9 Respiratory medicine

Disorders of the respiratory tract account for a major part of paediatric medicine both in hospital and in general practice. There are 5 key common presentations that the practitioner should be familiar with and we will focus on these first. Next, we will discuss the investigations we use in the care of children. Last, we provide a mini-catalogue of diseases and conditions that you will need to know about, and be able to treat.

We have discussed in Chapters 3 (  p.31) and 5 (  pp.48–50) the general approach to history and examination for patients with respiratory illness. Here are some additional points that you will need to take note of during your consultation.

See also  p.31.

Wheeze is a breath sound that is heard during expiration. It is often associated with prolongation of the expiratory phase of the breathing cycle. Wheeze indicates obstruction to airflow within the thorax. It can be high- or low-pitched; this differentiation indicates that the obstruction is likely to be in the smaller and larger airways, respectively. Also, wheezes can be monophonic or polyphonic; identifying these sounds will tell you whether the obstruction is likely to be in one or multiple airways.

Each of the conditions in the list above will require specific investigation and treatment. Wheeze due to asthma will require both acute and chronic treatment (see  pp.264–269).

Stridor is a noise heard during the inspiratory phase of breathing. It indicates either dynamic or fixed extrathoracic airway obstruction (anywhere from the nose to the thoracic inlet). When it arises acutely and is associated with respiratory distress, immediate attention is required (  pp.48–50, 284–285). The differential diagnosis of stridor is as follows.

There are specific treatments for many of these conditions. In persistent, non-medical causes of stridor, airway surgery may be required after endoscopy.

Cough is a protective response for removing secretions and particulate matter from the airway. Main feature sudden expulsion of air from lungs.

In general, we do not treat cough, but focus on underlying cause.

A chronic cough is one that has persisted for more than 8wks (British Thoracic Society 2008 guideline¹ for the assessment and management of children with chronic cough). Its causes are as follows:

Being short of breath can be due to heart or lung disease. In lung disease, this sensation arises because of lack of oxygen, difficulty breathing due to airway obstruction, or abnormal lung mechanics. Infants may not be able to express their discomfort—in this instance you will need to be able to identify signs of respiratory distress. The causes include the following.

Discussed in Chapter 5 (  p.50).

We are concerned about snoring in children when it indicates that the child has obstructive sleep apnoea (OSA), i.e. snoring in association with periods of ineffective breathing lasting longer than 2 breaths (e.g. breathing at a rate of 20/min, this would be 6s). This is as opposed to central apneas, which are a pause >20s in an otherwise well child. The most common cause of OSA is adenotonsillar hypertrophy. The other causes are as follows.

When snoring is associated with OSA, the underlying cause needs to be treated.

CXR is a key investigation in respiratory disease. It will give you information about lung volume (e.g. hyperinflation in asthma), signs of chronic inflammation (e.g. peribronchial cuffing), and evidence of congenitial lesions (e.g. lung cysts). However, it is an investigation that can be overused. It should not replace a thorough clinical examination, and think hard before requesting repeat studies.

A CXR is used to glean more clinical evidence about what the child’s underlying problem is. So, in each presentation consider why you have requested the test. Here are some examples.

A CXR is not needed every time a patient presents with ‘asthma’. However, if that child has never had an X-ray, or there is something atypical about the history, consider other possibilities:

Stridor Suspected tracheal lesion around the thoracic inlet.

Suspected cardiopulmonary disease or cor pulmonale from chronic upper airway obstruction.

Four tests are frequently performed at the bedside or in the laboratory are lung function testing, sweat test, and arterial blood sampling.

Spirometry can be achieved in ≥5-yr-olds, but measurements are easier in ≥7 year olds. Peak expiratory flow rate (PEFR) monitoring is useful in asthma. Other measurements include:

This test is used in the diagnosis of cystic fibrosis. Sweating is induced in an area of the forearm using pilocarpine, and a capillary tube is used to collect the sweat. A minimum of 15μL (and preferably >30μL) of sweat should be collected. In cystic fibrosis abnormal function of the sweat glands results in higher concentrations of chloride in the sweat:

Assessment of oxygen saturation (SpO₂) using a pulse oximeter is a non-invasive way of assessing a child’s oxygenation using a probe attached to a finger or toe.

Assessment of blood O₂, CO₂, and acid–base are important in critically ill children, or in those where you suspect significant lung disease.

Sometimes more detailed investigations are needed before you can select the best treatment for your patient. These include the following:

Asthma is a disease of chronic airway inflammation, bronchial hyper-reactivity, and reversible airway obstruction. It affects 10% of the population and can develop at any age, but typically half of the paediatric cases present before the age of 10yrs. There is often a family history of asthma or atopic disease.

In the child with chronic problems consistent findings include:

Not needed if there has been recent imaging. It may show:

The main medications used for maintenance are bronchodilators, which give short-term relief of symptoms, and prophylactic therapy, which reduces chronic inflammation and bronchial hyperreactivity. In the outpatient clinic our aim is to titrate these treatments so that the child can function normally, yet still avoid any detrimental effect on growth and development. See  p.267 for stepwise manner in which these drugs may be used.

When long-term oral steroids or high-dose inhaled steroids are used, special attention will need to be given to unwanted effects including:

Now rarely used in children, but you should be aware that there are a number of problems related to toxic blood levels, including:

There are a number of drug delivery devices that are available for use in children:

In the clinic you will need to make sure that your patient is getting and taking the medication prescribed. In all children you will need to see that they have the appropriate technique and device for their age.

Look for 5-breath tidal volume breathing technique.

Note that, if the infant is crying, less drug will be inhaled. Make sure that the person giving the medication:

The aim of treatment is to allow the child to lead a normal life. In the clinic you will come across children with seemingly distinct clinical patterns of their chronic asthma. Patients with frequent or persistent asthma should be seen in a specialist clinic. Nebulized treatment is used in severe acute asthma. It is not recommended in mild to moderate severity asthma. Instead, use multidosing (up to 10 puffs) bronchodilator.

Having reviewed the history and categorized your patient in terms of clinical pattern and severity, use a logical, stepwise approach to escalating therapy (see Box 9.1).

In this age group, a spacer device with an appropriate face mask is used, e.g. a small volume Aerochamber^® or Ablespacer^® which can take any inhaler; or a large volume Volumatic^® or Nebuhaler^®, which only fit certain inhalers. Prophylactic therapy with inhaled steroids is more effective than cromoglicate.

Cystic fibrosis (CF) is an autosomal recessive genetic disorder leading to a defect in the CF transmembrane receptor (CFTR) protein, which results in defective ion transport in exocrine glands. In the lung abnormal sodium and chloride ion transport causes thickening of respiratory mucus. The lung is therefore prone to inadequate mucociliary clearance, chronic bacterial infection, and lung injury. There are also similar effects—although not with superadded infection—in other organs that lead to pancreatic insufficiency, liver disease, and, in the male, infertility. There are over 1500 mutations in the CFTR gene; the most common is the ZF508 deletion. CF is the most common genetic disease in Caucasions (1/2500).

Since 2007 in the UK all newborn babies are screened for cystic fibrosis looking for an abnormally raised immunoreactive trypsinogen (IRT) and 29 CFTR gene mutations from blood-spot analysis on the Guthrie card.

Give particular attention to:

About 10–20% of CF patients present in the neonatal period with meconium ileus. However, most children with CF present with:

Full assessment of:

Lifelong therapy and supervision are required in CF. There is a variety of problems that can be expected at different ages.

The management of the child with CF requires close co-operation between local hospitals and regional centres. Patients and their families gain much from expert clinics, and from other patients and their families. Effective management requires a multidisciplinary team approach, which should include:

All patients with CF should have a thorough annual multisystem review. Table 9.1 summarizes the range of information that is needed. You will find following these parameters helpful when assessing progression, deterioration, and need for supraregional referral for heart–lung transplantation.

All children with CF should have physiotherapy at least twice a day. Parents and older children are taught how to do some of the following:

Most experts recommend antibiotic therapy.

See also  pp.166–167.

As the quality and outcome of neonatal intensive care for premature babies has improved, more and more infants with chronic lung disease (CLD) are being seen. There are a variety of lung conditions that affect premature babies and necessitate mechanical ventilation; these are discussed in Chapter 6, p.107.

The following can affect newborn of any gestational age:

On follow-up in the paediatric clinic you may see oxygen-dependency due to any of these conditions. CLD in this context is defined as abnormal CXR and use of supplementary oxygen beyond 28 days.

In many respects the approach to managing oxygen-dependent infants with compromised lung function is very similar to caring for infants with CF. A multisystem and multidisciplinary team approach is needed. This should include home and community liaison—the neonatal unit nurse specialist and health visitor are particularly helpful.

Wheeze is a common symptom in infants with CLD. Asthma treatments are often used in these children.

The ultimate aim of supervision of these patients is to withdraw oxygen in a safe and timely manner. The target oxygen saturation (SpO₂) in patients on supplemental oxygen via nasal cannulae is ≥92%. Withdrawal is appropriate when the infant is clinically well, gaining weight, and has an SpO₂ consistently above 92% with an oxygen requirement ≤0.1L/min. Children can be weaned from continuous low flow oxygen to night-time and naps only, or remain in continuous oxygen throughout the 24hr until the child has no requirement at all. Oxygen equipment should be left in the home for at least 3mths after the child has stopped using it. If this is in a winter period, it is usually left until the end of winter.

The following congenital abnormalities of the upper and lower airway are discussed in Chapter 23,  p.843.

Apnoea is defined as a lack of breathing. Obstructive apnoea refers to a lack of airflow in the face of respiratory effort. It is most often associated with sleep. The obstructive sleep apnoea syndrome (OSAS) may be due to tonsillar/adenoidal hypetrophy, macroglossia, or micrognathia.

(see also  p.31)

A thorough examination is needed:

A thorough history and examination should identify children who need further treatment. However, there is a place for the following as part of an assessment.

Surgery is indicated when the following criteria are met.

Any of:

Any of:

Up to 20% of the population have symptoms of allergic rhinitis, which include nasal congestion, itching, sneezing, and discharge.

Check for:

Ear, sinus, nose, and throat infections account for 80% of respiratory infections. The diagnosis URTI may mean any of the following.

Children often present with a combination of:

A thorough examination is needed. In infants you will need to make sure that there is not a serious infection and, in those with difficulty feeding because of blocked nose, that feeding will be adequate. In older children you will need to check for possible bacterial infection and give antibiotics when the following are identified.

Virus infection causes the majority of URTIs and antibiotics should not be prescribed. However, if bacterial tonsillitis, or pharyngitis due to group A β-haemolytic streptococcus, or acute otitis media is suspected, then they should be given after a throat swab has been taken for bacterial culture. A positive culture will mean that a 10-day course of antibiotics is required.

There are a number of laryngeal and tracheal causes of inflammation and airway obstruction. In the acute setting you will be concerned with three common conditions.

In practice the two main conditions that require differentiating are viral croup and acute epiglottitis. The history may help in this process (see Table 9.2).

Take a careful assessment of severity including:

The main priority in the emergency setting is to differentiate between acute epiglottitis and viral croup (see Table 9.2). If you are unsure, stabilize the child and ensure that nothing precipitates distress and possible airway obstruction. Try and keep the child, family, and staff calm. Alert emergency otolaryngologist and anaesthetist to the possibility of a need for emergency airway support.

Children with mild illness can be managed at home, but advise parents that if there is recession and stridor at rest then they will need to return to hospital. Infants <12mths may need closer attention. Treatments include the following.

In cases that require endotracheal intubation steroids should be given and, if there is evidence of secondary bacterial infection or bacterial tracheitis, antibiotics should be added.

The child with acute epiglottitis will need to be managed in the intensive care unit after endotracheal intubation. Once this procedure has been completed take blood cultures and start IV antibiotics.

The main symptoms of acute bronchitis in children are cough and fever. Two infections—Bordetella pertussis and Mycoplasma pneumoniae—may produce symptoms that persist for a number of weeks. Another condition often diagnosed in infants without fever or distress is ‘wheezy bronchitis’, or ‘recurrent bronchitis’. This condition has been the topic of much debate over the years as to whether these infants have asthma or not, and whether they should be treated as such.

Bordetella pertussis infection typically induces three stages of illness:

A whooping cough-like syndrome may be caused by Bordetella parapertussis, Mycoplasma pneumoniae, Chlamydia, or adenovirus.

There may be a typical history. In young infants, however, whoop is often absent, and apnoea is a more common finding. In older children, and parents, there may be a history of persistent and irritating cough.

A thorough examination is needed. In infants you will need to make sure that the problem is not pneumonia. Also, check the following:

Erythromycin for 14 days (or clarithromycin for 7 days) to reduce infectivity but this may have minimal effect on the cough.

Bronchiolitis, most commonly due to respiratory syncytial virus (RSV), affects everyone by the age of 2yrs. Whether you meet this infection in your first winter, or your second, determines how ill you will be. RSV invades the nasopharyngeal epithelium and spreads to the lower airways where it causes increased mucus production, desquamation, and then bronchiolar obstruction. The net effect is pulmonary hyperinflation and atelectasis. The other causes of bronchiolitis include infection with parainfluenza, influenza, adenovirus, rhinovirus, metapneumovirus, chlamydia, and Mycoplasma pneumoniae.

There is an increased risk of severe infection in infants with CHD, CLD of prematurity, immunodeficiency, and other lung disease.

In winter months infants with a typical history will have had coryza, followed by a dry cough, followed by worsening breathlessness. Other features in the history include:

Rarely, other presenting histories in babies include:

A thorough examination is needed in order to assess the degree of respiratory distress:

Key investigations include:

The treatment of RSV bronchiolitis is mainly supportive and includes:

Antiviral therapy with ribavirin should be reserved for immunodeficient patients and those with underlying heart or lung disease, although its benefit is uncertain.

Palivizumab is a monoclonal antibody to RSV and can be used as prophylaxis. Preterm babies and oxygen-dependent infants at risk of RSV infection can receive a monthly IM injection (for 5mths starting in October) to reduce risk of hospitalization and the need for mechanical ventilation.

Recurrent cough, wheeze, and tachypnoea may occur after RSV infection. These may require treatment and are best assessed in outpatients. Daily oral montelukast granules can sometimes help reduce the symptoms. A proportion of patients may develop asthma—they may have been predisposed to develop this problem irrespective of RSV in early infancy.

Pneumonia is an infection of the lower respiratory tract and lung parenchyma that leads to consolidation. Viruses alone account for 14–35% of all community acquired pneumonia in childhood. In 20–60% of children a pathogen is not found. Common infecting bacterial agents by age are:

Certain groups of children are at risk of pneumonia, e.g. those with:

The patient may have had a recent URTI and may also be complaining of pleuritic chest pain or abdominal pain. The typical history will have:

Check for the following:

The investigations that help in diagnosis include:

See Box 9.2 for summary of investigations.

There are a variety of changes ranging from lobar consolidation to the mere presence of patchy bilateral infiltrates. In general, routine CXR is not needed in children with mild uncomplicated LRTI. In other cases, look for pleural effusions, fluid levels, apparent round pneumonia, cavitation, hilar adenopathy, and any calcification. At follow-up, patients with history of significant acute X-ray change (e.g. lobar collapse, apparent round pneumonia, empyema) or continuing symptoms will require repeat X-ray.

Oral antibiotics are safe and effective in the treatment of community- acquired pneumonia. IV antibiotics are used in children who cannot absorb oral antibiotics or in those with severe symptoms. The specific choice of antibiotic is based on the following:

Consider whether any of the following are needed:

Chest physiotherapy is generally not beneficial in children with pneumonia and should not be performed.

The presence, in association with pneumonia, of a small effusion that does not cause any respiratory distress can be managed conservatively without the need for aspirating a sample. A fluid sample, however, is needed if there is:

After US of the chest and checking blood-clotting studies, a small chest drain (or pigtail drain) should be inserted into the pleural fluid unless effusion is small. Samples should be sent for the following:

The diagnosis of empyema can be based on the presence of:

After inserting the small-bore drain or pigtail catheter, fluid should be allowed to drain into standard commercially available systems (e.g. water-seal two-bottle system). The drain can be removed if draining <50mL in 24hrs.

In empyema, as opposed to simple pleural effusion, instillation of urokinase via the chest drain is recommended.

If the effusion or empyema fails to resolve over a period of 7 days then a surgical opinion may be sought. Sometimes a chest CT scan is needed . A definitive surgical procedure or large bore drain and manual disruption of loculation may be needed.

Worldwide, tuberculosis of the lung is a major health problem. TB should always be considered in children from endemic areas, as well as those at risk of immunodeficiency or taking immunosuppressive agents. Once diagnosed, TB is a notifiable disease and contact tracing is required so that those exposed to the patient undergo tuberculin testing and CXR screening. BCG vaccination appears to be protective against miliary spread, but is no longer routinely given.

Mycobacterium tuberculosis is spread from person to person by droplet infection. Once inhaled, some bacilli remain at the site of entry and the rest are carried to regional lymph nodes. The bacilli multiply at both sites; the primary focus along with the regional lymph nodes are collectively described as the primary focus. Organisms can then spread via the blood and lymphatics. The pathological sequence after infection is as follows.

A rare group of disorders in childhood and children (usually infants) present with progressive tachypnoea and hypoxia. The CXR shows widespread reticular shadowing but a high resolution CT scan is needed for diagnosis. Treatment should be undertaken in specialist centres as these children will require lung biopsy and may need treatment with steroids or chloroquine. A requirement for supplemental oxygen is common.

See also  p.726. LIP has the appearance of fibrosing alveolitis, but it is a pulmonary feature of HIV infection that responds to steroids.

See also  pp.724–727. Recurrent infection of the lower airway is common in patients with immunodeficiency such as: