Post on 14-Jan-2016
transcript
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
* For Best Viewing:
Open in Slide Show Mode Click on icon or
From the View menu, select the Slide Show option
* To help you as you prepare a talk, we have included the relevant text from ITC in the notes pages of each slide
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
in the clinic
Hyperthyroidism
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Terms of Use
The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets constitutes copyright infringement.
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Who has an elevated risk for hyperthyroidism?
Individuals with:
Diffuse or nodular goiters
Type 1 diabetes, other endocrine/ nonendocrine AI diseases
Family histories of hyperthyroidism or hypothyroidism
Medications that increase risk: Amiodarone
Alpha-interferon
Interleukin-2
Lithium
Iodide
Iodinated contrast agents in those with preexisting autoimmune or nodular thyroid disease
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Should clinicians screen for hyperthyroidism?
Screen: Individuals with risk factors
High risk comorbid conditions, family Hx, medication use
Consider screening: those with other medical conditions caused or aggravated by hyperthyroidism
e.g., osteoporosis, supraventricular tachycardia, A-Fib
Screen: Women >50 years
1 in 71 have unsuspected but symptomatic hyperthyroidism or hypothyroidism responsive to Rx
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
If clinicians screen for hyperthyroidism, which test should they use?
Serum TSH levels
Low in both overt and subclinical hyperthyroidism
(due to negative feedback by thyroid hormone levels on pituitary gland)
Screens for both hyperthyroidism & hypothyroidism
TSH assays: standardized, accurate, widely available
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
CLINICAL BOTTOM LINE: Screening…
Don’t screen: general population (not cost-effective)
Do screen: those with…
Diffuse or nodular goiters Type 1 diabetes, other endocrine/ nonendocrine AI diseases Osteoporosis, supraventricular tachycardia, or A-Fib Family Hx hyperthyroidism or hypothyroidism Amiodarone, α-interferon, interleukin-2, lithium, iodide use Women > 50 years of age
Use serum TSH test
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What symptoms should prompt clinicians to consider hyperthyroidism? Nervousness (frequency: 99%)
Increased sweating (91%)
Palpitations (89%) or tachycardia (82%)
Heat intolerance (89%)
Fatigue (88%)
Weight loss (85%)
Shortness of breath (75%), weakness (70%)
Leg swelling (65%)
Eye symptoms (54%)
Hyperdefecation (33%)
Menstrual irregularity (22%)
Emotional lability (30–60%)
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What physical examination findings indicate possible hyperthyroidism?
Tachycardia (100% frequency)
Goiter (100%)
Skin changes (97%)
Tremor (97%)
Bruit (77%)
Eye signs (30-45%)
Atrial fibrillation (10%)
Splenomegaly (10%)
Gynecomastia (10%)
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What lab tests should be used for diagnosis?
Serum TSH measurement If low: order free T4 or free T4 index (FT4I) If free T4 or FT4I not elevated: order total T3 or free T3
Radioiodine uptake (RAIU): helps determine cause
Thyroid scan: helps distinguish Graves disease, toxic multinodular goiter, toxic adenoma
If radioisotope studies contraindicated…
Blood tests: TSH-receptor antibodies; thyroid-stimulating immunoglobulins; thyroid-peroxidase antibodies; thyroglobulin; human chorionic gonadotropin; sed rate
Color Doppler US (thyroid)
Whole-body radioiodine scan
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Differential Diagnosis (with radioiodine uptake )
High or Normal
• Graves disease
• Toxic multinodular goiter
• Toxic adenoma
• HCG-induced hyperthyroidism
• TSH-producing pituitary tumor
Low
• Silent thyroiditis
• Postpartum thyroiditis
• Subacute (granulomatous) thyroiditis
• Iodine-induced hyperthyroidism
• Amiodarone-induced hyperthyroidism
• Iatrogenic hyperthyroidism
• Metastatic follicular thyroid cancer
• Struma ovarii
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Lab and Other Studies for Hyperthyroidism (plus indication)
TSH (suspected hyperthyroidism)
Free thyroxine FT4 (suppressed TSH)
Free triiodothyronine FT3 (suppressed TSH, normal FT4)
Thyroglobulin (suspected thyroiditis)
Erythrocyte sed rate ESR (suspected subacute thyroiditis)
TSH-receptor antibodies (euthyroid Graves ophthalmopathy; assess remission with antithyroid drug Rx in Graves disease; assess neonatal risk in pregnant patients with Graves disease)
Thyroid peroxidase antibodies (confirm Hashimoto thyroiditis and autoimmune thyroid disease; assess risk for Rx-induced thyroid dysfunction and postpartum thyroiditis
RAIU (confirmed biochemical thyrotoxicosis, if cause unclear)
Thyroid scan (confirmed biochemical thyrotoxicosis, if cause unclear)
Whole body scan (suspected struma ovarii)
Color Doppler US (type I vs. type II amiodarone-induced thyrotoxicosis)
Human chorionic gonadotropin HCG (choriocarcinoma)
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What alternative explanations should clinicians consider?
Infection
Sepsis
Anxiety
Depression
Chronic fatigue syndrome
Atrial fibrillation of other causes
Pheochromocytoma
TSH testing usually distinguishes these from hyperthyroidism
But serum TSH levels often low in pregnancy; hyperemesis gravidarum; euthyroid sick syndrome; central hypothyroidism; with some medications (glucocorticoids, dopamine, heparin)
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should clinicians consult an endocrinologist?
Presence of hyperthyroidism uncertain
Serum TSH level low, but T4 and T3 within reference range
TSH level normal, but T4 or T3 above reference range
Cause unclear
RAIU low or undetectable (Dx usually clear when elevated)
Uncertain or suspicious about risk for or presence of thyroid storm or Graves orbitopathy
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
CLINICAL BOTTOM LINE: Diagnosis…
To make diagnosis, use: History and physical exam Low serum TSH level with elevated serum levels for free T4,
FT4 I, total T3, or free T3
To identify cause, use: Clinical features RAIU and thyroid scan Additional tests (TRAb, TSI, TPO antibodies, thyroglobulin,
ESR, HCG, color Doppler US, whole-body scanning)
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What nondrug therapies should clinicians recommend?
Until thyroid disease adequately controlled…
Avoid heavy physical exertion
Reduce or eliminate caffeine intake
Avoid OTC decongestants and cold remedies
Discontinue smoking
Avoid exogenous sources of iodine
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
How should clinicians choose and prescribe drug therapy?
Beta-adrenergic blockade
Propranolol, atenolol, metoprolol, nadolol
For symptomatic hyperthyroidism of any cause
Side effects: CHF, asthma exacerbation
Antithyroid medications
Methimazole: preferred
Propylthiouracil: alternative (in 1st trimester pregnancy, if methimazole allergy, thyroid storm); beware liver failure
Inhibit thyroid hormone synthesis, lower thyroid hormone
Use for: Graves, toxic multinodular goiter, toxic adenoma
Don’t use for: low RAIU hyperthyroidism
Agranulocytosis occurs in 0.2%-0.4%
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Ancillary Therapy
Potassium iodine
Acutely reduces thyroid hormone release
Use before thyroidectomy for Graves
Don’t use before radioactive iodine therapy
Lithium
Reduces thyroid hormone release
Cholestyramine
Binds thyroid hormone in intestines
Nonsteroidal anti-inflammatory
Treats subacute thyroiditis
Glucocorticoids
For severe subacute thyroiditis
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should clinicians consider I-131 as primary therapy for hyperthyroidism?
Graves disease
Achieves remission in ≈90%
Good choice if no remission with antithyroid medications
Side effects
Hypothyroidism: in almost all patients within 3–6 months
Sialadenitis (due uptake by salivary glands)
Worsening of Graves orbitopathy
Possible small increase in thyroid cancer
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should clinicians consider I-131 as primary therapy for hyperthyroidism?
Toxic multinodular goiters & toxic adenomas
Note: Contraindicated in pregnancy!
Side effects
Hypothyroidism: 50%-75%
Worse symptoms from thyroid hormone in first 2 weeks
Thyroid storm, if severely hyperthyroid
Pretreat with β-adrenergic blockade &/or methimazole: if very symptomatic or free T4 or FT4I levels exceed upper limit of reference range more than 2-fold
Discontinue methimazole 7 days before I-13
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should clinicians consider thyroidectomy as primary therapy?
High RAIU hyperthyroidism (primary therapy)
Refractory amiodarone-induced cases (primary therapy)
Most often recommended for…
Those with thyroid nodules and suspected cancer
Those who can’t tolerate or refuse alternative forms Rx
Pregnancy
Patients who don’t achieve remission with antithyroid Rx
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
How should clinicians monitor patients who are being treated for hyperthyroidism?
At baseline:
Perform CBC w/ differential WBC count, liver panel
Once euthyroid:
Assess clinically
Measure serum TSH every 6 to 12 months for lifetime
Monitoring differs depending on chosen treatment…
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Antithyroid medications
Agranulocytosis, liver injury, vasculitis: discontinue
Fever or pharyngitis: repeat CBC with differential WBC
Symptoms of liver injury: order liver profile
Once symptoms resolved + results in reference range…
Discontinue β-adrenergic blocker + reduce antithyroid Rx
Continue clinical and lab assessments every 3–6 months
After 12-18 months reduced dose + normal TSH: ? remission
Taper or stop antithyroid Rx
Measure TRAb: normal = greater likelihood remission
No remission: consider I-131 or surgery
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Radioactive iodine (I-131)
Repeat clinical and lab assessments at 1-2 months
Measure TSH and free T4 in first 1-3 months
TSH suppression may last up to 6 wks after T4 and T3 fall to normal range
Start thyroid hormone-replacement when free T4 level low or TSH elevated
Adjust dose every 6-8-weeks until TSH in desired range
Thyroidectomy
Start levothyroxine before hospital discharge
Adjust dose every 6-8 weeks until TSH in desired range
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
What is subclinical hyperthyroidism, and what are the indications for treatment?
Definition: Low serum TSH levels + T4 and T3 levels within reference ranges
Asymptomatic or mild symptoms
RAIU typically in reference range
Thyroid scan findings consistent with underlying cause
TSH levels often normalize w/o treatment
Treat: if TSH <0.1 mU/L or symptomatic
Consider treating: if TSH ≥0.1 mU/L but still lower than reference range
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
How does a clinician recognize thyroid storm?
“Thyroid crisis” exaggerated manifestations of thyrotoxicosis
Unrecognized or inadequately treated thyrotoxicosis + precipitating event (infection, trauma)
Radioiodine therapy may precipitate
Dx often based on suspicious, nonspecific clinical findings
Cardinal manifestation: fever >102° F
Other features: Tachycardia, tachypnea; nausea/vomiting, diarrhea, CNS manifestations, anemia, hyperglycemia
Elevated serum total, free T4 and T3 levels; undetectable serum TSH level
Use Thyroid Storm Scoring System
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
Fever ° F Score
99–99.9 5
100–100.9 10
101-101.9 15
102-102.9 20
103-103.9 25
>104 30
CNS agitation
Absent 0 0
Mild 10
Moderate 20
Severe 30
Cardiac–pulse, bpm
99–109 5
110–119 10
120–129 15
130–139 20
≥140 25
Atrial fibrillation 10
Cardiac–CHF
Absent 0
Mild (edema) 5
Moderate (rales) 10
Severe (pulm edema)
15
Thyroid Storm Scoring System (feature, score)
GI signs
Absent 0
N, V, D, Pain 10
Jaundice 20
Precipitant history
Absent 0
Present 10
Total Score<25 = unlikely25-44 = suggestive>45 = likely
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
How does a clinician treat thyroid storm?
1. Decrease thyroid hormone synthesis
Propylthiouracil or methimazole
2. Inhibit thyroid hormone release
Sodium iodide (IV) or potassium iodide (oral)
3. Reduce heart rate
β-blocker (esmolol, metoprolol, propranolol) or diltiazem
4. Support circulation
Glucocorticoids in stress doses
Fluids (IV), oxygen, cooling
5. Treat precipitating cause
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should patients be hospitalized?
When thyroid storm present, impending, or suspected
Prognosis with aggressive therapy ≈20% mortality (was once 100%)
Dx usually based on suspicious, nonspecific findings
Do not wait for test results on serum TSH levels: delays potentially lifesaving therapy
Also, TSH levels don’t reliably distinguish thyroid storm from uncomplicated thyrotoxicosis
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
When should clinicians consult an endocrinologist or ophthalmologist?
Endocrinologist
Help developing optimal management plan
Unexpected events or Rx complications
Significant Graves eye disease present
Patient is pregnant
Thyroid storm present, impending, or suspected
Some guidelines suggest co-management in all cases
Ophthalmologist
Double vision or impaired visual acuity, visual fields, color vision
Significant eye discomfort
Proptosis >22 mm or extraocular muscle dysfunction
© Copyright Annals of Internal Medicine, 2012Ann Int Med. 157 (1): ITC1-1.
CLINICAL BOTTOM LINE: Treatment… If RAIU high or normal: Rx usually required
Inform patients on benefits and risks and jointly decide on preferred treatment
Graves disease: antithyroid meds, I-131, thyroidectomy
Toxic multinodular goiter: I-131 or thyroidectomy
Toxic adenoma:I-131 or thyroidectomy
Before definitive treatment, use antithyroid medications to improve thyroid hormone levels
If RAIU low: treat underlying cause or monitor
Condition may be transient