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Hyperthyroidism

Hyperthyroidism is a group of disorders characterized overproduction and secretion of thyroid hormones by the thyroid gland.


Presentation

Hyperthyroidism is characterized by the activation of sympathetic nervous system [3]. The common symptoms of hyperthyroidism include:

Older adults usually either have no symptoms, or have only subtle ones such as increased heart rate, easy fatigability and heat intolerance.

Goiter
  • In the patients with goiter, hyperthyroidism and symptoms of exophthalmos, and the patients with goiter, hyperthyroidism without symptoms of exophthalmos, IL-2 and TGF-β expression level were not different (p 0.05).[ncbi.nlm.nih.gov]
  • Toxic multinodular goiter: 60% of the cases of toxic multinodular goiter are caused by defects in the TSH (thyroid stimulating hormone) receptor gene. In 40% of the cases, the cause is unknown.[symptoma.com]
  • Toxic multinodular goiter Toxic multinodular goiter (Plummer disease) accounts for 15-20% of thyrotoxicosis cases (see the image below). It occurs more commonly in elderly individuals, especially those with a long-standing goiter.[emedicine.medscape.com]
  • (Remember that only a small percentage of goiters produce too much thyroid hormone; the majority of thyroid goiters actually become large because they are not producing enough thyroid hormone.)[web.archive.org]
Weight Loss
  • A 28-year-old woman presented with weight loss and tiredness. Investigations revealed hyperthyroidism. She was commenced on treatment and later became pregnant.[ncbi.nlm.nih.gov]
  • When the thyroid gland is overactive ( hyper thyroidism) the body’s processes speed up and you may experience nervousness, anxiety, rapid heartbeat, hand tremor, excessive sweating, weight loss, and sleep problems, among other symptoms.[endocrineweb.com]
  • A 13-year-old male presented with increasing height velocity (17.75 cm/year, 9.55SD), weight loss, and visual impairment. Initial biochemical evaluations revealed secondary hyperthyroidism.[ncbi.nlm.nih.gov]
  • Last year, he developed clinical symptoms of hyperthyroidism with a fast heartbeat, heat intolerance and weight loss. Blood examinations revealed low levels of FSH, LH, and testosterone.[ncbi.nlm.nih.gov]
  • Within 1 month, he experienced significant weight loss, no hand tremors, intolerance of heat, and perspiration proneness. We recommended an HIV examination; subsequently, AIDS was diagnosed based on the laboratory parameters.[ncbi.nlm.nih.gov]
Weakness
  • Neurological examination showed weakness in the muscles of the bilateral upper and lower limbs. Muscle weakness was more severe in the proximal site than in the distal site.[ncbi.nlm.nih.gov]
  • This disease should be considered in patients presenting with symmetric motor weakness and hypokalemia, whether or not symptoms of hyperthyroidism are elicited during the review of systems.[ncbi.nlm.nih.gov]
  • She presented with muscle weakness, nausea, vomiting, and diarrhea since one week. The initial diagnosis was TPP. However, biochemistry tests showed hypokalemia with metabolic alkalosis and renal potassium wasting.[ncbi.nlm.nih.gov]
  • Large-scale assessment of methodological quality of meta-analyses of hyperthyroidism treatment highlighted methodological strengths and weaknesses. Consideration of scientific quality when formulating conclusions should be made explicit.[ncbi.nlm.nih.gov]
  • It involves acceleration of body functions, and symptoms include increased heart rate, anxiety, weight loss, difficulty sleeping, tremors in the hands, weakness, and sometimes diarrhea.[labtestsonline.org]
Fatigue
  • We report the case of a 33-year-old euthyroid woman who presented to our hospital with palpitation, hand tremor, fatigue, and excessive sweating after HSG.[ncbi.nlm.nih.gov]
  • Patient 1 was a 77-year-old female with worsening fatigue while taking carbimazole over several years. Her thyroid function tests, however, were not suggestive of hypothyroidism.[ncbi.nlm.nih.gov]
  • Syndrome Possibly Explained by Lower Levels of Key Thyroid Hormones Mar. 20, 2018 — A new study reveals that chronic fatigue syndrome, a debilitating condition with unknown causes, can be explained by lower thyroid levels -- but may be distinct from[sciencedaily.com]
  • Increased energy (hyperactivity) Fatigue Unexplained weight loss Trouble sleeping Inability to tolerate heat Trouble concentrating in school Diarrhea Fast, pounding heartbeat Bulging eyes Irregular periods Shaking Hyperthyroidism can be treated by taking[cincinnatichildrens.org]
Fever
  • Familial Mediterranean fever (FMF) is a genetic autoinflammatory disorder characterized by serositis and recurrent fever.[ncbi.nlm.nih.gov]
  • CONCLUSION: This patient had life-threatening thyrotoxicosis complicated by neutropenic fever and infection, likely caused by a reaction to thionamides. She quickly recovered with broad-spectrum antibiotics.[ncbi.nlm.nih.gov]
  • PATIENT FINDINGS: A 29-year-old man who complained of dyspnea and asthenia for 1 month, recurrent fever for more than 20 days, and breathlessness for 1 week was admitted to our hospital.[ncbi.nlm.nih.gov]
  • He denied experiencing recent trauma, back pain, chest pain, abdominal pain, headache or dizziness, or a fever episode. Physical examination showed no specific findings.[ncbi.nlm.nih.gov]
  • Patients typically appear markedly hypermetabolic with high fevers, tachycardia, nausea and vomiting, tremulousness, agitation, and psychosis. Late in the progression of disease, patients may become stuporous or comatose with hypotension.[web.archive.org]
Polydipsia
  • ) Clinical features Early symptoms : anxiety, palpitations, rapid pulse, fatigue, muscle weakness, weight loss, diarrhea, hyperactive reflexes, increased sweating, heat intolerance, warm skin, excessive perspiration, menstrual changes, hand tremor, polydipsia[pathologyoutlines.com]
  • Overdosage of any thyroid drug may produce the signs and symptoms of thyrotoxicosis including, but not limited to: polydipsia, polyuria, polyphagia, reduced heat tolerance and hyperactivity or personality change.[web.archive.org]
  • The most common presenting symptoms are: rapid weight loss, tachycardia (rapid heart rate), vomiting, diarrhea, increased consumption of fluids (polydipsia), polyphasia, and increased urine production (polyuria).[en.wikipedia.org]
Palpitations
  • A 22-year-old lactating mother presented with symptoms of uneasiness, palpitation, tachycardia and exophthalmos. She had an abdominal lump suggestive of 26 weeks uterine size but her urine pregnancy test was negative.[ncbi.nlm.nih.gov]
  • The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Hyperthyroidism. Methimazole. All symptoms were alleviated.[ncbi.nlm.nih.gov]
  • We report the case of a 33-year-old euthyroid woman who presented to our hospital with palpitation, hand tremor, fatigue, and excessive sweating after HSG.[ncbi.nlm.nih.gov]
  • Abstract A 35-year-old Japanese man was emergently admitted to our hospital with chief complaints of palpitation and dyspnea. He has been treated for Basedow's disease.[ncbi.nlm.nih.gov]
  • Any time someone experiences strange sensations they run the risk of developing nervousness and anxiety as a result, especially if some of those symptoms,like heart palpitations, are frightening.[calmclinic.com]
Tachycardia
  • Fetal tachycardia was followed by intrauterine death at 30 wk in the second pregnancy and macerated stillbirth at 26 wk in the third pregnancy. Fetal tachycardia was detected at 17 wk in the fourth pregnancy.[ncbi.nlm.nih.gov]
  • In the present report, maternal therapy using MMI to resolve symptoms of fetal thyrotoxicosis, including fetal tachycardia and oligohydramnios, was successfully conducted.[ncbi.nlm.nih.gov]
  • Clinical features of fetal hyperthyroidism include tachycardia, goiter, growth restriction, advanced bone maturation, cardiomegaly, and fetal death.[ncbi.nlm.nih.gov]
  • We report the case of a young child with CCHS who presented with tachycardia, which was later found to be due to Grave's disease, after many months of investigation.[ncbi.nlm.nih.gov]
  • A 22-year-old lactating mother presented with symptoms of uneasiness, palpitation, tachycardia and exophthalmos. She had an abdominal lump suggestive of 26 weeks uterine size but her urine pregnancy test was negative.[ncbi.nlm.nih.gov]
Hypertension
  • KEYWORDS: Hashimoto's thyroiditis; hyperthyroidism; pregnancy; systolic arterial hypertension[ncbi.nlm.nih.gov]
  • BACKGROUND: Graves' hyperthyroidism commonly causes tachycardia and may result in pulmonary hypertension and high output cardiac failure.[ncbi.nlm.nih.gov]
  • CASE REPORT Herein, we present the case of a 38-year-old woman with untreated hypertension and hyperthyroidism. She presented with muscle weakness, nausea, vomiting, and diarrhea since one week. The initial diagnosis was TPP.[ncbi.nlm.nih.gov]
  • Electronic address: knishimura@psy.twmu.ac.jp. 3 Department of Medicine II, Endocrinology and Hypertension, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan.[ncbi.nlm.nih.gov]
  • Author information 1 Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare Systems, Los Angeles, California, USA.[ncbi.nlm.nih.gov]
Heart Murmur
  • Heart murmurs and a gallop rhythm can develop due to secondary hypertrophic cardiomyopathy.[en.wikipedia.org]
Diplopia
  • […] problems such as proptosis, conjunctival oedema, or ophthalmoplegia—and the dreaded complication of optic nerve compression is mercifully rare. 1 When it does occur, however, severe thyroid eye disease is difficult to treat and may result in disfigurement, diplopia[doi.org]
  • They may also notice diplopia or double vision. This is due to entrapment of the muscles. The eyes may become irritated and red: conjunctivitis. There may be periorbital edema, upper lid retraction, or lower lid retraction.[web.archive.org]
  • […] diarrhea Lower leg swelling Sudden paralysis Shortness of breath with exertion Decreased menstrual flow Impaired fertility Sleep disturbances (including insomnia ) Changes in vision Photophobia, or light sensitivity Eye irritation with excess tears Diplopia[emedicinehealth.com]
  • In severe cases, blurred vision, diplopia, or reduced color perception may develop. 16 Smoking increases the risk of developing Graves orbitopathy (odds ratio 3.7). 17 Pretibial myxedema, a less common finding, develops from fibroblast activation and[aafp.org]
Muscle Weakness
  • She presented with muscle weakness, nausea, vomiting, and diarrhea since one week. The initial diagnosis was TPP. However, biochemistry tests showed hypokalemia with metabolic alkalosis and renal potassium wasting.[ncbi.nlm.nih.gov]
  • Muscle weakness was more severe in the proximal site than in the distal site.[ncbi.nlm.nih.gov]
  • However, in the longer term, less desirable symptoms, such as muscle weakness, insomnia and trembling can also result. The pulse will likely increase, along with an inability to tolerate heat and abnormally high sweating.[thyroid-info.com]
  • They may include Being nervous or irritable Mood swings Fatigue or muscle weakness Heat intolerance Trouble sleeping Hand tremors Rapid and irregular heartbeat Frequent bowel movements or diarrhea Weight loss Goiter, which is an enlarged thyroid that[medlineplus.gov]
Muscle Cramp
  • cramps Dry skin Goiter (swelling of thyroid gland) Brittle nails Slow heart rate Irregular period Sensitivity to cold Constipation Carpal tunnel syndrome Treatment for hypothyroidism Levothyroxine sodium tablets (aka Synthroid) can be taken once a day[piedmont.org]
Increased Sweating
  • This leads to a wide range of symptoms including weight loss, increased appetite, increased sweating, intolerance to heat, anxiety and irritability. Hyperthyroidism can be treated by drugs, surgery or radiation.[symptoma.com]
  • Feeling too hot Increased sweating Muscle weakness Trembling hands Rapid heartbeat Tiredness/fatigue Weight loss Diarrhea or frequent bowel movements Irritability and anxiety Eye problems, such as irritation or discomfort Menstrual irregularities Infertility[hormone.org]
  • sweating, heat intolerance, warm skin, excessive perspiration, menstrual changes, hand tremor, polydipsia and increased appetite ( J Am Geriatr Soc 1996;44:50 ) Late symptoms : cardiac (palpitations, congestive heart failure, cardiomegaly, atrial fibrillation[pathologyoutlines.com]
Dry Skin
  • skin Gaining weight too quickly Low energy / activity level Abnormal menstrual cycles Never change a medication dose on your own.[cincinnatichildrens.org]
  • skin Goiter (swelling of thyroid gland) Brittle nails Slow heart rate Irregular period Sensitivity to cold Constipation Carpal tunnel syndrome Treatment for hypothyroidism Levothyroxine sodium tablets (aka Synthroid) can be taken once a day as a replacement[piedmont.org]
  • Other symptoms may include a lighter flow during menstrual periods, dry skin and brittle nails. Grave's disease can also affect the muscles that lift the eyelids. When the eyes seem to protrude, this is called exophthalmos.[massagetoday.com]
  • Some common symptoms of hypothyroidism include fatigue weight gain a puffy face trouble tolerating cold joint and muscle pain constipation dry skin dry, thinning hair decreased sweating heavy or irregular menstrual periods fertility problems depression[niddk.nih.gov]
Flushing
  • Iodine-containing medications need to be discontinued several weeks before therapy. 21 Safety Precautions Most of the radioactive iodine is eliminated from the body in urine, saliva, and feces within 48 hours; however, double flushing of the toilet and[aafp.org]
  • My eyes popped out, I became very hot, my skin was flushed and itchy, my blood pressure went up, my heart pounded in my ears, and I fainted on two occasions -- very scary.[massagetoday.com]
  • Tachycardia Hyperactivity Thyromegaly Other signs and symptoms include the following Prematurity Small for gestational age Poor weight gain despite a voracious appetite Irritability Poor sleep Hypertension Proptosis with lid retraction and stare Warm, flushed[clinicaladvisor.com]
  • […] symptoms that can occur with this disease: Breast development in men Clammy skin Diarrhea Feeling faint when you raise your hands High blood pressure Itchy or irritated eyes Itchy skin Nausea and vomiting Protruding eyes (exophthalmos) Skin blushing or flushing[mountsinai.org]
  • For 3 days after treatment with RAI, patient should double flush his toilet and wash his hands often. One should also avoid contact with young children and pregnant women during this time, to avoid harmful effects by radioactivity.[flexikon.doccheck.com]
Urticaria
  • […] difficulty sleeping muscle weakness hyperactivity oversensitivity to heat, excessive sweating, and warm, damp skin increased appetite increased bowel movements and urination infertility and a loss of interest in sex itchy skin with raised itchy swellings (urticaria[medicalnewstoday.com]
  • […] rate, which characterised by: Flushing of the face and hands Smooth, moist and warm skin Fine, soft and thinned scalp hair Distorted and overgrown nails (thyroid acropachy) that may lift off the nail bed ( onycholysis ) Generalised itching ( pruritus ) Urticaria[dermnetnz.org]
  • Urticaria, pruritus. Brisk reflexes. Goitre. Proximal myopathy (muscle weakness wasting). Gynaecomastia. Lid lag (may be present in any cause of hyperthyroidism).[patient.info]
Pruritus
  • One month after the initiation of antithyroid drug, the patient became euthyroid with improvement in jaundice and pruritus and normalization of hepatic tests and alpha antitrypsine clearance.[ncbi.nlm.nih.gov]
  • […] metabolic rate, which characterised by: Flushing of the face and hands Smooth, moist and warm skin Fine, soft and thinned scalp hair Distorted and overgrown nails (thyroid acropachy) that may lift off the nail bed ( onycholysis ) Generalised itching ( pruritus[dermnetnz.org]
  • Urticaria, pruritus. Brisk reflexes. Goitre. Proximal myopathy (muscle weakness wasting). Gynaecomastia. Lid lag (may be present in any cause of hyperthyroidism).[patient.info]
Anxiety Disorder
  • She consulted a psychologist who told her that she suffered from an anxiety disorder and recommended psychotherapy, which was not helpful.[mdedge.com]
  • disorder And more There’s hope![holtorfmed.com]
Polyuria
  • Overdosage of any thyroid drug may produce the signs and symptoms of thyrotoxicosis including, but not limited to: polydipsia, polyuria, polyphagia, reduced heat tolerance and hyperactivity or personality change.[web.archive.org]
  • The most common presenting symptoms are: rapid weight loss, tachycardia (rapid heart rate), vomiting, diarrhea, increased consumption of fluids (polydipsia), polyphasia, and increased urine production (polyuria).[en.wikipedia.org]
Amenorrhea
  • In addition, those with hyperthyroidism may present with a variety of physical symptoms such as palpitations and abnormal heart rhythms (the notable ones being atrial fibrillation), shortness of breath (dyspnea), loss of libido, amenorrhea, nausea, vomiting[en.wikipedia.org]
Tremor
  • For example, beta-blockers help slow down a rapid heart rate and reduce hand tremors. Updated on: 05/07/19 Hyperthyroidism Symptoms[endocrineweb.com]
  • We describe a 6-month-old boy with a de novo mutation in the TSHR gene who presented with accelerated growth, enlarging head circumference, tremor and thyrotoxicosis.[ncbi.nlm.nih.gov]
  • We report the case of a 33-year-old euthyroid woman who presented to our hospital with palpitation, hand tremor, fatigue, and excessive sweating after HSG.[ncbi.nlm.nih.gov]
  • Within 1 month, he experienced significant weight loss, no hand tremors, intolerance of heat, and perspiration proneness. We recommended an HIV examination; subsequently, AIDS was diagnosed based on the laboratory parameters.[ncbi.nlm.nih.gov]
  • The underlying hyperthyroidism is often subtle without typical symptoms such as palpitations, tremors, anxiety, and weight loss; this causes a difficulty in early diagnosis.[ncbi.nlm.nih.gov]
Hyperactivity
  • […] or a toxic nodule (when just one nodule is hyperactive).[columbiasurgery.org]
  • Congenital hyperthyroidism can be a cause of failure to thrive, hyperactivity, developmental delay, and craniosynostosis during infancy. Most commonly, the condition occurs in the setting of maternal autoimmune thyroid disease.[ncbi.nlm.nih.gov]
  • Increased energy (hyperactivity) Fatigue Unexplained weight loss Trouble sleeping Inability to tolerate heat Trouble concentrating in school Diarrhea Fast, pounding heartbeat Bulging eyes Irregular periods Shaking Hyperthyroidism can be treated by taking[cincinnatichildrens.org]
  • The ingestion of radioactive iodine shows how quickly the thyroid absorbs iodine (a primary component of thyroxine), along with which parts of the thyroid appear to be hyperactive.[massagetoday.com]
  • Hyperthyroidism can also be caused by the thyroid becoming inflamed (thyroiditis) or by nodules inside the thyroid which become hyperactive.[healthdirect.gov.au]
Insomnia
  • However, in the longer term, less desirable symptoms, such as muscle weakness, insomnia and trembling can also result. The pulse will likely increase, along with an inability to tolerate heat and abnormally high sweating.[thyroid-info.com]
  • A also developed insomnia, depressed mood, and intrusive ego-dystonic thoughts. These symptoms emerged 10 years after a subtotal thyroidectomy for hyperthyroidism (Graves’ disease).[mdedge.com]
  • Hyperthyroid patients typically experience symptoms such as anxiety, insomnia, weight loss, rapid heartbeat, sweating, diarrhea, and eye or vision changes.[holtorfmed.com]
  • . — Yvette D'entremont, SELF, "I'm a Scientist With Insomnia So I Researched How to Actually Get Better Sleep," 28 Nov. 2018 While an underactive thyroid can cause weight gain, an overactive one (which is diagnosed as hyperthyroidism ) increases your[merriam-webster.com]
Agitation
  • After tracheal extubation, the patient exhibited abnormal tachycardia, agitation, sweating, and hyperpyrexia. The clinical manifestation and the following thyroid function test indicate a high index of suspicion for impending thyroid storm.[ncbi.nlm.nih.gov]
  • Patients typically appear markedly hypermetabolic with high fevers, tachycardia, nausea and vomiting, tremulousness, agitation, and psychosis. Late in the progression of disease, patients may become stuporous or comatose with hypotension.[web.archive.org]
  • BWPS) for severity-assessment of Life-Threatening Thyrotoxicosis Temperature: 37.7 C / 99.9 F 37.8 C - 38.3 / 100 - 100.9 F 38.4 - 38.8 C / 101 - 101.9 F 38.9 - 39.4 C / 102 - 102.9 F 39.5 - 39.9 C / 103 - 103.9 F 40 C / 104 F CNS Effects: Absent Mild (agitation[formatio-reticularis.de]
  • […] excessive ingestion of thyroid hormone ("factitious hyperthyroidism") Includes a wide range of symptoms, such as ophtalmopathy, dermatopathy, fever, marked tachycardia, heart failure, tremor, nausea, vomiting, diarrhea, dehydration, restlessness, extreme agitation[pathologyoutlines.com]
  • Psychiatric symptoms seen with hyperthyroidism Anxiety Apathy (more often seen in older patients) Cognitive impairment Delirium Depression Emotional lability Fatigue Hypomania or mania Impaired concentration Insomnia Irritability Mood swings Psychomotor agitation[mdedge.com]
Excitement
  • When hyperthyroidism is suspected, drugs that excite the sympathetic nerves or promote the release of histamine should not be used during caesarean section.[ncbi.nlm.nih.gov]
  • We’re excited to provide more clinicians evidence-based information on standards of care and support those involved in formulary decisions with clinical outcomes.[turner-white.com]
  • This means they may be capable of acting on the thyroid in either direction, exciting hypoactive and depressing hyperactive thyroids. Although not certain, it suggests that these herbs may be used to treat both conditions—a fascinating possibility.[chrysalisnaturalmedicine.com]
  • The following clinical signs of hypothyroidism can be observed in dogs: Metabolic signs: lethargy; lack of endurance; increased sleeping; reduced interest, alertness and excitability; slow heart rate; weak heart beat and pulse; preference for warmth;[web.archive.org]

Workup

In addition to complete history, examination and base-line investigations, the following specific set of investigations are helpful in establishing the diagnosis of any thyroid disease [4].

  • Serum T3 an T4 levels
  • Serum TSH levels
  • Iodine uptake
  • Thyroid scan
  • Ultrasonography

In case of auto-immune thyroiditis, the most specific auto-antibody test is an ELISA (Enzyme Linked Immunosorbent Assay) test for anti-thyroid peroxidase antibody. The titres are significantly increased in case of Grave’s hyperthyroidism, but are very low or absent in case of toxic adenoma or toxic multi-nodular goiter.

Treatment

Hyperthyroidism is managed by providing symptomatic relief and anti-thyroid therapy, which includes anti-thyroid drugs, radio-active iodine-131 or thyroidectomy.

Anti-thyroid drugs

The drugs commonly used are carbimazole, and propylthiouracil. Both of these drugs interfere with the oxidation of iodides and binding of iodine to tyrosine [5] [6]. 

Advantages:

  • No surgery required
  • No use of radioactive iodine

Disadvantages:

  • Treatment is prolonged (6-24 months)
  • Failure rate is 50% and relapses may occur [7]
  • Very dangerous side-effect such as agranulocytosis, aplastic anemia and oropharyngeal bacterial infection can occur and may require discontinuation of the drug

Surgery

In toxic and nodular goiter surgery, subtotal or total thyroidectomy cures the disease by reducing the mass of overactive tissue [8]. 

Advantages:

  • Cure is rapid
  • Cure rate is high

Disadvantages:

Radioactive iodine (RAI)

Radioiodine destroys the thyroid cells without surgery. In this treatment, radioactive iodine is given orally which is taken up by the follicles. In the thyroid follicles, beta and gamma rays are emitted from the radioactive iodine which destroys the follicles [10].

Advantages:

  • No surgery
  • No prolonged drug treatment

Disadvantages:

Contraindications:

Prognosis

Hyperthyroidism resulting from toxic multi-nodular goiter and toxic adenoma mostly occurs in adults and remains throughout life. Long term high-dose anti-thyroid drugs are not recommended after the person becomes euthyroid. Instead, radio-active iodine ablation is recommended. Increased thyroid hormone causes left ventricular thickening that results in an increased risk of cardiac death and other cardiac problems. Eye problems usually improve after proper treatment.

Etiology

Hyperthyroidism can result from several different causes that are listed below [1].

  • Graves disease: It has an autoimmune etiology and is characterized by the presence of auto-antibodies that are capable of stimulating the thyroid gland.
  • Toxic multinodular goiter: 60% of the cases of toxic multinodular goiter are caused by defects in the TSH (thyroid stimulating hormone) receptor gene. In 40% of the cases, the cause is unknown.
  • Toxic adenoma: Toxic adenoma of the thyroid gland is caused by a point mutation in the TSH (thyroid stimulating hormone) receptor gene.
  • Thyroiditis: Different types of thyroiditis have their own etiologies. Hashimoto's thyroiditis has an autoimmune basis whereas De Quervian thyroiditis has a genetic predisposition in specific human leukocyte antigens (HLAs). Suppurative thyroiditis is caused by infections. Drugs such as lithium, amiodarone and interferon-alpha can also cause the development of thyroiditis.

Epidemiology

In the United States, the most commonly occurring form of hyperthyroidism is Grave’s disease. It constitutes around 60 to 80% of the total cases. The peak occurrence is in people with ages 20 to 40.

In iodine-deficient areas, the most common type is toxic multi-nodular goiter, comprising up to 15 to 20% of total cases. It typically presents in people older than 50 years of age.

Sex distribution
Age distribution

Pathophysiology

Thyroid hormone secretion is controlled by a complex feed-back mechanism which involves stimulatory and inhibitory factors. The hypothalamus releases thyrotropin-releasing hormone (TRH) which stimulates the pituitary gland to release thyroid stimulating hormone (TSH). Thyroid stimulating hormone in turn causes the release of T3 and T4 from the thyroid gland. Increased levels of T3 and T4 decrease the production of TSH by negative feed-back mechanism.

Any pathology involving the pituitary gland, thyroid or in the periphery leading to increased levels of circulating thyroid hormone results in thyrotoxicosis. Regardless of where the pathology lies, the result is an increase in the transcription of the cellular proteins which then leads to the increased basal metabolic rate [2].

Prevention

There are no current guidelines on the prevention of hyperthyroidism. Hyperthyroidism caused by Grave’s disease cannot be prevented as it is genetically mediated. However, people residing in iodine deficient areas must introduce iodine in their diets to prevent the occurrence of toxic multi-nodular goiter which is most likely to occur in such areas. This might greatly affect the over-all incidence of hyperthyroidism in these areas.

Also, people with a positive family history of hyperthyroidism or those residing in iodine deficient areas should get themselves periodically checked up for early diagnosis and treatment.

Summary

Hyperthyroidism is a term reserved for disorders that result in the overproduction of the thyroid hormone by the thyroid gland. Thyrotoxicosis is a term used to describe a state of thyroid hormone excess resulting from any source. The most common cause of thyroid hormone excess is Graves disease. Toxic multinodular goiter is the second most common cause.

Patient Information

Hyperthyroidism refers to the condition in which the levels of thyroid hormone in the body are high. This leads to a wide range of symptoms including weight loss, increased appetite, increased sweating, intolerance to heat, anxiety and irritability. Hyperthyroidism can be treated by drugs, surgery or radiation.

References

Article

  1. Lacka K, Fraczek MM. [Classification and etiology of hyperthyroidism]. Polski merkuriusz lekarski : organ Polskiego Towarzystwa Lekarskiego. Mar 2014;36(213):206-211.
  2. Benker G, Breuer N, Muller R, Wehr M. [Pathophysiology of various forms of hyperthyroidism]. Klinische Wochenschrift. Jun 19 1990;68(12):631-634.
  3. Chen JL CH, Tseng YJ, Chu WC. Hyperthyroidism is characterized by both increased sympathetic and decreased vagal modulation of heart rate: evidence from spectral analysis of heart rate variability. Clin Endocrinol (Oxf). 2006;64(6):611-616.
  4. Bernier MO, Aurengo A, Leenhardt L. [Hyperthyroidism. Etiology, physiopathology, diagnosis, evolution, treatment]. La Revue du praticien. May 15 2001;51(9):1023-1031.
  5. Gupta SK, Mithal A, Godbole MM. Single daily dose of carbimazole in the treatment of hyperthyroidism. The National medical journal of India. Sep-Oct 1992;5(5):214-216.
  6. Rubbens P. [Propylthiouracil therapy of hyperthyroidism]. Belgisch tijdschrift voor geneeskunde. Apr 15 1953;9(8):367-375.
  7. Jonas M, Ambroziak U, Bednarczuk T, Nauman J. Predicting a relapse of Graves' hyperthyroidism in adults during the early phase of treatment with anti-thyroid drugs. Endokrynologia Polska. Nov-Dec 2006;57(6):596-604.
  8. Snyder S, Govednik C, Lairmore T, Jiang DS, Song J. Total thyroidectomy as primary definitive treatment for Graves' hyperthyroidism. The American surgeon. Dec 2013;79(12):1283-1288.
  9. Boger MS, Perrier ND. Advantages and disadvantages of surgical therapy and optimal extent of thyroidectomy for the treatment of hyperthyroidism. The Surgical clinics of North America. Jun 2004;84(3):849-874.
  10. Chakrabarti B. Radio-iodine (NaI131) therapy in hyperthyroidism. Journal of the Indian Medical Association. Nov 2001;99(11):642-645.

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Last updated: 2019-07-11 21:55