Cretinism


What is Cretinism?

Cretinism is a congenital disorder meaning it is present at birth. In this disorder, there is reduced or absent thyroid function as well as the production of thyroid hormone. If this condition is not treated in time, it may result in severe stunted mental and physical growth of a baby. The condition is also referred to as congenital hypothyroidism.

In order to understand how this condition manifests, it is paramount to look at how the thyroid gland functions.

Cretinism Causes


Thyroid Gland – What is it?

This is an organ that is located within the lower part of the neck and it is butterfly shaped. This gland has the crucial function of producing the thyroid hormone also known as thyroxine (T4). In this hormone, there is presence of iodine, a substance that helps in the regulation of growth, in brain development, and in regulating body metabolic activity.

Cretinism Causes

While the exact cause of cretinism is not known, it is thought that genetic mutation is responsible for the disorder. The abnormalities in genes involve the production of enzymes, which are required for the synthesis of thyroid hormone to take place. Some of the possible causes of cretinism are

Hereditary

It is believed that the a small number of patients with cretinism have acquired genes, which make the thyroid gland to synthesis less than the required hormones. The anomalous genes will be acquired, but there is no any detected abnormality regarding the shape and size of the thyroid gland.

Cretinism causes genetics

A misplaced or missing thyroid gland

A majority of babies having cretinism will have their thyroid either underdeveloped or absent. While it is not known why this kind of birth defect occurs, the thyroid may be seen in a different location. For example, it may be found on the side of the neck or under the tongue.

Usually, in normal situations, thyroid gland is found at the center of the neck in front, particularly close to the top side of the windpipe. In other patients, the gland appears to be smaller than its normal size.

Whenever there are abnormalities like these occurring in a newborn, the result is less production of thyroid hormone or no hormone at all. The point to mention here is that this defect does come about as a result of inherited genes.

Iodine deficiency in pregnancy

When maternal iodine levels are insufficient, there is less production of thyroid hormones. Too much iodine presence on the mother during pregnancy may also affect the thyroid of the fetus.

Medication & thyroid problems during pregnancy

If the mother is diagnosed with problems of the thyroid, it could contribute to cretinism on the newborn. Also, if the mother had a treatment using anti-thyroid drugs, it could also attribute to the condition.

Dysfunction of hypothalamus or pituitary gland

If the pituitary gland does not function properly, this may affect the ability of thyroid gland to produce hormones. Some of the conditions that could result in cretinism due hypothalamic related causes are such as congenital defects, ischemic damage, and presence of tumors.

Signs & Symptoms

In most cases, the newborns show no symptoms at time of birth, and if they do, the symptoms are mild. It is for this reason that doctors use screening techniques to determine if there is presence of congenital hypothyroidism or cretinism. Among the signs and symptoms of this condition are:

  • The face of the newborn looks puffy, dull, and tends to have slow reaction
  • The tongue appears large, thick and protruded
  • There is low hair line and possibly dry brittle hair
  • You may notice that the newborn has larger anterior frontier while the posterior fontanel is persistent
  • Skin discoloration, usually appearing yellowish- a condition known as jaundice
  • A belly button that is protruding
  • Edema
  • Decreased muscle tone, commonly known as hypotonia
  • Low temperature or hypothermia
  • A low, hoarse cry
  • Inconsistent weight gain
  • Poor growth or short stature
  • Heart related problems such as slow pulse or abnormalities of the heart valve
  • Difficult with breathing – also known as dyspnea
  • Decreased activity of the newborn
  • Excess sleeping
  • Choking
  • Infrequent bowel movement or constipation
  • Undesirable feeding patterns

Diagnosis

Various methods are used to diagnosis this condition and they include:

Screening test

A test to help detect if there is presence of genetic and metabolic disorders is ordered by a doctor. The heel-prick method is used to obtain blood samples for screening. This test helps detect the disorder so as to prevent complications such as mental retardation, physical disabilities, or even death of the newborn.

Test for TSH or thyroxine levels:

If there is low levels of thyroxine or T4 and high levels of TSH, these could confirm cretinism or congenital hypothyroidism.

Imaging

A thyroid scan or technetium is ordered by a doctor to help determine if there are any structural abnormalities involving the thyroid gland. The aim of this imaging procedure is to distinguish if the condition is being caused by organification defects or congenital absence. When you talk about organificaiton, it is the process that is required to necessitate the synthesis of thyroid hormone.

Apart from the scan, the newborn may require X-rays. The X-rays are performed on the legs of the baby to view the ends of the bone at the joints of the knee.

Treatment

A child who is suspected to have cretinism requires early diagnosis and treatment. The first screening and tests can be done a few hours following the birth of the newborn. It is possible to prevent the brain and the nervous system from being effected by cretinism if the diagnosis is done within two weeks following the birth of the newborn. Some of the treatment options that may be applied are:

Thyroid hormone replacement

Thyroxine may be administered to the newborn. The newborn may have to get this treatment for the rest of their life, and its dosage could be increased gradually as the baby grows up.

Close monitoring of the condition

It important for the mother to make sure there is regular visit to the doctor for the child’s height, weight, development as well as general health to be examined. Blood tests are conducted occasionally to find out the level of the thyroid hormone.

Mental development of the baby is also monitored including the motor ability, personality behavior, communication, language, and adaptive behavior. The developmental growth of the child is also evaluated to determine any signs of delays in learning and speech.

Diet

Iodine supplements may be recommended to help in preventing damage of the brain. The newborns may also receive soy-based formulas as well as iron medication.

Physical activity

A child with cretinism is encouraged to have physical activities to help develop their motor skills.

Cretinism can lead to complications such as permanently diminutive physical development, abnormally enlarged thyroid gland- a condition known as goiter, and impaired mental abilities. Children who receive treatment during the first few weeks to months are likely to have normal intelligence. However, delayed treatment or no treatment could result in intellectual disability or delayed growth.

Proper screening of newborns could assist in detecting the disorder within the first trimester of pregnancy. Having adequate iodine by a pregnant mother could also help in preventing cretinism occurring in infants.

Reference List

  1. Cretinism. http://emedicine.medscape.com/article/122714-clinical
  2. http://howshealth.com/cretinism/
  3. http://www.primehealthchannel.com/cretinism.html
  4. http://www.medicinenet.com/script/main/art.asp?articlekey=6551
  5. https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/cretinism
  6. https://www.youtube.com/watch?v=LQIZqQ0VCBI
  7. http://www.differencebetween.info/difference-between-dwarfism-and-cretinism

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