Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Hypothyroidism Lecture PPT
HYPOTHYROID.
Thyroid gland.
?Thyroid is a small gland found in the middle of the
lower neck.
?Thyroid works with pituitary gland which
produces thyroid stimulating hormone(TSH).
?TSH stimulate the thyroid gland to produce the
thyroid hormone,T3 and T4.
Thyroxine Hormone
vIodine, a trace mineral, is essential for the
synthesis of thyroid hormone..
vThyroxine(T4) and triiodothyronine (T3).
v20 % of T3 derived directly from thyroid gland
and 80 % by conversion from T4.
vThyroid hormone regulate metabolism in every
cell of the body and play a role in virtually all
physiological function.
Regulating thyroid hormone.
o When the amount of thyroid hormone in the blood
drops, the pituitary gland secretes a hormone called
thyroid stimulating hormone(TSH).
o TSH then stimulate the thyroid gland to increase its
uptake of iodine from the blood, so that more
thyroxin(T4) can be synthesized.
o When necessary, thyroid is then converted to the
metabolically active triodothyroxine(T3), a process that
involves removing one iodine atom from T4.
TSH: THYROID STIMULATING
HORMONE.
?ELEVATED TSH.
?> 5mU/L
?LOW TSH.
HYPERTHYROIDISM ?< 0.5mU/L.
.
TEST
FROM
TO
UNITS
TSH
0.25
5.00
mU/L
FT4
9.0
25.0
pmol/L
FT3
3.5
7.8
pmol/L
THYROID TEST
? TSH--NORMAL RANGE--0.25--5.0 mU/L.
? Symptomatic primary hypothyroidism > 20
? Mild symptomatic hypothyroidism 10 to 20
? Primary hyperthyroidism < 0.05.
? Thyroxine(T4)
? Triiodothyronine(T3)
? Free T3
? Free T4
Labs.
Hyperthyroidism
? FT4
? TSH
Hypothyroidism
? FT4
? TSH.
Labs.
TSH
HIGH-TSH
LOW
FT4- LOW
HYPOTHYROIDISM
FT4 AND FT3-LOW
HIGH-FT4 AND
CENTRAL
FT3
HYPOTHYROIDISM.
HYPOTHYROID
THYROTOXICOSIS.
WHEN TO HAVE THYROID
FUNCTION TEST.
? Swelling in the neck
? Abnormal menstrual cycle
? Fertility problem
? High cholesterol
? Weight gain
? Puffiness of Face, dry skin, hair loss
? Fatigue, lethargy, Anemia etc..
THYROID REGULATION.
Physiological actions of Thyroxin
hormones.
? Potentiates brain development.
? Increases heart rate.
? Increases cardiac output.
? Increases ventilation rate.
? Thickens of endometrium in female.
Metabolic effects of Thyroid
hormones.
vThe hormone exerts action on every cell on
the body.
vCalorigenic effect or thermogenesis is the
major effect of throid hormone.
vThis thermogenic effect is mediated by
uncoupling of oxidative phosphorylation.
vBasal metabolic rate (BMR) is increased.
vThyroxine increases cellular metabolism.
vEarliest effect of T4 is stimulation of RNA
synthesis and consequent increase in protein
vsynthesis Higher concentration of T3 causes
protein catabolism and negative nitrogen
balance.
vLoss of body weight is a prominent feature of
hyperthyroidism.
vGluconeogenesis and carbohydrate oxidation
are increased.
vGlucose tolerance test shows rapid absorption.
vFatty acid metabolism is increased.
vCholesterol degradation is increased and
hence cholesterol level in blood is decreased,
which is another hallmark of hyperthyroidism.
CAUSE OF HYPOTHYROIDISM.
hypothyroidism.
? Hypothyroidism is a thyroid problem caused
by an underactive thyroid gland that produces
insufficient amount of thyroid hormones.
? Hypothyroidism is seen in both sexes, but is
more common in women.
? In pregnancy new born is at risk of cretinism.
? Cold intolerance
? Constipation.
? Lethargy
? Dry and course skin and hair
? Facial puffiness
? Anemia
? Impaired memory
? Confusion
? Dementia
? Low speech and motor activity.
Complications.
? Untreated condition, patient is at risk for?
? Diabetes.
? High blood pressure.
? Arthritis.
? Depression.
? Recurrent infection.
? Migraine.
Classification of hypothyroidism.
Due to failure
Due to
Due to failure
of the thyroid
hypopituitarism.
of
gland itself.
hypothalmus.
PRIMARY.
TERTIARY.
SECONDARY.
Hypothyroidism(GOITRE).
? Excess stimulation by TSH due to decreased
level of circulating thyroid hormones, leads to
enlargement of thyroid gland.
? Reason:
? 1. Iodine deficiency.
? 2.certain antithyroid drugs.
? 3.Hashimoto's thyroiditis.
This post was last modified on 30 November 2021