For MBBS students, undergraduate level, Thyroid disorders, endocrine diseases.

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THYROID DISORDERS
By Dr Nadia Shams
Professor of Medicine

2. Thyroid Regulation
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PLASMA T4 + FT4
HYPOTHALAMUS - TRH
ANT. PITUITARY - TSH
THYROID T4 and T3
PLASMA T3 + FT3
TISSUES FT4 to FT3, rT3
TSH -R

3. Metabolism of Thyroid Hormones
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Thyroid Gland
Thyroxine FT4
Reverse T3 (rT3) Triiodothyronine (FT3)
Tertrac etc.,
100 nm
5 nm
< 5 nm
45 nm 35 nm
20 nm

4. Thyroid Function Tests
1. TSH
2. Free T4
3. Free T3
4. Anti-Thyroid Antibodies
5. Nuclear Scintigraphy
6. FNAC of nodule
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5. Clinical Examination of Thyroid
 Palpate from behind the patient
 Remember the rule of finger tips
 Pemberton’s sign for retrosternal
Goitre.

6. Clinical Exam of Thyroid

7. Clinical Exam of Thyroid

8. THYROID HORMONES
TEST REFERENCE RANGE
TSH Normal Range 0.3 - 4.0 mU/L
Free T4 Normal Range 0.7-2.1 ng/dL
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9. Thyroid Antibodies
⚫ Anti Microsomal
⚫ Anti Thyroglobulin
⚫ Anti Thyroxine Per Oxidase
⚫ Anti Thyroxine antibodies
⚫ Thyroid Stimulating Antibodies
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10. CASE
⚫ A 30 years old girl presents with 3 months
history of lethargy, excessive weight gain,
swelling of feet, cold intolerance and
hoarseness of voice…
⚫ The most likely diagnosis is ???

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HYPOTHYROIDISM

12. Hypothyroidism
⚫ Epidemiology
– Most common endocrine disease
– Females > Males – 8 : 1
⚫ Presentation
– Often unsuspected and grossly under diagnosed
– 90 % of the cases are Primary Hypothyroidism
– Menstrual irregularities, miscarriages, growth retard.
– Vague pains, anaemia, lethargy, gain in weight
– In clear cut cases - typical signs and symptoms
– Low free T4 and High TSH
– Easily treatable with oral Levo-thyroxine
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13. Classification of Hypothyroidism
A. Primary
1. Autoimmune
- Hashimoto’s
2. Iatrogenic
- radioactive iodine
3. thyroiditis - Subacute
(Dequervain’s)
- Postpartum
4. Iodine deficiency
5. Secondary / Central
Pituitary/ hypothalamic
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14. Thyroid Failure - Organ Systems
Cardiovascular
• Decreased ventricular contractility
• Increased diastolic blood pressure
• Decreased heart rate
Central Nervous
• Decreased concentration
• General lack of interest
• Depression
Gastro-instestinal
• Decreased GI motility
• Constipation
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Thyroid Failure - Organ Systems
Musculoskeletal
⚫ Muscle stiffness, cramps, pain,
weakness, myalgia
⚫ Slow muscle-stretch reflexes,
muscle enlargement, atrophy
Renal
⚫ Fluid retention and oedema
⚫ Decreased glomerular filtration

16. Reproductive
⚫ Arrest of pubertal development
⚫ Reduced growth velocity
⚫ Menorrhagia, Amenorrhea
⚫ Anovulation, Infertility
Hepatic
⚫ Increased LDL / TC
⚫ Elevated LDL + triglycerides
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Thyroid Failure - Organ Systems

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Thyroid Failure - Organ Systems
Skin and Hair
⚫ Thickening and dryness of skin
⚫ Dry, coarse hair, Alopecia
⚫ Loss of scalp hair and / or
lateral eyebrow hair

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Multi system effects - Hypothyroidism
General
•Lethargy, Somnolence, Weight gain, Goitre, Cold Intolerence
Cardiovascular
•Bradycardia, Angina,CHF, Pericardial Effusion
•HyperlipIdemia, Xanthelasma
Haematological
Iron def. Anaemia,
Normocytic/chromic Anaemia
Reproductive system
•Infertility, Menorrhagia,Impotence, Inc. Prolactin

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Multi system effects - Hypothyroidism
Neuromuscular
•Aches and pains, Muscle stiffness
•Carpel tunnel syndrome, Deafness, Hoarseness
•Cerebellar ataxia,Delayed DTR, Myotonia
•Depression, Psychosis
Gastro-intestinal
•Constipation, Ileus, Ascites
Dermatological
•Dry flaky skin and hair
•Myxoedema, Malar flushes
•Vitiligo, Carotenimia, Alopecia

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Clinical Signs of Hypothyroidism
⚫ Coarse Hair; Dry cool and pale skin
⚫ Goitre
⚫ Hoarseness of voice
⚫ Non-pitting oedema (myxoedema)
⚫ Puffiness of eyes and face
⚫ Delayed relaxation of deep tendon reflexes
⚫ Slow hoarse speech and slow movements
⚫ Thinning of lateral 1/3 of eye brows
⚫ Bradycardia, pericardial effusion

21. Myxedema Coma
⚫ Precipitating factors :
⚫ Infection, trauma, stroke, cardiovascular,
hemorrhage, drug overdose, diuretics
⚫ Signs and Symptoms :
⚫ Mental confusion, hypothermia, bradycardia
⚫ ↓ Na, ↓ glucose, ↑ CO2, ↓ WBC, ↓ Hct, ↑
CPK
⚫ ↓ EKG voltage, myxedema, b-carotnenemia
⚫ Treatment
⚫ ICU transfer, T3 100 µg IV sixth hourly, 500 µg of
T4 , antibiotics, ventilation, hydrocortisone IV,
passive warming, careful volume management 23

22. Congenital Hypothyroidism
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24. Endemic Goiter
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26. Macroglossia
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27. Xanthomata
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Xanthelasma
Tuberous Xanthoma

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Oedema Xanthomata

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Myxoedema with Carotineamia

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Recovery after L-Thyroxine

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Pituitary Tumor – Secondary Hypo
Normal Pituitary Fossa

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Massive Pericardial Effusion in
Hypothyroidism

33. Investigations
⚫ Low T4
⚫ High TSH
⚫ ECG shows sinus bradycardia
⚫ TPO antibodies

34. Many Causes, One Treatment
⚫ Levothyroxine sodium (1.6µg/kg/day) approx.100
mcg per day
⚫ Monitor TSH levels at 6 to 8 weeks, after initiation of
therapy or dosage change
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35. Over-replacement risks
⚫ Reduced bone density / osteoporosis
⚫ Tachycardia, arrhythmia. atrial fibrillation
⚫ In elderly or patients with heart disease, angina,
arrhythmia, or myocardial infarction
Under-replacement risks
⚫ Continued hypothyroid state
⚫ Long-term end-organ effects of hypothyroidism
⚫ Increased risk of hyperlipidemia
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Inappropriate Dosage

36. Diet in Iodine deficiency
⚫ Iodized salt
⚫ Selenium supplementation
⚫ Avoid cabbage (goitrogens)
⚫ Avoid formula milk
⚫ Fish, meat, milk & eggs
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38. Case
A 55 year old woman is anxious, irritable with history of
frequent semi solid stools and she reports weight loss of
5 kgs in the past six months. She was having a painless
swelling in her neck for past 20 years.
The most likely
diagnosis is ???

39. Hyperthyroidism
 A hyper metabolic biochemical state
 It is a multi system disease with elevated
levels of FT4 or FT3 or both
 Because of negative feed back TSH will be
suppressed

40. Causes of Hyperthyroidism
1. Graves Disease – Diffuse Toxic Goiter
2. Plummer’s Disease – Toxic MNG
3. Sub Acute Thyroiditis
4. Toxic Single Adenoma
5. Pituitary Tumors – excess TSH

41. Common Symptoms
1. Nervousness
2. Anxiety
3. Increased sweating
4. Heat intolerance
5. Tremors
6. Hyperactivity
7. Palpitations
8. Weight loss despite increased appetite
9. oligo-menorrhea/ infertility

42. Common Signs
1. Hyperactivity
2. Sinus tachycardia /AF/ CHF
3. Systolic hypertension, wide pulse pressure
4. Warm, moist, soft and smooth skin/warm handshake

43. Signs
1. Excessive perspiration, palmar erythema,
Onycholysis
2. Lid lag and stare (sympathetic over activity)
3. Fine tremor of out stretched hands – format's
sign
4. Large muscle weakness(proximal myopathy)
5. Gynaecomastia

44. Specific to Graves Disease
1. Diffuse painless firm enlargement of thyroid
gland
2. Thyroid bruit
3. Eye manifestations – 50% of cases.
4. Skin/limb manifestations – 20% of cases
➢ non pitting edema, associated with erythema
and thickening of the skin, without pain or
pruritus - called pretibial myxedema

45. Non specific changes
1. Hyperglycemia, Glycosuria
2. Osteoporosis and hypercalcemia
3. ↓ LDL and Total Cholesterols
4. Atrial fibrillation, LVH, ↑ LV EF
5. Hyper dynamic circulatory state
6. High output heart failure
7. H/o excess Iodine, amiodarone, contrast
dyes

46. Diagnosis and investigations
1. Suppressed TSH (<0.05 µIU/mL)
2. Elevated FT4
3. Thyroid antibodies – anti-TPO, TSI, TRAb.
4. ECG
5. Nuclear Scintigraphy

47. Completely irregular rhythm
Atrial fibrillation

48. Graves Disease
I 123 or TC 99m Normal v/s Graves

49. Treatment Options
1. Symptomatic & supportive
2. Anti Thyroid Drugs – ATD
➢ Methimazole, Carbimazole
➢ Propylthiouracil (PTU)
3. Radio Active Iodine treatment – RAI Rx.
4. Thyroidectomy – Subtotal or Total
5. NSAIDs and Corticosteroids – for SAT

50. Symptom Relief
1. Rehydration
2. β – blockers
➢ Propranalol, Atenelol, Metoprolol
3. Treatment of CHF, Arrhythmias
4. Calcium supplementation
5. Lugol solution for ↓ vascularity of the gland

51. Radio Active Iodine (RAI Rx.)
 It is effective, safe, and does not require
hospitalization.
 Given orally as a single dose

52. Graves Disease
 The most common cause of thyrotoxicosis (50-60%).
 Organ specific auto-immune disease
 The most important autoantibody is
 Thyroid Stimulating Immunoglobulin (TSI) or TSA
 TSI acts as proxy to TSH and stimulates T4 and T3
 Anti-TPO antibodies
 Anti thyro globulin (anti-TG) Anti Microsomal and
other
 Autoimmune diseases - Pernicious Anemia
 RA, Myasthenia Gravis, Vitiligo, Adrenal insufficiency.

53. Surgical Treatment
 Subtotal Thyroidectomy, Total Thyroidectomy
 Hemi Thyroidectomy with contra-lateral
subtotal

54. Thyroid Storm
⚫ Symptoms
⚫ Fever
⚫ Agitation
⚫ Confusion
⚫ Tachycardia
⚫ Atrial fibrillation
⚫ CHF
⚫ Treatment
⚫ Rehydration
⚫ Propranolol 80 mg 6Hrly
⚫ Sodium Ipodate (500 mg/day)
⚫ Dexamethasone 2mg 6Hrly

55. Clinical Presentations

56. MNG and Graves
Huge Toxic MNG Diffuse Graves Thyroid

57. Proptosis
Lid lag
Thyroid Ophthalmopathy

58. Ophthalmopathy in Graves
Periorbital edema and chemosis

59. Ophthalmopathy in Graves
Occular muscle palsy

60. Severe Exophthalmos

61. Thyroid Dermopathy
Pink and skin coloured papules, plaques on the shin

62. Clubbing and Osteoarthropathy
Thyroid Acropathy

63. Onycholysis

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