2. Case
32 year old lady was evaluated for generalized
paraesthesias with aches and pains in different joints.
No arthritis was noted.
No fever/red eyes/ extraarticular
manifestations of collagen vascular diseases
Seen by a neurologist and investigated
Blood sugars : normal CPK: 300 U/L ( Normal < 200 )
Calcium parameters: normal
ANA/ dsDNA : negative RA factor : 86 ( Normal< 60 )
ESR: 26 mm / 1 hr Uric acid : 8.6 mg/dl (< 6 )
CBC: normal except for Hb: 9.8 gm/dl , MCV: 104
NCV: bilateral CTS
5. What further to look before
starting treatment ?
• Diagnosis
• Coexistent conditions
age of patient
severity of hypothyroidism
coexistent drugs
coexistent medical conditions
6. The patient was seen by
physician
Additional information generated
• Strong family history of hypothyroidism
• Delivered 6 months back and breast feeding
• Taking iron and calcium tablets
• Small firm goiter
• TSH > 100 IU/ml Free T4: 0.45 ng/dl
8. Etiology
PRIMARY HYPOTHYROIDISM
• Hashimoto’s thyroiditis-most common
Post partum thyroiditis
• Atrophic hypothyroidism
• Irradiation of thyroid
• Surgical removal
• Late stage invasive fibrous thyroiditis
• Iodine deficiency
• Drug therapy (Lithium, Interferon)
• Infiltrative Diseases:Sarcoidosis, Amyloidosis
Scleroderma, Hemochromatosis
9. Diagnosis
Thyroid hormones
feedback inhibit TSH
So
If T3, T4 reduces
TSH increases
Primary hypothyroidism
10. The spectrum of disease
Euthyroid
Free T4/ T4: normal
TSH : normal
Subclinical hypothyroidism
Free T4/ T4 : normal
TSH : elevated
Overt Hypothyroidism
Free T4/ T4 : low
TSH : elevated
11. The spectrum of disease
Euthyroid
Free T4/ T4: normal
TSH : normal
Subclinical hypothyroidism
Free T4/ T4 : normal
TSH : elevated
Overt Hypothyroidism
Free T4/ T4 : low
TSH : elevated
12. The spectrum of disease
Euthyroid
Free T4/ T4: normal
TSH : normal
Subclinical hypothyroidism
Free T4/ T4 : normal
TSH : elevated
Overt Hypothyroidism
Free T4/ T4 : low
TSH : elevated
13. Further testing
• Anti TPO antibody (Thyroid Peroxidase)
• Anti Tg( Thyroglobulin) antibody
marker of autoimmunity
• Ultrasound thyroid : usually not needed
• FNAC thyroid:
usually not needed in autoimmune thyroiditis
needed in infiltrative diseases
14. Treatment
• Treated with thyroid replacement
• Normal thyroid produces both T4 and T3 ,
predominantly T4
• T3 is formed in periphery by deiodination of T4
• Commercial preparations are usually only L-thyroxine
( T4)
15. Dose
Thyroxine ( T4)
• Strengths: 25 mcg, 50 mcg, 75 mcg,88 mcg, 100 mcg and 125
mcg
• Adults require 1.6 mcg/kg/day
• Elderly : 1.0 mcg/kg/day
T3 (Triodothyronine) : available as Tetroxin/ Cytomel
T3 as compare to T4 is
• 4 times more potent.
• Short duration of activity.
• Rapid onset of action
• Can be used for myxedema coma
16. Starting therapy
• Adults
50 to 100 mcg/day of thyroxine
• Elderly / Cardiac disease
25 mcg/day of thyroxine
• 80% bioavailability
• t1/2 1 week. Need 6 weeks for equilibration
17. Titrating therapy
• Call back after 6 –12 weeks with TSH
• Titrate 25-50 mcg/ day increments
• Repeat testing only by 3 months
• Only TSH is usually required for monitoring
• Target TSH – lower half of the normal range (~2.5-
3mU/L)
• Once TSH stable, repeat TFT annually. Ensure
compliance
18. Changes with treatment
• Begin to feel better within 2 weeks
• Full symptom relief may take 3-6 months after TSH
levels are normal
• Risk of over treatment
– atrial fibrillation
– osteoporosis
19. Our patient
• Started on 100 mcg/day thyroxine in empty stomach
• Called back after 6 weeks
TSH : 63 mIU/L
• Patient reports good compliance
• Increased doses to 125 mcg/day
• Called back after 3 months
TSH : 38 mIU/L
Not controlled ?
20. Follow up
• What are the cause for high dose requiremts ?
• Is thyroxine treatment during breast feeding harmful
to baby ?
• How long to continue treatment ?
22. What to do ?
• Space out tablets of thyroxine from other offending
drugs
• Can be converted to night dosing
• Empty stomach : 30-60 minutes before breakfast
• To minimize interference with food
• No dose adjustment for kidney and liver disease
23. Hashimoto’s thyroiditis
Chronic lymphocytic thyroiditis
• Most common cause of hypothyroidism
• Can be goitrous or non goitrous
• Anti TPO antibody positive
• Euthyroid Hashimoto’s : no treatment/ LT4 to reduce
goiter size and antibody levels
• Very rarely associated with thyroid lymphoma
• Can have co-existent papillary carcinoma
24. Postpartum thyroiditis
• Usually 2-6 months after delivery
• Transient thyrotoxicosis followed by hypothyroidism
/hypothyroidism
• Silent thyroiditis in postpartum period
• 23 % progress to permanent hypothyroidism
• More common with
severe hypothyroidism
higher Anti TPO antibody titre
26. Case continued
• Patient evaluated after spacing out the iron/calcium
tablets
• TSH : reduced to 2.8 mU/L
• Continued same dose of LT4 125 mcg/day
• Asked to come back after 3 months
TSH: < 0.01 mU/L
Next ?
27. Reversibility of primary
hypothyroidism
• Reversible hypothyroidism: Post partum
Drug induced( alfa interferon, Li )
Infectious ( Whipple’s disease, Sub acute thyroiditis) )
• 20 % of autoimmune hypothyroidism has been
found to be reversible
• Spontaneous disappearance of blocking antibodies
28. Do you need to treat subclinical
hypothyroidism
• 3-8 % of individuals have subclinical thyroid disease
•
• Most common cause is autoimmune thyroid disease
• 4.3 % progress to hypothyroidism is anti TPO
antibody present
1. TSH > 10 mU/ml
• Therapy indicated if 2. Anti TPO positive
3. Goiter present
4. Menstrual irregularities/ infertility
5. Childhood
6. Bipolar disease/ depression
7. Increasing TSH
29. Hypothyroid symptoms and normal
TFT (functional hypothyroidism)
• Many patients, especially in internet era
• Wilson's syndrome ( not Wilson’s disease) refers to the
presence of common and nonspecific symptoms,
relatively low body temperature, and normal levels of
thyroid hormones in blood.
ATA : no scientific basis for Wilson Syndrome
American Thyroid Association Statement on "Wilson's Syndrome" , Updated May 24, 2005
31. Functional somatic syndromes.
• More than 20% of adults report significant fatigue
• 30% have current musculoskeletal symptoms
• Typical adult has one of the symptoms every 4 to 6
days
• More than 80% of the general population has one of
these symptoms during any 2 to 4 week period.
Barsky AJ, Borus JF. Functional somatic syndromes Ann Intern Med 1999;130:910-21
32. Deja vu
• A lady with weight gain
• A lady with lowish resting heart rates
• Lady with tiredness
• Lady with memory loss
• Lady with “ low” pressure
• A lazy boy with poor school performance
Have you ever started thyroxine for these people ?
33. Messages
• Suspect hypothyroidism
• Thyroxine is the treatment for primary
hypothyroidism
• Dose changes in thyroxine according to TSH
• Some causes of primary hypothyroidism are
reversible
• Treat patients only with abnormal thyroid functions
35. Diagnosis
2.0 ng/dl TSH
Normal range for patient
Normal range of population
0.8 ng/dl
Free T4
4 mIU/L
Free T4
0.3 mIU/L
Euthyroid Subclinical
hypothyroidism
Not drawn to scale
36. Disclaimer
The material for these slides were derived from various sources including
pictures and cartoons from the world wide web. I have tried my best to
acknowledge all possible sources and references. However, if I have overlooked
any particular reference, it is not done intentionally. Anyone reproducing
materials from this presentations should acknowledge the author of the original
work. The case given is imaginary and is given only to support the purpose of
this talk. Any similarity to published case report/ patient is unintentional.