CONGENITAL
HEART DISEASES Clinical
features Exercise
intolerance Cyanosis:
is another common symptom which concern children with particular types
of heart diseases that are defined cyanotic. The cyanosis consist in
blue-purple color of skin and mucous membrane (lips, tongue)
due to the fact that blood that t reached the organs and tissues through
the arteries is not sufficiently oxygenated. Blood adequately oxygenated
has a red color where as the less is the content in oxygen the more
the color becomes blue. There are two major causes of cyanosis: heart
causes in which venous blood because of a cardiac defect by-passes the
lungs and goes down the aorta and the arteries without being oxygenated;
lung causes in which the lung functions are impaired. There are numerous
congenital cyanotic heart diseases the most frequent of which are Tetralogy
of Fallot, complete Transposition of the Great Arteries and pulmonary
atresia. Cyanosis determines a lack of oxygen for organs and tissues
with the consequences that the child will have a reduce tolerance to
exercise, growth failure, clubbing of the fingers and toes (swelling
of ending phalanx associated with nails more convex than normal). The
physiologic reaction to cyanosis is an increase in the red blood cells
production, phenomenon called polycythemia and it is useful because
with an increased number of red blood cells the blood capacity to carry
oxygen is improved. In case of severe or long lasting cyanosis the rd
blood cells number becomes excessive, blood becomes thicker with difficulties
to flow, that can cause trouble on brain circulation. Children with
blood thicker than normal are more susceptible to dehydration that may
contribute to turn blood thicker; they should avoid hot weather and
dispose of sufficient amount of liquid. Even exposure to cold is poorly
tolerated because it increases tissues oxygen consumption. About exercise
the child must feel free to find his own limit and should never be obliged
to do physical activities he doesn¹t want to do. Sometimes
cyanosis represent a normal phenomenon. New-born have acrocyanosis (cyanosis
of the extremities) due to immaturity of the peripheral circulation
in the neonate. Even when they cry vigorously
holding the breath new-born can develop cyanosis; there can be
a suspicion of cyanosis in children who present a blue staining around
the mouth after exposure to cold o a bath with cold water ; this is
frequent in fair-haired children with pale skin because it is easy to
see the color of the venous blood through a skin without
pigment. Cardiac
murmurs are sound that are appreciated by the physician during heart
auscultation. Murmurs are present even in children with normal heart,
thus the presence of a murmur does not necessarily mean presence of
heart problem. Murmurs present in child with normal heart are called
innocent or functional murmur to distinguish them from the pathologic
murmurs which sign an heart disease, for example a valvular problem
or abnormal communication between cardiac chambers. More than 50% of
the children have an innocent murmur which is recognized on its auscultatory
characteristics and on the basis of laboratory examination performed
with ECG, chest x-ray and echocardiography. A child with an innocent
murmur has an healthy heart and can do every kind of physical activity.
Innocent murmur generally appear during puberty. Respiratory
infections are more frequent in children with heart diseases that
cause an increase in pulmonary blood flow 4atrial septal defect, ventricular
septal defect, endocardial cushion defect, patent ductus arteriosus).
This is due to the fact that increased pulmonary blood flow obstruct
the system that normally defends bronchi and lungs from infections.
Once settled, respiratory infections usually last more than in children
without heart disease. |
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