• Knowledgebase: Information on Specific Illnesses

    Here you will find discussions of specific illnesses and their management.

    58. Down Syndrome - Top

    Definition
    A chromosome abnormality resulting in mental retardation and other abnormalities.

    Causes, Incidence and Risk Factors
    In most cases, Down syndrome is caused by an extra chromosome 21. Downs children have a widely recognized characteristic appearance. The head may be smaller than normal (microcephaly) and abnormally shaped. Prominent facial features include a flattened nose, protruding tongue, and upward slanting eyes (Mongolian slant). The inner corner of the eyes may have a rounded fold of skin (epicanthal fold) rather than coming to a point. The hands are short and broad with short fingers and often have a single palmar crease (simian crease). Retardation of normal growth and development is typical and most affected children never reach average adult height. The average mental age achieved is 8 years old.
    Congenital heart defects are frequently present in these infants. Early mortality is often a result of cardiac abnormalities. Gastrointestinal abnormalities such as esophageal atresia (obstruction of the esophagus) and duodenal atresia (obstruction of the duodenum) are also relatively common. Obstruction of the gastrointestinal tract may require major surgery shortly after birth. Children with Down's syndrome also have a higher than average incidence of acute lymphocytic leukemia (ALL).


    Symptoms
    decreased muscle tone at birth
    sutures - separated
    asymmetrical or odd-shaped skull
    round head with flat area at the back of the head (occiput)
    small skull (microcephaly)
    slanting eyes, unusual for ethnic group (often called Mongolian slant or upward slant)
    small mouth with protruding tongue (see tongue problems)
    broad short hands
    single crease on the palm (simian crease)
    retarded growth and development
    delayed mental and social skills (mental retardation)
    iris lesion (an abnormality of the colored part of the eye, called Brushfield spots)
    Signs And Tests
    A heart murmur may be revealed by listening to the chest with a stethoscope (auscultation). Characteristic abnormalities are revealed by a physical examination.
    Inability at birth to pass a tube from the nose into the stomach may indicate obstruction of the esophagus (esophageal atresia) while early and massive vomiting may indicate obstruction of the duodenum or lower segments of the gastrointestinal tract.
    Tests include:

    physical exam (diagnosis often suspected and made by examination)
    chromosome studies (demonstrates three 21-chromosomes)
    X-ray, chest (to determine presence of cardiac abnormalities)
    echocardiogram (to determine nature of cardiac abnormality)
    ECG
    X-ray, gastrointestinal (to determine obstruction if symptoms are suggestive)



    Treatment
    There is no specific treatment for Down syndrome. Special education and training is offered in most communities for mentally handicapped children. Specific heart defects may require surgical correction. The potential for visual problems, hearing loss, and increased susceptibility to infection will require screening and treatment at appropriate intervals.

    Expectations (Prognosis)
    The normal life span is shortened in Down syndrome by congenital heart disease and by increased incidence of acute leukemia. The average mental age achieved is approximately 8 years old.

    Complications
    vision problems
    hearing loss
    increased incidence of acute leukemia
    frequent ear infections
    increased susceptibility to infection
    gastrointestinal obstruction (imperforate anus, and similar problems)
    cardiac abnormalities
    esophageal atresia
    duodenal atresia
    other gastrointestinal abnormalities
    - Updated: March 5, 2001

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    • James L Horwitz, MD

    David C. Thomas, MD

    Barbara Lindberg, PNP