What is myxedema

Myxedema is mainly caused by thyroid dysfunction or hypothyroidism. Patients with hypothyroidism often experience edema, which is caused by the metabolic disorder of mucus substances in the body. Myxedema has a direct relationship with the thyroid gland. The main clinical symptoms are fear of cold, loss of appetite, body temperature lower than normal, weight gain, and decreased intelligence. Severe cases can cause bradycardia or heart enlargement.

Causes

Hypothyroidism may be caused by abnormalities of the thyroid gland itself, the pituitary gland, or occasionally the hypothalamus; those related to the thyroid gland include certain drugs (radioactive iodine, antithyroid agents, lithium, para-aminosalicylic acid); neck radiation therapy, thyroidectomy, and Hashimoto's thyroiditis.

Pathogenesis

Primary pituitary disease or damage causes decreased secretion of thyroid stimulating hormone (TSH), which can also lead to secondary thyroid insufficiency. Common cases include pituitary tumors and partial pituitary removal and postpartum pituitary necrosis (Sheehan syndrome). Similarly, hypothalamic dysfunction leads to a decrease in the secretion of thyroid-releasing hormone, thereby reducing the secretion of pituitary TSH, which can also cause secondary thyroid dysfunction.

Clinical manifestations

1. Cretinism: Symptoms appear within a few weeks after birth. Symptoms include low basal metabolic rate, less activity, fear of cold, loss of appetite, slow reaction, and body temperature below normal. Physical development is delayed, with uneven dwarfism, intellectual development is retarded, eyelids are wide, the distance between the eyes is widened, the nose is sunken and flat, the lips are thick and the tongue is large, the eyelids are swollen, the hair is coarse and brittle, the skin is sallow, dry and scaly, and there is non-pitting edema, a short neck, a distended abdomen, short and thick limbs, reduced muscle tone, and a hoarse cry.

2. The clinical manifestations of juvenile myxedema vary with the age of onset. The disease in young children is generally similar to cretinism but milder. In older children or adolescents, the disease is mostly similar to adult myxedema, but is accompanied by varying degrees of growth retardation.

3. Adult myxedema causes decreased sweating, fear of cold, fatigue, poor appetite, weight gain, intellectual impairment, low body temperature, apathetic facial expression, swollen cheeks and eyelids, pale complexion, anemia, ivory-colored skin, dry, rough, scaly and thickened skin, especially on the arms and thighs, non-pitted myxedema, sparse and fine outer eyebrows, loss of axillary and pubic hair, slow-growing and brittle nails with vertical and horizontal stripes, sparse and brittle teeth, muscle relaxation and weakness, bradycardia, heart enlargement, pericardial effusion, and severe cases may lead to coma.

complication

Muscle relaxation, bradycardia, cardiomegaly, and pericardial effusion may occur.