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1. Subclinical Hyperthyroidism Cheryl P. Sterling, MD, MPH
VCU/MCV Hospitals
February 20, 2003
2. Case Presentation 48 yo Black female with well controlled HTN, h/o borderline hyperthyroidism
No specific complaints or concerns
Meds:
HCTZ for BP control
FHx remarkable for HTN, DM, no other endocrine D/Os, no known AIDz
SHx unremarkable
3. Case Presentation 48 yo Black female with well-controlled HTN, h/o borderline hyperthyroidism
ROS positive for low but normal appetite, no wgt loss, no signif fatigue
Pap UTD
No prior BMD study
Physical exam = nonobese female; no obvious features c/w hyperthyroid state
4. Case Presentation LABS
WBC 6.0, Hgb 12.4, Platelets 378
BMP unremarkable except for Ca 8.9
LFTs wnl
Fasting Lipid Profile
Chol 173, HDL 45
TG 120, LDL 97 Serial thyroid testing
11/00 TSH 0.15
3/01 TSH 0.35
7/01 TSH 0.22
9/02 TSH 0.16
2/03 TFTs
TSH - 0.21
Total T4 - 8.4
T3RU 37.2%
FTI - 10
5. Clinical Question Premenopausal female patient with hx of borderline hyperthyroidism, no obvious clinical signs nor subjective symptoms of thyroid hormone excess
What are the management options for this patient in your practice?
6. The Thyroid Subclinical Hyperthyroidism
- Characterized by the presence of low or undetectable plasma TSH concentration and normal circulating free thyroid hormones.
Also referred to as mild hyperthyroidism
Exogenous vs. endogenous
7. Common Signs/Symptoms Fatigue
Weight loss
Heat intolerance
Hyperhidrosis
Nervousness
Insomnia
Muscle weakness
Hyperdefecation Tremor
Dyspnea
Palpitations
Menstrual irregularity
Anxiety
Irritability
Exophthalmos
Lid lag or stare
8. Subclinical Hyperthyroidism
9. Etiology Presage to overt hyperthyroidism
Early Graves disease
Multinodular goiter
Hashimotos
Thyroiditis
Subacute
Silent
Postpartum
Thyroid carcinoma Iodine-associated hyperthyroidism
e.g. amiodarone
Solitary autonomous adenoma
Nonthyroidal illness
Steroid or dopamine administration
Health food supplement
10. Biochemical Assessment Thyroid stimulating hormone (TSH):
Is the single most reliable test to diagnose thyroid disease.
The assay is accurate, widely available, safe, and a relatively inexpensive diagnostic test.
Also serum free and total T4, free and total T3.
Free thyroxine index = indirect measure of free T4
T3 resin uptake = indirect estimate of unsaturated binding sites on thyroxine binding globulin
11. Diagnostic Assessment Thyroid scan or radioactive iodine (123I) uptake
Hot versus Cold nodule
Thyroid ultrasound
Anatomic abnormalities
Does not reveal information regarding thyroid function
Serial examination
12. Diagram of thyroid testing
13. Evidence-based Research? Detection and management of subclinical thyroid disorders
Small prospective, nonrandomized studies
Cross-sectional studies
Case reports
Meta-analyses
Subgroup analysis in Framingham study
14. Short/Long-term Effects Alteration in cardiac morphology and function
Cross-sectional studies demonstrating:
Increased heart rate
Increased LV mass
Enhanced LV function
Impaired diastolic filling
Increased risk of atrial fibrillation and stroke in older patients
15. Adverse Effects Alteration in bone metabolism
Postmenopausal women with subclinical hyperthyroidism have increased bone loss
Neuropsychological effects
Reduced quality of life
Anxiety, depression
Increased risk of dementia, Alzheimers disease
16. Journal Article Subgroup analysis from Framingham Study
Prospective study w/10 yr follow-up
Purpose Is low serum thyrotropin in clinically euthyroid older persons a risk factor for subsequent atrial fibrillation?
2007 persons, age > 60 years
4 groups:
low, slightly low, normal, high thyrotropin levels
17. Results
18. Journal Article Cross-sectional, case-control study in Italy
Purpose Effects of endogenous subclinical hyperthyroidism in the young and middle-aged
23 patients, 23 controls from areas of mild-moderate iodine deficiency
Assessment of
Thyroid status
S/sx of thyroid hormone excess and quality of life
Cardiac morphology and function
19. Results
20. Conclusions
21. Subclinical Hyperthyroidism
22. Subclinical Hyperthyroidism
23. Subclinical Hyperthyroidism - Individualize management
- Discuss benefits vs. risks
- Of each treatment option, e.g. periodic monitoring of CBC, LFTs, TFTs
- Financial considerations
- Drug interactions, potential toxicities
- Also consider potential issues of nonadherence
24. The Answer(To My Clinical Question) Continue close observation with serial TFTs, including total and free T3
Discuss with patient possible treatment options
Thyroid scan with RAIU
Antithyroid medications, if necessary
Refer to endocrinology for management
25. References
26. References