hypothyroidism and hyperthyroidism., Slides of Clinical Medicine

Download hypothyroidism and hyperthyroidism. and more Slides Clinical Medicine in PDF only on Docsity!

Topic:

Hypo &

Hyperthyroidism

Hyperthyroidism

Definition:

Hyperthyroidism is an overactive thyroid gland that produces too much thyroid

hormone.

Who is at risk:

• (^) An overactive thyroid can affect anyone, but it’s about 10 times more

common in women than men, and typically happens between 20 and 40

years of age.

• (^) A recent pregnancy, which raises the risk of developing thyroiditis. Which can

lead to hyperthyroidism.

• (^) A family history of thyroid disease, particularly Graves’ disease.

Primary

Due to thyroid hormone deficiency

Secondary

Due to TSH deficiency 01 02

Tertiary

Due to thyrotropin-releasing hormone deficiency Extra-thyroidal; panel 03 04

Hypothyroidism can be classified as:

Peripheral

What is the main cause of

hypothyroidism?

Hashimoto’s disease, an autoimmune disorder,

is the most common cause of hypothyroidism.

With this disease, your immune system attacks

the thyroid. The thyroid becomes inflamed

and can’t make enough thyroid hormones.

How is hypothyroidism transmitted?

In some of these cases, an affected

person inherits the mutation from one

affected parent. Other cases result from

new (de novo ) mutations in the gene

that occur during the formation of

reproductive cells (eggs or sperm) or in

early embryonic development

Causes of Hyperthyroidism

Primary Secondary

• (^) Autoimmune  (^) Graves’ disease  (^) Ashimoto’s (Hashitoxicosis - rare)
• (^) Toxic multinodular
• (^) Goiter toxic adenoma
• (^) Exogenous thyroid hormone intake
• (^) Postpartum thyroiditis
• (^) Neoplastic (usually metastatic thyroid cancer - very rare)
• (^) Drug-induced (amiodarone) TSH-producing pituitary adenoma
• (^) Gestational hyperthyroidism (seen with hyperemesis gravidarum)
• (^) Trophoblastic disease

Others

Investigations/Diagnostic

Tests

• (^) TSH is the principal test for evaluating thyroid function.
• (^) free T3 (fT3) and free T4 (fT4) are not necessary when screening for hypothyroidism  (^) may measure in suspected hyperthyroidism to confirm the diagnosis of thyrotoxicosis (elevated fT3 and normal fT4)  (^) may measure to rule out TSH-producing pituitary adenoma (elevated TSH, fT3, fT4)
• (^) a thyroid ultrasound should be done if the physical exam suggests nodularity
• A thyroid uptake scan should be done to differentiate the causes of a hyperthyroid state

Diagnosis Algorithm

roid TSHATY <0.3 m U / L Hyperthyroidism suspected

1. 3 - 5.5 m U / L Euthyroid >5.6 m U / L Hypothyroidism Suspected Ft 4 Elevated Normal Ft 3 Hyperthyroidism^ Elevated^ Normal Confirmed Review Etiology and Rx Monitor fT Review clinical diagnosis repeat TSH at 6 to 12 months if indicated. fT 4 Normal Low Hypothyroidism Confirmed Treatment – thyroid replacement therapy Monitor TSH Wait 6-8 weeks after start of treatment or Change in dosage before re-testing TSH Consider Dose increase Consider dose reduction TSH Elevated TSH Normal Appropriate dose established. Test TSH annually TSH Suppressed Review clinical diagnosis

Hypothyroidism Treatment

For treatment steps are as follows:

1. First understand the cause of disease because Hypothyroidism is a disorder of

diverse causes.

2. Medical History:

• (^) A comprehensive medical history can uncover symptoms
• (^) that will help establish the diagnosis and confirm by history and to document pretreatment thyroid function abnormalities and Patients should be asked about symptoms.

3. Physical Examination:

• (^) Findings from the physical examination that may indicate hypothyroidism include goiter or bradycardia, edema.

4. Laboratory Evaluation.

• (^) Serum TSH measurement should be performed

THEN, Give: Treatment plan

• (^) Levothyroxine sodium is the treatment of choice for the routine management of

hypothyroidism.

• (^) Levothyroxine, also known as L-thyroxine, is a synthetic form of the thyroid

hormone thyroxine. It is used to treat thyroid hormone deficiency.

• (^) Dosage: Therapy is usually initiated in patients under the age of 50 years with

full replacement.

• (^) Adults with hypothyroidism require approximately 1.7 μg/kg of body weight per

day for full replacement.

• (^) Children may require higher doses (up to 4 μg/kg of body weight per day).
• (^) Older patient s may need less than 1 μg/kg per day.

Special Considerations:

Elderly patients:

Symptoms should be monitored and TSH levels.

Pregnancy:

TSH Requirement increases which leads to an increase in Levothyroxine concentration.

In Subclinical Hypothyroidism:

As many as 15% of patients older than 65 years, as well as many other adults, have

hypothyroid symptoms called subclinical hypothyroidism, and usually feel better if

treated with levothyroxine.

In MyxedemaComa:

Coma caused by myxedema is a rare, life-threatening

state associated with altered sensorium caused by hypothyroidism.

Therapy of myxedema coma

Includes intravenous administration of levothyroxine and/or liothyronine sodium at a

dose of 500-800 mcg.

Use of Other Thyroid Hormone Preparations

● Liothyronine is a manufactured form of the

thyroid hormone triiodothyronine. It is most

commonly used to treat hypothyroidism and

myxedema coma.

● Dosage:

 Adults—At first, 25 micrograms (mcg) once a

day.

 Children at 5 micrograms once a day

Treatment plan for hyperthyroidism

These include

1. Antithyroid Drugs. ● (^) The ATDs, include Methimazole Mechanism of action: ● (^) Interfere with the oxidation of the iodide ion and iodotyrosyl groups. Eventually, thyroglobulin gets depleted, and circulating thyroid hormone levels decrease. Propylthiouracil (preferred for pregnant) Mechanism of action: ● Acts by inhibiting the enzyme thyroid peroxidase, which usually converts iodide to an iodine molecule and incorporates the iodine molecule into amino acid tyrosine and thyroid hormone biosynthesis. ● (^) Dosage: ● (^) Initial daily doses of methimazole generally range from 10 to 40 mg, and for propylthiouracil, 100 to 600 mg for 6 weeks to 2 years orally.

Hyperthyroidism and pregnancy:

● The goal of treatment during pregnancy is to maintain

euthyroidism, using the smallest doses of ATDs possible.

 Hyperthyroid pregnant patients should be seen at 4- to 6-week

intervals.

 Surgery is felt to be necessary because of the inability to

adequately control hyperthyroidism with ATDs,