Hypothyroidism: Difference between revisions
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==[[Hypothyroidism overview|Overview]]== | ==[[Hypothyroidism overview|Overview]]== | ||
Thyroxine (T4) and triiodothyronine (T3) are produced from the thyroid gland. Thyroid hormones are important in regulating different body functions, and their deficiencies are associated with different symptoms including the decrease in energy metabolism, decreased appetite, cold intolerance, and slightly low basal body temperature (low basal metabolic rate). Iodine deficiency is recognized as the most common cause of hypothyroidism world widely. In developed countries and areas of iodine sufficiency, the most common cause of hypothyroidism is [[chronic autoimmune thyroiditis]] [[Hashimoto's thyroiditis|(Hashimoto’s thyroiditis)]] with a more prevalence in women than men. Symptom and signs of hypothyroidism is mostly related to the magnitude of the thyroid hormone deficiency, and the acuteness with which the deficiency develops rather than the cause of hypothyroidism. However, the typical clinical manifestations of hypothyroidism may vary depending on the origin of the disease. Clinical scenario- if associated with secondary and tertiary hypothyroidism, may present other coexisting endocrine deficiencies such as hypogonadism and adrenal insufficiency, that may mask the manifestations of hypothyroidism. Although hypothyroidism diagnosis is mainly a laboratory diagnosis, the coexisting conditions and wide variation in clinical presentation may make the diagnosis hard. Subclinical hypothyroidism on the other hand is mostly asymptomatic, but may be transformed to clinical. Recent researches have shown subclinical hypothyroidism may have various consequences, such as hyperlipidemia and increased risk for the development of cardiovascular disease, even heart failure, somatic and neuromuscular symptoms, infertility and other complications.2895281 | Thyroxine (T4) and triiodothyronine (T3) are produced from the thyroid gland. Thyroid hormones are important in regulating different body functions, and their deficiencies are associated with different symptoms including the decrease in energy metabolism, decreased appetite, cold intolerance, and slightly low basal body temperature (low basal metabolic rate)<ref name="pmid19949140">{{cite journal |vauthors=McDermott MT |title=In the clinic. Hypothyroidism |journal=Ann. Intern. Med. |volume=151 |issue=11 |pages=ITC61 |year=2009 |pmid=19949140 |doi=10.7326/0003-4819-151-11-200912010-01006 |url=}}</ref>. Iodine deficiency is recognized as the most common cause of hypothyroidism world widely. In developed countries and areas of iodine sufficiency, the most common cause of hypothyroidism is [[chronic autoimmune thyroiditis]] [[Hashimoto's thyroiditis|(Hashimoto’s thyroiditis)]] with a more prevalence in women than men.<ref name="pmid18177256">{{cite journal |vauthors=Aoki Y, Belin RM, Clickner R, Jeffries R, Phillips L, Mahaffey KR |title=Serum TSH and total T4 in the United States population and their association with participant characteristics: National Health and Nutrition Examination Survey (NHANES 1999-2002) |journal=Thyroid |volume=17 |issue=12 |pages=1211–23 |year=2007 |pmid=18177256 |doi=10.1089/thy.2006.0235 |url=}}</ref> Symptom and signs of hypothyroidism is mostly related to the magnitude of the thyroid hormone deficiency, and the acuteness with which the deficiency develops rather than the cause of hypothyroidism. However, the typical clinical manifestations of hypothyroidism may vary depending on the origin of the disease. Clinical scenario- if associated with secondary and tertiary hypothyroidism, may present other coexisting endocrine deficiencies such as hypogonadism and adrenal insufficiency, that may mask the manifestations of hypothyroidism. Although hypothyroidism diagnosis is mainly a laboratory diagnosis<ref name="pmid18415684">{{cite journal |vauthors=Lania A, Persani L, Beck-Peccoz P |title=Central hypothyroidism |journal=Pituitary |volume=11 |issue=2 |pages=181–6 |year=2008 |pmid=18415684 |doi=10.1007/s11102-008-0122-6 |url=}}</ref>, the coexisting conditions and wide variation in clinical presentation may make the diagnosis hard. Subclinical hypothyroidism on the other hand is mostly asymptomatic, but may be transformed to clinical. Recent researches have shown subclinical hypothyroidism may have various consequences, such as hyperlipidemia and increased risk for the development of cardiovascular disease, even heart failure, somatic and neuromuscular symptoms, infertility and other complications <ref name="pmid8371604">{{cite journal |vauthors=O'Brien T, Dinneen SF, O'Brien PC, Palumbo PJ |title=Hyperlipidemia in patients with primary and secondary hypothyroidism |journal=Mayo Clin. Proc. |volume=68 |issue=9 |pages=860–6 |year=1993 |pmid=8371604 |doi= |url=}}</ref><ref name="pmid7605150">{{cite journal |vauthors=Diekman T, Lansberg PJ, Kastelein JJ, Wiersinga WM |title=Prevalence and correction of hypothyroidism in a large cohort of patients referred for dyslipidemia |journal=Arch. Intern. Med. |volume=155 |issue=14 |pages=1490–5 |year=1995 |pmid=7605150 |doi= |url=}}</ref>.<ref name="pmid2895281">{{cite journal |vauthors=Schuessler B, Hesse U, Dimpfl T, Anthuber C |title=Epidural anaesthesia and avoidance of postpartum stress urinary incontinence |journal=Lancet |volume=1 |issue=8588 |pages=762 |year=1988 |pmid=2895281 |doi= |url=}}</ref><ref name="pmid11836274">{{cite journal |vauthors=Hollowell JG, Staehling NW, Flanders WD, Hannon WH, Gunter EW, Spencer CA, Braverman LE |title=Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III) |journal=J. Clin. Endocrinol. Metab. |volume=87 |issue=2 |pages=489–99 |year=2002 |pmid=11836274 |doi=10.1210/jcem.87.2.8182 |url=}}</ref><ref name="pmid3753833">{{cite journal |vauthors=Zimmerman RS, Brennan MD, McConahey WM, Goellner JR, Gharib H |title=Hashimoto's thyroiditis. An uncommon cause of painful thyroid unresponsive to corticosteroid therapy |journal=Ann. Intern. Med. |volume=104 |issue=3 |pages=355–7 |year=1986 |pmid=3753833 |doi= |url=}}</ref> | ||
==[[Hypothyroidism classification|Classification]]== | ==[[Hypothyroidism classification|Classification]]== |
Revision as of 16:13, 18 July 2017
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Hypothyroidism Main page |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahshid Mir, M.D. [2]
Synonyms and keywords: Myxedema; myxoedema; thyroid activity decreased; hypothyroid
Overview
Thyroxine (T4) and triiodothyronine (T3) are produced from the thyroid gland. Thyroid hormones are important in regulating different body functions, and their deficiencies are associated with different symptoms including the decrease in energy metabolism, decreased appetite, cold intolerance, and slightly low basal body temperature (low basal metabolic rate)[1]. Iodine deficiency is recognized as the most common cause of hypothyroidism world widely. In developed countries and areas of iodine sufficiency, the most common cause of hypothyroidism is chronic autoimmune thyroiditis (Hashimoto’s thyroiditis) with a more prevalence in women than men.[2] Symptom and signs of hypothyroidism is mostly related to the magnitude of the thyroid hormone deficiency, and the acuteness with which the deficiency develops rather than the cause of hypothyroidism. However, the typical clinical manifestations of hypothyroidism may vary depending on the origin of the disease. Clinical scenario- if associated with secondary and tertiary hypothyroidism, may present other coexisting endocrine deficiencies such as hypogonadism and adrenal insufficiency, that may mask the manifestations of hypothyroidism. Although hypothyroidism diagnosis is mainly a laboratory diagnosis[3], the coexisting conditions and wide variation in clinical presentation may make the diagnosis hard. Subclinical hypothyroidism on the other hand is mostly asymptomatic, but may be transformed to clinical. Recent researches have shown subclinical hypothyroidism may have various consequences, such as hyperlipidemia and increased risk for the development of cardiovascular disease, even heart failure, somatic and neuromuscular symptoms, infertility and other complications [4][5].[6][7][8]
Classification
The table below presents a classification of isolated thyroid disorders and its causes based on the classification:
Origin of the defect | Causes | ||||||
---|---|---|---|---|---|---|---|
Endagenous causes | Exagenous causes | ||||||
Thyroid | Pituirtary | Hypothalamus | Surgery or radiation | Other causes | |||
Primary hypothyroidism | + | - | - |
|
|
| |
Transient hypothyroidism | + | + | - |
|
|||
Central Hypothyroidism | Secondary
OR Pituitary originated |
- | + | - |
|
|
|
Tertiary
OR Hypothalamus originated |
- | - | + |
|
|
|
Classification of thyroiditis based on the duration algorythm
History, signs, and symptoms suggestive of hypothyroidism | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Measure FT4 and TSH | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Normal FT4, Elevated TSH>5.5 | Decresased level of FT4 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subclinical hypothyroidism | Elevated TSH > 5.5 | Normal TSH level OR Decreased TSH level < 0.2 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Check anti-thyroid autoantibodies and TPOAb | Check TRH | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Increased | Normal | Normal or increased | Decreased | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
•Autoimmune thyroiditis • Resistance to TSH | •Iodine deficeincy •Thyroiditis | •Pituitary related hypothyroidism | •Hypothalamus related hypothyroidism | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Differential diagnosis
Disease | History and symptoms | Laboratory findings | Additional findings | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Fever | Goiter | Pain | TSH | Free T4 | T3 | T3RU | Thyroglobin | TRH | TPOAb | |||
Primary hypothyroidism | Autoimmune | + | +/-
Diffuse |
- | ↑ | ↓ | N/↓ | Normal | N/↑ | Normal | ↑ |
|
Thyroiditis | + | +/- | + | ↑ | ↓ | Normal | Normal | N/↑ | Normal | Normal |
| |
Others | - | +/- | - | ↑ | ↓ | Normal | Normal | N/↑ | Normal | Normal |
| |
Transient hypothyroidism | +/- | - | +/- | ↑ | ↑ | Normal | Normal | ↑ | Normal | Normal |
| |
Subclinical hypothyroidism | - | - | - | ↑ | Normal | Normal | Normal | ↑ | Normal | N/↑ |
| |
Central Hypothyroidism | Pituitary | + | - | - | N/↓ | N/↓ | N/↓ | ↓ | Normal | Normal | Normal |
|
Hypothalamus | + | - | - | ↑ | Normal | ↓ | Normal |
| ||||
Resistance to TSH/TRH | - | - | - | ↑ | N/↓ | N/↓ | Normal | Normal | ↑/↓ | Normal |
|
History and symptom
The symptoms and signs of clinical hypothyroidism are listed in the table below. The appearance of symptoms depends on the degree of hypothyroidism severity.
Symptoms | Constituitional | HEENT | Neuromuscular | Complications |
---|---|---|---|---|
More common |
|
|
| |
Less common |
|
|
|
- ↑ McDermott MT (2009). "In the clinic. Hypothyroidism". Ann. Intern. Med. 151 (11): ITC61. doi:10.7326/0003-4819-151-11-200912010-01006. PMID 19949140.
- ↑ Aoki Y, Belin RM, Clickner R, Jeffries R, Phillips L, Mahaffey KR (2007). "Serum TSH and total T4 in the United States population and their association with participant characteristics: National Health and Nutrition Examination Survey (NHANES 1999-2002)". Thyroid. 17 (12): 1211–23. doi:10.1089/thy.2006.0235. PMID 18177256.
- ↑ Lania A, Persani L, Beck-Peccoz P (2008). "Central hypothyroidism". Pituitary. 11 (2): 181–6. doi:10.1007/s11102-008-0122-6. PMID 18415684.
- ↑ O'Brien T, Dinneen SF, O'Brien PC, Palumbo PJ (1993). "Hyperlipidemia in patients with primary and secondary hypothyroidism". Mayo Clin. Proc. 68 (9): 860–6. PMID 8371604.
- ↑ Diekman T, Lansberg PJ, Kastelein JJ, Wiersinga WM (1995). "Prevalence and correction of hypothyroidism in a large cohort of patients referred for dyslipidemia". Arch. Intern. Med. 155 (14): 1490–5. PMID 7605150.
- ↑ Schuessler B, Hesse U, Dimpfl T, Anthuber C (1988). "Epidural anaesthesia and avoidance of postpartum stress urinary incontinence". Lancet. 1 (8588): 762. PMID 2895281.
- ↑ Hollowell JG, Staehling NW, Flanders WD, Hannon WH, Gunter EW, Spencer CA, Braverman LE (2002). "Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III)". J. Clin. Endocrinol. Metab. 87 (2): 489–99. doi:10.1210/jcem.87.2.8182. PMID 11836274.
- ↑ Zimmerman RS, Brennan MD, McConahey WM, Goellner JR, Gharib H (1986). "Hashimoto's thyroiditis. An uncommon cause of painful thyroid unresponsive to corticosteroid therapy". Ann. Intern. Med. 104 (3): 355–7. PMID 3753833.