Acute upper respiratory tract infections in childhood

Upper respiratory tract infections (URTIs) are the scourge of young children and their parents. In the first 5 years of life children average 6-8 episodes per annum. The timing and frequency of these infections depends largely on the level of exposure; therefore they occur earlier and more often in those with older siblings and those who attend daycare (Fig. 45.1). By far the majority of URTIs are viral in origin, are of mild severity, and are of short duration (5-7 days). These illnesses are selflimiting and require no specific pharmacological intervention (Tables 45.1 and 45.2).

The age of the child is the major predictor of type, severity and extent of a viral respiratory tract infection (Table 45.2). Nevertheless, these recurring URTIs of early childhood are important, particularly when they occur repeatedly during the winter months. Local complications of viral URTIs do occur in a significant percentage, especially acute otitis media and acute sinusitis (Fig. 45.2). Progression of the infection into the lower respiratory tract is a risk, particularly with some of the more potent respiratory viruses such as parainfluenza (viral 'croup') and respiratory syncytial virus (RSV; acute viral bronchiolitis).

The proportion who develop these complications depends largely upon the child's age and the specific infecting virus, plus other host and environmental factors as outlined in Figure 45.3.

A dditional issues with URTIs are: the clinical problem of differentiating common viral pharyngitis from uncommon streptococcal pharyngitis; viral URTIs can lead to significant systemic illnesses (such as Henoch-Schonlein purpura); and the most common trigger of severe acute exacerbations of asthma in young children is a viral URTI.

An obvious difficulty with URTIs is the arbitrary definitions used to describe them, such as rhinitis, pharyngitis, tonsillitis and stomatitis. There is clearly substantial overlap with these syndromes as the viral infection will cross anatomical boundaries. Indeed, viral inflammation of the respiratory tract is usually diffuse rather than focal, while bacterial infections of the respiratory tract (such as streptococcal tonsillitis) are more anatomically localised.

By far the most common form of URTI is the 'common cold', which is also known as viral nasopharyngitis, acute coryzal illness or viral catarrh, but overall it is probably best described as an uncomplicated viral URTI.

Common cold (uncomplicated

Viral urti)

This is defined as an acute illness where the major symptoms

are:

• nasal (snuffliness, sneezing and rhinorrhoea)

• sore throat

• conjunctival irritation (red, watery eyes).

The symptoms are mild, fever is minimal or absent and all symptoms resolve between 5 and 7 days. The usual pathogen responsible for an uncomplicated viral URTI is rhinovirus, of which there are numerous specific strains. However, there are a large number of potential respiratory viruses which can produce this syndrome (Table 45.1). These viruses are highly infectious and spread via both droplets (particularly by sneezing) and nasal secretions on hands and fomites (clothing, handkerchiefs, toys, cot sides). Viral shedding is maximal in the 7 days after inoculation and most have a short incubation period (2-3 days). Therefore, close proximity such as household contacts with older schoolage siblings, daycare attendance, overcrowding, lower socioeconomic status and poor personal hygiene are all associated with high rates of URTI (Fig. 45.3).

Local ENT complications of the common cold include otitis media and acute sinusitis (Fig. 45.2), and a small proportion progress to involve the lower respiratory tract.

Ulcerative pharyngotonsillitis

This is due to an adenovirus infection and typically occurs in infants and toddlers. It produces an isolated exudative tonsillitis resembling streptococcal tonsillitis or Epstein-Barr pharyngitis. Other respiratory viruses (including RSV and parainfluenza) usually cause a more diffuse nasopharyngitis rather than this focal tonsillar inflammation. The enteroviruses (coxsackie and echovirus) and herpes simplex virus can also produce ulcerative pharyngotonsillitis.

Epstein-Barr virus pharyngitis/tonsillitis

Although this typically occurs in older, schoolage children it can cause an exudative tonsillitis in the very young. The tonsillitis is associated with a membrane and marked cervical lymphadenopathy plus generalized symptoms, including fever, lethargy, anorexia and headache.

Herpangina

This typically occurs in preschool children and is due to one of the enteroviruses (coxsackie or echoviruses). It results in a number of discrete mouth ulcers, localised to the posterior portion of the oropharynx — tonsillar pillars, pharyngeal wall, uvula and palate. This is in contrast to the anterior ulcers of herpes simplex virus.

Acute sinusitis (rhinosinusitis)

This complication occurs in approximately 5% of viral URTIs and generally involves the maxillary sinuses. The usual manifestation is a profuse, mucopurulent nasal discharge with nasal obstruction. Uncomplicated acute viral sinusitis normally resolves without specific treatment in 7-10 days. Thus, if the child has a mucopurulent nasal discharge continuing beyond 10 days the possibility of secondary bacterial sinusitis needs to be considered.

A Cochrane review of five randomised control trials involving over 400 children found 10 days of antibiotics will reduce the probability of persistence of nasal discharge in the short to medium term; however, the benefits are modest and no long term benefits have been documented. The reviewers concluded that larger, well designed studies are indicated before the question about antibiotics for acute sinusitis in children can be dogmatically answered. The usual organisms responsible for acute bacterial sinusitis are pneumococcus, Haemophilus influenzae, and Moraxella catarrhalis. Amoxicillin is therefore generally considered the antibiotic of choice.

Acute otitis media

This local complication of viral URTIs is characterized by earache, fever, reduced hearing, and non specific discomfort and irritability in the very young child. Examination shows a red tympanic membrane with loss of the normal anatomical landmarks on the tympanic membrane. Less commonly the eardrum is visibly bulging. This complication of viral URTI most commonly occurs in the very young, particularly between 6 months and 2 years of age. Virtually all children will have at least one episode of otitis media and some are particularly prone to this complication. The microbiology of otitis media has been accurately documented in a recent large study from Finland. In this study, middle ear fluid was obtained (by myringotomy) in over 90% of 2500 episodes of clinical acute otitis media during the first 2 years of life. A bacterial pathogen, particularly pneumococcus, M. catarrhalis and H. influenzae, was cultured in over 80%.

Although this suggests that young children with acute otitis media should be treated with an antibiotic, such as amoxicillin plus clavulanic acid (Augmentin), the evidence is unimpressive. A Cochrane Review of seven randomised control trials (over 2000 children) found no reduction in earache at 24 hours between antibiotics and placebo, and only a 6% absolute reduction in pain at 2-7 days. The authors found approximately 80% of all children with acute otitis media, irrespective of treatment, will be pain free by 2-7 days. Thus, the benefit of antibiotics is small and is possibly outweighed by the 5% risk of adverse effects (rash, diarrhoea and/or vomiting). Consequently, simple oral topical analgesics (anaesthetic ear drops) may be the best option.

However, as with streptococcal pharyngitis, in patients at increased risk of suppurative complications of otitis media (particularly Aboriginal, Torres Strait Islanders and Pacific Islanders) the threshold for prescribing antibiotics should be substantially lower. The duration of antibiotic administration has also been addressed in a Cochrane Review, which concluded that 5 days antibiotics is adequate treatment for uncomplicated ear infections in children. This review considered those randomised control trials which compared short course antibiotics (less than 7 days) to longer course (7 or more days) and found no difference in outcome.

Streptococcus pneumoniae is the most common reported bacterial cause of acute otitis media (between one third and one half of all cases) and initial trials of multivalant conjugate vaccines against the serotypes responsible for otitis media have been shown to be effective.

Approach to management of respiratory tract infections

Uncomplicated viral URTIs (common cold)

It should be evident that antibiotics are not indicated in this condition. A Cochrane Review has demonstrated that antibiotics offer no advantage over placebo; further, antibiotics were associated with a 6% rate of adverse events (rashes and gastrointestinal symptoms).

The possible role of nasal decongestants has been addressed in three randomised control trials in children. A combined 'antihistamine with decongestant' in all three studies failed to show efficacy in young children. The most recent was a single dose study which resulted in temporary relief of nasal congestion but was associated with a high rate of adverse events, particularly sedation. Almost 50% of the children receiving the 'antihistamine and nasal decongestant' were asleep within 2 hours of the medication, compared to 27% in the placebo. Obviously, from the parents' viewpoint this 'adverse' event may be seen as desirable. Nevertheless, antihistamines have been associated with paradoxical excitability, hallucinations, agitation and seizures.

Furthermore, 10% of all poison centre calls are related to overdose with various cough and cold medications. Use of alternative treatments such as echinaecia have been popularised over recent years. The use of echinaecea for preventing and treating the common cold has been the subject of a Cochrane Review. These reviewers concluded that, although the majority of available

studies report positive results, the quality of the trials is poor and the results are inconclusive, due to heterogeneity of both the preparations used and the outcome measures employed. Obviously, further high quality multicentre randomised control trials are indicated to address this question appropriately.

Prevention of URTIs

R educe exposure

(Table 45.4)

Reducing exposure to respiratory viruses is extremely difficult. In day care settings, cohorting of children into smaller and age specific groups is of benefit. While the cohorting, or exclusion, of children suffering from URTIs may help, unfortunately person to person spread often occurs before the child has obvious symptoms of an URTI. Simple measures such as hand washing by both staff

and children, improving ventilation and reducing overcrowding are all of value.

Reduced exposure to environmental tobacco smoke

While the evidence relating to respiratory infections and passive smoking relates predominantly to lower respiratory infections, there is also evidence that URTIs in young children are increased in those exposed to environmental tobacco smoke.