ACUTE CROUP
Croup is a clinical term to describe 'a heterogeneous group of upper airway disorders, all characterized by typical
TABLE 16.16: Common causes of acute croup
Bacterial
• Acute epiglottitis (H.
influenzae)• Bacterial tracheitis (Staph. aureus)
• Diphtheria
Viral (Parainfluenza)
• Acute Iaryngotracheobronchitis
• Acute infectious laryngitis
Allergic (?)
• Acute spasmodic laryngitis
brassy or metallic cough with or without stridor, hoarseness and respiratory distress, due to variable degree of airway obstruction'.
Most of these cases are viral in origin, with diphtheria becoming a rarity in vaccination era. Common causes of croup may be classified according to site of lesion or according to the etiology (Table 16.16).
Acute epiglottitis (AE) is an uncommon but lifethreatening cause of croup, caused by H. influenzae type b (Hib) infection.
Clinically, AE is rare in infancy, with maximum incidence in 2-5 years age group.
Typically, these cases are apparently well at bedtime but wake up in night with—(a) high fever and sore throat, (b) rapidly progressive respiratory distress with stridor and drooling, (c) brassy cough, i.e. croup, dysphonia and dysphagia, (d) hyperextension of neck-a protective action to keep the airway open, and (e) cyanosis, agitation or impaired sensorium.
Throat examination reveals a swollen cherry-red epiglottis, though it should be deferred till resuscitation facilities are available as use of tongue depressor may lead to sudden laryngospasm.
Diagnosis depends on-(a) throat examination, (b) X-ray neck showing Thumb sign on lateral view and Steeple sign on AP view (Fig. 16.7), and (c) laryngoscopy in doubtful cases.
Treatment: Epiglottitis is an emergency, which requires— (a) immediate hospitalization, (b) airway maintenance with endotracheal intubation or tracheostomy, (c) fluid and electrolyte correction, and (d) antibiotics.
Anxietyprovoking interventions such as phlebotomy, venous cannulation or throat examination should be avoided until the airway is secure.IV Ceftriaxone 50 mg/kg/d q8-12hr (or cefotaxime) for 7-10 days, is the drug of choice due to rising incidence of ampicillin-resistant HiB infections. Nebulizations, steroids and racemic epinephrine are of no proven value.
Most cases recover within 2-3 days of therapy, though mortality is high (5-10%) in untreated cases.
Acute laryngotracheobronchitis (ALTB) is the commonest cause of croup in childhood, usually due to
parainfluenza viruses (75%), and less frequently by other viruses, e.g. adenovirus, RSV, etc. Secondary bacterial infection is rare.
Clinically, ALTB presents in 1-3 years age group, with a characteristic sequence of events:
• Mild upper respiratory illness with brassy cough for 1-2 days, followed by
• Progressive stridor, croup and respiratory distress, which typically worsens at night, partly relieves in day and then recurs again on subsequent nights,
• Gradually recovery in 3-7 days with residual cough. On examination, high fever is rare and throat is usually
normal. Air entry may be reduced in acute phase with few rhonchi or crepitations. Signs of hypoxia, e.g. cyanosis or altered sensorium may develop in severe cases.
Complications are uncommon (lt;15%) and include direct extension of infection, e.g. otitis media, bacterial tracheitis and bronchopneumonia. Recurrences till 5-6 years of age are common.
Diagnosis is clinical, though lateral X-ray of the neck may show Steeple sign—narrowing of tracheal air column below the glottic area. Careful throat examination for absence of cherry-red epiglottis and thumb sign on neck X-ray excludes epiglottitis.
Treatment includes:
• Humidified oxygen to maintain SpO2 gt;95%;
• Racemic epinephrine (1:1000) nebulisation as 0.5 ml/ kg, mixed with normal saline to make total volume of 5 ml (maximum dose 5 ml of undiluted solution).
Second dose may be repeated after 2 hours, if required.• Steroids, either as single dose of PO/IV dexamethasone (0.6 mg/kg) or nebulized budesonide (1 mg) twice a day for 2 days.
• Correction of fluid/electrolyte imbalance, and
• Constant monitoring.
Benefits of multiple doses of steroids are uncertain. Endotracheal intubation or tracheostomy may be needed in severe cases. Antibiotics have no role in ALTB per se, though may be given if epiglottitis can't be excluded. Sedatives are contraindicated and may mask signs of impending respiratory failure.
Acute infectious laryngitis is the more localized variant of ALTB with similar etiology and milder clinical presentation, limited to hoarseness or loss of voice without respiratory distress.
Acute spasmodic laryngitis also has similar clinical presentation with following differences:
• Absence of fever or other features of infection,
• Family history of similar episodes in some cases,
• Shorter duration of episodes
Exact cause is unknown, probably related to GER, atopy or emotional disturbances.
Bacterial tracheitis is more likely a serious complication of ALTB rather than a separate disease, due to superadded Staph. aureus infection.
Clinically, most cases are lt;3 years old and present after few days of ALTB attack with—high fever, toxic appearance, brassy cough and thick purulent secretions on endotracheal suction.
Diagnosis: Chest X-rays may show subglottic airway narrowing with ragged tracheal air-column (irregular tracheal walls) and patchy lung infiltrates.
Treatment: Apart from supportive measures, specific anti-staphylococcal therapy with cloxacillin or vancomycin is essential.
Foreign bodies (FB) are important cause of croup, stridor and sometimes accidental deaths in pre-school children, once lodged in supraglottic region or deeper airways, e.g. trachea or bronchi.
Laryngeal FB present with sudden choking, dyspnea, stridor or croup. Whistle sign—a typical whistling sound on inspiration and expiration may be present in laryngeal obstruction due to toy whistles.
Considering immediate risk of death, first-aid measures, e.g. back-blows and chest thrust maneuver in infants and Heimlich maneuver in older children may be attempted, provided: (a) FB is witnessed or strongly suspected, (b) expert help is not immediately available. (Ch 27.1.1). However, since these procedures carry a risk of converting partial obstruction to complete airway block, it is essential to obtain expert help as early as possible.
Diagnosis may be confirmed on lateral neck X-ray (d/d esophageal FB), or direct laryngoscopy, which is also required from removal. Pre-procedure tracheostomy is advisable in dyspneic children.
Bronchial FB may be asymptomatic or presents with signs of airway irritation, e.g. cough, dyspnea, blood- streaked sputum or recurrent respiratory infections.
These FB are more common on right side due to straighter right bronchus.
Clinicoradiological signs depend on the extent of obstruction with two distinct pathologies—(a) partial ball-valve obstruction, leading to distal emphysema, and (b) complete obstruction with distal collapse.
Bronchoscopic removal is the treatment of choice, preferably with a rigid bronchoscope due to wider lumen and separate oxygen channel.
Chest X-ray is essential in all these cases to determine the extent of pulmonary pathology, even after FB removal. While most collapse/emphysema improve after FB removal, persistent lesions may require lobectomy, due to risk of recurrent infections and bronchiectasis.
Laryngomalacia is the commonest congenital abnormality of larynx, characterized by developmentalfloppiness of arytenoid cartilages, epiglottis or aryepiglottic folds, leading to inspiratory airway obstruction. About 1 / 3rd of these cases also have tracheomalacia or bronchomalacia.
Clinically it presents in neonatal period with inspiratory stridor of variable intensity that worsens in supine position and relieved in prone position, with/without hoarse cry. Respiratory distress is rarely severe, though some cases with prolonged or severe obstruction may develop thoracic deformity and growth failure. Presence of coexisting GERD enhances the severity of manifestations. Diagnosis is clinical, based on postural changes in intensity of stridor and disproportionately less respiratory distress. Direct laryngoscopy may be needed to exclude other causes of stridor (Ch 16.4.3) in early infancy.
Treatment: No specific therapy is indicated, as most children outgrow it by 3-6 months of age, after growth and maturity of airways. Nursing in the prone position and slow careful feeding is enough for most cases. Endotracheal intubation or tracheostomy is rarely required.
Surgical intervention, e.g. supraglottoplasty should be considered only in very severe and persistent cases. Proton pump inhibitors may be useful in cases with associated GERD or laryngopharyngeal reflux disease.
16.8