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AD_HTT_027_034___MAY08_09 6/5/09 12:28 PM Page 27 HowtoTreat PULL-OUT SECTION www.australiandoctor.com.au COMPLETE HOW TO TREAT QUIZZES ONLINE (www.australiandoctor.com.au/cpd) to earn CPD or PDP points. inside Bronchiolitis Bronchitis Croup Influenza Pertussis Pneumonia The authors DR JO HARRISON, consultant respiratory physician, department of respiratory medicine, Royal Children’s Hospital, Melbourne, Victoria. ACUTE RESPIRATORY infections in children Background ACUTE respiratory infections are a major cause of morbidity and mortality worldwide. They are responsible for one in five deaths in children under the age of five years, with pneumonia the cause in 90% of these deaths. Childhood mortality from respiratory infections in developed countries such as Australia is fortunately rare, but these diseases remain a significant cause of morbidity. They are the most common infections experienced ASSOCIATE PROFESSOR JOHN MASSIE, consultant respiratory physician, department of respiratory medicine, Royal Children’s Hospital, Melbourne, Victoria. Table 1: Classification of acute respiratory infections by healthy children and result in significant numbers of medical visits and hospital admissions, particularly in the preschool age group. Based on the site of infection, acute respiratory infections may be classified as acute upper or acute lower respiratory infections (table 1). This article reviews the most common types of acute respiratory infections, their clinical features, diagnoses and management. cont’d next page Acute upper respiratory infections Acute lower respiratory infections Nasopharyngitis Laryngotracheobronchitis (croup)* Pharyngotonsillitis Bronchitis Otitis media Bronchiolitis Epiglottitis Pneumonia Laryngotracheobronchitis (croup)* Influenza* Influenza* Pertussis** *Croup and influenza involve both upper and lower airways **Pertussis starts as a coryzal illness, but the main recognisable clinical feature of cough is lower airway in origin www.australiandoctor.com.au 8 May 2009 | Australian Doctor | 27 A D _ 0 2 8 _ _ _ MA Y 0 8 _ 0 9 . p d f Pa ge 2 8 3 0 / 4 / 0 9 , 1 1 : 4 4 AM HOW TO TREAT Acute respiratory infections in children Bronchiolitis Epidemiology BRONCHIOLITIS is the most common cause of acute lower respiratory infection in children during the first year of life. It is the most common cause of admission to hospital in this age group, accounting for more than 50% of all such admissions in Australia. The peak incidence of bronchiolitis occurs in infants aged 2-6 months, with more than 80% of cases occurring in babies under 12 months of age. The most common infectious agent responsible for bronchiolitis is respiratory syncitial virus (RSV), and the epidemiology of bronchiolitis is mainly determined by the epidemiology of this viral infection. RSV infections are most common in winter and spring in temperate climates, with up to 75% of all cases identified between July and September in temperate regions of Australia. In tropical and subtropical climates, epidemics tend to occur in the rainy season. There is virtually no protection to young infants from transplacental antibodies, or from breast milk. Furthermore, active RSV infection does not result in lasting immunity, so recurrent RSV infection is common and can occur within the same season. Almost all children experience at least one RSV infection during the first two years of life, although only 10% of those infected develop acute bronchiolitis. Most babies with bronchiolitis can be managed at home, with about 1% requiring admission to hospital. Factors that make hospital admission more likely include young age (particularly babies under three months of age), prematurity (particularly gestation less than 32 weeks), congenital cardiac disease and chronic lung disease. Indigenous children in Australia are also more likely to require admission, with rates of hospitalisation almost eight times those of non-Indigenous children. Spread of RSV occurs via large droplets transferred to the individuals’ hands, where the virus can survive for up to one hour. The virus is then transferred to the eyes or nose, resulting in infection. RSV can also survive on hard surfaces for as long as 30 hours. The incubation period of RSV is between three and eight days. Pathogenesis RSV invades the epithelial cells of the respiratory tract and spreads from cell to cell 28 | Australian Doctor | 8 May 2009 Active RSV infection does not result in lasting immunity, so recurrent RSV infection is common. Figure 1. Infant with acute viral bronchiolitis. Note hyperinflation, prominent perihilar bronchial markings and some patchy airspace shadowing. Note: for infants with a clear clinical presentation, a chest X-ray is not required for the diagnosis of bronchiolitis. portation factors. • Clinical assessment. Clinical features that should prompt urgent paediatric review of an infant with suspected bronchiolitis are listed in table 2. The stage of illness (disease trajectory) is an important consideration in determining which patients require review, as babies in the early stages of infection are at risk of further deterioration, whereas those who have been symptomatic for five days or more are most likely to be improving. Specialist management Table 2: Clinical features of severe bronchiolitis • Poor feeding (fluid intake <50% of normal in the preceding 24 hours, poor urine output) • Lethargy • Apnoea • Respiratory rate > 70 breaths per minute • Nasal flaring or grunting • Severe chest wall recession • Cyanosis • Oxygen saturation <92% by inducing cell fusion and the formation of syncytia. Ciliated epithelial cells are destroyed and there is necrosis of the bronchiole epithelia, along with oedema of the bronchiole walls and increased secretion of mucus. Signs and symptoms Bronchiolitis presents most frequently in infants aged 36 months, with breathing difficulties, cough (may be dry/irritating or moist), poor feeding and fever. In very young babies (typically those under 1-2 months), the only symptom may be apnoea. Examination findings include: • Tachypnoea. • Increased work of breathing (intercostal and subcostal recession, tracheal tug and sometimes expiratory grunting). • Chest hyperinflation. • Widespread crackles and/or wheeze heard on auscultation. These symptoms are usually preceded by an initial coryzal phase lasting for 2-3 days. Assessment and diagnosis The diagnosis of bronchiolitis is clinical, based on the typical symptoms and examination findings described above. Although fever is common, the finding of a high fever (temperatures >40°C) is unusual and should prompt careful consideration of alternative diagnoses. In hospital settings the clinical diagnosis is usually confirmed by identifying RSV, or another respiratory virus, in a respiratory sample (usually nasopharyngeal aspirate). Immunofluorescent (IF) antibody methods allow rapid identification of the virus responsible and enable infants with the virus to be isolated, which is important for infection control. IF results are available within a few hours and this method has excellent specificity and good sensitivity. The presence of the virus is then usually confirmed by viral culture, but this result is not available for up to one week. Chest X-rays are not usually helpful for diagnosing bronchiolitis (they usually demonstrate a range of findings from hyperinflation, atelectasis and patchy infiltrates) (see figure 1). The main role is if a differential diagnosis is suspected clinically, for example, because of localised chest signs (pneumonia) or a heart murmur (cardiac disease). GP therapy Mild bronchiolitis can usually be managed at home with appropriate advice and reassurance to the parents. www.australiandoctor.com.au Parents or carers should be given information on how to recognise signs of deterioration in their infant and be strongly advised to bring them back for reassessment if it occurs. Additional therapies such as bronchodilators, systemic and inhaled corticosteroids, nebulised adrenaline or antibiotics have been well shown to have no role in the treatment of the infant with bronchiolitis. In some cases, bronchodilators can exacerbate ventilation/perfusion mismatch and make infants more hypoxic. This is important to consider, as it can be tempting to treat the wheeze with bronchodilators ‘in case’ the diagnosis is asthma. Children over 12 months may also have bronchiolitis and not respond to bronchodilators, although by this age a trial of a bronchodilator, especially in an atopic child or one with a family history of asthma, is reasonable. However, we would recommend a trial dose (administered through a spacer) be given first under observation to assess response. When to refer A small number of babies with bronchiolitis will require admission to hospital. In deciding which babies require admission, several factors are taken into consideration, including: • Age. • Presence of underlying comorbidities such as congenital heart disease. • Premature birth or chronic lung disease. • Socioeconomic factors. • Geographical and trans- Treatment of RSV infection in hospitalised infants is largely supportive and generally includes supplemental oxygen and fluid replacement either by nasogastric tube or intravenously. Nasal suction is often helpful, but other therapies, including physiotherapy, are not. Early introduction of continuous positive airway pressure (CPAP) for infants with severe respiratory distress often obviates the need for intubation and mechanical ventilation. RSV prophylaxis Palivizumab is a human recombinant monoclonal RSV antibody that is administered as a monthly injection during the RSV season. Although it does reduce hospitalisation and admission rates to ICU in high-risk groups (for example, former preterm infants, those with chronic lung disease or acyanotic congenital cardiac disease), it has not been shown to reduce the need for mechanical ventilation. Consequently, its efficacy and cost-effectiveness have been challenged and it is only available for babies in the high-risk groups in their first RSV season. Prognosis The prognosis for most babies who develop acute bronchiolitis in Australia is very good and overall mortality rates are very low. Fifty per cent of previously healthy infants with bronchiolitis will be symptom free after 14 days. About 10%, however, develop a post-bronchiolitic syndrome with symptoms of cough and wheeze that persist for several weeks and can recur intermittently for several years, usually in association with subsequent viral infections. Most eventually recover completely, so that by the age of 13 years there is no increase in wheezing episodes. RSV bronchiolitis in infancy is not a risk factor for asthma in adulthood. cont’d page 30 A D _ 0 3 0 _ _ _ MA Y 0 8 _ 0 9 . p d f Pa ge 3 0 3 0 / 4 / 0 9 , 1 1 : 4 7 AM HOW TO TREAT Acute respiratory infections in children Bronchitis ACUTE bronchitis is a common clinical syndrome in children, caused by inflammation of the trachea, bronchi and bronchioles, usually in association with a viral respiratory tract infection. Acute bronchitis is rarely bacterial in otherwise healthy children. Symptoms of acute bronchitis usually include cough that produces phlegm and may be associated with retrosternal pain during deep breathing or coughing. Generally the clinical course is self-limiting, with complete healing and full return to function typically seen within 10-14 days after symptom onset. Epidemiology The annual incidence of bronchitis in children in the developed world is 20-30%, with an equal incidence in males and females. Acute bronchitis occurs most commonly in children younger than two years, with a second peak seen in children aged 9-15 years. tussis, whereas Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis may be significant pathogens in preschoolers. The cause of the cough in acute bronchitis is multifactorial but involves mucosal injury, epithelial damage and the release of inflammatory cytokines as well as transient bronchial obstruction and hyper-responsiveness in a proportion of patients. Signs and symptoms Acute bronchitis usually begins with symptoms similar to those of the common cold. of acute bronchitis, with bacteria implicated in fewer than 10% of cases. The organism responsible is not usually identified in clinical practice, but when viruses are identified they are usually one of the common respiratory viruses such as influenza A or B, parainfluenza or RSV. Bacteria that can cause acute bronchitis in otherwise healthy school-age children include Mycoplasma pneumoniae and Bordetella per- Pathogenesis Respiratory viruses are by far the most common cause Acute bronchitis usually begins with symptoms similar to those of the common cold, such as coryza, malaise, chills, low-grade fever, sore throat, and back and muscle pain. The initial watery nasal discharge becomes thicker and discoloured after several days and is accompanied by a cough. Purulent nasal discharge is common with viral respiratory pathogens and, by itself, does not imply an underlying bacterial infection. The cough is initially dry and harsh but then loosens and becomes productive. Children younger than five years rarely expectorate, and sputum may be seen in vomitus. Parents frequently note a rattling sound in the chest. Examination findings are frequently normal although the pharynx may be injected. Auscultation typically reveals clear lung fields, although scattered crackles or wheezing can sometimes be heard. Recurrent episodes of acute or chronic bronchitis are unusual and should prompt consideration of alternative diagnoses such as asthma or suppurative lung disease (cystic fibrosis, immunodeficiency, ciliary dyskinesia). GP therapy The vast majority of children with acute bronchitis can be managed as outpatients unless their illness is complicated by severe underlying disease. Treatment is directed at symptoms and includes analgesics and antipyretics, ensuring adequate fluid intake and avoid- ing exposure to irritants, particularly tobacco smoke. Although prescribed frequently, antitussives and expectorants are not useful. There is growing concern about side effects from antitussives in children under two years and a recent Cochrane review failed to find any benefit in any age 1 group. Antibiotics do not relieve symptoms or improve the natural history of acute bronchitis in otherwise healthy patients. When to refer Children with acute bronchitis rarely require referral to a paediatrician unless they have complicating underlying disease. However, persistence of symptoms for more than one month or recurrence of symptoms of productive cough should prompt consideration of alternative diagnoses such as asthma, suppurative lung disease or retained foreign body. These will usually require referral to a paediatrician for confirmation. Croup CROUP, also known as laryngotracheobronchitis, is caused by a viral infection of the upper airway. This infection results in a classic triad of hoarse voice, barking cough and inspiratory stridor. The condition usually affects children from six months to six years of age. Table 3: Assessing clinical severity of a child with croup • Mild: barking cough, no or intermittent stridor, no chest retractions • Moderate: persisting stridor at rest, some chest wall recession or tracheal tug, child easily pacified and interested in surroundings • Severe: persisting stridor at rest, marked tracheal tug and chest wall recession, lethargic or restless, pulsus paradoxis Epidemiology The annual incidence of croup depends on the incidence of infection with viruses that cause this condition, but peaks occur in autumn and spring. The peak incidence occurs in children aged 1-2 years and is about 60 per 1000 child-years. For reasons that are not clear, croup is rare in babies under six months of age and uncommon in children older than six years. Pathogenesis Croup is due to a viral URTI that causes generalised mucosal inflammation and oedema of the larynx, trachea and bronchi, followed by epithelial necrosis and shedding. The key area of airway narrowing is the subglottis, with airway obstruction at this site responsible for stridor. Laryngeal inflammation also results in impaired vocal cord movement, leading to the characteristic cough. In addition, fibrinous exudate can sometimes result in pseudomembrane formation, which results in further compromise of the airway. Several viruses have been implicated in causing croup, but parainfluenza virus types 1 and 3 are responsible for about 80% of cases. Influenza types A and B, RSV, adenovirus and metapneumovirus are responsible for most of the other cases. Signs and symptoms Croup normally starts with the typical barking cough, which often comes on 30 | Australian Doctor | 8 May 2009 Table 4: Diagnosing croup Differential diagnosis Key features Croup Triad of barking cough, stridor, hoarse voice; six months to six years Epiglottitis Toxic (high temperature), drooling, muffled voice, no cough, may be unimmunised for H influenzae type B Retropharyngeal abscess Sore throat, fever, drooling, no cough Foreign body Sudden onset, no fever, stridor and/or wheeze, difficulty feeding/swallowing if foreign body is oesophageal *Stridor at rest indicates airway narrowing of at least 70% (ie, 30% or less residual lumen) suddenly during the night. Usually this is preceded by a 1-2-day history of non-specific symptoms of a viral URTI, such as rhinorrhoea, sore throat and fever. Stridor may develop, which can be associated with difficulty breathing. In more severe cases the child may have evidence of respiratory distress, with tachypnoea, tracheal tug and chest wall retractions. Auscultation usually reveals a clear chest, although air entry may be reduced in more severe cases. Symptoms tend to be worse at night and may fluctuate in severity, typically becoming more severe if the child becomes upset. Croup typically lasts for 2-3 days, but the cough can persist for up to two weeks, typically becom- ing looser in nature after the first few days. Assessment and diagnosis Croup is a clinical diagnosis based on the symptoms and signs described above. Although there are several clinical scoring systems these are only useful as research tools and a basic classification (table 3), provides a simpler guide to assessment and management. GP therapy Formerly a popular treatment, steam inhalation is not useful in the management of croup and carries the risk of scalds. Antibiotics also have no role in the treatment of croup. However, sitting the child upright on their www.australiandoctor.com.au parent’s knee and keeping them calm is very important. Corticosteroids are used to treat upper airway obstruction by reducing airway oedema and inflammation. They should be prescribed for all but the mildest cases of croup. Recommended doses are oral prednisolone 1mg/kg, or dexamethasone 0.3mg/kg given either orally or intramuscularly. The onset of action seems to be within 1-2 hours. There is no effect on the cough, and single doses, repeated as necessary, should be prescribed (rather than a three-day course as recommended for asthma). Doses are given at 24-hour intervals and if more than three doses are required the child should see a paediatrician. Parents whose children develop recurrent croup should be encouraged to give a dose of corticosteroid as soon as they can predict a viral URTI will develop into croup. When to refer Croup can cause life-threatening upper airway obstruction, and children with more severe illness need to be managed in a centre with access to staff trained in the management of paediatric airways. All children under 12 months should be referred for a paediatric assessment, in part so that alternative diagnoses can be excluded. Older children should also be referred if they: • Have tracheal, sternal or subcostal indrawing at rest. • Look toxic. • Appear dehydrated, cyanosed or exhausted. Children with milder symptoms should also be referred if their family circumstances make home care inappropriate or there is uncertainty about the diagnosis (see table 4). If patients with recurrent croup have residual symptoms of stridor or exer- cise limitation between episodes, referral to a paediatric respiratory physician or ENT surgeon is warranted. Emergency management Systemic corticosteroids are prescribed if this has not already been done. Children with more severe croup may require treatment with nebulised adrenaline (1mL 1% solution mixed with 3mL normal saline; or 1:1000 undiluted at a dose of 0.5mL/kg to a maximum of 4mL), which reduces laryngeal inflammation, thus improving the child’s airway. In the circumstance of a child requiring adrenaline, the GP should call an ambulance for transfer to hospital. Nebulised adrenaline lasts for up to two hours, but rebound worsening of the airway narrowing can occur and this must be borne in mind. Repeat doses of adrenaline should be given as needed. A small number of children with croup will require intubation to maintain their airway. Nebulised budesonide (one 1mg/2mL nebule) can be used as an alternative to adrenaline, although its onset of action is not as rapid. The main role for nebulised budesonide is for parent-initiated therapy in those rare circumstances when children have a history of frequent severe episodes and access to ambulance support is poor. Prognosis Overall most children with croup have a mild illness that can be managed at home, with fewer than 5% requiring admission to hospital. Of those admitted, only 1-2% need intubation, with a mortality rate for intubated children of about 0.5%. Fortunately, complications are rare in children with croup although secondary bacterial infection can occur, leading to pneumonia or tracheitis. A D _ 0 3 1 _ _ _ MA Y 0 8 _ 0 9 . p d f Pa ge 3 1 3 0 / 4 / 0 9 , 1 1 : 4 8 AM Influenza Signs and symptoms INFLUENZA is a highly infectious respiratory disease caused by the influenza viruses. Three subtypes cause disease in humans — influenza A, B and C — but only the first two cause clinically significant disease. Influenza infections are often more severe than infections caused by other respiratory viruses and cause constitutional as well as respiratory symptoms. Epidemiology Outbreaks of influenza are unpredictable and occur in distinct patterns. Pandemics occur every 30-40 years and are due to the emergence of a novel virus. Pandemics typically occur outside the usual season and spread rapidly throughout the world. They typically have high attack rates in all age groups and result in high rates of mortality, even in previously healthy young adults. Epidemics occur much more frequently, usually every 1-3 years, and are associated with lower excess mortality. They occur as a result of antigenic drift of the viruses, a process that results in the emergence of new strains of virus caused by mutations within the virus antibody binding sites. Pathogenesis Influenza is spread from person to person via respiratory droplets. The virus binds to respiratory epithelial cells, which are rich in receptors, and enters the cell, where it replicates. New influenza virions are then shed into the respiratory secretions. During this process, inflammatory cytokines are produced, which are responsible for the systemic symptoms of influenza. The pathogenesis and virulence of the influenza virus depend on host factors such as immunocompetence, and viral factors, including antigenic variation, ability of viral shedding to take place and restriction of the cytopathic effect of the virus to allow continued replication to take place. The incubation period for influenza is usually 1-4 days. Children can be infectious for several days before their symptoms appear and can continue to shed the virus for more than 10 days. Uncomplicated influenza results in respiratory symptoms including dry cough, sore throat, rhinitis and otitis media, accompanied by systemic symptoms including fever, myalgia, headache, malaise, fatigue, nausea and vomiting. These symptoms are typically of acute onset but can be difficult to differentiate from other respiratory infections such as RSV. Influenza usually lasts for up to a week, although the cough and malaise can persist for 2-3 weeks in some individuals. Influenza virus may be responsible for most of the respiratory illness discussed in this article — bronchiolitis, bronchitis, croup and pneumonia. Complications of influenza can occur in patients with preexisting respiratory disease, but infection can also result in secondary bacterial pneumonia, cause febrile convulsions and be associated with encephalopathy, transverse myelitis, myocarditis and myositis in previously healthy children. Assessment and diagnosis The influenza virus may be isolated from cell culture and, while this remains the gold standard and is essential for monitoring circulating strains, it is too slow to be useful as a bedside test. Suitable samples include nasopharyngeal aspirates or swabs, throat swabs, sputum when available, or bron- choalveolar lavage fluid. Rapid results are obtained by directly detecting viral antigens from these samples using the technique of reverse-transcription PCR, which provides a sensitive assay able to differentiate influenza A and B from other viruses. GP therapy The main treatments for influenza are symptomatic, in particular, maintaining fluids and encouraging rest. Antibiotics have no role unless secondary bacterial infection is suspected. In recent years antiviral therapy with oseltamivir (Tamiflu) and zanamivir (Relenza) have become available. The difficulty is picking which children have influenza as the cause for their symptoms. A recent Cochrane review showed that oseltamivir reduced the median duration of illness by 26% (36 hours) in healthy children with laboratory-confirmed influenza. There were not enough data on ‘at-risk’ children (eg chronic respiratory or cardiac causes) to make a recommendation although there is no reason why a similar biological response would not be anticipated. Commencement of therapy within 48 hours of symptom onset is required. There is some evidence that oseltamivir may be effective for prophylaxis if a household contact has confirmed influenza. When to refer Patients who look unwell or in whom the complications described above are suspected should be referred to a paediatrician or emergency department with facilities to care for children. There should be a lower threshold for referral among patients with complex underlying medical conditions. Influenza vaccination This is really in the domain of preventive therapy. For many years there has been a standard recommendation for children with complex medical conditions to receive influenza vaccination (see The Australian Immunisation Hand3 book 9th edition). However, otherwise healthy children can benefit too. A recent report from SA highlighted that there were more hospitalisations from influenza in the <2-year age group than in those over 65, and even in those over 85. After three deaths from influenza in 2007 in WA in previously healthy children, routine vaccination for children aged between six months and five years has been recommended in that state. Children can be immunised with influenza vaccine from six months of age. Children under nine years need two doses at least one month apart the first time they receive the vaccine (single doses are required in subsequent years). The principal contraindication is allergy to eggs. Pertussis WHOOPING cough is an acute respiratory tract infection first described in the 1500s. Most cases are caused by Bordetella pertussis, with B parapertussis responsible for about 5% of cases. Epidemiology Whooping cough epidemics occur every 2-5 years. There are 20-40 million cases of whooping cough annually worldwide, 90% of which occur in low-income countries and result in an estimated 200,000-300,000 fatalities a year. Whooping cough is spread by respiratory droplets and is highly contagious. After exposure to an acute case, 70-100% of unvaccinated household contacts and 50-80% of unvaccinated school contacts will become infected. Infants under 12 months are at highest risk of complications and death. Young infants do not always have the characteristic whoop and can present with apnoea even before the cough is recognised. whooping cough are paroxysms of cough followed by an inspiratory whoop and/or vomiting. These symptoms are usually preceded by a catarrhal phase lasting a week or two that resembles the common cold, with coryza and a non-productive cough. The paroxysmal phase lasts for several weeks, usually reaching its peak of severity in the first two weeks before gradually improving over the next 6-12 weeks. Young infants do not always have the characteristic whoop and can present with apnoea even before the cough is recognised. Infants with pertussis may look well between paroxysms, without chest signs. Petechial and/or subconjunctival haemorrages may be evidence of the severity of the coughing paroxysms. Young infants are at greatest risk of complications including encephalopathy, pneumonia and feeding problems. Pathogenesis Humans are the sole reservoir for B pertussis and B parapertussis. B pertussis is a Gram-negative pleomorphic bacillus that spreads via aerosolised droplets from coughing of infected individuals. B pertussis attaches to and damages ciliated respiratory epithelium. Signs and symptoms The characteristic symptoms of Assessment and diagnosis Pertussis can be diagnosed clinically in any patient with an acute cough that has lasted for two weeks or more and which does not have another explanation, especially if there is also a history of paroxysms, whoop or post-tussive vomiting. Contact history is also helpful. The clinical diagnosis can be confirmed by specific diagnostic tests, www.australiandoctor.com.au which include direct testing of nasopharyngeal swabs with nucleic acid amplification testing (NAAT), culture, PCR or direct immunofluorescent assays. An additional finding may be of a significant lymphocytosis although this is non-specific. Serology (B pertussis-specific IgA) is often insensitive in the early stages of the disease and particularly unreliable from infants. GP management Prevention Vaccination remains the main preventive measure for control of spread of this disease. The recommended schedule for pertussis vaccination is at two, four, and six months, and four years of age. Infants are not protected until they have had three doses. An adult pertussis booster vaccine (Boostrix) is given to adolescents who are in year 10 at secondary school. Adults who have not been vaccinated with pertussis-containing vaccine for more than 10 years have waning immunity and may contract pertussis and pass it on. More than half of infants aged under one year admitted to hospital with pertussis have an adult family member with clinical or laboratory-proven pertussis. Although not yet funded (but licensed for use) adults planning a pregnancy should have adult pertussis-containing vaccine. Women already pregnant can be vaccinated immediately after delivery. Treatment Antibiotics do not alter the clinical course of whooping cough but eliminate B pertussis from the nasopharynx, rendering patients non-infectious. The most effective antibiotic is clarithromycin 7.5mg/kg (up to a maximum of 500mg) twice daily for seven days. For patients unable to tolerate macrolides, trimethoprim-sulfamethoxazole is an alternative antibiotic, given for seven days. The dose is 20mg trimethoprim with 100mg sulfamethoxazole per dose, twice daily for children under six months of age. This dose should be doubled for older children. A person who has been coughing for more than 21 days is no longer infectious, and antibiotic treatment is not indicated. Antibiotics should also be given to household contacts if the household includes an infant under 24 months of age or a child of any age who is not fully vaccinated. Antibiotics should also be given to a contact who is a pregnant woman during the last month of her pregnancy. cont’d next page 8 May 2009 | Australian Doctor | 31 A D _ 0 3 2 _ _ _ MA Y 0 8 _ 0 9 . p d f Pa ge 3 2 3 0 / 4 / 0 9 , 1 2 : 5 4 PM HOW TO TREAT Acute respiratory infections in children from previous page Exclusion from school or child care Children with whooping cough must be excluded from school or child care until five days after they start their course of antibiotics. The Australian Immunisation Handbook recommends that unimmunised close contacts should be excluded from childcare for 14 days from the date of last exposure or until five days after start3 ing a course of antibiotics. States and territories also have guidelines/legislative requirements relating to exclusion times for unimmunised children from school or childcare, so GPs are advised to contact their local public health unit for information regarding their own state/territory requirements. When to refer Infants under 12 months with pertussis should be assessed by a paediatrician, as they are at highest risk of complica- tions such as apnoea, poor feeding, pneumonia or encephalopathy. Older children or adolescents (who will not have been vaccinated for some years) may simply present with a troublesome cough and at times the differential diagnosis is unclear. Pertussis serology (pertussis-specific IgA) can be helpful in these circumstances. cardio-respiratory monitoring, fluid support and continuous oxygen therapy if there is hypoxia with coughing. Investigations such as nasopharyngeal PCR or culture are performed but antibiotics are usually prescribed if the clinical suspicion of pertussis is high. Specialist management Prognosis Specialist management involves Infants born prematurely and patients with underlying cardiac, pulmonary, neuromuscular or neurological disease are at high risk for complications of pertussis (pneumonia, seizures, encephalopathy, death). The cough may persist for three months (‘the 100-day cough’) and recrudesce with any subsequent respiratory infection, although rarely enough to warrant readmission to hospital. Pneumonia PNEUMONIA can be defined as inflammation and consolidation of the lung parenchyma, caused by an infectious organism. Most cases of pneumonia in children are community acquired and occur in previously healthy children. The diagnosis is clinical and does not require chest X-ray confirmation. Figure 2A. A chest X-ray of a four-year-old child who presented with high fever, lethargy and cough. On examination there was reduced air entry in the right lower zone with bronchial breath sounds. The chest X-ray shows opacification in the right lower lobe with some air bronchograms. Note: the right heart border appears clear suggesting the infection is not in the middle lobe. Figure 2B. The same four-year-old child after 36 hours of intravenous penicillin. He is more tachypnoiec with high fever. The air entry on the right is further reduced and the percussion note is stony dull. This suggests the pneumonia has become complicated by a pleural effusion or empyema. The chest X-ray now shows more extensive opacification with mediastinal shift to the left and evidence of the effusion/empyema. Heart shifted to the left, suggesting large volume of pleural fluid. Epidemiology Pneumonia is most common in younger children, with an annual incidence of 35-40 cases per 1000 children under five years of age, which falls to seven cases per 1000 in adolescents aged 12-15 years. The age of the child is important in determining the likely pathogen responsible. In neonates, group B streptococcus and Gram-negative enteric bacteria are the most common pathogens. Beyond the neonatal period, viruses are by far the most commonly implicated pathogens in children during the preschool years, with RSV, parainfluenza, adenovirus, rhinovirus, influenza and cytomegalovirus all potential causes in this age group. In children over five years of age, S pneumoniae is the most common cause, with M pneumoniae and Chlamydia pneumoniae the next most frequent causative organisms. Pathogenesis S pneumoniae is carried in the nasopharynx in about 50% of healthy children without causing symptoms. Various factors can lead to invasive disease, such as the acquisition of a new serotype or concomitant viral infection such as influenza, which increases the attachment of the streptococcus to the respiratory epithelium. The organisms reach the lower respiratory tract by haematogenous seeding, although inhalation of infectious particles may be implicated. In the alveoli, the organisms multiply and spread from alveolus to alveolus via the pores of Kohn. Signs and symptoms Pneumonia frequently starts with a high fever accompanied by tachypnoea. Cough is often absent initially, particularly when the infection is due to S pneumoniae. This is 32 | Australian Doctor | 8 May 2009 More extensive opacification which may be the pleural space fluid or more extensive pneumonia. because the inflammatory process occurs predominantly within the alveoli (where there are few cough receptors) in the early stages of this infection. Cough then becomes more prominent as inflammation spreads and debris accumulates in the airways. Respiratory rate can be hard to count in healthy restless children, but tachypnoea is an important sign in pneumonia, as it is associated both with severity and with increased likelihood of underlying consolidation. Chest recession may be an accompanying clinical feature. Auscultation typically reveals crackles and/or bronchial breathing. Localised signs increase the chance of the infection being bacterial, while generalised signs may be more typical of viral or mycoplasma infection. However, these are not particularly specific or sensitive findings. The presence of wheeze suggests either a viral or, particularly in school-age children, a mycoplasma infection. The classic mycoplasma prodrome is high fever and headaches before the cough appears, but almost any presentation could also be mycoplasma. It is generally stated that mycoplasma is more common in the school-age group (compared with preschoolers/infants), although this assertion is being questioned. Children with pneumonia may present with abdominal pain, particularly if the infection involves the lower lobes. The pain can be quite severe and is due to referred pain from the diaphragmatic pleura. Older children may also complain of chest pain. Assessment and diagnosis Pneumonia can be diagnosed clinically in most cases, although it is extremely difficult to distinguish bacterial from viral causes on clinical grounds. Routine chest X-ray in children with uncomplicated lower respiratory tract infections is not necessary. A chest X-ray is helpful if the diagnosis is in doubt, or the child does not respond to therapy as expected, or complications (such as parapneumonic effusion or empyema) are suspected. Other investigations, including FBC and acute-phase reactants, are also unnecessary in most cases and do not help distinguish between viral and bacterial pathogens. Urine testing for the presence of antigens is another unhelpful test, as their presence is not specific for pneumonia. However, culture of a clean-catch sample of urine should be performed in a febrile child if the infective cause is unknown, to exclude the possibility of an underlying UTI. Serology (IgM) for mycoplasma has little role in the GP setting because of the delay in receiving results. Blood cultures should be performed in children with more severe disease who require admission to hospital, although these prove positive in fewer than 10% of cases. Nasopharyngeal aspirates are useful for diagnosing viral infections, particularly in younger children who require admission to hospital. The presence of bacteria in these samples cannot be used to make a diagnosis, as they are commonly found as commensals. In children with pneumonia complicated by parapneumonic effusion, pleural fluid should be obtained if possible. This should be sent for bacterial antigen detection as well as microscopy and culture. GP therapy It is difficult to differentiate viral, mycoplasma and bacterial causes of pneumonia by clinical examination. Added to this is concern regarding the increasing incidence of antibiotic resistance. Thus, young children presenting with mild symptoms of lower respiratory tract infection do not require antibiotics. In more severe cases, if antibiotics are prescribed, amoxycillin (10-25mg/kg eight-hourly) should be the first choice, as it is effective against the most common pathogens, is well tolerated and cheap. Alternatives to amoxycillin include roxithromycin (2.54mg/kg 12-hourly). www.australiandoctor.com.au Macrolide antibiotics may be used as first-line treatment in children over five years, as mycoplasma infections become more common in this age group. An essential part of the management of pneumonia in children in the community is the provision of information to the child’s family to allow them to manage fever, prevent dehydration and identify signs of deterioration in the child’s condition. When to refer If pulse oximetry is available, a key indication that the child is likely to require admission to hospital is hypoxaemia, that is, an oxygen saturation of <92%. Other indications include tachypnoea (respiratory rate >70 breaths/minute in infants less than 12 months or >50 breaths/minute in older children) as well as poor feeding or evidence of dehydration, apnoea or grunting, or if the family is unable to provide appropriate care. Patients should be reviewed regularly within the first 48 hours of illness, as failure to improve, or deterioration, within this time frame is an indication for review by a paediatrician. Specialist management Oxygen is provided if the child is hypoxic. Antibiotics are given if this has not been done previously, and may be administered intravenously in severe cases of pneumonia or if the child is unable to absorb oral antibiotics (eg, due to vomiting). The first-line IV antibiotic for an uncomplicated pneumonia should be benzylpenicillin 30mg/kg six-hourly (60mg/kg four-hourly if infection is severe, but referral in these circumstances is advised). Chest physiotherapy is not beneficial and has no place in the management of pneumonia in children. The development of respiratory failure may necessitate transfer to the intensive care unit for ventilatory support. Parapneumonic effusions may require surgical drainage. Prognosis Death from pneumonia is rare in the developing world and the vast majority of children recover completely. Most children with a S pneumoniae infection respond within 24 hours; failure to do so suggests more serious infection or development of complications such as parapneumonic effusion/empyema. Other complications can occur, such as lung abscess and metastatic infections, including osteomyelitis and septic arthritis. Children with no pre-existing conditions who follow a standard course with rapid resolution of symptoms do not need a progress chest Xray if one was taken initially. cont’d page 34 A D _ 0 3 4 _ _ _ MA Y 0 8 _ 0 9 . p d f Pa ge 3 4 3 0 / 4 / 0 9 , 1 1 : 5 1 AM HOW TO TREAT Acute respiratory infections in children GP’s contribution DR GED FOLEY Mosman, NSW Case study JS, 18 months, presented with a history of an URTI four weeks before, followed by an intermittent cough. Over the preceding two days the cough had become worse and was associated with fever, malaise, rapid breathing and poor appetite. There was no relevant past or family history. On examination, JS was febrile with a temperature of 38.5°C and his respiratory rate was 48 breaths/minute. ENT examination was normal. Respiratory examination revealed scattered expiratory wheeze and scattered crackles. JS was prescribed amoxycillin and supportive measures and a review in four days was arranged. He returned in three days, at which time he was still febrile and coughing. On examination his temperature was 38.0°C, pulse 120 beats/minute and respiratory rate 40 breaths/minute. He was once more found to have scattered expiratory wheeze, although now he had some focal signs at the right midzone and base, with localised inspiratory crackles and slightly reduced air entry. The possibility of an atypical infection was considered and erythromycin was added. He was also given inhaled salbutamol via a spacing device and second-daily review was organised. Initially JS improved on this regimen and was more settled after two days. However, at further review (seven days after initial presentation), he had deteriorated again. He was febrile with a temperature of 37.9°C, tachypnoeic and O2 saturation was 94% on room air. He had intercostal recessions and the focal signs at the right base were more marked. He was referred to the emergency department. JS was an inpatient for only two days and was treated with oxygen and roxithromycin. Subsequent sero-logy indicated infection with Chlamydia pneumoniae. His cough persisted for many weeks, and six months later he still has some mild shadowing in the right middle lobe on chest X-ray (being monitored by the paediatric team). Questions for the author Is there a case for initiating amoxycillin treatment together with a macrolide antibiotic when a child presents with How to Treat Quiz focal chest signs and a clinically severe infection? No. The appropriate strategy was employed — starting with a simple antibiotic (amoxycillin) in this age group. The development of focal signs would warrant a chest X-ray if the child was not improving. Atypical organisms and viral infections may cause localised disease but I would be covering for bacterial infection if signs were localised. Previous studies have suggested that young children with purulent rhinorrhoea, fever and a chesty cough have focal areas of pulmonary infection that are not apparent on examination. Should we be initiating antibiotic treatment in such children? No. This constellation of features is most likely viral in origin. If the child looks systemically well and there are no pulmonary signs, there is no need to start antibiotics. Persistent symptoms, and particularly tachypnoea and chest signs, are likely to warrant antibiotic treatment. We are currently seeing many cases of pertussis in the schoolage population. Should we be offering antibiotic treatment to classmates who have been in close contact with a patient with pertussis? Data on contact prophylaxis are scarce, and defining close contact can be problematic. The principles as outlined in the ninth immunisation handbook are to protect young children (<24 months) who have not been immunised completely (this would include all infants under six months, none of whom have had three doses of DTPa). If any contacts come from such a household or include a woman in her last month of pregnancy (if she delivers, the baby could be at risk of pertussis) the contact should receive antibiotic prophylaxis. I would also offer prophylaxis (and immunisation) to contacts who have not been immunised. References 1. Smith SM, Schroeder K, Fahey T. Over-the-counter medications for acute cough in children and adults in ambulatory settings. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD001831. DOI: 10.1002/14651858.CD0018 31.pub3. 2. Matheson NJ, Harnden A, Perera R, Sheikh A, Symmonds-Abrahams M. Neuraminidase inhibitors for preventing and treating influenza in children. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD002744. DOI: 10.1002/14651858.CD0027 44.pub2. 3. National Health and Medical Research Council. The Australian Immunisation Handbook 9th Edition 2008: www.health.gov.au/internet/ immunise/publishing.nsf/ Content/Handbook-home INSTRUCTIONS Complete this quiz online and fill in the GP evaluation form to earn 2 CPD or PDP points. We no longer accept quizzes by post or fax. The mark required to obtain points is 80%. Please note that some questions have more than one correct answer. Acute respiratory infections in children — 8 May 2009 1. Jared, six months, presents with a twoday history of a fever and cough, preceded by a runny nose for a few days. On examination he is tachypnoeic with chest wall recessions and widespread crackles and wheeze. Your provisional diagnosis is bronchiolitis. Which TWO features would be suggestive of severe infection? a) Fluid intake <50% of normal in the preceding 24 hours b) Respiratory rate of 40 breaths per minute c) Lethargy d) Oxygen saturation of 95% 2. Which TWO statements about bronchiolitis are correct? a) Bronchiolitis is best diagnosed by chest X-ray b) Treatment of bronchiolitis in hospitalised infants is largely supportive with supplemental oxygen and fluid replacement c) Bronchodilators are a useful additional therapy in infants under 12 months of age d) About 10% of children develop a postbronchiolitic syndrome with cough and wheeze that can recur intermittently for several years 3. Which TWO statements about bronchitis in children are correct? a) Most cases of acute bronchitis are due to viruses b) Antitussives and expectorants are useful for symptomatic relief of bronchitis in children c) Antibiotics will relieve symptoms of bronchitis and result in shorter recovery times in most patients d) Recurrent episodes of bronchitis are uncommon 4. Which TWO statements about croup are correct? a) Stridor at rest indicates airway narrowing of at least 30% b) Key features of severe croup include drooling and a toxic appearance c) All children under 12 months with symptoms of croup should be referred for a paediatric assessment d) Features of severe croup may include lethargy or restlessness 5. Tania, two years, presents with a hoarse voice, barking cough and stridor, which came on overnight. Which TWO statements about the management of croup are correct? a) Steam inhalation is useful in the management of mild croup b) Oral corticosteroids should be prescribed for all but the mildest cases of croup c) Children with more severe croup may require nebulised adrenaline d) There is no role for nebulised budesonide in the management of croup 6. Which THREE statements about influenza in children are correct? a) Children with influenza are not infectious before their symptoms appear b) Influenza virus may be responsible for ONLINE ONLY www.australiandoctor.com.au/cpd/ for immediate feedback bronchiolitis, bronchitis, croup and pneumonia c) Detection of the influenza virus by culture is essential for monitoring strains but too slow to be a useful bedside test d) Children under nine years need two doses at least one month apart the first time they receive influenza vaccine 7. Which TWO statements about clinical features and diagnosis of pertussis infection are correct? a) Whooping cough is not highly infectious, with only about 30% of unvaccinated household contacts becoming infected after exposure b) The characteristic paroxysmal phase of whooping cough is usually preceded by a 12-week catarrhal phase c) Young infants with pertussis infection can present with apnoea even before the cough is recognised d) Bordetella pertussis-specific IgA serology is the gold standard test for diagnosis in the early stages of the disease, especially in infants 8. Which TWO statements about managing and preventing pertussis infection are correct? a) Antibiotics will reduce the severity and risk of complications of whooping cough b) A person with whooping cough who has been coughing for more than 21 days is no longer infectious c) Antibiotics should be given to household contacts of those with whooping cough if the household includes an infant under 24 months of age d) Adults who received the full course of recommended vaccinations in childhood have lifelong immunity to pertussis 9. Which TWO statements about causes and presentation of pneumonia in children are correct? a) Streptococcus pneumoniae is the most common cause of pneumonia in preschoolaged children b) Cough is frequently the first symptom in children with pneumonia, particularly when the infection is due to S pneumoniae c) Tachypnoea is associated with increased severity of pneumonia and increased likelihood of underlying consolidation d) Children with pneumonia may present with abdominal pain 10. Which TWO statements about diagnosing and managing pneumonia in children are correct? a) All children with a clinical diagnosis of pneumonia require X-ray confirmation of the diagnosis b) An FBC will help to distinguish between viral and bacterial causes of pneumonia c) If oral antibiotics are prescribed, amoxycillin is generally the first choice in children under five years d) Macrolide antibiotics may be used as first-line treatment in children over five years CPD QUIZ UPDATE The RACGP now requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2008-10 triennium. You can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept the quiz by post or fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online. HOW TO TREAT Editor: Dr Wendy Morgan Co-ordinator: Julian McAllan Quiz: Dr Wendy Morgan NEXT WEEK Excessive daytime sleepiness is a common symptom in general practice.The next How to Treat focuses on the primary brain disorders that can cause excessive daytime sleepiness (especially narcolepsy and idiopathic hypersomnia). The authors are Dr Anup Desai, senior staff specialist, department of respiratory and sleep medicine, Prince of Wales Hospital, Randwick; consultant physician in private practice, Camperdown (Brain and Mind Research Institute) and Randwick; and clinical senior lecturer, faculty of medicine, University of Sydney; and Dr Ben Kwan, respiratory advanced trainee registrar, Prince of Wales Hospital, Randwick, NSW. 34 | Australian Doctor | 8 May 2009 www.australiandoctor.com.au