Post on 23-Aug-2020
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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