Frontal Chest X-Ray of a 3 month old female infant. The x-ray illustrates hyperinflated lungs, this results from an upper respiratory tract infection of the small bronchi and bronchioles which causes epithelial necrosis (death of cells or tissues) and initiates an inflammatory response. The edema, which is a swelling of soft tissues resulting from excess fluid accumulation, and exudate (exudate is fluid, such as pus or clear fluid, that leaks out of blood vessels into nearby tissues) result in a partial obstruction and lead to alveolar air trapping, which in turn causes the hyperinflation of the lungs. There is also bilateral peribronchial interstitial thickening, sometimes called peribronchial cuffing, this happens when excessive fluid or mucus builds up in the smaller airways of the lungs and causes localized patches of atelectasis (lung collapse) Peribronchial cuffing causes the area around the brochus to appear more prominent on x-ray. Findings: Viral Bronchiolitis RSV positive.
Bronchiolitis refers to an acute infectious inflammatory disease of the upper and lower respiratory tract that results in obstruction and inflammation of the bronchioles, which are the smallest air passages in the lungs. It is a very common cause of illness and hospitalization in young children and is much more prevalent in the winter months. It usually occurs in children below two years of age with the majority of cases presenting in infants aged between three and six months old.(1) The inflammation is caused by a viral infection with the most common culprit being ‘respiratory syncytial virus’ or RSV which is responsible for around 70 % of all bronchiolitis cases.(2) Other viruses that can cause bronchiolitis are rhinovirus, adenovirus, influenza (flu), coronavirus and human metapneumovirus.
Frontal Chest X-Ray of a 16 day old infant. This x-ray shows bilateral hyperinflation of the lungs with a flattened diaphragm. The right apical shows atelectasis (partial collapse or incomplete inflation of the lung) as do the left basal regions. Findings Severe Viral Bronchiolitis.
Bronchiolitis is often a mild disease but some infants have an increased risk to develop a more serious form that requires hospital attention and treatment, as illustrated in Image 2. Certain conditions such as, underlying congenital heart or lung defects, prematurity, a weakened immune system, low birth weight or exposure to tobacco smoke, can increase the risk of developing severe bronchiolitis. Mild symptoms of bronchiolitis are similar to those of the common cold and include, stuffiness, increased fretting, runny nose, mild cough and low-grade fever. After a few days, the cough worsens and is accompanied by wheezing on exhalation. Severe bronchiolitis is indicated by persistently increased difficulty in breathing; patients may present with an increased respiratory rate, nasal flaring, accessory muscle use and grunting. There could also be hypoxemia (abnormally low oxygen levels in the blood) apnea (periods of lack of breathing), cyanosis (blue skin and nails due to lack of adequate oxygenation), or acute respiratory failure.(3,4) If a child shows any of these respiratory distress signs, immediate medical attention should be sought.
1. Paediatric Society of New Zealand. (2005). “Best Practice Evidence Based Guideline: Wheeze and Chest Infection in Infants Under 1 Year”. The Society.
2. Papadopoulos NG; Moustaki M; Tsolia M; Bossios A; Astra E; Prezerakou A (2002). Am J Respir Crit Care Med.
3. American Academy of Pediatrics Subcommittee on Diagnosis and Management of Bronchiolitis. Diagnosis and management of bronchiolitis. Pediatrics 2006; 118:1774.
4. Scottish Intercollegiate Guidelines Network. Bronchiolitis in children. A national clinical guideline. 2006. http://www.sign.ac.uk/pdf/sign91.pdf