RESPIRATORY DISTRESS

Respiratory distress (RD) is a medical emergency suggestive of underlying hypoxia and compensatory ventilatory efforts.

Clinical indicators of RD, in order of progressive severity include: (a) tachypnea, (b) labored breathing,

TABLE 16.7: Causes of acute respiratory distress

• Respiratory causes

- Upper airway: Diphtheria, croup, foreign body

- Lower airway: Bronchiolitis, asthma

- Pulmonary: Pneumonia

- Pleural: Empyema, pneumothorax

• Cardiovascular diseases (pulmonary edema)

- Congenital heart diseases

- Pericardial effusion

- MyocarditisZmyocardiopathy

• Neurological disorders

- CNS: Meningitis, encephalitis

- Neuromuscular: Poliomyelitis, Guillain Barre syndrome

• Metabolic acidosis

- Diabetic ketoacidosis

- Renal tubular acidosis

- Dehydration

• Poisonings, e.g.

i.e. inter-/subcostal indrawing, nasal faring and use of accessory muscles, (c) cyanosis, (d) air hunger with altered sensorium, and terminally, (e) respiratory failure. Etiology: While RD is a sign of innumerable respiratory and extra-respiratory pathologies (Table 16.7), acute respiratory infections and asthma are two dominant causes in children, together accounting for gt;80% cases. Diagnosis: Etiological diagnosis depends on: (a) age of onset, (b) duration, onset and course of RD, (c) coexisting symptoms, (d) clinical examination (not limited to respiratory system only) and relevant investigations. Chest X-ray is mandatory in all cases, even in absence of clinical findings.

Management: All children with RD, irrespective of cause and severity need to be hospitalized immediately, followed by oxygen supplementation and ventilatory assistance as required. For further details, see Ch 27.2 on acute respiratory failure.

16.4.3 STRIDOR_________________________________________

Stridor is a harsh, medium-pitched inspiratory sound due to obstruction of upper airways, i.e.

Stridor is common in infants even with minor infections, due to smaller larynx, rigid cricoids cartilage and loose submucous connective tissue around glottic region. However, onset of acute stridor in a previously well child indicates life-threatening emergency.

Etiology: Acute infectious croup and foreign body are two most common causes of stridor beyond infancy, while its presence in newborn indicates congenital airway anomalies, e.g. laryngomalacia or congenital subglottic stenosis (Table 16.8).

TABLE 16.8: Causes of stridor

TABLE 16.9: Causes of wheezing

Acute stridor

• Infections: Diphtheria, acute infectious croup

• Foreign body inhalation

• Allergic - anaphylaxis, angioneurotic edema

• Hypocalcemic tetany (laryngismus stridulus)

• Psychogenic: Hysteria

PersistentZRecurrent stridor

• Developmental: Laryngomalacia

• Oro-facial: Choanal atresia, Pierre Robin syndrome

• Extrinsic airway compression:

- Quinsy, retropharyngeal abscess etc.

- Mediastinal tumors or lymph nodes

- Pulmonary lobar emphysema, lung cysts

- Retrosternal thyroid/goiter

• Intrinsic airway obstruction:

- Congenital webs, stenosis or clefts

- Tumors, e.g. papillomas

- Post-tracheostomy stenosis

• Neurological: Unilateral vocal cord palsy

Diagnostic evaluation in stridor includes:

• Detailed history, related to:

- Age of onset: Stridor is present since birth in congenital anomalies, while Iaryngomalacia manifests after 2-3 weeks. Infections and foreign body inhalation are more common in older infants and children.

± Course: Persistent stridor indicates congenital anomalies or foreign body. In laryngomalacia, stridor gradually improves with advancing age.

± Associated symptoms, e.g. barking/brassy cough or hoarse cry (croup, vocal cord palsy), drooling of saliva (epiglottitis, foreign body, quinsy), snoring (adenoidal hypertrophy), dysphagia (supraglottic lesion) and fever (infective croup, quinsy).

± Worsening factors, e.g. crying or supine position (laryngomalacia, macroglossia), during night (croup), after feeding (H-type TEF).

± Past history of upper respiratory infection (Croup), choking spells (foreign body, TEF), endotracheal intubation (vocal cord palsy, tracheal stenosis).

± Concomitant illness, e.g. atopy (angioneurotic edema, spasmodic croup), psychogenic disorders (hysteria).

• Clinical examination, specially for-

± Facial dysmorphism (congenital airway anomalies)

± Expiratory stridor (subglottic or tracheal lesions)

± Throat examination for membranes (diphtheria), cherry-red epiglottis (acute epiglottitis), etc. Throat examination should be deferred till resuscitative measures are available, in suspected acute epiglottitis, due to risk of sudden laryngo- spasm and death.

• Relevant investigations include:

± X-ray of neck (AP/lateral) to show Steeple sign, i.e. narrowed tracheal air-column in the subglottic stenosis or Thumb sign in epiglottitis.

• Hyper-reactive airway disorders (HRADs)

- Bronchial asthma

- Acute bronchiolitis

- Post-infectious wheeze (in infants)

- Tropical pulmonary eosinophilia (TPE)

- Loefher syndrome

- Environmental exposure to dust, smoke etc.

- Others - aspergillosis

• Chronic broncho-pulmonary disorders

- Aspiration pneumonia: GERD, H-type TEF

- Bronchopulmonary dysplasia

- Bronchiolitis obliterans

• Endo-bronchialZtracheal lesions

- Foreign body/aspiration

- Endobronchial tuberculosis

• Extrinsic airway compression

- Mediastinal tumors, nodes

- Aberrant mediastinal vessels

• Miscellanoeus: CCF, hysterical wheezing

± CT/MRI of neck and chest for extrinsic lesions, e.g. retropharyngeal abscess, mediastinal mass. Virtual bronchoscopy may help to detect foreign bodies in airways.

± Laryngo/bronchoscopy in persistent stridor, which is also to be used for removal of obstruction.

± Other investigations in select cases, e.g. eso- phagoscopy, to exclude external pressing lesions.

16.4.4 WHEEZING

Wheezing indicates expiratory airway obstruction, usually at the distal bronchial or bronchiolar level, due to bronchospasm, mucosal edema and/or excessive mucus production. Young children are more susceptible for wheezing due to narrower airways. Rhonchi, the auscultatory equivalent of wheeze, are almost invariably present.

Etiology: Bronchial asthma and acute bronchiolitis are commonest causes of recurrent and non-recurrent wheezing, respectively (Table 16.9). Unlike adults, infants may also wheeze during lower respiratory tract infections, e.g. pneumonia, due to transient airway hypersensitivity and narrower bronchial lumen.

Diagnostic evaluation in a wheezy child includes:

• Detailed history, specially related to:

± Age of onset: Wheezing in early infancy is most likely due to bronchiolitis or pneumonia. Asthma rarely manifests before 6 months of age.

± Similar preceding attacks indicates asthma, though tropical eosinophilia, GER and H-type TEF should also be excluded.

± Past history of viral upper respiratory infection (bronchiolitis), asthma, aspiration (GER, H-type TEF), helminthiasis (tropical eosinophilia).

± Family history of atopic disorders (asthma).

TABLE 16.10: Causes of hemoptysis

TABLE 16.12: Causes of chest pain

• Infections

- Acute: Pneumococcal pneumonia (rusty sputum)

- Chronic: TB, lung abscess, bronchiectesis

• Vascular

- Pulmonary hypertension, e.g. mitral stenosis (frothy)

- AV malformations of lung/bronchi

• Traumatic

- Chest-wall injury/bronchial foreign body

- Post-surgery/bronchoscopy

• Bleeding disorders: DIC (pulmonary hemorrhage)

• Others: Lung cysts/tumors, Goodpasture syndrome

- Environmental history of air pollution or passive smoking (allergic, asthma).

• Clinical examination, specially for:

- Growth failure (asthma, chronic lung disease),

- ENT checkup to exclude allergic rhinitis,

- Chest findings, including character of rhonchi,

- Signs of congestive cardiac failure.

• Relevant investigations:

- Blood: Eosinophilia, IgE levels (allergic)

- Nasal discharge smear: Eosinophils (allergic)

- Pulmonary function tests for asthma

- X-ray chest/sinuses to exclude infections

- Milk scan to exclude H-type TEF fistula and GERD

- Other relevant tests, especially for allergy

Important differences between two most common causes of wheezing in childhood, i.e. bronchial asthma and acute bronchiolitis are given in Table 16.17.

Other uncommon presentations of respiratory diseases in children are as follows:

Hemoptysis, i.e. expectoration of blood or blood-mixed sputum is uncommon in childhood (Table 16.10) and must be differentiated from more common hematemesis (Table 16.11) or spitting of swallowed blood in epistaxis.

Management of hemoptysis include: (a) immediate supportive therapy with airway suction, oxygen supple­mentation, blood transfusions and vasopressors, e.g. IT epinephrine or IV pitressin infusion followed by, (b) bronchoscopy to embolize bleeding vessel, if identified, and (c) treatment of primary cause.

Chest pain is a common but usually a benign complaint in childhood due to multiple causes (Table 16.12).

Chest-wall related: (commonest)

• Trauma: Accidents, heavy exercise

• Inhammatory: Costochondritis, herpes-zoster

• Compressive myelopathy

Pulmonary

• Pleural: Pleurisy, pleurodynia, pneumothorax

• Severe/persistent cough or dyspnea, e.g.

• Rare: Pulmonary infarction, tumors

Gastrointestinal

• Esophagitis, e.g. in GERD, acid peptic disease

• Sub-diaphragmatic abscess

Cardiovascular

• Pericarditis

• Coronary: Aortic stenosis, Kawasaki disease

• Others: Mitral valve prolapse, cardiomyopathies

Psychiatric

• Anxiety or panic disorder

• Attention-seeking behavior

Diagnosis is usually obvious on clinical evaluation, e.g.

(a) location of pain, (b) relation with respiration, exercise or posture, (c) history of preceding trauma/infection, and (d) associated signs of musculoskeletal, respiratory or cardiac disease, supported by relevant investigations.

Presence of syncope, dyspnea or irregular pulses along with chest pain indicates possibility of a significant cardio-pulmonary disease.

Hiccups, i.e. frequent, rhythmic clonic contraction of dia­phragm is a common but generally benign and self­limiting problem. Persistent hiccups may be due to:

• Phrenic nerve/diaphragm irritation, e.g. in basal pleu- risy/pneumonia, GERD, mediastinal tumors, etc.,

• CNS disorders, e.g. head injury or posterior fossa lesions, and

• Systemic causes, e.g. uremia or alcohol intoxication. Occasionally, acute hiccups may be caused by presence of a foreign body in ear, due to vagal stimulation. Physiological measures, e.g. breath-holding and

pharyngeal stimulation are effective in most cases, though severe intractable cases may need medical therapy with haloperidol or metoclopramide and treatment of primary cause.

16.6