Hypothyroidism

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Hypothyroidism Main page

Patient Information

Overview

Classification

Primary hypothyroidism
Hashimoto's thyroiditis
Secondary hypothyroidism
Tertiary hypothyroidism

Differentiating different causes of hypothyroidism

Screening

Diagnosis

History and symptoms

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 wide. In developed countries and areas of iodine sufficiency, the most common cause of hypothyroidism is chronic autoimmune thyroiditis (Hashimoto’s thyroiditis), with a higher prevalence in women than in men.[2][3] Signs and symptoms of hypothyroidism are mostly related to the magnitude of the thyroid hormone deficiency and the acuteness with which the deficiency develops rather than the cause of hypothyroidism.[4] 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 the diagnosis of hypothyroidism is mainly a laboratory diagnosis,[5] 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 hypothyroidism. Recent evidence has shown that 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.[6][7]

Classification

The table below presents a classification of isolated thyroid disorders and its causes based on the classification[8] [9][10][11]:

Origin of the defect Causes
Endagenous causes Exagenous causes
Thyroid Pituirtary Hypothalamus Surgery or radiation Other causes
Primary hypothyroidism + - -
Transient hypothyroidism + + -
  • Major surgeries
Central Hypothyroidism Secondary

OR

Pituitary originated

- + -
Tertiary

OR

Hypothalamus originated

- - +

Differentiating different causes of hypothyroidism

Various kinds of hypothyroidism can be differentiated from each other on the basis of history and symptoms and laboratory findings:[1][3][5]

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 ↑
  • May be accompanied by other autoimmune diseases
Thyroiditis + +/- + ↑ ↓ Normal Normal N/↑ Normal Normal
  • Infectious thyroiditis associated with neck pain
Others - +/- - ↑ ↓ Normal Normal N/↑ Normal Normal
  • History of hyperthyroiditis
  • Drug history
Transient hypothyroidism +/- - +/- ↑ ↑ Normal Normal ↑ Normal Normal
  • May present primarily with hyperthyroiditis
Subclinical hypothyroidism - - - ↑ Normal Normal Normal ↑ Normal N/↑
  • Asymptomatic
Central Hypothyroidism Pituitary + - - N/↓ N/↓ N/↓ ↓ Normal Normal Normal
  • Other pituitary hormone deficiencies signs
Hypothalamus + - - ↑ Normal ↓ Normal
  • Other pituitary hormone deficiency signs
Resistance to TSH/TRH - - - ↑ N/↓ N/↓ Normal Normal ↑/↓ Normal
  • Rare

Diagnosis

Hypothyroidism diagnosis can be made based on the laboratory findings:[8][9][10][11]

 
 
 
 
 
 
 
 
 
 
 
 
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

History and symptom

The common symptoms and signs of clinical hypothyroidism are listed in the table below. The appearance of symptoms depends on the degree of hypothyroidism severity: [12][13][14]

Symptoms Constituitional HEENT Neuromuscular Complications
More common
Less common
  • Slowed speech and movements

References

  1. ↑ 1.0 1.1 McDermott MT (2009). "In the clinic. Hypothyroidism". Ann. Intern. Med. 151 (11): ITC61. doi:10.7326/0003-4819-151-11-200912010-01006. PMID 19949140.
  2. ↑ 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.
  3. ↑ 3.0 3.1 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.
  4. ↑ 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.
  5. ↑ 5.0 5.1 Lania A, Persani L, Beck-Peccoz P (2008). "Central hypothyroidism". Pituitary. 11 (2): 181–6. doi:10.1007/s11102-008-0122-6. PMID 18415684.
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ 8.0 8.1 Colon-Otero G, Menke D, Hook CC (1992). "A practical approach to the differential diagnosis and evaluation of the adult patient with macrocytic anemia". Med. Clin. North Am. 76 (3): 581–97. PMID 1578958.
  9. ↑ 9.0 9.1 Gharib H, Tuttle RM, Baskin HJ, Fish LH, Singer PA, McDermott MT (2005). "Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society". J. Clin. Endocrinol. Metab. 90 (1): 581–5, discussion 586–7. doi:10.1210/jc.2004-1231. PMID 15643019.
  10. ↑ 10.0 10.1 Rugge JB, Bougatsos C, Chou R (2015). "Screening and treatment of thyroid dysfunction: an evidence review for the U.S. Preventive Services Task Force". Ann. Intern. Med. 162 (1): 35–45. doi:10.7326/M14-1456. PMID 25347444.
  11. ↑ 11.0 11.1 Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, Pessah-Pollack R, Singer PA, Woeber KA (2012). "Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association". Thyroid. 22 (12): 1200–35. doi:10.1089/thy.2012.0205. PMID 22954017.
  12. ↑ Carlé A, Pedersen IB, Knudsen N, Perrild H, Ovesen L, Laurberg P (2014). "Hypothyroid symptoms and the likelihood of overt thyroid failure: a population-based case-control study". Eur. J. Endocrinol. 171 (5): 593–602. doi:10.1530/EJE-14-0481. PMID 25305308.
  13. ↑ Diaz A, Lipman Diaz EG (2014). "Hypothyroidism". Pediatr Rev. 35 (8): 336–47, quiz 348–9. doi:10.1542/pir.35-8-336. PMID 25086165.
  14. ↑ Samuels MH (2014). "Psychiatric and cognitive manifestations of hypothyroidism". Curr Opin Endocrinol Diabetes Obes. 21 (5): 377–83. doi:10.1097/MED.0000000000000089. PMC 4264616. PMID 25122491.
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