Myxedema or severe hypothyroidism is clinical condition where the thyroid gland does not produce any thyroid hormone. In some cases, myxedema condition is also being referred to as underactive thyroid. Myxedema typically present with a distinct facial appearance, hoarse slow speech, and dryness of the skin.
The symptomatology of myxedema varies depending on the severity of the hormonal deficiency. In general, the hormones progress in severity with age and starts to worsen with each passing year. Mild symptoms of myxedema like weight gain and fatigue hallmarks the beginning of the progression of the disease. The chronic decrease in body metabolism gives rise to more obvious symptomatology like:
Myxedema in children happens when the infant is born without a thyroid gland. Infants with hypothyroid will present with jaundice, protruding tongue, frequent choking, puffy face, poor muscle tone, constipation, and excessive sleepiness.
Patients that have signs and symptoms of myxedema should submit for blood test for thyroid hormone quantitative analysis. Blood levels of Thyroxine (T4) usually appears low due to thyroid gland dysfunction or aplasia (absence). The levels of thyroid stimulating hormone (TSH) from the pituitary gland is usually increased as a compensatory reaction to the decreasing thyroid hormone levels in an attempt to increase its level by stimulating the thyroid gland to produce more . Women who are pregnant and those who intend to be pregnant with previous history thyroid dysfunction must submit for this thyroid test because of the risk of recurrence .
In general, thyroid deficiency in myxedema is adequately replaced by synthetic thyroid hormones like levothyroxine. The daily maintenance of oral synthetic hormones reverses the signs and symptoms of myxedema among patients . Fatigue symptoms gradually decreases within 1 to 2 weeks from the start of hormonal replacement. Treatment with oral synthetic thyroid hormones are usually given for life as maintenance.
The thyroid deficiency in myxedema is easily treated with synthetic thyroid hormones which are taken for life. Myxedema that complicates to coma and cardiovascular crisis carries a high mortality in up to 50% among those with late therapeutic interventions. Even if these myxedema complications are diagnosed and addressed promptly, mortality remains high at 25% . Factors like old age, concomitant cardiac dysfunction, sepsis, persistent hypothermia, and hypotension worsens the prognosis of myxedema crisis .
Myxedema as clinical condition that produce deficient thyroid hormones can result from a number of medical condition or event. These include:
In the United States, myxedema is a common disorder of the elderly . Myxedema or severe hypothyroid is seen in 8% of women and 2% of men beyond the age of 50 years old. In countries worldwide with no iodine food supply insufficiency, almost 8% of women above the age of 50 are suffering from myxedema.
The most common causes of myxedema internationally are autoimmune disorder and post-operation thyroid ablation. In regions with insufficient iodine supply however, iodine deficiency is the leading cause of the hypothyroid disorder. Neonatal myxedema is observed among patients with severe iodine deficiency clinically expressed as cretinism. This clinical condition abounds in the mountainous regions of Africa, Asia and South America. There are no racial predilection to the disease with women more prone in up to 4 times more than men.
The thyroid hormone is a vital hormone in the human body needed for proper cell growth or maturity, modulates other hormones, and energy production. The low energy states leads to chronic inactivity that leads to obesity if hypothyroid states in myxedema is left unabated. The decreasing rate of drug metabolism can make the patient prone to over dosage from common medications like hypnotics, sedatives, anesthetics, and morphine. Neurologic symptoms in myxedema is due to the decreased thyroid hormones triiodothyronine (T3) and thyroxine (T4) which reduces the cerebral oxygen and glucose consumption. Cardiac function is significantly depressed due to the decreased contractility of the myocytes due to the low T3 hormones that decreases available supply of adenosine triphosphate (ATP) for the heart cells .
The decrease in cardiac output and the increase in the vascular resistance may lead to signs of cardiac failure like pulmonary effusion and pericardial effusion with edema. The fluid accumulation in the lungs impairs the oxygen exchange function of the organ. Long standing low cardiac output will lead to renal insufficiency and compromises the kidney. The low serum thyroid hormonal levels decreases intestinal motility that advertently leads to megacolon, gastric atony, and paralytic ileus.
Myxedema with congenital causes are not preventable. Patients scheduled for surgical intervention for goiter and other thyroid masses should submit for close monitoring to prevent complications of hypothyroidism from ensuing. Proper dosage of thyroid drugs should always be observed to prevent untoward complications like myxedema. Mild infections of the thyroid gland like thyroiditis must ardently be treated to prevent dysfunction.
Myxedema or underactive thyroid is a medical condition where there is not enough thyroid hormone in the circulation. Myxedema is common among women beyond the age of 60 years old causing a physiologic imbalance to the body systems. Untreated myxedema leads to obesity, infertility, heart diseases, and arthritis. The therapeutic goal in the treatment of myxedema is the replacement of thyroid hormone with synthetic thyroid hormones which corrects the hormonal imbalance.