HYPOTHYROIDISM .pdf

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1. HYPOTHYROIDISMHYPOTHYROIDISM

PRESENTED BY :-PRESENTED BY :-
MUKESH PATELMUKESH PATEL ROLL NO. :- 71ROLL NO. :- 71

2. INTRODUCTION
Definition :-
Hypothyroidism a hypometabolic clinical state resulting
from inadequate production of thyroid hormones.

3. ETIOLOGY AND PATHOGENESIS
Hypothyroidism is caused by reduced thyroid hormone production
either due to structural or functional derangements in the thyroid.
It is more common in women than in men.
It can be result from a defect anywhere in the hypothalamic -
pituitary - thyroid axis.

5. Types of Hypothyroidism :-
(1) Primary Hypothyroidism :- More than 90%
Due to intrinsic abnormality in the thyroid gland itself.
There may be the enlargement of the thyroid gland (goiter).
Causes :-
Autoimmune hypothyroidism :- Hashimoto thyroiditis.
Iatrogenic :- Post-ablative ( removal/excision).
:- Adverse effect of drugs.
Iodine deficiency :- common cause in infants and children.

6. Genetic defects
:- congenital biosynthetic defect (Dyshormonogenetic goiter).
:- Defect in thyroid development ( thyroid dysgenesis).
(2) Secondary Hypothyroidism :-
Due to pituitary and hypothalamic diseases.
Causes :-
Pituitary failure. (Rare)
Hypothalamic failure.(Rare)

7. ETIOLOGY
The clinical manifestations of hypothyroidism, depending upon the
age at onset of disorder, are divided into 2 forms :-
CRETINISM 1.
MYXOEDEMA 2.
1 . CRETINISM :- It is Hypothyroidism that develops in infancy or
early childhood.
Endemic cretinism Sporadic cretinism Genetic defects

8. Cretinism formerly was fairly common in areas where there was endemic
dietary iodine deficiency [e.g. mountainous areas such as the Himalayas].
It is now less frequent due to the widespread supplementation of salt with
iodine.
(1) Endemic Cretinism :-
(2) Sporadic Cretinism :-
It is caused due to enzyme defects that interfere with thyroid hormone
synthesis.
(3) Genetic Defects :-
Rarely Cretinism may be due to genetic defects that interfere with
biosynthesis of thyroid hormone(Dyshormonogenetic goiter).

9. Normally, maternal T3 and T4 cross the placenta and they are important to
the development of brain in the fetus.
CLINICAL FEATURES :-
In cretinism there is impaired development of skeletal system and central
nervous system.
Severe mental retardation, Short stature, coarse facial features, Protruding
tongue and umbilical hernia.
:- If there is deficiency of the thyroid hormone in the pregnant women before
the development of the fetal thyroid gland, there will be a severe mental
retardation in the fetus.
:- If reduction of thyroid hormones occurs later in pregnancy, after the fetal
thyroid has developed, the fetal brain may develop normally.

11. (2) MYXOEDEMA :- It is Hypothyroidism that develops in older children
and adults.
Clinical Features :-
Initial symptoms :- Tiredness, overweight, apathy and mental sluggishness,
which may mimic depression.
Symptoms are due to decreased circulating thyroid hormones.
Myxoedematous patients have broadening and coarsening of facial features,
Oedema of the hands and feet, enlargement of the tongue and deepening of
the voice.
The skin cool and pale because of decreased blood flow due to cutaneous
vasoconstriction.

12. Nervous system :-
- Hypothyroid adults are lethargic, show memory loss and slowed mental
processes.
Heart :-
- Reduced cardiac output produces shortness of breath.
- Coronary atherosclerosis is common due to increase in total cholesterol
and low density lipoprotein levels.
Gastrointestinal tract :-
- Decreased sympathetic activity results in constipation.

14. Laboratory Findings in Hypothyroidism
Diagnosis of Hypothyroidism depends on laboratory evaluation
because of the nonspecific nature of symptoms
Decreased serum T3/T4 in patients with hypothyroidism of any origin
Increased serum TSH is observed in primary hypothyroidism. It is the
most sensitive screening test.
Hypercholesterolemia :- caused by decreased synthesis of LDL.

15. ROBBINS
RAMADAS NAYAK
REFERENCESREFERENCES :-:-

16. THANK YOU
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