Download Hyperthyroidism

Disease/Medical Condition
HYPERTHYROIDISM
Date of Publication: January 27, 2017
(also known as “thyrotoxicosis” and “overactive thyroid disease”; includes Graves’ disease [also known as “Graves-Basedow disease” and
“Basedow’s disease”], toxic multinodular goitre [also known as “Plummer’s disease” and “Parry’s disease”], and several types of thyroiditis)
Is the initiation of non-invasive dental hygiene procedures* contra-indicated? No
■ Is medical consult advised? Yes, if previously undiagnosed hyperthyroidism or enlarged thyroid gland is suspected1, in which
case the patient/client should see his/her primary care physician.
■ Yes, if previously diagnosed hyperthyroidism is suspected to be undertreated (with manifest signs/symptoms of
hyperthyroidism) or over treated (with manifest signs/symptoms of hypothyroidism2), in which case the patient/client should
see his/her primary care physician or endocrinologist. Immediate medical assistance should be sought if thyrotoxic crisis is
suspected. Even if the hyperthyroid patient/client is under good medical care, acute oral infection should also prompt
consultation with patient/client’s physician.
■ Yes, if patient/client taking antithyroidal thioamide drugs (such as carbimazole, methimazole, and propylthioruracil [PTU])
presents with fever, sore throat, or oral ulcerations. This may indicate agranulocytosis (i.e., dangerously low level of
neutrophils, which are a type of white blood cells), which requires urgent medical care.
■ Yes, if patient/client is about to, or has recently received (within past week), radioactive iodine therapy, in order to clarify
duration of restricted (1.83 m distance from other persons) period.
Is the initiation of invasive dental hygiene procedures contra-indicated?** Possibly, depending on the
certainty of diagnosis and level of control.
■ Is medical consult advised? .......................................... See above.
■ Is medical clearance required? ..................................... Yes, if undiagnosed or severe hyperthyroidism is suspected.
–
Yes, if patient/client is taking antithyroidal thioamide drugs. These medications (particularly PTU) may rarely cause
thrombocytopenia (low platelet count) or hypoprothrombinemia (low prothrombin level), both of which impair blood clotting,
as well as leukopenia (low white blood cell count), which increases risk of serious infection. A physician can order blood tests
(e.g., platelet count, prothrombin time, and white blood cell count) to rule out the presence of these complications. PTU
may also increase the anticoagulant effects of warfarin, which is commonly used in the management of atrial fibrillation.
■ Is antibiotic prophylaxis required? ................................. No, in the absence of cardiac valvular pathology or atrial
fibrillation.
■ Is postponing treatment advised? .................................. Yes, if patient/client has very recently been treated with
radioactive iodine (which is usually administered as one oral dose) in order to protect the dental hygienist, other staff, and
patients/clients from radiation exposure. Depending on the dose of I131 given, duration of postponement should be 1 to 3
days post-administration for non-pregnant oral healthcare providers and 1 to 5 days for pregnant oral healthcare providers 3.
Patients/clients treated with I131 should maintain a distance of at least 1.83 metres (6 feet) from other persons during the
restricted period.
■ Yes, if hyperthyroidism is suspected in an undiagnosed or untreated patient/client; a complete medical evaluation is
indicated before commencement of invasive procedures.
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Diagnostic tests for hyperthyroidism include serum measurement of thyroid stimulating hormone (TSH; also known as thyrotropin), thyroid
hormone, and thyroid binding globulin (TBG), and, less commonly, administration of radioactive iodine to measure uptake by the thyroid gland
(RAIU). Treatment may involve antithyroid drugs (including propylthiouracil, methimazole, and carbimazole) that interfere directly with
thyroid hormone synthesis, radioactive iodine, or subtotal thyroidectomy. The adrenergic component in thyrotoxicosis can be managed with
β-blocker drugs such as propranolol.
Signs/symptoms of decreased thyroid activity include cold intolerance, dry skin, fatigue, poor memory retention, and weight gain despite
decreased appetite.
I131 concentrations are present in the saliva for as long as 7 days post-administration.
cont’d on next page...
Disease/Medical Condition
HYPERTHYROIDISM
(also known as “thyrotoxicosis” and “overactive thyroid disease”; includes Graves’ disease [also known as “Graves-Basedow disease” and
“Basedow’s disease”], toxic multinodular goitre [also known as “Plummer’s disease” and “Parry’s disease”], and several types of thyroiditis)
Is the initiation of invasive dental hygiene procedures contra-indicated?** (cont’d)
■ Yes, if severe, poorly controlled hyperthyroidism is suspected (in order to avoid risk of thyrotoxic crisis); such patients/
clients should be referred for urgent medical care, with dental hygiene care postponement until the underlying metabolic
disturbance has been corrected.
■ Yes, if cardiovascular signs/symptoms (e.g., chest pain, palpitations) occur in the course of dental hygiene treatment;
conditions such as angina pectoris are exaggerated in thyrotoxicosis. The management protocol for the specific situation
should be followed.
■ In general, the patient/client with mild symptoms of untreated hyperthyroidism (often passing as acute anxiety) is not in
danger when receiving dental hygiene therapy, and the well-managed (euthyroid) patient/client requires no special regard.
Oral management implications
■ Palpation of the thyroid gland should be part of the head and neck examination by the dental hygienist. Diffuse enlargement
or nodules may be detected.
■ Patients/clients with a history of hyperthyroidism should be queried regarding the presence of cardiovascular disease.
■ Blood pressure should be monitored, because it may be elevated in patients/clients with poorly controlled disease.
■ Stress management and brief appointments are important for patients/clients with poorly controlled disease to minimize risk
of precipitating a thyrotoxic crisis.
■ Patients/clients with untreated or partially treated hyperthyroidism are very sensitive to the effects of epinephrine or other
sympathomimetics. Their use is contraindicated until good medical management is implemented. Improper use can cause the
patient/client to experience a hypertensive crisis, tachycardia, and/or dysrhythmia.
■ Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, can increase the amount of circulating thyroid hormone,
making control of hyperthyroidism more difficult.
■ Thyrotoxic crisis – a medical emergency – may be precipitated by trauma, infections, and surgical procedures in untreated or
poorly treated patients/clients with severe hyperthyroidism.
■ Development of autoimmune connective tissue diseases such as Sjögren’s syndrome and systemic lupus erythematosus should
be considered when evaluating the patient/client who has a history of Graves’ disease.
Oral manifestations
■ Mild tremor of the tongue is common.
■ Increased susceptibility to caries, periodontal disease, enlargement of extraglandular thyroid tissue (mainly lingual thyroid
tissue on the posterior dorsal tongue), osteoporosis of alveolar bone (and entirety of mandible and maxilla), and burning
mouth syndrome are less common manifestations.
■ In children, the teeth and jaw develop quickly. Premature loss of deciduous teeth and accelerated eruption of permanent
teeth are common.
■ Sialolith formation may be induced by the antithyroid drug propylthioruracil (PTU).
■ Decreased sense of taste may infrequently result from antithyroid drugs such as PTU and methimazole.
■ Salivary gland swelling and pain, as well as loss of taste, are acute risks of radioactive iodine therapy. Longer term
complications are hyposalivation, xerostomia, mouth pain, recurrent sialoadenitis, and caries.
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Disease/Medical Condition
HYPERTHYROIDISM
(also known as “thyrotoxicosis” and “overactive thyroid disease”; includes Graves’ disease [also known as “Graves-Basedow disease” and
“Basedow’s disease”], toxic multinodular goitre [also known as “Plummer’s disease” and “Parry’s disease”], and several types of thyroiditis)
Related signs and symptoms
■
Hyperthyroidism is characterized by an excess of thyroid hormone4 in the bloodstream, usually resulting from an overactive
thyroid gland. Causes of hyperthyroidism include Graves’ disease5; congenital hereditary goitre6; functional ectopic thyroid
tissue; multinodular goitre; thyroid adenoma (a benign tumour of the thyroid gland); ingestion of thyroid hormone
(thyrotoxicosis factitia) or thyroid-active agents (e.g., iodocasein for weight reduction); pituitary disease; and subacute
painful and subacute painless (postpartum) thyroiditis (each of which has a transient hyperthyroidism phase). In rare cases,
metastases of follicular carcinoma of the thyroid gland can cause thyrotoxicosis.
■
Although less common than hypothyroidism, hyperthyroidism exhibits a similar female preponderance – by an 8:1 female-tomale ratio. By far, Graves’ disease is the most common cause of hyperthyroidism in Canada; it occurs in nearly 2% of women
and 0.2% of men, usually presenting between 20 and 50 years of age.
■
Diffusely enlarged goitre usually accompanies Graves’ disease. Palpable nodules (which secrete excessive amounts of thyroid
hormone) are present in the less common toxic multinodular goitre.
■
Direct and indirect effects of excessive thyroid hormone (which increases metabolic activity) cause the clinical picture in
Graves’ disease and other thyrostimulatory disorders. Common signs/symptoms are nervousness, irritability, restlessness,
insomnia, emotional lability, fatigue (associated with general muscle weakness), tachycardia (abnormally rapid resting heart
beat), palpitations, elevation of blood pressure (systolic more than diastolic), heat intolerance, and weight loss.
■
Patients/clients find it difficult to sit still, are continually moving, and often have a tremor of the hands and of closed
eyelids. In younger patients/clients, common findings are short attention span and weight loss despite an increased appetite.
In females, menstruation tends to be decreased.
■
The patient/client’s skin is warm and moist, and the complexion is rosy. Frequent blushing and hyperhidrosis (profuse
sweating) are common. Excessive melanin pigmentation of the skin (but not of the oral mucosa) and palmar erythema may be
present. Hair becomes fine and friable, and the nails soften.
■ Atrial fibrillation7 is rare in persons under 50 years of age, but occurs in about 20% of older patients/clients with Graves’
disease. Congestive heart failure (CHF) may occur, as may dyspnea (shortness of breath) unrelated to CHF, which instead is
related to weakness of the respiratory muscles.
■
Ophthalmopathy is seen in 50% of patients/clients with Graves’ disease, and is linked to an eye-specific autoimmune process.
Its features are periorbital edema and inflammation of the extraoccular muscles, in addition to an increase in orbital
connective tissue and fat. This results in eyelid retraction, lid lag on blinking, chemosis (conjunctival swelling), and unilateral
or bilateral exophthalomos (abnormal protrusion of the eyeball). Disease progression may lead to double vision and loss of
vision secondary to compressive optic neuropathy or exposure keratopathy. Unlike many complications of Graves’ disease,
exophthalmos is usually irreversible even after antithyroid treatment.
■
Thyrotoxic patients/clients often show eye signs unrelated to Graves’ ophthalmopathy. These signs – related to
overstimulation of the sympathetic nervous system – include infrequent blinking, stare with widened palpebral fissures, jerky
eyelid movement, and failure to wrinkle the brow on upward gaze.
■
In fewer than 2% of patients/clients with Graves’ disease, dermopathy occurs. This manifests as nonpitting edema, usually
over the anterolateral aspects of the tibia (shin). In chronic cases, discrete nodules and plaques can be seen.
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Thyroid hormone is a collective term for thyroxine (T4) and triiodothyronine (T3), both of which are secreted by the thyroid gland. T4 is
converted to T3 in the peripheral tissues.
Graves’ disease is an autoimmune disorder, in which stimulatory antibodies lead to an overactive thyroid gland.
Goitre is generalized enlargement of the thyroid gland, and may be either diffuse or nodular.
Atrial fibrillation is an arrhythmia in which the heart’s two upper chambers (atria) beat irregularly and out of coordination with the two lower
chambers (ventricles). Treatment is important to prevent stroke and improve quality of life.
cont’d on next page...
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Disease/Medical Condition
HYPERTHYROIDISM
(also known as “thyrotoxicosis” and “overactive thyroid disease”; includes Graves’ disease [also known as “Graves-Basedow disease” and
“Basedow’s disease”], toxic multinodular goitre [also known as “Plummer’s disease” and “Parry’s disease”], and several types of thyroiditis)
Related signs and symptoms (cont’d)
■
Hyperthyroidism is characterized by an excess of thyroid hormone4 in the bloodstream, usually resulting from an overactive
thyroid gland. Causes of hyperthyroidism include Graves’ disease5; congenital hereditary goitre6; functional ectopic thyroid
tissue; multinodular goitre; thyroid adenoma (a benign tumour of the thyroid gland); ingestion of thyroid hormone
(thyrotoxicosis factitia) or thyroid-active agents (e.g., iodocasein for weight reduction); pituitary disease; and subacute
painful and subacute painless (postpartum) thyroiditis (each of which has a transient hyperthyroidism phase). In rare cases,
metastases of follicular carcinoma of the thyroid gland can cause thyrotoxicosis.
■
Another rare complication of Graves’ disease is thyroid acropachy. This condition is characterized by clubbing and soft tissue
swelling of the distal phalanx of the fingers and toes, often with discolouration and thickening of the overlying skin.
■
If left untreated, hyperthyroidism may lead to thyrotoxic crisis (thyroid storm), a rare life-threatening medical emergency
heralded by the onset of nausea, vomiting, anorexia, abdominal pain, and extreme restlessness. High fever, profuse
sweating, marked tachycardia, cardiac arrhythmias, congestive heart failure, pulmonary edema, and delirium soon develop,
followed by stupor, coma, severe hypotension, and death if untreated. Nearly all persons who develop thyrotoxic crisis have
long-standing hyperthyroidism, with goitre, eye signs, and wide pulse pressure8.
■
Glucose intolerance and, more rarely, diabetes mellitus may occur with hyperthyroidism. Other metabolic effects include
increased bone loss (osteoporosis), which may be seen in radiographs.
■
Risk of death from thyroid cancer, and possibly several other cancers, is slightly increased if hyperthyroidism is treated with
radioactive iodine.
References and sources of more detailed information
■ CDHO Knowledge Network Advisory
http://www.cdho.org/Advisories/CDHO_Advisory_Hyperthyroidism.pdf
■ Thyroid Foundation of Canada
http://www.thyroid.ca/thyrotoxicosis.php
http://www.thyroid.ca/thyroiditis.php#null
http://www.thyroid.ca/fact_sheet1.php (Medications for Hyperthyroidism)
http://www.thyroid.ca/fact_sheet4.php (Propranolol)
http://www.thyroid.ca/ophthalmopathy.php (Graves’ Eye Disease)
http://www.thyroid.ca/pregnancy_fertility.php
http://www.thyroid.ca/childhood.php
http://www.thyroid.ca/surgical_treatment.php
http://www.thyroid.ca/Thyroid%20Function%20in%20Health%20and%20Psychiatric%20Disorders.pdf
■ RDH Magazine, Dentistry IQ Network
http://www.rdhmag.com/articles/print/volume-16/issue-4/columns/periodontics/patients-with-thyroid-dysfunctions-require
-risk-management-before-dental-procedures.html
■ Pinto A and Glick M. Management of patients with thyroid disease: oral health considerations. JADA 2002;133(July):849-858.
http://www.ugr.es/~jagil/pinto_tiroides.pdf
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Pulse pressure is the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP). For example, if BP is 120/80 mmHg,
then pulse pressure is 40.
cont’d on next page...
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Disease/Medical Condition
HYPERTHYROIDISM
(also known as “thyrotoxicosis” and “overactive thyroid disease”; includes Graves’ disease [also known as “Graves-Basedow disease” and
“Basedow’s disease”], toxic multinodular goitre [also known as “Plummer’s disease” and “Parry’s disease”], and several types of thyroiditis)
References and sources of more detailed information (cont’d)
■ Chandna S and Bathla M. Oral manifestations of thyroid disorders and its management. Indian J Endocrinol Metab 2001
Jul;15(Suppl2):S113-S116.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169868/
■ Sisson JC et al. Radiation Safety in the Treatment of Patients with Thyroid Diseases by Radioiodine
Recommendations of the American Thyroid Association. Thyroid. 2011;21(4):335-347.
http://www.thyca.org/download/document/184/ataradiation.pdf
131
I: Practice
■ The Royal Australian and New Zealand College of Radiologists
http://www.insideradiology.com.au/pages/view.php?T_id=44#.V_VqXRQondk (Iodine-131 Therapy)
■ American Thyroid Association
http://www.thyroid.org/radioactive-iodine/
■ Patton LL (ed.) and Glick M (ed.). The ADA Practical Guide to Patients With Medical Conditions (2 nd edition). Hoboken: John
Wiley & Sons Inc.; 2016.
https://books.google.ca/books?
id=OTJiCgAAQBAJ&pg=PA96&lpg=PA96&dq=antibiotic+prophylaxis+for+dental+procedures+in+hyperthyroidism&source=bl&ots
=cIX4x6sGgf&sig=0C9XNYnfT8b2HNtP2Ugz9lcGgo&hl=en&sa=X&ved=0ahUKEwj4_4GJxsnPAhWW2YMKHbc6C3UQ6AEIMTAD#v=onepage&q=antibiotic%20prophylaxis%
20for%20dental%20procedures%20in%20hyperthyroidism&f=false
■ Little JW, Falace Da, Miller CS and Rhodus NL. Dental Management of the Medically Compromised Patient (8 th edition).
St. Louis: Elsevier Mosby; 2013.
■ Ibsen OAC and Phelan JA. Oral Pathology For The Dental Hygienist (6th edition). St. Louis: Elsevier Saunders; 2014.
■ Darby M (ed.) and Walsh M (ed.). Dental Hygiene: Theory and Practice (4 th edition). St. Louis: Elsevier Saunders; 2015.
■ Regezi JA, Sciubba JJ, and Jordan RCK. Oral Pathology: Clinical Pathologic Correlations (6 th edition). St. Louis: Elsevier
Saunders; 2012.
■ Malamed SF. Medical Emergencies in the Dental Office. St. Louis: Elsevier Mosby; 2015.
*
Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
**
Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling
teeth and root planing, including curetting surrounding tissue.
Date: October 10, 2016
69 Bloor St. E, Suite 300, Toronto, ON M4W 1A9 t: 416-961-6234 ● tf: 1-800-268-2346 ● f: 416-961-6028 ● www.cdho.org
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