6. Primary hypothyroidism
Primary hypothyroidism(90%)
(TSH)
free (T4)
Congenital
Aquired
o Hashimotos thyroiditis
o I deficiency
o Goitrogens
o Cytokines
o Thyroid infiltration
o drugs
o Iatrogenic
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7. Central Hypothyroidism or 2ndry
Secondary (central) hypothyroidism
1. serum T4
2. serum TSH
Acquired
o Pituitary &hypothalamic disorders
o Dopamine & or severe stress
Congenital
o TSH deficiency/structural abnormality
o TSH receptor defect
o TRH deficiency
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8. Other types
Transient H
Silent thyroiditis (postpartum & Subacute)
Withdrawal of thyroxine Rx
After Rx or surgery for Graves' disease
Consumptive H
hemangiomas ,hemangioendotheliomas
Resistance to Thyroid Hormone
generalised or pituitary dominant
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9. Other types con..
Subclinical hypothyroidism
Asymptomatic patient
TSH
Normal FT4 & FT3
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10. Clinical (overt) H
o Symptomatic patient
o Elevated TSH level
o low levels of FT4 and FT3
Euthyroid sick syndrome
o Pts without known thyroid disease
o FT4
o TSH not elevated.
severe illness, caloric deprivation, or major surgery.
Serum TSH tends to be suppressed in severe nonthyroidal illness
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11. Myxedema crisis
• A life-threatening state with
• Impaired cognition {confusion to somnolence to coma
(myxedema)}
• Elderly women (stroke or stopped taking thyroxine)
• Convulsions & CNS signs
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12. Precipitating events
1. Infection, sepsis
(pneumonia)
2. Cold exp
3. CVA
4. Drug effect
5. MI
6. GI bleeding
7. Trauma
8. burns
9. CHF
10. Hypoxia
11. Na
12. Capnea
13. Glycemia
14. Ca
15. DKA
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14. Effect of Hypothyroidism on Organs
Cardiovascular
• VC
• HR
• DBP
Central Nervous
• Concentration
• Lack of interest
• Depression
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15. Effect of Hypothyroidism on Organs
GIS
o GI motility
o Constipation
Hepatic
o LDL / TC
o LDL + triglycerides
Renal
o Fluid retention
o GFR
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17. Reproductive
o Arrest of pubertal development
o Reduced growth velocity
o Menorrhagia, Amenorrhea
o Anovulation, Infertility
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Effect of Hypothyroidism on Organs
18. 18
Effect of Hypothyroidism on Organs
Skin and Hair
Thickening and dryness of skin
Dry, coarse hair, Alopecia
Loss of scalp hair and / or lateral
eyebrow hair
21. Drug Clearance
Clearance of many drugs are decrease :
o Antiepileptic
o Anticoagulant
o Anesthetic
o Hypnotic & Opioid
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22. Hashimoto's encephalopathy
A steroid-responsive syndrome associated with:
o TPO antibodies
o myoclonus & slow-wave activity on EEG
o An immunemediated rather than effect of an altered
thyroid state on the CNS
22
23. 23
FREETHYROXINEorFT4
EUTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH
TFT: Best screening test for hypothyroidism is the serum TSH
How to interpret results ?
Nine Square Game To evaluate our Thyroid patient
Lab Exam
27. Hyponatremia, Hypoglycemia & Anemia
levels of LDL,TG, LP, liver enzymes, CK &
Prolactin
Semen analysis
FNA biopsy
Ab against TPO and TG are high
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Other Abnormalities:
28. The Dx of Myxedema Coma
Abn TSH & FT4 + nonpitting edema
Hypoventilation , Hypothermia & Stupor
Hyponatremia , Hypoglycemia , Hypotension and Infection
are confirmatory
30. Goal is to normalize TSH (lower half of the reference
range)
Levothyroxine (HL 7 days) on empty stomach
Levothyroxine dosage according to:
o Clinical response
o TSH
Keep TSH (0.4 and 2.0 milli- units/L)
30
Treatment
31. Clinical assessment for adrenal insufficiency and
angina
Levothyroxine doses
o Healthy young and middle aged adults 25–75 mcg/d
o Lower doses for very mild hypothyroidism
o Treat pregnant women with higher doses of 100–150
mcg/d
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Treatment con..
32. Determinants of Thyroxine Requirements
Age
Severity and duration
Weight
Malabsorption
Pregnancy
Presence of CVD
Concomitant drug therapy
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33. Smaller doses (25–50 mcg /d):
o CAD
o 60 y
Higher initial doses:
o severely hypothyroid
The dose can be increased by 25 mcg every 1–3 weeks
until the pts is euthyroid
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34. Larger initial IV doses of levothyroxine
o 400 mcg as a loading dose
o followed by 50–100 mcg IV/d
IV liothyronine (T3, Triostat) 5–10 mcg /8 h /48 h
Blankets warming for hypothermia
Intubation & MV for hypercapnia
Infections
hydrocortisone
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Myxedema Crisis Rx
35. During pregnancy
1st trimester
TSH drops
FT4 rise
FT4 is helpful in
evaluation
Check TSH /4wk
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