Ghai Essential Pediatrics8th

•Heavy tapestry attracts dust and therefore, light plain cloth sheets should be used as curtains in the child's room.

•Carpets, stuffed furniture, loose clothing, wall hangings, calendars and books attract lot of dust and should be cleaned periodically.

•The bed of the child should be made of light material and should be aired regularly.

•Caressing of animal pets should be discouraged, as the child may be sensitive to their fur.

•Generally, it is not necessary to restrict the diet of the child because bronchial asthma due to food allergy is unusual.

•Adolescent patients should be advised to refrain from smoking.

•Exposure to strong or pungent odors such as wet paint, disinfectants and smoke should be minimized.

•The child should avoid attics or basements, especially if these were unoccupied and closed for some days.

Pharmacotherapy

The pharmacologicaltherapy of bronchialasthma involves use of medications that relax smooth muscle and dilate the airways and that decrease inflammation and thereby prevent exacerbations. The medications used for longterm treatment of asthma include bronchodilators, steroids, mastcell stabilizers, leukotriene modifiers and theophylline (Table 14.5).

Bronchodilators. This group of drugs provides immediate symptomatic relief. They may be short-acting and long­ acting. The commonly used short-acting bronchodilators are adrenaline, terbutaline and salbutamol. All of these have quick onset of action. Adrenaline stimulates both a and p receptors, thus having cardiac side effects. Terbutaline and salbutarnol are specific P2-agonist and hence have a few cardiac side effects. Adrenaline is given subcutaneously. The other two agents can be administered by oral or inhalation or parenteral route. Inhalation route is preferred because of quick onset of action and fewer side effects.

Long-acting beta-agonists include salmeterol and formoterol. Both these drugs are specific P2-agonist and have a longer duration of action of 12-24 hr. The onset of action is delayed by 1h-1 hr. Their safety and efficacy has been demonstrated in children above four yr of age.

Corticosteroids. Asthma is a chronic inflammatory disease of airways. Corticosteroids being potent anti-inflammatory agents, are useful for the longterm treatment. Systemic glucocorticoids used early in the treatment of acute exacerbation can lessen the need for visits to emergency department and hospitalization. The advantage of inhaled corticosteroids is application of the medication to sites where it is specifically needed, reducing the risk for systemic adverse effects.

Disorders of Respiratory System --

The commonly used inhaled steroids include beclo­ methasone, budesonide and fluticasone. Budesonide and fluticasone are considered to be superior to beclo­ methasone. The main concern with the use of inhaled steroids is the effect on growth. An approximately 20% reduction in growth velocity during the first year of treatment with inhaled steroids is reported. Subsequently the growth velocityrecovers and children ultimately attain predicted adult height.

Mast cell stabilizers. Cromolyn sodium reduces bronchial reactivity andsymptoms induced by irritants, antigens and exercise. Indications for use of cromolyn includes mild to moderate persistent asthma and exercise induced asthma. It should be given at least for 6-8 weeks before declaring it ineffective. Nedocromil is another nonsteroidal drug used for control of mild to moderate asthma. Ketotifen is mast cell stabilizer. It is administered orally. Significant clinical improvement may be evident after 14 weeks of therapy.

Leukotriene modifiers. Leukotriene inhibitors are preferred agents for the treatment of mild to moderate persistent asthma and exercise-induced asthma. Leukotriene inhi­ bitors act either by decreasing the synthesis of leukotrienes (zileuton) or by antagonizing the receptors (montelukast and zafirlukast). Montelukast and zafirlukast have received approval for use in pediatric asthma. Monte­ lukast can be used in children above one year of age while zafirlukast above 12 yr of age.

Theophylline. Theophylline has concentration-dependent bronchodilator effects. The bronchodilator effect is exerted by inhibition of phosphodiesterase. In addition, theo­ phylline has anti-inflammatory and immunomodulatory effects at therapeutic serum concentration that appears to be distinct from its bronchodilator properties. Most guidelines recommend theophylline as an alternative second-line therapy in combination with inhaled gluco­ corticoids in moderate persistent asthma in older children 5 yr and younger, as a second-line therapy for mild persis­ tent asthma in older children and adult and as adjunctive therapy (largely for control of nocturnal symptoms) in moderate or severe persistent asthma.

Irnmunotherapy. This consists of administering gradually increasing quantities of an allergen extract to a clinically sensitive subject, so as to ameliorate the symptoms associated with subsequent exposure to causative allergen. This is considered only occasionally in highly selected children who are sensitive to a specific allergen such as grass pollen, mites, etc. It is done only under specialist supervision and involves longterm case.

Pharmacological Management

For optimal use of pharmacological agents one should go in a stepwise manner that includes: (i) assessment of seve­ rity of asthma; (ii) selection of medication; (iii) selection of appropriate inhalation device; and (iv) monitoring.

Assessment of severity Successful management of asthma requires grading the severity of the disease according to thefrequency andseverity of symptoms and

functional impairment. This is assessed by asking the frequency of symptoms including disturbance of sleep, effect on day-to-day activity of child and need for

medication, hospital visit and hospitalization. Result of pulmonary function tests by spirometer provides objective evidence of severity. PEFR measurement is an alternative to spirometry in day-to-day practice, in children older than 5-6 yr of age.

Children with asthma can be classified into 4 groups on the basis of information obtained from parents and PEFR measurement, i.e. episodic, mild persistent, moderate persistent and severe persistent asthma (Table 14.6).

Selection of medication After the assessment of severity, appropriate medications are selected. The stepwise treatment of asthma according to its severity is given in Table 14.7. Episodic asthma should be treated with salbutamol or terbutaline when required. If inhalation cannot be used due to any reason oral route can be used. Mild persistent asthma needs daily treatment with maintenance medication. They can be cromolyn sodium 5-10 mg by inhalation route, 6-8 hourly or inhalation steroids at a dose of 200 µg/day in two divided doses or slow release theophylline 5-15 mg/kg/day in two divided doses. The selection of either preparation is based on feasibility for inhalation, problems of compliance and cost of medications. The drug of choice in mild persistent asthma is a low dose inhaled steroid. If inhalation is not feasible due to any reason (cost of medication, not able to take inhalation) a trial of leukotriene modifiers or oral theophylline can be given. Moderate persistent asthma needs to be treated with inhalation steroid 200-400 µg/day in 2 divided doses and long-acting -agonist (formoterol, salmeterol). Montelukast can be used at this step as add on treatment for better control of asthma symptoms.

Severe persistent asthma needs inhalation steroids at the dose of 400-800 µg/day in 2-3 divided doses. For relief of symptoms long-acting -agonist and slow release theophylline needs to be given regularly. Montelukast can be used at this step as add on treatment for better control of asthma symptoms. If there is persistence of symptoms low dose prednisolone may have to be used, preferably alternate day.

Drugs used as maintenance treatment of asthma can be administered by inhalation or oral route. Drugs used by

Disorders of Respiratory System --

Table 14.7: Stepwise treatment of asthma

the inhalation route are more effective, i.e. have a rapid onset of action and have fewer side effects. Most important in the delivery of effective therapy to asthmatic children is the optimal use of appropriate inhalation devices.

Metered dose inhaler. A metered dose inhaler (Fig. 14.4) is a device, which delivers a fixed amount of medication in

Use of metered dose inhaler

Remove cap and shake inhaler in vertical direction

Breathe out gently

• Put mouthpiece in mouth and at start of inspiration (which should be slow and deep), press canister down and continue to inhale deeply

• Hold breath for 10 seconds or as long as possible; then breathe out slowly

• Wait for a few seconds before repeating the inhalation once again

Fig. 14.4: Metered dose inhaler

aerosol form each time it is activated. It can be used for exacerbation and maintenance therapy. They are effective but require considerable coordination, i.e. press and breath coordination. This may not be possible in young children. After actuation the drug comes out at a pressure and a significant amount of the drug gets deposited in the oropharynx. To overcome this problem of coordination it is used with spacer. MDIs continue to work past the labeled number of doses because of excess propellant. Therefore, a track of number of actuations should be kept to ensure that children receive adequate therapy when needed.

Metered dose inhaler with spacer. Use of spacer inhalation device with a MDI (Fig. 14.5) should be encouraged as it results in a large proportion of the medication being deposited in the lung, with less impaction in the oropharynx. They also overcome the problems of poor technique and coordination of actuation and inspiration, which occur, with the use of MDis alone. Furthermore, use of spacer allows MDI to be used for the young patient. MDI used with spacer has been found to be comparable to nebulizer in deliveringsalbutamol in acute exacerbation of asthma in children. Spacers have the limitation of being bulky, relatively costly and cannot be used in young infants and toddlers. A homemade spacer prepared from mineralwaterbottle has been shown to be equally effective in delivering salbutamol in acute exacerbation.

Metered dose inhaler with spacer with facemask. Attaching a facemask to the spacer facilitates their use in very young infants (Fig.14.6).

Dry powder inhaler (DPI). These are breathe-activated devices like rotahaler (Fig. 14.7), diskhaler, spinhaler,

Fig. 14.5: Metered dose inhaler with spacer

I

•Attach babyUsemaskoftoMDIthewithmouthspacerend ofandspacerbaby mask

•Shake MDI and insertit in the MDI end of spacer device

•Cover baby's mouth and nose with baby mask

•Press canister and encourage the child to take tidal breathing with mouth open (if possible)5-10times

•Remove baby mask and wait for 30-60 seconds before repeating the above step

Fig. 14.6: Metered dose inhaler with spacer and baby mask

turbohaler and acuhaler. They can be used in children above 4-5 yr of age. They have the advantage of being portable and eliminate the need to co-ordinate actuation with breathing. In addition they are environmental friendly, as they do not contain CFC. Moreover, the effect of powder inhalers is dependent upon a certain inspiratory flow rate and therefore, there is a risk of reduced effect

during episodes of acute wheeze or in children with low pulmonary function.

Nebulizers. Nebulizers with air compressors are bulky and inefficient aerosol delivery systems (Fig. 14.8). With the advent ofefficient spacer systems, the need for nebulizers has greatly diminished. There is a place for the use of nebulized -agonist in acute severe asthma in young irritable and hypoxic children who do not tolerate MDI used with spacer and facemask, because this allows the delivery of a large dose.

The following measures can improve the amount of drug delivered to the lung by nebulizer: the total fill volume should be about 3-5 ml. Tapping the side of nebulizer chamber during operation induces the droplets on the sides to fall back into the reservoirs, minimizing the loss. The optimal flow rate is 6-121/min; at this flow, 30-50% of aerosol in the respirable range of 1-5 mm. Creating a hole is the gas supplytube so that nebulization will occur only during inhalation, when the hole is closed, also decreases the aerosol loss. Slow, deep inhalations and breath holding can improve delivery.

It is important to select an appropriate device by which the maintenance medication has to be administered. Inhalation method should be chosen on individual basis. A rough guide is as follows:

Children below 4-yr-old: MDI with spacer with facemask can be used successfully.

For children between 4- and 12-yr old: MDI with spacer is preferred.

For children above 12-yr-old: MDI may be used directly. However, use of spacer improves drug deposition in airways.

Monitoring and modification of treatment After start­ ing appropriate treatment patients should be seen every 4-12 weeks. On each visit a detailed history regarding frequency of symptoms, sleep disturbance, physical activity, school absenteeism, visit to a doctor, need for bronchodilators (rescue drug) and PEFR is recorded. The patient or parents should be encouraged to maintain a symptom diary. Patient is assessed as controlled, partially controlled or uncontrolled (Table 14.8).

On each visit physician should examine the child, look for adverseeffectsof drugs and record height and weight.

Use of nebulizer

•Connect compressor to mains

•Connect output of compressor to nebulizer chamber by the tubings provided

•Put measured amount of drug in the nebulizer chamber and add normal saline to a total of 2.5-3 m

•Switch on the compressor and look for aerosol coming out from other end of the chamber

•Attach face mask to this end of nebulizer chamber and fit it to cover nose and mouth of the child

•Encourage child to take tidal breathing with open mouth

Fig. 14.8: Nebulizer

Pulmonary functions/PEFR should be measured in older children. Inhalation technique and compliance should be checked each time.

If disease is partially controlled or uncontrolled the causes could be poor compliance, wrong technique of inhalation, continueduseofemptycanister, inappropriate doses, infection (otitis media, sinusitis, pneumonitis) continued exposure to allergens or under assessment of illness. Many asthmatic childrenhaveallergic rhinitis and its treatment has a beneficial effect on asthma. Asthmatic children also have a higher incidence of sinusitis, which may trigger asthma. Bronchial hyper-responsiveness and asthma symptoms improve with therapy for these upper respiratory diseases.

If no cause is found a step up, i.e. increase in dose and frequency of medication, is required. Therapy can be stepped down if control is sustained for 3-6 months and follow a gradual stepwise reduction in treatment.

Exercise Induced Bronchoconstriction

Some children in addition to varying severity of asthma may develop bronchoconstriction after exercise. To avoid

FEVl forced expiratory volume in first second; PEFR peak expiratory flow rate

Uncontrolled

3 features of partly controlled asthma in any week

unpleasant experience they avoid participation in outdoor games. These children may be treated with appropriate stepwise management, may require additional medi­ cations like short and long-acting beta-agonists or leuko­ triene modifiers. Short-acting beta-agonists should be taken before going for exercise, as their duration of action is short. Long-acting beta-agonists can be taken in the morning and they continue to prevent exercise-induced bronchoconstriction throughout daytime. Leukotriene modifiers are alternative to long-acting beta-agonists.

Seasonal Asthma

A small proportion of children get symptoms of asthma for a shorter period in a particular season. They remain asymptomatic for the rest of the year. These children can be started on maintenance treatment 2 weeks in advance. Medications are selected according to severity of asthma. These children should be examined again after discon­ tinuing the medications after the season is over.

Education of Parents

Education of parents is an important aspect of asthma treatment. A description of the pathogenesis of asthma in plain language shouldbe made. It needs to be emphasized that there is a wide spectrum of severity of asthma and that most children can lead active and normal lives. Parents also need to be involved in the steps required to minimize exposure to potential environmental triggers. Parents are also asked to maintain a record of daily symp­ toms such as cough, coryza, wheeze and breathlessness. A record of sleep disturbances, absence from school due to illness and medication required to keep the child symptom free is advised. These records help in stepping up or down the pharmacotherapy of the asthmatic child.

The parents should understand how the medicines work and how to take the medicines including the use of spacer and also the potential harmful effects of drugs. Those concerned about the use of steroids need to be reassured that in the conventional inhalation dosage, the risk of serious asthma out weights the side effects of medication.

Peak flow monitoring done properly by informed parents can help by: (i) detecting early deterioration in lung func­ tion; (ii) managing asthma in patients who have difficulty in sensing the changes in severity of airway obstruction; and (iii) managing patientswhose asthma severity changes very rapidly.

Home Treatment of Acute Exacerbation

An important part of health education is instructing the parent/patient on how to recognize and manage acute exacerbation of asthma at home. A written action plan should be given to them. Acute exacerbation can be identi­ fied by increase in cough, wheeze and breathlessness. PEFR, if measured, may be decreased by 15% from the baseline. For acute exacerbation parentsshould administer short-acting 2-agonists by MDI± spacer± facemask, one

puff at a time, repeated every 30-60 seconds up to a maximum of 10 puffs with monitoring of symptoms. If symptoms are relieved and PEFR is increased at the end of inhalation the child can be continued on salbutamol or terbutaline every 4-6 hr and a visit to treating physician is planned. If there is no improvement or partial improve­ ment or there are symptoms of life threatening attack at any time, the child should be immediately transferred to a hospital.

Administration of a single dose of prednisolone (1-2 mg/kg) before going to hospital is advised in patient with symptoms of life threatening asthma or lack of satis­ factory improvement after inhalation therapy at home.

Management of Acute Exacerbations

Increase in the symptoms in form of cough, wheeze and/ or breathlessness is termed as exacerbation of asthma. The severity of exacerbation is variable and can be classified as mild, moderate, severe or life threatening on the basis of physical examination, measurement of PEFR/FEVl and oxygen saturation (Table 14.9).

Management of Life-threatening Asthma

Such patients should immediately receive oxygen inhalation. An injection of terbutaline or adrenaline is given subcutaneously, inhalation of salbutamol or terutaline and ipratropium is started, and hydrocortisone 5 mg/kg isgiven IV and arrangement made to transfer the patient to ICU preferably with an accompanying physician.

If the patient shows improvement, the salbutamol or terbutaline inhalation is continued every 20-30 min, hydrocortisone (3-5 mg/kg) is continued every 6-8 hr till patient starts accepting orally. If patient does not improve or deteriorates, a slow IV infusion of magnesium sulphate (50 mg/kg) is given over 30 min. Alternatively, a loading dose of theophylline is infused. If there is no improvement with this management, patient is prepared for mechanical ventilation. Patient is also screened for causes of poor response such as acidosis, pneumothorax, electrolyte imbalance and infection.

Mild Acute Asthma

Such patients should be given 2-agonists by nebulizer or MDI + spacer with or without face mask. One puff of the medication may be given every minute up to 10 puffs. If case of significant improvement the patient can be sent home on inhalation or oral beta-agonists every 6-8 hr along with general instructions and called back after 1-2 weeks for reassessment and longterm treatment. In case of no response or poor response the patient should be treated as moderate exacerbation.

Acute Moderate and Severe Asthma

Such patients should be treated with inhalation beta­ agonist as described in treatment of mild asthma. It is repeated every 20 min, oxygen inhalation is begin and oral

dose of prednisolone 1-2 mg/kg is given. At end of one hour the patient is assessed for improvement. In case of improvement the child is continued on inhalation of2-agonists every 30 min and the interval is gradually increased to every 4 6- hr. Oxygen inhalation is stopped if able to maintain oxygen saturation of >95%. Prednisolone is continued once daily for 5-7 days and then stopped without tapering.

The patient can be discharged from hospital when the need for bronchodilators is every 4--6 hourly, able to feed and speak well, maintains oxygen saturation of >95% in room airandthe PEFRis >75% of predicted. These patients should be educated about the disease, need for regular followup and avoidance of triggers. They should be assessed for longterm treatment.

In case of no improvement at end of one hour the inhalation of salbutamol is continued and ipratropium 250 µg is also added every 20 min. Hydrocortisone is administered at a dose of 10 mg/kg IV and reassessed at end of two hours. If good response the patient is treated like the early responders. If case of no response, injectable theophylline bolus followed by continuous infusion is started. Such patients may respond well to magnesium infusion at doses of 50 mg/kg dissolved in dextrose over 30 min. If no improvement these patients should be prepared for possible mechanical ventilation.

Monitoring during Acute Treatment

This includes vital signs (heart rate, respiratory rate) and for chest indrawing, oxygen saturation and sensorium.

Foreign Body Aspiration

Young children between 1 and 4 yr of age are especially prone to aspirate small objects in their air passages. The incidence of foreign body location is similar in the right andleftsides. Unlessrecognizedandtreated,these children have significant morbidity, such as recurrent wheezing, coughand pneumonia. Immediate responsetoforeignbody aspiration is achoke,gag, coughor localizedwheeze. After the initial episode, symptoms may improve for some time and the whole episode maybe forgotten. Subsequently, the course of illness depends on the nature of foreign body, its size, extent and the site of obstruction. Foreign bodies of organic or vegetable source swell up and cause more symptoms. Apartialobstruction maycause'ballvalve'type effect leading to localized hyperinflation. The overlying chest wall may show hyperresonance, diminished vocal resonance and reduced air entry. In small children, it may be difficult to elicit hyperresonance. Thus a localized area of reduced air entry in a child with chronic respiratory illnessshouldarousesuspicion ofaforeign body. Complete obstruction and surrounding inflammation cause distal atelectasisand suppuration ofthesurroundingparenchyma of the lungs. The elastic recoil of the bronchi is lost and the bronchi show segmentaldilatation with eventual develop­ ment of bronchiectasis.

These children are treated by removal of foreign body through a rigid bronchoscope. Bronchoscopy should be undertaken if the clinical and radiological features suggests the diagnosis even if the history of foreign body aspiration is not forthcoming.

Suggested Reading

Global Strategy for Asthma Management and Prevention (covering asthma care in adults and children older than 5 yr) http:// www.ginasthma.org

Kabra SK, Lodha R, Menon PR. Long term treatment of asthma. In: Essential Pediatric Pulmonology, 2nd edn., Kabra SK, Lodha R eds. New Delhi, Nobel Vision 2010;186-98

Rodriguez C, Sossa M, Lozano JM. Commercial versus home-made spacers in delivering bronchodilator therapy for acute therapy in chil­ dren. Cochrane Database Syst Rev 2008 Apr 16;(2):CD005536

Saharan S, Lodha R, Kabra SK. Management of status asthmaticus in children. Indian J Pediatr 2010;77:1417-23

Suggested Reading

Foltran F, Ballali S, Passali FM, et al. Foreign bodies in the airways: a meta-analysis of published papers. Int J Pediatr Otorhinolaryngol 2012; 76:512-9

Lung Abscess

Lung abscessin childrenis most frequently a complication of bacterial pneumonia especially those due to 5. aureus, and K. pneumoniae. It may also develop in sequestration

of lung tissue or in association with foreign bodies, bronchial cysts or stenosis. Staphylococcal lungs abscess

areoften multiple, while those complicatingaspirationare solitary. The abscess may rupture into the pleural space leading to pyopneumothorax. The main pathological changes are necrosis and liquefaction with inflammation in the surrounding lung tissue.

Clinical Features

The patient has fever, anorexia, lethargy, pallor, cough with foul smelling expectoration. Physical signs may be minimal. Amphoric breath sounds, coarse crepitations and whispering pectoriloquy are characteristic but often not elicitable. The diagnosis is confirmed by plain X-ray film, and ultrasound or CT scan of chest.

Treatment

Appropriate antibiotics to which the organisms isolated from the sputum or bronchoscopic aspirate are sensitive, areadministeredfor 4 to 6 weeks. Physiotherapyiscarried out for effective drainage of the pus. Surgical resection of the involved area of lung is indicated if medical therapy is not effective.

Bronchiectasis

Bronchiectasis is a chronicsuppurative disease characteri­ zed by destruction of the bronchial and peribronchial tissues, dilatation of the bronchi and accumulation of infected material in the dependent bronchi.

Etiology

Most cases follow recurrent episodes of respiratory infec­ tions such as bronchitis, postmeasles or postpertussis pulmonary infections, cystic fibrosis and pneumonitis in infancy and earlychildhood. Infections damagethe bron­ chial wall and cause segmental areas of collapse, which exert anegativepressureonthe damagedbronchi,causing them to dilate. The bronchial dilation is widespread and patchy. The bronchi may show cylindrical, fusiform or saccular dilatation.

Aspiration of foreign body, food, or mucus plug in the bronchus may occlude the bronchial lumen and cause segmentalareas of collapse. The bronchi are dilated due to negativepressurebythecollapsedsegment. Iftheocclusion is relieved before the stagnant secretions are infected and the bronchial wall is damaged, the bronchiectasis is reversible. Thebronchialdilatationsaregenerallysegmental orlobar. Extrinsiccompressionbytuberculouslymphnodes often causes collapse of right middle lobe.

Congenitaldisordersofbronchisuchasbronchomalacia, communicating typeofbronchial cyst orsequestratedlung may be the cause of bronchiectasis in some cases. Kartagener syndrome is characterized by bronchiectasis, situs inversus and sinusitis and is attributed to primary ciliary dyskinesia.

Cystic fibrosis is characterised by recurrent lower respiratory infections associated with malabsorption. These patients have history of meconium ileus during

neonatal period. Thisis a commoncauseofbronchiectasis in the Western countries.

Immunodeficiency syndromes may be responsible for recurrent pulmonaryinfectionsandbronchiectasis. Young syndrome patients have sinusitis, bronchiectasis and a?oospermia.

Clinical Manifestations

The onset is insidious. The respiratory infections tend to persist longer and recur frequently with waxing and waning. Oftenthe illness can be tracedback to an episode of measles or whooping cough. A history of inhalation of foreign body is usually not forthcoming as it is often forgotten. The general health is poor, with recurrent infections. The patient complains of loss of appetite, irritability and poor weight gain; clubbing of fingers is seen in chronic cases.

The most prominent symptom is cough with copious mucopurulent expectoration. Cough is more marked in some postures because of irritation of the infected secretions draining into fresh areas of lung. Likewise the cough is more marked when the child wakes up in the morning due to a change of posture. Younger children may not expectorate and often swallow the sputum. In the course of illness, the sputum may become blood streaked or even frank hemoptysis may occur.

Investigations

X-ray film of the chest shows honeycombing of the involved area indicating multiple small abscess cavities. Bronchographywhichwasconsideredasgoldstandardfor diagnosis of bronchiectasis has been replaced with high resolution computerized scan (HRCT of chest). Broncho­ scopyisundertakenwherethereisapossibilityofsurgical intervention. Sputum should be sent for culture and sensitivity. Tuberculin reaction is done to exclude tuber­ culosis. Pilocarpine iontophoresis is done for estimating sweat chloride in patients with suspected cystic fibrosis.

Prevention

Most cases follow acute respiratory infections, which are inadequatelytreated. Allpulmonaryinfectionsshould be treated promptly and adequately till the chest is clear of all signs, long after the fever has subsided. Even in ordinary pulmonary infections, airway should be kept patent by encouraging postural drainage. Measles and whooping cough should be prevented by specific immunization. Prompt medical help should be sought if there is any suspicion of inhalation of a foreign body.

Management

During acute exacerbations, bacterialinfections shouldbe controlled and airway kept clear of secretions. This is facilitated by effective cough at regular intervals and postural drainage. Assistance by a specially trained pulmonary physiotherapist may be useful. Surgical

resection of the involved area should be undertaken only in children who have marked symptoms and in whom in disease is localized. Extrinsic compression of bronchi requires surgical intervention.

Cystic Fibrosis

Cystic fibrosis (CF) is the most common life limiting recessive genetic disorder in caucasians with an incidence of approximately 1 in 2500 children born in the United Kingdom. It is less common in African Americans (1 in 15000) and in Asian Americans (1:31000). It also affects other ethnic groups such as black population with an inci­ dence of 1 in 17,000 and the native American population with an approximate incidence of 1 in 80,000.

The incidence in migrant Indian populations in the UK has been estimated between 1 in 10000 and 12000. The precise incidence of CF among Indians is unknown.

Etiology

Mutation in the gene encoding the chloride conductance channel, CF transmembrane conductance regulator (CFTR) is the underlying cause. The failure of chloride conductance by epithelial cells leads to dehydration of secretions that are too viscid and difficult to clear. The defective gene is located at long arm of chromosome 7; the most common mutation is delta F508.

Clinical Features

The features depend on age of diagnosis and treatment received. The common clinical presentation includes meconium ileus in neonatal period, recurrent bronchiolitis in infancy and early childhood, recurrent lower respi­ ratorytract infections, chroniclung disease, bronchiectasis, steatorrhoea and with increasing age pancreatitis, and azoospermia. Pancreatic insufficiency is present in >85% of CF patients (Table 14.10).

Diagnosis

The diagnosis should be suspected by the presence of a typical phenotype or family history and confirmed by the demonstration of a high sweat chloride (>60 mEq/1) on at least two occasions and/or by identifying CF causing mutations. Nasal potential difference measurements can be used as an adjunct to sweat test but is not widely available.

Management

The treatment of cystic fibrosis includes respiratory management, nutritional care, anticipation and early diag­ nosis of liver disease, diabetes and other organ dys­ function.

The principles of respiratory management include airway clearance techniques, antibiotics and anti­ inflammatory agents. The aim of nutrition management is to achieve normal growth and development. Nutritional management of CF includes the following measures:

Disorders of Respiratory System -

Table 14.10: Common clinical features of cystic fibrosis (%)

•Increasing caloricintake by encouraging parents to feed the child more frequently. If appetite is poor due to persistent infection; feeding may be given by naso­ gastric route or by gastrostomy.

•Supplement fat soluble vitamins at twice the recom­ mended doses. These should be given along with food and enzymes.

•Enteric coated tablets or spherules of pancreatic enzymes are given with each feed. Enzymes are started at doses of 1 2000IU of lipase/kg in divided doses and increased by observing improvement in malabsorption by noting weight gain, nature of stool and abdominal symptoms.

Suggested Reading

Cystic Fibrosis Foundation. Cystic Fibrosis Foundation evidence­ based guidelines for management of infants with cystic fibrosis. J Pediatr 2009;155:573-93

Flume PA, Mogayzel PJ Jr, Robinson KA, et al. Cystic Fibrosis Foun­ dation Pulmonary Therapies Committee. Cystic fibrosis pulmonary guidelines: pulmonary complications: hemoptysis and pneumothorax. Am J Respir Crit Care Med 2010;182:398-406

Kabra SK, Kabra M, Lodha R, et al. Cystic fibrosis in India. Pediatric Pulmonol 2007;42:1087-94

Acute Respiratory Distress Syndrome (ARDS)

It is defined as pulmonary edema not originating from the heart. Most common cause is severe pneumonia followed by sepsis. Other predisposing factors include

shock, tissue injury, aspiration, toxins, microthrombi, intravascular coagulation, uremia and increased intra­ cranial pressure.

Pathogenesis

There is increased permeability of alveolar capillary membrane leading to aggregation of leukocytes in pulmonary circulation. Mediators such as free oxygen radicals and platelet activating factors are released and injure vascular epitehlium. In the acute stage there is edema and hyaline membrane formation. Subsequently fibrosis occurs. Microthrombi formation in vessels contributes to increased pulmonary vascular resistance and right to left shunting.

Clinical Features

ARDS can occur at any age. Initially symptoms are less and lungs are clear. Later on within 6-8 hr, patient becomes breathless. After 12 hr of insult, refractory hypo­ xia occurs followed by hypercapnia. Radiologically most lung fields are affected with reticular opacities. Mortality is very high, being 50-60% even in good centers.

Treatment

Patient should be managed in an intensive care unit with cardiorespiratory monitoring and artificial ventilation. Ventilation is achieved by high PEEP or inverse ratio ventilation. The cause of ARDS should be treated simultaneously.

Suggested Reading

Saharan S, Lodha R, Kabra SK. Management of acute lLmg injury/ ARDS. Indian J Pediatr 2010;77:1296-302

Diagnostic Approach to Chronic Cough

Chronic cough can be quite distressing. Parents are concerned and often seek consultation. The diagnosis can be made in most cases by a careful analysis of the following: Age of the child; nature of cough and sputum; relationship to the time of posture; presence of wheezing or stridor; effect of season; response to previous therapy; state of nutrition; physical signs in the chest and presence or absence of clubbing of fingers.

Type of cough. Staccato paroxysms of cough suggest whooping cough or chlamydia infection. Barkingorbrassy cough associated with changes in the voice indicate laryngotracheal disease. In case of postnasal drip, cough appears to be like an attempt to clear the throat and described as a hawking cough. Cough of psychogenic nature has a honking character (Table 14.11).

Sputum. Purulent sputum indicates the presence of suppurative lung disease. The sputum is mucoid in cases of asthma; yellow sputum may be present in some cases due to the presence of large number of eosinophils. Hemoptysis indicates the possibility of bronchiectasis,

Table 14.11: Causes of chronic cough in relation to age at presentation

tuberculosis,rnitralstenosis, cysticfibrosisor foreignbody in the bronchus.

Wheezing. Wheezing is indicative of asthma.

Seasonal cough. Chronic cough, which is more common in certain seasons during the year should arouse the suspicion of asthma. Chronic cough occurring only in winter months is usually indicative of viral etiology.

Nutrition of the child. Severe nutritional disturbance in association with chronic cough is found is cases of tuberculosis, bronchiectasis, pertussis, cystic fibrosis, severe chronic asthma or immune deficiency syndromes.

Investigations

Chest X-rayfilm, examination of the sputum, bloodcounts and tuberculin test may be necessary for arriving at a definitive diagnosis. Bronchoscopy may be necessary in some cases. CT scan of chest is noninvasive important investigation.

Management

Bronchial asthma should be excluded before evaluating other causes of cough. Any predisposing factor(s) should be managed.

Nonspecific therapy. Cough suppressants are preferably avoidedin children. Theseare indicatedonly, if the cough is dry and exhausting or, if it disturbs sleep and prevents adequate nutrition, e.g. in whooping cough. Dextro­ methorphan is an effective cough suppressant and is non­ habit forming. Physiotherapy, e.g. chest clapping, vibrations and postural drainage are useful in facilitating removal of bronchial secretions. Bronchodilators are useful in the treatment of children with cough due to occult asthma because of retained tracheobronchial secretions. Muco­ ciliary transport of secretionsis helped by beta-adrenergic agonists and thexanthinegroupof drugsboth inasthmatic as well nonasthmatic children with chronic bronchitis.