There is little known relative to the functions of the thymus. It is
most active during the growth of the body, attaining its greatest
weight from the eleventh to fifteenth years, after which it gradually
atrophies, though a certain amount of the tissue remains throughout
life. There is usually a gradual atrophy of the organ after puberty,
associated with increase of connective and adipose tissues. In cases
where it does not atrophy, there is often hyperplasia of the entire
lymphatic system in the body.
There is some relationship between the thymus and sexual organs, and in
experiments where the organ has been removed, ossification is delayed,
muscular weakness and tremor occur, there is hyperplasia of the
thyroid, parathyroids, and adrenals, and general cachexia, acidosis,
and mental deterioration take place.
The inferior thyroid and internal mammary arteries from above, and
the pericardiophrenic from below, comprise its arterial supply. The
nerve supply is from the sympathetic, vagus, and possibly the phrenic.
In cases of exophthalmic goiter there is frequently an associated
enlargement of the thymus, which may be shown by the X-ray, due to
failure of normal involution or a renewal of growth, that may be
definitely influenced by adjustment of the osteopathic lesions.
In some of the acute infections as pneumonia the thymus may atrophy
with some fatty degeneration and increase of connective tissue. This
also occurs in starvation. If the condition is not of long standing
recovery will take place.
In =status lymphaticus= there is hyperplasia of the thymus and
enlargement of the lymphoid tissue of the body, and hypoplasia of the
cardiovascular system. This is a constitutional defect, so that slight
injuries or infections may prove fatal. It is found in some cases that
there is hypoplasia of the chromaffin system. Whether this latter
condition is primary or secondary has not been settled.
In males the secondary sexual characteristics are not fully developed.
The figure resembles the feminine type. The skin is pasty, and the
beard is lacking or but little developed. In females the distribution
of the hair may be somewhat similar to the male sex, slender limbs and
chest, and disturbances of the menstrual function are noticeable.
The thyroid, thymus and lymphatic tissues are usually enlarged, while
there is hypoplasia of the adrenals and chromaffin system.
The condition is met with in children who have a weak muscular system,
increased adipose tissue, pasty complexion, enlarged tonsils and
adenoids, and frequently are anemic. In children where the thymus is
enlarged there may be excessive lymphocytosis.
The enlarged thymus may compress the trachea, interfering with
breathing so that cyanosis and temporary loss of consciousness occur.
Young children may die in the attack, probably due to compression
of the trachea or to heart shock. Death in adults has occurred from
trifling injuries, shocks, infections, and anesthesia. The underlying
cause is probably a constitutional weakness.
=Diagnosis= is made from the clinical signs, percussion of the thymus
and the X-ray picture, although these may not be positive. An excessive
lymphocytosis is suggestive.
=Treatment= should consist of good general care of the patient,
avoidance of injuries and shocks as far as possible, and careful
attention to all lesions, especially of the upper chest and neck.
By following this plan the child may overcome the condition. X-ray
treatment is being employed with success in some cases. Operations
have been successful in thymic hyperplasia where it has complicated
exophthalmic goiter, and also in serious mechanical pressure in
children.