Lung grows by progressive alveolarization,
generally before the age of 8 years. Following an infectious syndrome, a
reduced pulmonary perfusion that leads to an arrest of progressive growth
and alveolarization of the lung. Swyer-James-Macleod Syndrome generally
follows a severe bronchiolitis but has also been described following
infection by Mycoplasma pneumoniae and Streptococcus pneumoniae.