Thyroid disorders Dr Enas Abusalim

Thyroid physiology

• The hypothalamic –pituitary –thyroid axis

• And peripheral conversion of T4 to T3 , WHERE , AND BY WHAT ENZYME ??

• Only relatively small concentrations of T4 and T3 are biologically active , WHY ?

• WHAT IS THE DAILY REQIUREMENT OF IODIDE IN ORDER TO MAINTAIN NORMAL THYROID FUNCTION ?

Common presentations in thyroid diseases

• Enlargement of the thyroid gland ( goiter ),

• Incidental finding of abnormal thyroid function test ,

• Symptomatic hypothyroidism or hyperthyroidism .

Who should be tested for abnormal thyroid function ?

Who should be tested for abnormal thyroid function ? • Patients with signs and symptoms of either hypothyroidism or

hyperthyroidism , WHICH ARE ?

• All pregnant patients as a routine screen during booking visit ,

• Goiterous enlargement of thyroid gland ,

• In the presence of other autoimmune diseases ( INCLUDING ………….???)

• As follow up post thyroid resection , or thyroid cancer treatment .

Hyperthyroidism

• What is THYROTOXICOSIS ??

• How does it differ from the term hyperthyroidism ?

• What are the causes of hyperthyroidism ? Most common ?

Graves disease

Toxic multinodular goiter

Toxic adenoma

Graves disease

• An autoimmune disorder

• Affecting the thyroid gland ( hypersecreting and goiterous enlargement ) , periorbital fat ,ocular muscles ( proptosis , diplopia , chemosis ophthalmoplegia ) , and skin ( pretibial myxedema ) .

• Caused by antibodies against which receptor ?????

• Can Graves ophthalmopathy occur in a euthyroid individual ?

• Family history of autoimmune thyroid disease often present , and is a risk factor for the development of Graves .

What does physical examination of the thyroid gland reveal in Graves Disease ?

Diagnosis

• TSH level is the first step in a patient who presents with signs and symptoms of abnormal thyroid function .

• Normal range is variable according to age , pregnancy , but is usually between 0.4-4 milli-international units /L in young non-pregnant patients .

• If abnormal this should be followed by measurement of T4 levels ( not T3 , WHY ??)

• Normal range of T4 is 4.6-12 ug/dl

• Anti –TSH receptor antibodies ( TSI , TBII )

• WHAT IS NEXT ?

For any patient with signs and symptoms of hyperthyroidism, and abnormal thyroid function test , the next step is a RAIU scan . How is it beneficial????

Treatment of hyperthyroidism

• For Graves disease treatment options are :

Antithyroid drugs ,

Radioactive iodine ablation of the thyroid gland , ( any contra-indications ??).

And thyroid surgery .

In addition to symptomatic relief by beta-blocker therapy to suppress excess adrenergic tone ( propranolol for example , which has the additional benefit OF ???)

• How should treatment be monitored after initiation of management ??

• What is the expected outcome of radioactive iodine ablation of the thyroid gland in graves disease ??

Treatment of multinodular goiter and solitary thyroid nodule • What is the gold standard treatment option , and how does it differ

from treatment of graves disease post treatment ???

• What is Jod-Basedow phenomenon ?

• What are the indications of thyroidectomy in a hyperthyroid patient ??

• If a cold thyroid nodule was found in a RAIU done for multinodular goiter what would be your next best investigation ?

Hypothyroidism

• The most common cause is ??? Other causes ??

• Name possible medications known to cause hypothyroidism ??

• How does an associated coeliac disease effect the management of a hypothyroid patient ?

Hashimotos thyroiditis

• An autoimmune disorder caused by antibodies against TPO ,and thyroglobulin .

• Signs and symptoms ??

• How does it affect blood pressure and lipid profile ?

• Tendon reflexes ??

• Is RAIU scan required ?

• Is an Ultrasound required ?

Treatment of hypothyroidism

• Levothyroxine therapy is the mainstay of thyroid hormone replacement ,

• What are the precautions you must inform your patient about while taking thyroid replacement therapy ??

Destructive thyroiditis

• Definition :

• Types :

1- Subacute thyroiditis

2-Silent thyroiditis

3-post partum thyroiditis

• Diagnosis :

• Treatment :

Thyroid EMERGENCIES !!!

Thyroid Storm

And myxedema Coma

Thyroid Strom

• This is a life threatening condition presenting as

1- severe thyrotoxicosis

2- coupled by secondary systemic decompensation

Clinical presentation :

• Hyperthermia

• Tachycardia ( sinus or arrhythmias )

• Heart failure

• Jaundice ,Elevation in liver function test and fulminant hepatic failure

• Diarrhea , nausea , vomiting , abdominal discomfort ,

• Agitation , disorientation .

• What precipitated this condition ???

• What precipitates this condition ???

Surgery ,

Infection ,

Parturition ,

Acute iodine exposure ,

Radioactive iodine ,

Medications including salicylates and pseudoephedrine

How is it treated ??

1- supportive measures , including ABCs……etc. .

2- decreasing thyroxin production by thyroid gland , HOW ??

3- decreasing peripheral conversion of T4 to T3 , HOW ??

4- address associated adrenergic and thermoregulatory changes

5- treat all precipitating factors

6- aggressively reverse any systemic decompensation and organ dysfunction .

Myxedema coma

• Systemic decompensation caused by severe hypothyroidism ,

• Caused by ???

Myxedema coma

• Systemic decompensation caused by severe hypothyroidism ,

• Caused by ???

Non-adherence

MI , stroke

Heart failure

Cold exposure

Hypoglycemia

Acidosis

GI-bleeding ………….etc.

manifestations

• Mental state changes ( including lethargy , stupor , psychosis m and coma )

• Hypothermia ( temp less that 34.4 C )

• Bradycardia

• Hypoventilation and type 2 respiratory failure

• Hypotension

• Hyponatremia ( by which mechanism ???)

• Hypoglycemia

Management

1- supportive , including warming , ABCs….,and management of organ dysfunction .

2- TSH and free T4 , and CORTISOL should be check promptly, DON’T WAITE FOR TEST RESULTS , TREAT ASAP ,

3-REPLACE CORTISOL IF DEFICIENCY IS SUSPECTED PRIOR TO REPLACEMENT OF THYROXIN , WHY???

4-IV LEVOTHYROXINE

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