During the first days and months of life, some disorders may be immediately diagnosed. Congenital hypothyroidism, characterized by a reduced basal metabolism, an enlargement of the thyroid gland, and disturbances in the autonomic nervous system, occurs slightly more frequently in babies with Down syndrome. A routine blood test for hypothyroidism that is performed on newborns will detect this condition if present.
Several other well-known medical conditions, including hearing loss, congenital heart disease, and vision disorders, are more prevalent among those with Down syndrome.
Recent studies indicate that 66 to 89% of children with Down syndrome have a hearing loss of greater than 15 to 20 decibels in at least one ear, due to the fact that the external ear and the bones of the middle and inner ear may develop differently in children with Down syndrome. Many hearing problems can be corrected. But, because of the high prevalence of hearing loss in children with Down syndrome, an objective measure of hearing should be taken to establish hearing status. In addition to hearing disorders, visual problems also may be present early in life. Cataracts occur in approximately 3% of children with Down syndrome, but can be surgically removed.
Approximately half of the children with Down syndrome have congenital heart disease and associated early onset of pulmonary hypertension, or high blood pressure in the lungs. Echocardiography may be indicated to identify any congenital heart disease. If the defects have been identified before the onset of pulmonary hypertension, surgery has provided favorable results.
Seizure disorders, though less prevalent than some of the other associated medical conditions, still affect between 5 and 13% of individuals with Down syndrome, a 10-fold greater incidence than in the general population. There is an unusually high incidence of infantile spasms or seizures in children less than one year of age, some of which are precipitated by neonatal complications and infections and cardiovascular disease. However, these seizures can be treated with anti-epileptic drugs.
The incidence and severity of these associated medical ailments will vary in babies with Down syndrome and some may require surgery