1. Hypothyroidism
Update Evidence-Based Guideline
Recommendations
Dr.Hi sham Abid Aldaba gh
Int e rna l Medi c ine Spe c i a l i s t
Kingdom of Saudi Arabia
Ministry of Health
General Directorate of Health
Affairs in Gurayat
General Gurayat Hospital
2. Learning Objectives
Be able to practice procedures concerning the
following topics about Hypothyroidism(according to
evidence-based guideline recommendations):
1- Diagnosis.
2- Screening.
3- Treating.
4- Monitor treatment.
5-Follow up.
3. Hypothyroidism may occur as a result of primary
gland failure or insufficient thyroid gland
stimulation by the hypothalamus or pituitary gland.
Autoimmune thyroid disease is the most common
etiology of hypothyroidism in the United States.
4. The prevalence increases with age, and is higher in
females than in males.
About one in 300 persons in the United States has
hypothyroidism.
Clinical symptoms of hypothyroidism are nonspecific
and may be subtle, especially in older persons.
The best laboratory assessment of thyroid function is
a serum thyroid-stimulating hormone test (TSH).
There is no evidence that screening asymptomatic
adults improves outcomes.
5. Untreated hypothyroidism can contribute to
hypertension, dyslipidemia, infertility, cognitive
impairment, and neuromuscular dysfunction.
In the majority of patients, alleviation of symptoms
can be accomplished through oral administration of
synthetic levothyroxine, and most patients will
require lifelong therapy.
Thyroid hormone requirements increase during
pregnancy.
6. Subclinical Hypothyroidism(SH)
Subclinical hypothyroidism is a biochemical
diagnosis defined by a normal-range free T4 level and
an elevated TSH level. Patients may or may not have
symptoms attributable to hypothyroidism.
8. 1- How to make the diagnosis of hypothyroidism?
By measuring TSH. normal range values (0.45-4.5
mIU/L). Grade A.
Higher cutoff TSH levels must be considered for
elderly patients. Grade A.
Patients with physical signs suspected of
hypothyroidism, require a diagnostic workup that
includes thyroid hormone assays. Grade B.
If the patient has clinical findings or a high
probability of overt hypothyroidism, the
measurement of both TSH and free T4 are
required. Grade D.
9. To rule out SH, an initial TSH determination is
suggested. If elevated, a repeat test adding free
T4 should be performed 2-3 months later to
confirm the diagnosis. Grade D.
The progression to OH in patients with SH
depends on the presence of thyroid antibodies
and TSH baseline levels. Measurement of
TPOAb and thyroid US in patients with SH is
useful to help predict a higher risk of
progression to overt hypothyroidism. Grade A.
10. 2- Who should be screened for hypothyroidism?
Women of fertile age and upwards, especially older
than 60 years. Grade A.
Risk groups population including persons with
previous radiation treatment of the thyroid gland,
previous thyroid surgery, or thyroid dysfunction,
TPOAb positivity, use of certain drugs such as
amiodarone. Grade A or lithium, T1DM, Sjogren’s
syndrome, systemic lupus erythematosus,
rheumatoid arthritis, vitiligo, Down’s syndrome,
Turner syndrome, heart failure, dyslipemia,
hyperprolactinemia and anemia. Grade B.
In the presence of goiter and clinical features of
hypothyroidism. Grade D.
In patients with a family history of AITD. Grade A.
11. 3- When should anti-thyroid antibodies be measured?
Anti-thyroid peroxidase antibody (TPOAb)
measurements should be considered when
evaluating patients with subclinical hypothyroidism.
Grade B.
To confirm the presence of thyroid autoimmunity in
primary hypothyroidism. Grade C.
When evaluating patients with recurrent
miscarriage, with or without infertility. Grade A.
If autoimmunity is suspected as the cause of
hypothyroidism. Grade B.
For diagnosis of AITD. Grade B.
In the risk groups for AITD. Grade B.
12. 4- What are the preferred thyroid hormone
measurements in addition to TSH in the assessment of
patients with hypothyroidism?
Apart from pregnancy, assessment of serum free
T4 should be done instead of total T4 in the evaluation of
hypothyroidism. Grade A.
Assessment of serum free T4, in addition to TSH, should
be considered when monitoring L-thyroxine therapy.
Grade B.
In pregnancy, the measurement of total T4 or a free
T4 index, in addition to TSH, should be done to assess
thyroid status. Grade B.
Serum total T3 or assessment of serum free T3 should
not be done to diagnose hypothyroidism. Grade A.
TSH measurements in hospitalized patients should be
done only if there is an index of suspicion for thyroid
dysfunction. Grade A.
13. 5- When should thyroid ultrasonography be
performed?
Routine thyroid US is not recommended in
patients with either clinical or subclinical
hypothyroidism. However, it should be
considered for patients with negative thyroid
antibodies to identify patients with autoimmune
thyroiditis. Grade A.
Thyroid US can also be considered for those
patients with subclinical hypothyroidism to help
in the evaluation of the risk of progression to
overt hypothyroidism. Grade A.
Thyroid US should be performed for patients
with hypothyroidism and abnormal thyroid
palpation. Grade D.
14. 6- Is there an association between heart failure and
subclinical hypothyroidism?
Data concerning the effects of subclinical
hypothyroidism on the cardiac function and
structure are conflicting.
There are consistent evidence regarding the
association of subclinical hypothyroidism with
congestive heart failure in elderly patients,
particularly for TSH level > 10 mIU/L, Grade A,
but not for younger patients.
There is no evidence concerning the role of
levothyroxine treatment in reducing the
incidence or progression of congestive heart
failure on SH patients.
15. 7- Is subclinical hypothyroidism associated to
cardiovascular risk?
There is available evidence suggesting an association between
subclinical hypothyroidism and CHD events and mortality,
particularly for subjects younger than 65. Grade A.
TSH concentrations ≥10 mIU/L were consistently associated
with increased risk of CHD events and CHD mortality. Grade A.
All patients with TSH level persistently > 10 mIU/L should be
treated, because at this TSH level, patients have an increased
likelihood of progression to overt disease Grade A, and a higher
risk of congestive heart failure, cardiovascular disease and
mortality. Grade A.
For patients with mildly increased serum TSH levels (4.5-10
mIU/L), treatment should be considered for those patients
younger than 65 with increased cardiovascular risk ,
particularly when TSH level is persistently > 7 mIU/L. Grade A.
16. 8- Should elderly patients be considered for
treatment?
Routine treatment is not recommended for elderly
(> 65 yr) and very-elderly (> 80 yr) patients with
subclinical hypothyroidism at TSH levels < 10
mIU/L. Grade A.
Also treatment is not recommended for SH if the
aim is to improve cognitive function in elderly
people Grade A. However in > 65 years old,
treatment can be considered on an individual
basis. Grade D.
17. 9- How should patients with hypothyroidism be
treated?
Levothyroxine is the drug of choice to treat
hypothyroidism. Grade A.
Routine use of combined therapy with levothyroxine
and triiodothyronine for hypothyroid patients is not
recommended. Grade A.
Levothyroxine therapy could be considered also for
symptomatic middle-aged patients for a short period of
time. If a clear beneficial effect is observed,
levothyroxine therapy could be maintained. Grade D.
Treatment could be considered for patients with
persistently mildly increased TSH levels with positive
TPOAb and thyroid sonographic findings typical of
autoimmune thyroiditis. Grade B.
18. 10- How should levothyroxine be used?
Levothyroxine should be administered at least
after 2 hours fast, 30 minutes before food intake
Grade A. As an alternative, it could be
administered in the evening. Grade B.
In clinical hypothyroidism, an initial levothyroxine
daily dose of 1.6-1.8 μg/kg ideal body weight is
recommended. Grade B.
In subclinical disease, an initial daily dose of 1.1-1.2
μg/kg. Grade D.
Individual adjustment of levothyroxine therapy
should be considered. Grade D.
19. 11- How to initiate and adjust doses in elderly and in
patients with cardiopathy?
In elderly patients (> 60 years) and also in those
with ischemic cardiac disease or heart failure,
start levothyroxine therapy at lower doses (12.5-25
μg/day) Grade D, especially in subclinical
hypothyroid patients. Grade B.
20. 12- How should levothyroxine therapy be monitored?
Patients being treated for established
hypothyroidism should have serum TSH
measurements done at 4–8 weeks after initiating
treatment or after a change in dose. Once an
adequate replacement dose has been determined,
periodic TSH measurements should be done after 6
months and then at 12-month intervals, or more
frequently if the clinical situation dictates
otherwise. Grade B.
21. 13- In patients with hypothyroidism being treated
with L-thyroxine who are pregnant, what should the
target TSH ranges be?
The following upper-normal reference ranges are
recommended: first trimester, 2.5 mIU/L; second
trimester, 3.0 mIU/L; and third trimester,
3.5 mIU/L. Grade C.
22. 14- How to approach hypothyroid patients with
persistently high levels of TSH despite high
levothyroxine dose?
After poor compliance and incorrect ingestion
have been ruled out, consider possible food and
drug interactions. Grade B, and also malabsorption
syndromes that can alter levothyroxine absorption
and metabolism. Grade D.
23. 15- How to approach patients with persistent
hypothyroid symptoms?
If hypothyroid symptoms persist despite adequate
treatment, other comorbidities should be
discarded. Grade C.
Increased levothyroxine dose or combination
therapy with triiodotironine are not
recommended. Grade B.
24. Key Concepts
TSH is the corner stone in approaching patients
with hypothyroidism.
Levothyroxine is the drug of choice to treat
hypothyroidism.
Thyroid hormone requirements increase during
pregnancy.
TPOAb should be considered in approaching AITD.
Most Hypothyroidism patients require life long
treatment.
25. References
American Thyroid Association Guideline Recommendations,
2012
ABE&M todos os direitos reservados. 290 Arq Bras
Endocrinol Metab. 2013;57/4 Guidelines of hypothyroidism
DAVID Y. GAITONDE, MD; KEVIN D. ROWLEY, DO; and
LORI B. SWEENEY, MD, Dwight D. Am Fam
Physician. 2012 Aug 1;86(3):244-251.
Gabriela Brenta1, Mario Vaisman2, José Augusto Sgarbi3,
Liliana Maria Bergoglio4, Nathalia Carvalho de Andrada5,
Pedro Pineda Bravo6, Ana Maria Orlandi7, Hans Graf8, Latin
American Thyroid Society (LATS), 2013.
26. Topics for Research
Prevalence and Etiology of Hypothyroidism
in Al Gurayat Province.
Efficacy of Iodine Supplement Procedures
Upon Thyroid Disorders.
Effectiveness of Treatment of Thyroid
Disorders.
