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cl:thyroid-disorders:hypothyroidism [on November 3, 2019]
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., LytvynL., Heen, AF., FellerM., MoutzouriE., ... & FarhoumandPD. (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. BMJ365l2006.]]** 
 +  * **[[https://​www.cmaj.ca/​content/​192/​18/​E469|SymondsCet al. (2020). Levothyroxine prescribing and laboratory test use after a minor change in reference range for thyroid-stimulating hormoneCMAJ192(18)E469-E475.]]** 
 +</​alert>​ 
 + 
 +  * In the absence of symptomselevated TSH levels <10 should not be treated.  
 +    * Routine management is to repeat a TSH level in q3-6 months 
 +    * You should howevercheck 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/​|GosiSKY.GarlaVV. (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]]