A l-year-old infant has biphasic stridor, barking cough and difficulty in breathing since 3-4 days. He has high-grade fever and leukocyte count is increased Which of the following would not be a true statement regarding the clinical condition of the child? (DNB June 2011)
|A||It is more common in boys than in girls|
|B||Subglotic area is the common site of involvement|
|C||Antibiotics are mainstay of treatment|
|D||Narrowing of subglottic space with ballooning of hypo-pharynx is seen|
Croup is a common respiratory illness in childhood.
a. It is an inflammatory condition involving the larynx, trachea and bronchi.
b. Most common site involved is subglottis.
c. Pathology-There is some degree of laryngeal inflammation, loose areaolar tissue of subglottis swells up; resulting in hoarseness, a barking cough and varying degrees of respiratory distress over time.
d. Etiology - Mostly it is viral in origin. Most common viruses involved are parainfluenzae 1 and 2. Others are influenza A and B, respiratory syncytial virus, adenovirus and measles. Bacterial super-infection can occur in cases of laryngotracheobronchitis and laryngotracheobronchopneumonitis.
e. Age - most commonly seen between the ages of 1 and 6 years with a peak incidence being around 18 months of age and the majority of cases below 3 years of age.
f. It is more common in boys than girls.
g. Laryngotracheitis generally starts with several days of rhinorrhea, pharyngitis, low-grade fever and a mild cough. Over the next 12 to 48 hours, a progressively worsening "barky" cough, hoarseness and inspiratory stridor are noted, secondary to some degree of upper airway obstruction and laryngeal inflammation. The onset is often rapid and typically in the early morning hours (e.g. 2:00 am).
h. On examination, the child will be noted to have coryza, a hoarse voice, and varying degrees of pharyngeal inflammation, tachypnea, and stridor. More severe cases may involve nasal flaring, moderate tachypnea, retractions and cyanosis. Some children with croup may not be able to maintain adequate oral intake of fluids. Alveolar gas exchange is usually riormal. with hypoxia seen only in severe cases.
i. The diagnosis is usually made on clinical grounds. Laboratory studies add little to the diagnosis of croup if bacterial infection is not suspected. White blood cell counts may be elevated above 10,000 with a predominance of polymorphonuclear cells.
j. Chest radiographs may show subglottic narrowing (in 50% of children with croup) called as "Steeple sign':
Ref. Dhinqra 5thled p 308; Mohan Bansal p 478
k. The most important diagnostic consideration is distinguishing acute epiglottitis from acute laryngotracheitis. Epiglottitis describes a bacterial infection of the epiglottis. It is most commonly caused by H. influenzae type B. In epiglottitis fever is of very high grade, patient has a toxic look, there is marked stridor and odynophagia On chest X-ray thumb sign is seen.
l. Once the diagnosis of croup is made, mist therapy, corticosteroids and epinephrine are the usual treatments. Since croup is chiefly viral in etiology, antibiotics play no role. Mist therapy (warm or cool) is thought to reduce the severity of croup by moistening the mucosa and reducing the viscosity of exudates, making coughing more productive. For patients with mild symptoms, mist therapy may be all that is required and can be provided at home.
m. For more severe cases, further intervention may be required like oxygen inhalation by mask, racemic epinephrine given by nebulizer, corticosteroids and intubation or tracheostomy.