- Last edited on April 30, 2020
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cl:thyroid-disorders:hypothyroidism [on April 21, 2020] |
cl:thyroid-disorders:hypothyroidism [on September 3, 2023] (current) psychdb [Treatment] |
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====== Hypothyroidism ====== | ====== Hypothyroidism ====== | ||
+ | {{INLINETOC}} | ||
===== Primer ===== | ===== Primer ===== | ||
- | **Hypothyroidism** is a disorder of the endocrine system where the thyroid gland does not produce enough thyroid hormone. | + | **Hypothyroidism** is a disorder of the endocrine system where the thyroid gland does not produce enough thyroid hormone. Hypothyroidism can be due to various etiologies including Hashimoto thyroiditis, postpartum thyroiditis, and congenital hypothyroidism. Hypothyroidism can result in a spectrum of neuropsychiatric symptoms, and can also be caused by psychotropic medications such as lithium. |
+ | ==== Thyroid Hormones ==== | ||
+ | <WRAP group> | ||
+ | <WRAP half column> | ||
+ | Remember that the thyroid produces tri-iodothyronine (T3) and thyroxine (T4), which are iodine-containing hormones that control the body’s metabolic rate. T3 binds nuclear receptors with greater affinity than T4, and thus is the "active" hormone. | ||
+ | </WRAP> | ||
+ | <WRAP half column> | ||
+ | <callout icon="fa fa-lightbulb-o" type="success" title="Mnemonic"> | ||
+ | The mnemonic ''**7 B's**'' can be used to remember the main functions of thyroid hormone: | ||
+ | * ''B''asal metabolic rate | ||
+ | * ''B''lood sugar (increases glycogenolysis and gluconeogenesis) | ||
+ | * ''B''reak down lipids (increases lipolysis) | ||
+ | * ''B''rain maturation | ||
+ | * ''B''one growth (synergism with growth hormone) | ||
+ | * ''β''-adrenergic effects in heart, which increases contractility (this is why β-blockers alleviate adrenergic symptoms in thyrotoxicosis) | ||
+ | * Stimulates surfactant synthesis in ''B''abies | ||
+ | </callout> | ||
+ | </WRAP> | ||
+ | </WRAP> | ||
+ | ===== Etiologies ===== | ||
+ | ==== Hashimoto Thyroiditis ==== | ||
+ | <alert icon="fa fa-arrow-circle-right fa-lg fa-fw" type="success"> | ||
+ | See also article: **[[cl:thyroid-disorders:hashimotos|]]** | ||
+ | </alert> | ||
+ | **Hashimoto thyroiditis** (also known as Hashimoto's Disease) is an autoimmune disorder with antithyroid peroxidase (antimicrosomal) and antithyroglobulin antibodies. It is the most common cause of hypothyroidism in iodine-sufficient regions (i.e. - most Western and affluent nations). On physical exam, individuals may have a moderately enlarged, nontender thyroid. | ||
+ | |||
+ | ==== Postpartum Thyroiditis ==== | ||
+ | **Postpartum thyroiditis** is a self-limiting thyroiditis that can last for up to 1 year after delivery. Individuals can go between transient hyperthyroidism or hypothyroidism. Following the self-limited phase, most individuals will return back to a euthyroid state. On physical exam, the thyroid is typically painless and normal in size. | ||
+ | |||
+ | ==== Congenital Hypothyroidism ==== | ||
+ | **Congenital hypothyroidism** in the fetus can occur due to antibody-mediated maternal hypothyroidism, and thyroid dysgenesis. | ||
+ | |||
+ | ==== Subacute thyroiditis (de Quervain) ==== | ||
+ | Self-limited disease often following a viral infection (e.g. - flu). Individuals may be hyperthyroid early in course of illness, followed by hypothyroidism. Hypothyroidism can remain permanent in about 15% of cases. On physical exam, individuals will have jaw pain, and tender thyroid. ESR may also be elevated. | ||
+ | |||
+ | ==== Iodine deficiency ==== | ||
+ | When an individual does not have adequate iodine, the thyroid will progressively enlarge as it tries to keep up with an increased demand for thyroid hormone production. This results in a prominent goiter that develops, and is seen on physical exam. Iodine deficiency is the most common cause of thyroid enlargement and goiter worldwide. | ||
+ | |||
+ | ==== Lithium-induced ==== | ||
+ | <alert icon="fa fa-arrow-circle-right fa-lg fa-fw" type="success"> | ||
+ | See main article: **[[meds:mood-stabilizers-anticonvulsants:1-lithium|]]** | ||
+ | </alert> | ||
+ | |||
+ | Lithium decreases production and release of thyroxine (T4) from the thyroid gland. It also interferes with de-iodination of T4 to T3 (tri-iodothyronine). T3 is the metabolically active form of thyroid hormone.[([[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3568739/|Kibirige, D., Luzinda, K., & Ssekitoleko, R. (2013). Spectrum of lithium induced thyroid abnormalities: a current perspective. Thyroid research, 6(1), 1-5.]])] | ||
+ | ===== Comparison ===== | ||
+ | <panel type="info" title="Hypothyroidism vs. Hyperthyroidism" subtitle="" no-body="true" footer=""> | ||
+ | <mobiletable 1> | ||
+ | ^ ^ [[cl:thyroid-disorders:hypothyroidism|Hypothyroidism]] ^ [[cl:thyroid-disorders:hyperthyroidism|Hyperthyroidism]] ^ | ||
+ | ^ Neuropsychiatric | Hypo-activity, lethargy, fatigue, weakness, depressed mood, reflexes (delayed, diminished) | Hyperactivity, restlessness, anxiety, insomnia, fine tremors (due to increased β-adrenergic activity), reflexes (brisk) | | ||
+ | ^ Ocular | Periorbital edema | Ophthalmopathy in Graves disease (including periorbital edema, exophthalmos), lid lag/retraction | | ||
+ | ^ Metabolic | Cold intolerance, decreased sweating, weight gain (due to lowered basal metabolic rate), hyponatremia (due to decreased free water clearance) | Heat intolerance, sweating, weight loss | | ||
+ | ^ Cardiovascular | Bradycardia, dyspnea on exertion (cardiac output) | Tachycardia, palpitations, dyspnea, arrhythmias (e.g. - atrial fibrillation), chest pain, hypertension | | ||
+ | ^ Gastrointestinal | Constipation. decreased appetite | Diarrhea, increased appetite | | ||
+ | ^ Dermatologic | Dry cool skin, coarse brittle hair, diffuse alopecia, brittle nails; puffy facies and generalized nonpitting edema (myxedema) | Warm moist skin, fine hair, onycholysis, pretibial myxedema in Graves disease | | ||
+ | ^ Reproductive | Abnormal uterine bleeding, decreased libido, infertility | Abnormal uterine bleeding, gynecomastia, decreased libido, infertility | | ||
+ | ^ Laboratory Findings | • Elevated TSH\\ • Decreased free T3 and T4\\ • Hypercholesterolemia (due to decreased LDL receptor expression) | • Decreased TSH \\ • Elevated free T3 and T4\\ • Decreased LDL, HDL, and total cholesterol | | ||
+ | </mobiletable> | ||
+ | </panel> | ||
+ | |||
+ | ===== Neuropsychiatric Symptoms ===== | ||
+ | ==== Psychosis ==== | ||
+ | <alert type="info" icon="fa fa-book fa-lg fa-fw"> | ||
+ | See also: | ||
+ | * **[[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC419396/|Heinrich, T. W., & Grahm, G. (2003). Hypothyroidism presenting as psychosis: myxedema madness revisited. Primary care companion to the Journal of Clinical Psychiatry, 5(6), 260.]]** | ||
+ | * **[[https://www.karger.com/Article/FullText/520128|Pattaravimonporn, N. et al. (2021). Myxedema Psychosis after Levothyroxine Withdrawal in Radioactive Iodine Treatment of Differentiated Thyroid Cancer: A Case Report. Case Reports in Oncology, 14, 1596-1600.]]** | ||
+ | </alert> | ||
+ | |||
+ | * In patients with psychosis, hypothyroidism should be considered as a possible secondary cause of psychosis.[([[https://www.karger.com/Article/FullText/520128|Pattaravimonporn, N. et al. (2021). Myxedema Psychosis after Levothyroxine Withdrawal in Radioactive Iodine Treatment of Differentiated Thyroid Cancer: A Case Report. Case Reports in Oncology, 14, 1596-1600.]])] | ||
+ | * This is especially true for patients with a history of thyroid problems or thyroidectomy regardless of the presence of other signs and symptoms of hypothyroidism or the level of T3 and T4 in the thyroid function test.[([[https://www.karger.com/Article/FullText/520128|Pattaravimonporn, N. et al. (2021). Myxedema Psychosis after Levothyroxine Withdrawal in Radioactive Iodine Treatment of Differentiated Thyroid Cancer: A Case Report. Case Reports in Oncology, 14, 1596-1600.]])] | ||
===== Treatment ===== | ===== Treatment ===== | ||
- | * [[https://www.ncbi.nlm.nih.gov/pubmed/31088853|Bekkering, G. E., Agoritsas, T., Lytvyn, L., Heen, A. F., Feller, M., Moutzouri, E., ... & Farhoumand, P. D. (2019). Thyroid hormones treatment for subclinical hypothyroidism: a clinical practice guideline. BMJ, 365, l2006.]] | + | <alert type="info" icon="fa fa-book fa-lg fa-fw"> |
+ | See also: | ||
+ | * **[[https://www.ncbi.nlm.nih.gov/pubmed/31088853|Bekkering, G. E. et al. (2019). Thyroid hormones treatment for subclinical hypothyroidism: a clinical practice guideline. BMJ, 365, l2006.]]** | ||
+ | * **[[https://www.cmaj.ca/content/192/18/E469|Symonds, C. et al. (2020). Levothyroxine prescribing and laboratory test use after a minor change in reference range for thyroid-stimulating hormone. CMAJ, 192(18), E469-E475.]]** | ||
+ | </alert> | ||
+ | |||
+ | * In the absence of symptoms, elevated TSH levels <10 should not be treated. | ||
+ | * Routine management is to repeat a TSH level in q3-6 months | ||
+ | * You should however, check an anti-TPO Ab to rule out [[cl:thyroid-disorders:hashimotos|Hashimoto‘s]], as subclinical hypothyroid may be treated if Anti-TPO is high, because there is an increased risk of progression to overt hypothyroidism in the future.[([[https://www.ncbi.nlm.nih.gov/books/NBK536970/|Gosi, S. K. Y., & Garla, V. V. (2019). Subclinical hypothyroidism.]])] | ||
===== Resources ===== | ===== Resources ===== | ||
==== Articles ==== | ==== Articles ==== | ||
* [[https://www.cbc.ca/news/canada/montreal/thyroid-cancer-depression-1.5335655|CBC: At 23, I had my cancerous thyroid removed. My family doctor thought I was depressed]] | * [[https://www.cbc.ca/news/canada/montreal/thyroid-cancer-depression-1.5335655|CBC: At 23, I had my cancerous thyroid removed. My family doctor thought I was depressed]] |