HYPOTHYROIDISM BY ZAHID QAMAR

7/30/2019 HYPOTHYROIDISM BY ZAHID QAMAR

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It is the functional or structural de arrangement in

the synthesis of thyroid hormone

It can result from a lack of a thyroid gland or fromiodine-131 treatment, and can also be associated withincreased stress.

A 2011 study concluded that about 8% of womenover 50 and men over 65 in the UK suffer from anunder-active thyroid and that as many as 100,000 ofthese people could benefit from treatment they arecurrently not receiving.[1]

INTRODUCTION


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1.8% of total population.

Second only to DM as most common endocrine

disorder.

Incidence increases with age.

More common in females.

2-3% of older women.

Hypothyroidism


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PRIMARY HYPOTHYROIDISM Hoshimotos thyroiditis-most common

Idiopathic hypothyroidism-probably old Hoshimotos Irradiation of thyroid Surgical removal Late stage invasive fibrous thyroiditis Iodine deficiency

Drug therapy (Lithium, Interferon) Infiltrative Diseases:

Sarcoidosis, AmyloidosisScleroderma, Hemochromatosis

Etiology


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SECONDARY HYPOTHYROIDISM

5% of cases.

Pituitary or hypothalmic neoplasm.

Congenital hypopituitarism.

Pituitary necrosis (Sheehans syndrome)


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Occurs in hypothalamus

Results when the hypothalamus fails to produce

sufficient thyrotropin-releasing hormone (TRH).TRH prompts the pituitary gland to producethyroid-stimulating hormone (TSH). Hence may alsobe termed hypothalamic-pituitary-axis

hypothyroidism. It accounts for less than 5% ofhypothyroidism cases

Tertiary hypothyroidism


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Cretinism

Myxedema

Clinical Manifestations


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Hypothyroidism in infancy or early child hood.

Endemic iodine deficiency areas of the world i.e

himalya , waziristan & other hilly areas etc. it may be sporadic cretinism (hypothyroidism due

to inborn errors of metabolism)

Cretinism


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Impaired development of CNS & skeletalsystem.

Severe mental retardation(Related to time at whichthyroid deficiency occur in utero)

Maternal thyroid deficiency before the development of fetal thyroid

gland leads to severe mental retardation.

Short stature

Coarse facial features

Protruding tongue

Umbilical hernia.

Clinical features of

cretinism


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Hypothyroidism occuring in older children andadults is called myxedema.

CLINICAL FEATURES includeGeneralized apathy

Mental sluggishness in early stages may lead todepression

Individuals with myxedema are listless, cold intolerant , obese ,

have constipation & pericardial effusions.

Myxedema (Gull disease)


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Non-specific.

May be confused with other conditions especially in

postpartum depression and elderly.Maintain high index of suspicion.

In older patients, hypothyroidism may be confusedwith Alzheimers and depression.

Patient may end up getting treated for depression.

Signs and Symptoms

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Common signs and symptoms

S/S % pts affected

Weakness 99

Skin changes 97

Slow speech 91

Eyelid edema 90

Cold sensation 89

Decreased sweating 89

Cold skin 83

Thick tongue 82

Facial edema 79

Coarse hair 76

Skin pallor 67

Forgetfulness 66

Constipation 61


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In Primary Hypothyroidism

Serum TSH is high.

Free thyroid hormone are depressed.

In Secondary Hypothyroidism

Both TSH and free thyroid hormones are low.

Diagnosis


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Generally

Once diagnosis of primary hypothyroidism is made,additional imaging or serologic testing is unnecessary

if gland is normal on exam.

In secondary hypothyroidism, further testing withpituitary provocative testing and imaging to rule outmicroadenoma. In general, evidence of decreased levelsof more than one pituitary hormone is indicative of apanhypopituitary problem.


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Lab Values

TSH level Free T4 level Free T3 level Likely Diagnosis

High

High (>10 U/mL

[{10mU/L]}

High (6-1uU/mL

{6-10mU/L])

High

High

Low

Low Low Primary Hypothyroidism

Normal Normal Subclinical hypothyroidism with

high risk for future development

of overt hypothyroidism

Normal Normal Subclinical hypothyroidism

with low risk for future development

of overt hypothyroidism

High Low Congenital absence of T4-T3

converting enzyme; amiodarone

Cordarone) effect on T4-T3

conversion

High High Peripheral thyroid hormone

resistance

Low Low Pituitary thyroid deficiency

or recent withdrawal of

thyroxine after excessive

replacement therapy

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HYPOTHYROIDISM BY ZAHID QAMAR