1. THYROID DISEASES

2. PRESENTING PROBLEMS IN THYROID DISEASE
Hypothroidism
Thyrotoxicosis
Goitre
Malignancy and other tumors
Autoimmune disease
Sick euthyroid syndrome

3. Clinical syndromes TSH T4 T3 Disease
Undetectable Raised Raised Primary thyrotoxicosis
Undetectable Normal Raised Primary T3-toxicosis
Undetectable Normal Normal Subclinical thyrotoxicosis
Undetectable Raised L, N, H Sick euthyroidism/non-thyroidal illness
Undetectable Low Low Secondary hypoth,Transient thyroiditis
Normal Low Low Secondary hypothyroidism
elevated Low Low Primary or Secondary hypothyroidism
Elevated > Low Low Primary hypothyroidism
elevated Normal Normal Subclinical hypothyroidism
Elevated Normal Normal Artefact
Elevated High High Non-compliance R,Secondary thyrotoxicosis

4. Thyrotoxicosis Etiology Multinodular goitre
Autonomously functioning solitary thyroid nodule
Thyroiditis
Subacute (de Quervain's) Post-partum
Iodide-induced Drugs (e.g. amiodarone) Radiographic contrast media Iodine prophylaxis programme
Extrathyroidal source of thyroid hormone Factitious hyperthyroidism Struma ovarii
TSH-induced TSH-secreting pituitary adenoma Choriocarcinoma and hydatidiform mole
Follicular carcinoma ± metastases

5. Graves Disease Autoimmune disorder
Abs directed against TSH receptor with intrinsic activity. Thyroid and fibroblasts
Responsible for 60-80% of Thyrotoxicosis
More common in women

6. Clinical features weight loss with a normal or increased appetite
heat intolerance
palpitations, tremor and irritability
Tachycardia, AF
palmar erythema
lid lag. lid retraction
palpable goitre, but experienced clinicians can discriminate the diffuse soft goitre of Graves' disease from the irregular enlargement of a multinodular goitre.
Graves' disease causes other features of ophthalmopathy, including periorbital oedema, conjunctival irritation, exophthalmos and diplopia.
Pretibial myxoedema

8. Graves Disease Other Manifestations
Pretibial mixoedema
Thyroid acropachy
Onycholysis
Thyroid enlargement with a bruit frequently audible over the thyroid

9. Graves Disease Eye Signs
N - no signs or symptoms
O – only signs (lid retraction or lag) no symptoms
S – soft tissue involvement (peri-orbital oedema)
P – proptosis (>22 mm)(Hertl’s test)
E – extra ocular muscle involvement (diplopia)
C – corneal involvement (keratitis)
S – sight loss (compression of the optic nerve)

10. Diagnosis of Graves Disease
TSH , free T4 
Thyroid auto antibodies
Nuclear thyroid scintigraphy (I123, Te99)

11. Management
Antithyroid drugs are introduced at high doses, e.g. carbimazole mg daily or prophylthiouracil mg daily. There is subjective improvement within days and the patient is usually clinically and biochemically euthyroid at 3-4 weeks, when the dose can be reduced. The maintenance dose is determined by measurement of T4 and TSH(1-2y).
Subtotal thyroidectomy Patients must be rendered euthyroid with antithyroid drugs before operation. Potassium iodide, 60 mg 8-hourly orally, is often added for 2 weeks before surgery to inhibit thyroid hormone release and reduce the size and vascularity
Radioactive iodine 131I is administered orally as a single dose and is trapped and organified in the thyroid
B-blockers to control symptoms, steroid for ophthalmopathy

12. Hypothyroidism Clinical features
depend on the duration and severity of hypothyroidism.
infiltration of many body tissues by the mucopolysaccharides, hyaluronic acid and chondroitin sulphate
low-pitched voice and poor hearing
slurred speech due to a large tongue
carpal tunnel syndrome
non-pitting oedema (i.e. myxoedema)
periorbital puffiness is often striking and
facial pallor due to vasoconstriction and anaemia
lemon-yellow tint to the skin due to carotenaemia, purplish lips and malar flush
bradycardia., cold intolerance.

14. Hypothyroidism etiology
Primary
HASHIMOTO'S thyroiditis posess positive thyroid peroxidase autoantibodies and a firm goitre who may or may not be hypothyroid
'spontaneous atrophic hypothyroidism' for hypothyroid patients without a goitre in whom TSH receptor-blocking antibodies may be more important than antiperoxidase antibodies.
Post-thyroid abalation
Iodin and other drugs
Radiation
Secondary hypothyroidism
Hormone resistance

15. Transient Hypothyroidism
during the first 6 months after subtotal thyroidectomy
131I treatment of Graves' disease
post-thyrotoxic phase of subacute thyroiditis
post-partum thyroiditis.

16. Lab Investigations of Hypothyroidism
TSH , free T4 
Ultrasound of thyroid – little value
Thyroid scintigraphy – little value
Anti thyroid antibodies – anti-TPO
S-CK , s-Chol , s-Trigliseride 
Normochromic or macrocytic anemia
ECG: Bradycardia with small QRS complexes

17. Treatment of Hypothyroidism
Levothyroxine
If no residual thyroid function 1.5 μg/kg/day
Patients under age 60, without cardiac disease can be started on 50 – 100 μg/day. Dose adjusted according to TSH levels
In elderly especially those with CAD the starting dose should be much less (12.5 – 25 μg/day)

18. SUBACUTE (DE QUERVAIN'S) THYROIDITIS
patients are usually females aged years
In its classical painful form, subacute thyroiditis is a virus-induced (e.g. Coxsackie, mumps or adenovirus) transient inflammation of the thyroid gland.
pain may radiate to the angle of the jaw and the ears, and is made worse by swallowing, coughing and movement of the neck
inflammation in the thyroid gland is associated with release of colloid and stored thyroid hormones, but also with damage to follicular cells and impaired synthesis of new thyroid hormones. As a result, T4 and T3 levels are raised for 4-6 weeks until the pre-formed colloid is depleted.
a period of hypothyroidism of variable severity before the follicular cells recover and normal thyroid function is restored within 4-6 months
Low-titre thyroid autoantibodies appear transiently in the serum, and the erythrocyte sedimentation rate (ESR) is usually raised
NSAID ,prednisolone 40 mg daily for 3-4 weeks

19. Acute Thyroiditis Bacterial – Staph, Strep
Fungal – Aspergillus, Candida, Histoplasma, Pneumocystis
Radiation thyroiditis
Amiodarone (acute/ sub acute)
Painful thyroid, ESR usually elevated, thyroid function normal

20. Chronic Thyroiditis Hashimoto’s Autoimmune
Initially goiter later very little thyroid tissue
Rarely associated with pain
Insidious onset and progression
Most common cause of hypothyroidism
TPO abs present (90 – 95%)

21. Thyroiditis
The most common form of thyroiditis is Hashimoto thyroiditis, this is also the most common cause of long term hypothyroidism
The outcome of all other types of thyroiditis is good with eventual return to normal thyroid function

22. Solitary Thyroid Nodule
History
Duration, recent enlargement, voice change, H/O hypo/hyperthyroidism, irradiation, F/H goitre/cancer
Physical examination
Dominant nodule, movement on deglutition, cervical lymph nodes, fixation, hardness
Thyroid function studies
Serum TSH
T4 & T3 levels
Antibody levels; ATA, AMA 1:100
Thyroid imaging; Scanning (99mTc, 123I, 131I)

23. Solitary Thyroid Nodule
CXR
Ultrasound
Solid/cystic
Multicentric
Lymph node involvement
Ultrasound-assisted FNA
CT/MRI of neck
Mainly for large/recurrent cancers
Vascular/lymphatic invasion
Cervical/mediastinal metastasis

24. Solitary Thyroid Nodule
FNAC Result
Benign Observe and repeat FNAC 1 year
Malignant Surgery
Indeterminate serum TSH normal Surgery
Serum TSH low Scintiscan
Inadequate Repeat FNA

25. Thyroid Cancer Incidence 1% M/F ratio 3:1 Risk factors
Radiation exposure
External
Medical treatment for benign conditions
Medical treatment for malignancies
Environmental exposure- Nuclear weapons or accidents
Internal
Medical treatment of benign condition with I131
Diagnostic tests with I131
Environmental- fallout from nuclear weapons
Other factors
Diet- Iodine deficiency, goitrogens
Hormonal factors- female gender predominance
Benign thyroid disease
Alcohol

26. Thyroid Cancer Pathology Papillary carcinoma; Follicular carcinoma
60-70% of all cases
Multifocal
Nonencapsulated, but circumscribed
Lymphatic spread
80% 10 year survival
Follicular carcinoma
15-20% of thyroid cancers
Usually encapsulated
60% 10 year survival

27. Thyroid Cancer Hurthle cell neoplasm Medullary cancer
5% of thyroid cancers
Variant of follicular cancer
Lymph node spread slightly higher than follicular cancer
Lees avidity for 131I
Medullary cancer
Parafollicular C cells
Autosomal dominance inheritance in 20%
Unilateral involvement in sporadic, bilaterality in familial forms
Calcitonin secretion
Metastasis both by lymphatic and blood stream
10 year survival 90% in localised disease, 70% with cervical mets, 20% with distant mets

28. Thyroid cancer Anaplastic cancer Lymphoma Undifferentiated
Rapidly growing, often inoperable
Invade locally, metastasize both locally and distantly
Mean survival 6 months
5 year survival rate 7%
Lymphoma
Rare, rapidly enlarging tumour
Primary or secondary
Seventh decade, 6:1 F/M ratio
5 year survival rate 75-80%, when confined to thyroid

29. Thyroid cancer Treatment of thyroid cancer Papillary cancer
< 1.5 cms Lobectomy & isthmusectomy
> 1.5 cms Total thyroidectomy
Follicular cancer Total thyroidectomy
Hurthle Total thyroidectomy
Medullary Total thyroidectomy & central neck dissection

30. Thyroid cancer Adjuvant therapy Surveillance TSH suppression
Post operative radioactive Iodine ablation
External beam radiotherapy
Surveillance
Serum thyroglobulin levels
CXR or CT scan
Repeat 131I if positive