Thyroid disordersDr 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 thyroidfunction ?

Who should be tested for abnormal thyroidfunction ?

• Patients with signs and symptoms of either hypothyroidism orhyperthyroidism , 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 diseaseToxic multinodular goiterToxic adenoma

Graves disease

• An autoimmune disorder• Affecting the thyroid gland ( hypersecreting and goiterousenlargement ) , 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 thyroidgland reveal in Graves Disease ?

Diagnosis

• TSH level is the first step inpatient who present with signs andsymptoms of abnormal thyroid function .

• Normal range is variable according to age , pregnancy , but is usuallybetween 0.4-4 milli-international units /L in young non-pregnantpatients .

• 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 RAIUscan .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 excessadrenergic 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 andsolitary thyroid nodule

• What is the gold standard treatment option , and how does it differfrom 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 can 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 ,andthyroglobulin .

• 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 hormonereplacement ,

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

Destructive thyroiditis

• Definition :• Types :1- Subacute thyroiditis2-Silent thyroiditis3-post partum thyroiditis

• Diagnosis :• Treatment :

Thyroid EMERGENCIES !!!

Thyroid StormAnd myxedema Coma

Thyroid Strom• This is a life threatening condition presenting as1- 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 changes5- treat all precipitating factors6- aggressively reverse any systemic decompensation and organdysfunction .

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 andcoma )

• 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 organdysfunction .2- TSH and free T4 , and CORTISOL should be check promptly, DON’TWAITE FOR TEST RESULTS , TREAT ASAP ,3-REPLACE CORTISOL IF DEFICIENCY IS SUSPECTED PRIOR TOREPLACEMENT OF THYROXIN , WHY???4-IV LEVOTHYROXINE

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