This an illness is caused by the hypo secretion of thyroid hormone in childhood. Hypo cheap of pituitary TSH may cause hypo task of thyroid gland. Congenital lacks that thyroid gland also aid in advance of cretinism (Fig. 12.8).


The characteristic functions are as follows:

(i) Morphological features:

1. Linear development is severely re­tarded resulting dwarfism.

2. Shunted skeletal growth.

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3. Quick club like fingers.

4. Rough, dry, wrinkled and scaly skin.

5. Scanty development of hairs.

6. Bloated face appearance.

7. Idiotic look.

8. Thick and enlarged tongue (macroglossia).

9. Overabundance saliva secretion.

10. Negative muscle growth.

11. Pot-bellied abdomen.


12. Teeth room deformed.

13. Reduced sexual growth.

(ii) Physiological features:

1. Reduced heart rate.


2. Short body temperature.

3. Short BMR.

4. Fat is irregularly distributed.

5. Low blood sugar level.


6. Reflexes room sluggish.

7. Immune device is reduced.

8. Low RBC count.

(iii) emotional features:


1. Cretins are frequently deaf and also dumb.

2. The kid is subnormal in intelli­gence.

3. Have actually various levels of psychological retardation and also idiocy.

(iv) Sexological features:

1. Retarded growth of sex organs and sex glands.

2. Second sex personalities are un­derdeveloped.


(B) Myxoedema (Gull’s disease):

This dis­ease is caused by hypo activity of thy­roid gland in adult. It is also caused by the hypo secretion of pituitary TSH.

It is defined by adhering to features.

(i) Morphological features:

1. Skin colour i do not care yellow early to buildup of mucinous pro­tein deposit in the cutaneous tis­sue.

2. Skin reflects appearance of swollen swellings.

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3. Puffy face.

4. Ede in neck region.

5. Rarely often, rarely fat deposition, particularly in clavicular, and buttock region.

6. Ns of hair from eyebrows, pu­bis, axillae.

7. Tongue and also larynx are thick­ened.

(ii) Physiological features:

1. Low BMR.

2. Short blood street level.

3. Diminished heart rate and cardiac output.

4. Low blood pressure.

5. Nitrogen excretion is reduced.

6. Much less appetite.

7. Much less peristaltic task in GI tract.

8. Cholesterol level becomes high.

9. Sluggish muscle contractibility.

(iii) emotional features:

1. The patient is lethargic and sleepy.

2. Dull in appearance.

3. Suffers indigenous loss that memory.

4. Reflexes are very slow.

(iv) Sexological features:

1. Sexual attributes are diminished.

2. Major sex organs and also sex glands room degenerated.

3. Loss of libido effect.

4. Failure of fertility power.

Due to Hyper secretion of Thyroid Hormone:

Grave’s condition (Exophthalmic goiter):

This disease is brought about by hyper secretion of thy­roid hormone in both infant and also adult life. Hyper secretion of pituitary TSH or thyro­toxicosis may aid in development of hyper activity of thyroid gland. This an illness may be mediated by one immunoglobulin recognized as LATS (Long acting thyroid stimulator). LATS binding to TSH receptors and activates thyroid cabinet functions even in lack of cir­culating TSH.

It shows adhering to features:

(i) Morphological features: (Fig. 12.9)


1. Enlarged thyroid gland.

2. Diminished body weight.

3. Skin i do not care soft and also sweaty.

4. Ns of fat depot.

5. Hands are usually worm and moist.

6. Hairs are fine and friable.

7. Muscles become easily fatigued.

8. Large protruded eye round i.e. Exoph­thalmic eye.

9. Retraction that the upper eye lid.

(ii) Physiological features:

1. BMR is significantly increased.

2. Osteoporosis bring away place due to loss of calcium and also phosphorus.

3. Shows hyperglycemia and also glycosauria.

4. Protein catabolism is increased.

5. Enhanced blood pressure.

6. Boosted cardiac output.

7. Higher loss that sodium and also potas­sium v urine.

8. Requirement of vit. B complexes in­creased.

9. Increased appetite.

10. Loud heart sounds.

(iii) mental features:

1. Patient i do not care nervous and emo­tional.

2. Person becomes restless and also sleep­less.

(iv) Sexological features:

1. Increase in libido effect.

2. Disturbances in menstrual bicycle in woman.

3. The fertility strength becomes reduced.

Special note:


It is the enlargement the thyroid gland.

It can be divided into following types:

(A) basic goiter:

It is caused by the defi­ciency the iodine in the body.

It is again subdivided into three types:

(i) Colloid goiter:

This form is influential in locations where the drink water is deficient in iodine. In order to pro­duce common levels of hormone, the gland i do not care hypertrophied. The follicles are distended with colloid. Input of iodinated salt is the preven­tive measure up (Fig. 12.10).


(ii) diffusive parenchymatous goiter:

The follicular epithelial cells present hyper­trophy and also multiply in number due to which lumen of the follicle be­come obliterated.

(iii) Nodular goiter:

This type is charac­terized through the figure of nodu­lar ede in some component of the gland. That is brought about by distinct much eleva­tion the T3 with much less elevation the T4 level.

(B) toxicity goiter:

When swelling or enlarge­ment the the thyroid gland outcomes in ex­cess cheap of thyroid hormones, this problem is called toxic goiter (Fig. 12.11).


The main cause for this goiter is the in­gestion that chemicals, like anti-thyroid drugs, prefer methylthiouracil, propylthiou­racil and also carbimazole. The existence of goitrogenic building materials in cabbage, tur­nip etc. I beg your pardon contain a chemistry sub­stance goitrin. Through these impacts follicu­lar cells come to be hypertrophied and hy­perplastic. This leader to hyper secretion.

(C) Exophthalmic goiter:

Due to hyper secretion of thyroid hormone, thyroid gland becomes enlarged. As a result there is a protrusion that the eyeball called exoph­thalmic goiter as result of swelling of the extra ocular muscles and also connective organization within the bony wall of the orbit.

Table 12.2: Difference between Hypo and also Hyperthyroidism


1. T3 and T4 level are lessened

2. BMR becomes low

3. Perspiration becomes lessened

4. Impaired minister glucose absorption

5. Short blood cholesterol

6. Decreased protein anabolism

7. Weight get

8. Lessened appetite

9. Low body temperature

10. Cold intolerance

11. Dry palm

12. Sleepiness, tiredness

13. Goiter might or may not be current

14. Short pulse rate and less cardiac calculation


1. T3 and T4 levels space increased.

2. BMR i do not care high.

3. Perspiration i do not care increased.

4. Magnified intestinal glucose absorption.

5. High blood cholesterol.

6. Boosted protein anabolism.

7. Weight loss.

8. Enhanced appetite.

9. High human body temperature.

10. Warm intolerance.

11. Moist palm.

12. Restlessness, insomnia.

13. Goiter present.

14. High pulse rate and increased cardiac output.


(D) Hokkaido goiter:

During the synthetic of thyroid hormones, inorganic iron is taken up from the blood and converted right into organic kind by reacting through the amino acid tyrosine. High concentration the iodine inhibits organification that iodine and causes hypothyroidism.

Cause of Hypothyroidism:

Decreased secretion of thyroid hormones may reason hypothyroidism.

The causes are given below:

Nature of Hypothyroidism Causes:

(a) Primary:

i. Iodine deficiency in the food and also drinking water.

ii. Defective synthesis of the thyroglobulin and also secretion can lead to hypothyroidism.

iii. Hereditary failure in the advance of the thyroid hormone receptors.

iv. Inborn error in thyroid hormone biosynthesis.

v. Radiation iodine therapy may reason hypothyroidism.

vi. The entry of goitrogenic substances.

vii. Failure of the counter of T3 and also T4 in peripheral tissue.

(b) Secondary:

i. As result of pituitary adenoma, pituitary ablation or pituitary destruction.

ii. Pituitary TSH deficiency.

iii. Defect in TSH receptor of thyroid gland.

iv. Defect in secretion of TSH-RH that hypothalamus.

v. Damages of Hypothalamohypophysial system.


Causes of hyperthyroidism:

Excess se­cretion that thyroid hormone may cause hy­perthyroidism.

It is brought about by following ways:

(i) Graves’ disease is one autoimmune dis­ease in i beg your pardon circulating antibodies formed against TSH receptor. The anti­bodies space TSH-R-Ab. It may bind come TSH receptor on thyroid follicle membrane and thus stimulating the cheap of T3 and T4.

(ii) Lesions top top thyroid gland may reason of hyper secretion of T3 and T4 also under short TSH.


It results as soon as tissues room exposed come over-secretion that thyroid hor­mones. Graves’ an illness and Plummer’s dis­ease are good examples.


It is the inflammation disor­der that thyroid gland.

Hasimoto’s disease:

Hashimoto (1912) observed this pathophysiology the thyroid gland. That is led to due to damages of thyroid gland tissue and hypo function. The clinical functions are—exaggeration of typical lobu­lar pattern, devastation of epithelial cells, degeneration of follicular basement mem­brane, infiltration of lymphocytes etc. The diagnosis of this an illness is confirmed by the finding of high titers that thyroid autoantibod­ies in the serum (Fig. 12.12).