87- What are the differences between neurological and myxedematous cretin?
Endemic cretinism can manifest as either neurological or myxedematous
cretinism. The differences between the two are summarized in the table given
below.Parameters Neurological cretin Myxedematous cretin
Mental retardation Severe Less severe
Deaf-mutism Present May be present
Squint Present Absent
Cerebral diplegia Often present Absent
Linear growth Usually normal Severe retardation
Myxedematous features Absent Present
Goiter Present Absent
Thyroid function tests Normal Hypothyroid
X-ray knee Normal Epiphyseal dysgenesis
Therapy Rehabilitation L-Thyroxine- Why do some individuals with severe iodine defi ciency develop myxedematous
cretinism , while others develop neurological cretinism?
Severe maternal and fetal iodine defi ciency results in endemic cretinism and
may manifest as neurological or myxedematous cretin. The exact cause for
variation in the presentation of endemic cretinism is not known; however, it is
thought that clinical manifestation of endemic cretinism is the result of two
pathophysiologic events. Severe thyroid hormone defi ciency (as a consequence
of severe maternal and fetal iodine defi ciency) during early intrauterine period
results in impaired brain development and, consequently, irreversible neuronal
damage. This occurs in both variants of endemic cretinism. Subsequent mani-
festation as either neurological or myxedematous cretinism depends on the
response of thyroid gland to severe iodine defi ciency, i.e., either goiter or atro-
phy. Those who develop goiter (and consequently compensated euthyroxin-
emia) manifest as neurological cretins, whereas those with thyroid gland
atrophy (and consequently severe and persistent hypothyroxinemia) manifest
as myxedematous cretins. It is speculated that environmental factors like sele-
nium defi ciency and exposure to thiocyanate may modulate thyroid gland
response to iodine defi ciency. However, it should be noted that some individu-
als have features of both neurologic and myxedematous cretinism (mixed
cretin).
3 Thyroid Disorders in Children