Symptoms and manifestations of congenital hypothyroidism

1. Causes

Primary hypothyroidism (elevated TSH), also known as sporadic cretinism or cretinism, is mainly due to abnormal development, absence or ectopic thyroid tissue during embryonic development, and multiple defects in the synthesis of thyroid hormone, including sodium/iodine pump gene defects causing iodine transport abnormalities, peroxidase defects, tyrosine deiodinase defects, thyroglobulin synthesis defects, etc., resulting in insufficient thyroid hormone secretion, leading to metabolic disorders, delayed growth and development, and mental retardation.

2. Clinical manifestations

1. Typical manifestations of primary hypothyroidism

(1) Slow growth or even stagnation, and uneven body proportions.

(2) Motor and intellectual development are delayed.

(3) Special facial features: indifferent expression, pale face, bloated face, wide and low nose bridge, wide eyes, thick lips, thick tongue that sticks out of the mouth. Rough skin, sparse and dry hair, enlarged abdomen, umbilical hernia. Deformed spine, yellow palms and soles.

(4) Hypometabolism: low body temperature, cold limbs, fear of cold, enlarged heart, slow heart rate, and dull heart sounds.

Difficulty feeding, bloating, constipation.

2. Special manifestations: ① Pseudo-hypertrophy; ② Deafness and dumbness; ③ Precocious puberty.

3. The main manifestations of endemic hypothyroidism are intellectual disability, deafness, and neuromuscular movement disorders. It can be divided into neurological type and myxedema type. The overlapping of the two types of symptoms is called mixed type.

3. Diagnosis

1. Serum thyroid hormone (T3, T4) decreases, thyroid-stimulating hormone (TSH) increases, and free T3 (FT3) and free T4 (FT4) and thyroxine-binding globulin are measured when necessary.

2. Thyroid autoimmune antibodies include thyroglobulin antibody (TGAb), thyroid peroxidase antibody (TPOAb) and TSH receptor antibody (TR-Ab).

3. The basal metabolic rate decreases, and blood cholesterol, myocardial enzymes and creatine kinase increase.

4. Thyroid B-ultrasound, 99technetium or 131I thyroid scan can help diagnose thyroid deficiency, thyroid hypoplasia and ectopy.

5. The left carpal bone anteroposterior radiograph shows that the bone age is significantly behind the actual age. Infants under 6 months old need to take knee joint anteroposterior radiographs. The electrocardiogram shows low voltage, low T wave and other changes.

6.TRH stimulation test is used to identify secondary hypothyroidism.

IV. Treatment and Prognosis

1. Iodine-added salt is an effective way to fundamentally prevent and treat endemic hypothyroidism.

2. Early diagnosis (within 3 months after birth), early treatment, adjusting the dosage according to age, paying attention to individualized dosage, and insisting on lifelong treatment can enable the child to grow and develop normally and have roughly normal intellectual development.

3. Thyroid hormone replacement therapy should start with a small dose, gradually increase to a sufficient dose, and then use a maintenance dose. L-thyroid hormone 50μg/tablet, maintenance dose: newborn 10μg/(kg.d); infant 8 μg/(kg.d); child 6 μg/(kg.d). Dry thyroid tablets 40mg/tablet, maintenance dose: 2 ~ 6mg/(kg.d).

4. Regularly review thyroid function, bone age, and monitor height, weight, etc. to guide dosage adjustments.

5. The prognosis depends on how early the diagnosis and treatment are started and whether the patient follows the doctor's instructions and persists with the treatment.