Signs and Symptoms of Hypothyroid
The signs and symptoms of hypothyroidism or hypothyroid are nonspecific and may be confused with those of other clinical conditions, especially in postpartum women and the elderly. Because of the variety of possible manifestations, family physicians must maintain a high index of suspicion for the disorder, especially in high-risk groups.
Patients with severe hypothyroidism generally present with signs and symptoms that may include lethargy, weight gain, hair loss, dry skin, forgetfulness, constipation and depression. Not all of these signs and symptoms occur in every patient, and many may be blunted in patients with mild hypothyroidism.
Treatment for Hypothyroid
Thyroid Hormone Replacement
Selecting appropriate agent:
Thyroid medications were once prepared from desiccated samples of ground thyroid glands from cows, and standardization was based on the iodine content of the extract rather than its T3 or T4 content. The actual thyroid hormone content of the products varied considerably from manufacturer to manufacturer, and even within products from the same manufacturer, depending on the thyroid status of the cows. Fortunately, this method of preparing thyroid hormone has been abandoned, and replacement is now accomplished primarily with synthetic thyroid hormones.
Healthy adult patients with hypothyroidism require thyroid hormone replacement in a dosage of 1.7 μg per kg per day, with requirements falling to 1 μg per kg per day in the elderly. Thus, levothyroxine in a dosage of 0.10 to 0.15 mg per day is needed to achieve euthyroid status. For full replacement, children may require up to 4 μg per kg per day.
In young patients without risk factors for cardiovascular disease, thyroid hormone replacement can start close to the target goal. In most healthy young adults, replacement is initiated using levothyroxine in a dosage of 0.075 mg per day, with the dosage increased slowly as indicated by continued elevation of the TSH level.
Levothyroxine, initiated in a low dosage in older patients and those at risk for the cardiovascular compromise that could occur with a rapid increase in resting heart rate and blood pressure. In these patients, the usual starting dosage is 0.025 mg per day. This dosage, increased in increments of 0.025 to 0.050 mg every four to six weeks until the TSH level returns to normal.
Thyroid hormone is usually, given once daily, but some evidence suggests, weekly dosing effective.
Monitoring thyroid function
In patients with an intact hypothalamic-pituitary axis, the adequacy of thyroid hormone replacement, followed with serial TSH assessments. However, changes in the TSH level lag behind serum thyroid hormone levels. Thus, the TSH level, evaluated no earlier than four weeks after an adjustment in the levothyroxine dosage. The full effects of thyroid hormone replacement on the TSH level may not become apparent until after eight weeks of therapy.
In patients with pituitary insufficiency, measurements of free T4 and T3 levels, performed to determine whether patients remain euthyroid. In these patients, the goal is to maintain free thyroid hormone levels in the middle to upper ranges of normal to ensure adequate replacement.
TSH or free T4 levels, monitored annually in most patients with hypothyroidism. Generally, once a stable maintenance dosage of levothyroxine, achieved, that dosage will remain adequate until patients, 60 to 70 years of age. With age, thyroid binding may decrease, and the serum albumin level may decline. In this setting, the levothyroxine dosage need, reduced by up to 20 percent.
As thyroid hormone has a large volume of distribution, parentral replacement is unnecessary in patients who are unable to take medication orally for a few days to a week. However, some patients may be unable to take oral medications for much longer periods. Intravenous administration, advised in these patients and in those who need to begin thyroid hormone replacement but cannot take oral medications. Only about 70 to 80 percent of an oral dose of replacement medication, absorbed. Therefore, parenteral replacement, initiated at 70 to 80 percent of the usual oral dose.
Conditions that affect Thyroid Hormone Replacement Requirements:
Thyroid hormone is highly protein bound, medical conditions, alter the amount of binding hormones and drugs that compete the process, change the amount of available thyroid hormone. The replacement dosage, changed in response to alterations in binding status.
With conditions that cause an increase in serum binding proteins, such as high estrogen states (e.g., pregnancy), oral contraceptive use or postmenopausal estrogen replacement, the dosage of levothyroxine, increased. In contrast, androgens decrease levels of thyroid binding proteins, necessitating a reduction in the dosage.
Older patients also have lower serum protein levels and require reductions in their maintenance dosage over time. A number of medications reduce the absorption of thyroid hormone from the intestines, requiring an increase in the replacement dosage. Other drugs accelerate the metabolism of thyroid hormone, and an increase in the replacement dosage is then, required. When these medications, started or adjusted, the TSH value, monitored to determine whether additional thyroid hormone replacement, indicated.
Treatment in Newborns:
In Newborns treatment, started immediately after diagnosis to prevent developmental complications. Newborns not treated with in 6 weeks of life, at a significantly higher risk of developmental retartdation.TSH and T4 levels, tested monthly until normalized. Afterwards, TSH, measured once every 3 months until the patient is 3 years of age, and every 6 months thereafter. About 20% of children with chronic autoimmune thyroiditis may become euthyroid (thyroid levels within normal limits) later in life. Rarely surgery, required to treat extremely large goiters.
Hypothyroidism is a common endocrinological disorder with many different causes. Diagnosis relies on detailed history and physical exam to illicit potential causes of hypothyroidism. Key laboratory tests are serum TSH and freeT4 levels. Treatment is through thyroid replacement therapy and should begin immediately after diagnosis. TSH, T3, and T4 levels, monitored regularly.