Hypothyroidism is an endocrine disorder that results from thyroid hormonal deficiency. In the U.S. and other regions that have sufficient iodine consumption, autoimmune thyroid or the Hashimoto disease, normally causes hypothyroidism, while worldwide, iodine deficiency is the leading cause.
Pathophysiology
Hypothyroidism can be caused by malfunctioning of the hypothalamus, thyroid, or pituitary gland, as all of these result from the same “negative feedback mechanism” (McCann, 2011, p. 496). Despite belonging to the same mechanism the hypothalamus malfunction rarely causes hypothyroidism, and when it does, it is called ‘secondary hypothyroidism’. While the malfunction of the gland is referred to as ‘primary hypothyroidism’.
Chronic autoimmune thyroiditis also known as the chronic lymphocytic thyroiditis ensues when autoantibodies damage thyroid gland tissue. Hashimoto’s disease is the chronic autoimmune thyroiditis linked to goiter (McCann, 2011). The cause of this abnormality (autoimmune mechanism) has not been discovered yet. Hereditary causes present plausible reasons as well as leukocyte antigen subtypes, which pose a greater risk. Around the thyroid, the antibodies diminish the effect of thyroid hormone by blocking the thyroid stimulating hormone (TSH) receptor and by attacking thyroid cells (McCann, 2011).
Signs and Symptoms
In many people suffering from hypothyroidism, there have been very little to no symptoms documented. The two most common and mild symptoms include fatigue and feeling cold. Trouble concentrating and difficulty in remembering things has also been associated with hypothyroidism (Longo et al., 2011). Constipation, dyspepsia, change in voice (hoarseness), trouble hearing, heavy menstrual periods in females followed by light periods, loss of appetite couples with weight gain and trouble breathing have been the documented symptoms of hypothyroidism (Longo et al., 2011). Among prominent signs to investigate the matter, dry skin, hair loss or brittle hair, slower heart rate, swelling in limbs, and carpal tunnel syndrome are the most common (Longo et al., 2011).
Causes
The most common cause of hypothyroidism is Hashimoto’s thyroiditis (Pooler, 2009). It is the most common cause of goiter and hypothyroidism in both children and adults. Hashimoto’s thyroiditis is predominantly a disease of women, where the female to male ratio is 5:1 (Pooler, 2009). The course of the disease varies across patients depending upon their unique situations. Typically goiter ensues first and hypothyroid manifests in later stages. There is a probability that hypothyroidism might affect all body functions.
Diagnoses
Official medical diagnoses of hypothyroidism depend on patient history and physical examination, where laboratory tests confirm the disease. Low serum thyroxine T4 coupled with higher TSH levels are indicators of primary hypothyroidism (Pooler, 2009). Antithyroid antibodies test should be performed when there is enough suspicion of Hashimoto thyroiditis. In this case, the anti-TPO antibody titres test is performed.
Treatment
Replacement therapy is used to treat hypothyroidism. Triiodothyronine T3 or T4, depending on the circumstances, is synthetically prepared, where a majority of patients are treated with T4. Serum TSH levels indicate the required dosage of T4 replacement therapy. The moment TSH reaches normal levels the T4 dosage is deemed sufficient. This procedure is to treat hypothyroidism only. Among the elderly, the procedure is a little complicated where the dosage needs to follow “go low and go slow” policy (Pooler, 2009, p. 994). This precaution is necessary as there is an increased risk of prompting acute coronary syndromes among the elderly patients.
References
Longo, D. L., Fauci, A. S., Kasper, D. L., Hauser, S. L., Jameson, J. L., & Loscalzo, J. (2011). 341: disorders of the thyroid gland. Harrison’s principles of internal medicine. (18th ed.). New York: McGraw-Hill.
McCann, J. A. S. (2011). Professional guide to pathophysiology 3rd edition. NY: Lippincott Williams and Wilkins.
Pooler, C. (2009). Porth pathophysiology: concepts of altered health states. Lippincott Williams & Wilkins.
