Congenital cytomegalovirus (CMV) infection refers to a condition where cytomegalovirus is transmitted in the prenatal period. CMV is a member of the virus family herpesviridae and is the most common intrauterine infection.Human cytomegalovirus is one of the vertically transmitted infections that lead to congenital abnormalities. Others include toxoplasmosis, rubella, herpes simplex, and syphilis. Presentation
For infants who are infected by their mothers before birth, two potential adverse scenarios exist:

Generalized infection may occur in the infant, and can cause complications such as low birth weight, microcephaly, seizures, petechial rash similar to the "blueberry muffin" rash of congenital rubella syndrome, and moderate hepatosplenomegaly (with jaundice). Though severe cases can be fatal, with supportive treatment most infants with CMV disease will survive. However, from 80% to 90% will have complications within the first few years of life that may include hearing loss, vision impairment, and varying degrees of learning disability. Another 5% to 10% of infants who are infected but without symptoms at birth will subsequently have varying degrees of hearing and mental or coordination problems. CMV is the most common cause of non-genetic sensorineural hearing loss in children. The onset of hearing loss can occur at any point during childhood, although commonly within the first decade. It is progressive and can affect both ears. The earlier the mother contracts the virus during pregnancy the more severe the effects are on the fetus, similarly the incidence of SNHL is dependent on which trimester of pregnancy CMV is contracted.
Auscultation of the chest can reveal displaced heart beat and valve prolapse. There can be a heart murmur occurring during systole caused by proximity between the sternum and the pulmonary artery. Lung sounds are usually clear yet diminished due to decreased base lung capacity.Many scales have been developed to determine the degree of deformity in the chest wall. Most of these are variants on the distance between the sternum and the spine. One such index is the Backer ratio which grades severity of deformity based on the ratio between the diameter of the vertebral body nearest to xiphosternal junction and the distance between the xiphosternal junction and the nearest vertebral body. More recently the Haller index has been used based on CT scan measurements. An index over 3.25 is often defined as severe. The Haller index is the ratio between the horizontal distance of the inside of the ribcage and the shortest distance between the vertebrae and sternum. Chest x-rays are also useful in the diagnosis. The chest x-ray in pectus excavatum can show an opacity in the right lung area that can be mistaken for an infiltrate (such as that seen with pneumonia). Some studies also suggest that the Haller index can be calculated based on chest x-ray as opposed to CT scanning in individuals who have no limitation in their function.Pectus excavatum is differentiated from other disorders by a series of elimination of signs and symptoms. Pectus carinatum is excluded by the simple observation of a collapsing of the sternum rather than a protrusion.