Hypothyroidism

Introduction Hypothyroidism is a syndrome in which thyroxine secretion is insufficient or insufficient. The causes include: 1 substantial thyroid disease, such as thyroiditis, excessive destruction of glandular tissue caused by surgery or radioisotope treatment, abnormal development, etc.; 2 thyroxine synthesis disorders, such as long-term iodine deficiency, long-term antithyroid drug treatment, congenital Thyroid hormone synthesis disorder, idiopathic hypothyroidism caused by an autoantibody (TSH receptor blocking antibody); 3 pituitary or hypothalamic lesions.

Cause

1. Congenital thyroid hypoplasia: a hereditary disease, but its genetic characteristics are not clear, often familial, siblings can occur at the same time. Most of them are partial thyroid dysplasia. Radioisotope scan can reveal residual thyroid tissue in the neck, sometimes ectopic thyroid. Occasionally, the mother may develop an autoimmune disease, receive 131 I treatment or other harmful substances to cause fetal thyroid development disorders.

2. Large goiter: mostly hereditary, called familial goiter large cretinism. Due to abnormal synthesis or metabolism of thyroxine. The anomalies can occur in 8 different stages, but some defects have only been reported in one or two families.

(1) Thyroid uptake or transport of iodine disorders: It may be that the defect of the enzyme causes the "iodine pump" function of the iodide to enter the cell to be abnormal, and the iodine absorption rate and the salivary iodine/plasma iodine ratio are lowered.

(2) Defects in iodine organication: The peroxidase deficiency causes the thyroid gland to fail to change the inorganic iodide into organic iodine, and the perchlorate excretion test is abnormal. There are many types, among which those who cause complete iodine and organic dysfunction can produce cretinism, but do not cause deafness; and incomplete iodine incomplete dysplasia for goiter and deafness, but no mental retardation (Pendred synthesis) Expropriation).

(3) Iodine tyrosine coupling defect: thyroxine synthesis disorder due to defects of complex enzyme, and urinary 131 I excretion increased.

(4) Deiodination disorder: The defect of deiodinase hindered the reuse of iodine, and it was observed that the excretion of 131 I-labeled iodized tyrosine urine increased.

(5) Abnormal thyroglobulin metabolism: thyroid globulin synthesis disorder produces abnormal iodized protein. They cannot be deiodinated and are excreted in large amounts from the urine, so the amount of iodine histidine increased in the urine, and abnormal proteins were also found in plasma chromatography.

(6) thyroxine secretion difficulties: macrophage cytoplasmic granules proteolytic enzyme defects caused by thyroglobulin decomposition release T3, T4 disorders.

(7) The thyroid gland does not respond to thyrotropin (TSH): very rare, the thyroid is not swollen, the 131I test is normal, the TSH is increased and the biological activity is normal, and the thyroid tissue metabolism test in vitro also has no response to TSH.

(8) The surrounding tissue does not respond to thyroxine: abnormal nuclear receptors prevent thyroxine from exerting its physiological effects.

an examination

1. pale, pale face and cheeks, apathy, dementia, dry skin, thickening, rough, more desquamation, non-recessed edema, hair loss, palms and hands are yellow, weight gain, a small number of patients The nails are thick and brittle.

2. Neuropsychiatric system: memory loss, mental retardation, lethargy, unresponsiveness, anxiety, dizziness, headache, tinnitus, deafness, nystagmus, ataxia, slow sputum reflex, prolonged Achilles tendon reflex, severe dementia , stiff and even drowsy.

3. Cardiovascular system: bradycardia, decreased cardiac output, low blood pressure, low heart bluntness, enlarged heart, coronary heart disease, but generally no angina, and heart failure sometimes accompanied by pericardial effusion and pleural effusion, Mild edema cardiomyopathy occurs in severe cases.

4. Digestive system: anorexia, bloating, constipation, severe paralytic ileus, gallbladder contraction and swelling, most of the patients have gastric acid deficiency leading to pernicious anemia and iron deficiency anemia.

5. Exercise system: muscle weakness, weakness, pain, rigidity, may be associated with joint diseases such as chronic arthritis.

6. Endocrine system: female menorrhagia, long-term amenorrhea infertility; male impotence, loss of libido, a small number of patients with secondary pituitary enlargement.

Differential diagnosis

Should be differentiated from anemia, congestive heart failure, etc.:

Congestive heart failure: Myocardial failure is divided into left heart failure and right heart failure. Left heart failure is mainly characterized by fatigue and fatigue, difficulty in breathing, and initial labor-induced breathing difficulties. It eventually evolves into difficulty breathing during rest and can only sit and breathe. Paroxysmal dyspnea is a typical manifestation of left heart failure, more than a sudden onset of sleep, chest tightness, shortness of breath, cough, wheezing, especially severe acute pulmonary edema and severe asthma, sitting breathing, extreme Anxiety and coughing foamy mucus sputum (typically pink foamy sputum), purpura and other symptoms of lung stagnation. Right heart failure is mainly characterized by lower extremity edema, jugular vein engorgement, loss of appetite, nausea and vomiting, oliguria, nocturia, separation of drinking water and urination. The main signs are the pulmonary bottom wet rales or the whole lung wet rales, the second sound of the pulmonary valve is hyperthyroidism, galloping and alternating veins, hepatomegaly, positive liver and neck reversal, X-ray examination with left ventricular or left atrial enlargement the Lord. Laboratory examination showed that the left heart failure had prolonged arm time, and the floating catheter measured the pulmonary artery capillary wedge compression pressure; right heart failure had prolonged arm lung time and venous pressure increased significantly.

Anemia: bad face, dizziness, fatigue, palpitations, shortness of breath, bad spirit. Most accurately, blood tests were performed and found to have lower values for red blood cells and hemoglobin than normal.

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