 100 000 Aboriginal and Torres Strait Islander children aged 5–14 years.13 In contrast, there were no cases of rheumatic fever among in non-Indigenous children.13 The risk of adverse effects from an antibiotic probably outweighs any benefit in preventing rheumatic fever in non-Indigenous children.4

Use penicillin V if treating streptococcal sore throat

Penicillin V (phenoxymethylpenicillin) has proven efficacy, a narrow antimicrobial spectrum, and is inexpensive.14 Amoxycillin, however, has a higher rate of adverse effects than penicillin V15; it is also likely to cause a rash in people with undiagnosed glandular fever.4

Reserve macrolides (roxithromycin or erythromycin) for people who are allergic to penicillin. Extensive use of macrolides as first-line therapy is likely to lead to resistance.16

Twice-daily effective as more frequent dosing

Twice-daily dosing of penicillin V is as effective as 3–4 times-daily dosing.4 Prescribe 500 mg (child: 10 mg/kg up to 500 mg) orally, 12-hourly for 10 days.4 Roxithromycin can be used in those hypersensitive to penicillin.

Reserve macrolides for those with pertussis or hypersensitivity to penicillin

Help reduce antibiotic resistance by reserving macrolides (roxithromycin or erythromycin) for people who are allergic to penicillin.16

Penicillin hypersensitivity is less common than generally believed

Ask detailed questions if a patient claims to be allergic to penicillin, rather than taking the statement at face value. Use this information to distinguish allergic reactions from common adverse effects such as gastrointestinal symptoms. Only 10% to 20% of patients who report a penicillin allergy are truly allergic to the drug when assessed by skin testing.17

Use roxithromycin for streptococcal sore throat in those hypersensitive to penicillin

For patients who may need an antibiotic for confirmed or highly suspected streptococcal sore throat (see above) but who are hypersensitive to penicillin, use:

  • roxithromycin 300 mg orally, daily (child: 4 mg/kg up to 150 mg orally, 12-hourly) for 10 days.4

Amoxycillin is more appropriate than a macrolide in acute exacerbations of COPD
Only use macrolide antibiotics (e.g. erythromycin, roxithromycin) to treat acute exacerbations of COPD if there is no response to amoxycillin, doxycycline or amoxycillin+clavulanic acid. Macrolides are not more effective and are less likely to inhibit Haemophilus influenzae, one of the more common bacterial pathogens.4

Prescribe macrolides to people with pertussis who present within 3 weeks of initial symptoms

While antibiotic therapy in the early stages of pertussis minimises spread, people are seldom infectious after cough has been present for more than 3 weeks.4,18 Commence antibiotics if a patient presents within 3 weeks of initial symptoms.4,18

AzithromycinB, clarithromycin and erythromycin are appropriate macrolides for treatment of pertussis.
Erythromycin should be avoided in infants < 1 month of age as it may cause pyloric stenosis.4

B. Azithromycin is not PBS-subsidised for treatment of pertussis.

Cough and cold medicines have limited efficacy

Limited evidence for cough and cold medicines

There is no good evidence for the effectiveness of over-the-counter cough and cold medicines.19 Trials of these medicines, where they exist, are often small and of poor quality.20
If recommending a cough and cold medicine, choose a simpler formulation with ingredients you know well. Avoid recommending cough and cold combination products which include both an expectorant and an antitussive (such a combination is illogical) or an expectorant and an antihistamine (the anticholinergic effect of the antihistamine opposes the effect of the expectorant).

Advise patients that different types of cough and cold medicines may be sold under the one 'umbrella' brand and they should check the active ingredient.

Cough and cold medicines should not be given to infants under 2

Cough and cold medicines should not be given to infants under 2 years because of the poor evidence of effectiveness and the risk of toxicity.21,22

There are rare reports of deaths and serious adverse effects among very young children who have been given cough and cold medicines.20,23-25 These were often associated with inadvertent or non-intentional overdose by carers who gave the infant more than one formulation, an adult formulation, or who made dosage errors.20,21

Provide advice to patients on appropriate symptomatic relief

Advise patients to rest and take an analgesic (paracetamol or ibuprofen) if they have headache, muscle pain, or fever. Saline solution can help clear mucus and ease chest tightness. A few drops of saline solution in an infant–s nostrils will clear mucus that interferes with feeding.26

Although trials of effectiveness have shown mixed results27, steam inhalations may also clear mucus, but they should not be used in children. Adults should breathe in steam during a hot shower or by placing their head over a sink of hot (not boiling) water and trapping the steam by using a towel.
A home remedy such as honey and lemon, rather than a cough and cold medicine, is the simplest and cheapest way to treat symptoms.28

Beta2 agonists have little role in treating acute cough

Evidence does not support the use of beta2 agonists in people with acute bronchitis.29 Although subgroup analyses in a few small trials (n < 80) suggest that adults with acute bronchitis and signs of airway obstruction may improve slightly after using a beta2 agonist, this evidence is weak and must be weighed against the risk of adverse effects such as tremor and anxiety.29

External reviewer

Prof CB Del Mar, Dean, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland

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