Endocrinology Lect2,3 2003

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  • Endocrinology Lect2,3 2003

    1. 1. ENDOCRINOLOGY THYROID DISORDERS
    2. 2. Thyroid Disorders <ul><li>Thyroid secretes thyroxine (T4) and small amount of triiofothyronine (T3). </li></ul><ul><li>@ 85% of T3 is converted from T4 in the tissues [ liver, muscle, and kidney] </li></ul><ul><li>The hormones are transported in the plasma almost entirely bound to thyroxine – binding globulin (TGB),pre-albumin, and albumin. </li></ul>
    3. 3. <ul><li>Production is stimulated by TSH in response to thyrotrophin – releasing hormone (TRH) and free T4 (FT4) --- has a negative effect on TSH release. </li></ul><ul><li> FT4   TSH   TRH  thyroid production of T4 T3 </li></ul>
    4. 4. Hyperthyroidism <ul><li>Caused by excess circulating T4 or T3 </li></ul><ul><li>It is a common condition with a prevalence of 20/1000 </li></ul><ul><li>Both male and females effected equally </li></ul><ul><li>90% of cases are caused by: </li></ul><ul><ul><li>Graves disease </li></ul></ul><ul><ul><li>Toxic multinodular goiter </li></ul></ul><ul><ul><li>Toxic solitary goiter </li></ul></ul>
    5. 5. Graves Disease <ul><li>Onset may be insidious </li></ul><ul><li>Atrial fib is rare in young patient but occur in over 50% of males patient over 60 y/o </li></ul><ul><li>Results from IgG antibodies against the TSH – receptor </li></ul><ul><li>These antibodies are termed thyroid – stimulating antibodies (TSAb) </li></ul><ul><li>May be responsible for thyroid enlargement in this disease </li></ul>
    6. 6. <ul><li>The cardinal signs of Graves’ disease are: </li></ul><ul><ul><li>Diffuse goiter </li></ul></ul><ul><ul><li>Vascular bruit can be heard over these goiters </li></ul></ul><ul><ul><li>Pretibial myxoedema </li></ul></ul><ul><ul><li>Tachycardia with a bounding pulse </li></ul></ul><ul><ul><li>Exophthalmos </li></ul></ul><ul><ul><li>Lid lag (usually on downward eye movement) </li></ul></ul><ul><ul><li>Lid retraction </li></ul></ul><ul><ul><li>Peri-orbital puffiness </li></ul></ul><ul><ul><li>Increased lacrimation </li></ul></ul><ul><ul><li>Conjunctival edema and ulceration </li></ul></ul>
    7. 7. <ul><li>In the elderly a ‘masked’ hyperthyroidism may be found. If presentation of a 60 y/o with atrial fib, heart failure and weight loss </li></ul><ul><li>THINK HYPERTHYROIDISM!!! </li></ul><ul><li>Diagnosis is made clinically with confirmation by labs: </li></ul><ul><ul><li>T3 and T4 and undetectable TSH levels </li></ul></ul><ul><ul><li>if a single nodule is suspected a thyroid scan may provide useful information </li></ul></ul>
    8. 16. Treatment Options <ul><li>Anti-thyroid drugs: </li></ul><ul><ul><li>Carbimazole or methimazole followed by propylthiouracil </li></ul></ul><ul><li>Beta-blocking drugs in the initial stages of management </li></ul><ul><li>Sub-total thyroidectomy </li></ul><ul><li>Radioactive iodine therapy </li></ul><ul><li>THE CHOICE OF THERAPY DEPENDS UPON A NUMBER OF FACTORS, ESPECIALLY THE PATIENTS AGE AND PREVIOUS HISTORY </li></ul>
    9. 17. <ul><li>Any questions? </li></ul>
    10. 18. Hypothyroidism <ul><li>Also known as Myxoedema results from the reduced secretion of T3 and T4 from the thyroid. </li></ul><ul><li>Hashimoto’s accounts for over 90% of the cases </li></ul><ul><li>Secondary hypothyroidism is much less common and is caused by pituitary disease [ absence of TSH leads to atrophy of thyroid gland] </li></ul>
    11. 19. Clinical Presentation <ul><li>Affects all the systems of the body, but the wide range of clinical features means that the diagnosis will be missed. </li></ul><ul><li>Dominant features in children are: </li></ul><ul><ul><li>Reduction in growth velocity </li></ul></ul><ul><ul><li>Arrest of pubertal development </li></ul></ul><ul><li>Clinical presentation in adults may vary greatly </li></ul>
    12. 20. <ul><li>Non – pitting edema [most marked on the skin of the eyelids and hands]  often associated with loss of eyebrow and scalp hair </li></ul><ul><li>Dryness of the skin </li></ul><ul><li>Reduced body hair </li></ul><ul><li>Bradycardia </li></ul><ul><li>Hypothermia </li></ul><ul><li>Pericardial and pleural effusions [ can occur and is life threatening] </li></ul>
    13. 21. <ul><li>Diagnosis is based on </li></ul><ul><ul><li>Clinical suspicion </li></ul></ul><ul><ul><li>Prolonged relaxation time of peripheral reflexes </li></ul></ul><ul><ul><li>A low voltage EKG </li></ul></ul><ul><ul><li>Biochemical estimation of T4 and TSH </li></ul></ul><ul><ul><li>Thyroid Antibodies Assays </li></ul></ul><ul><li>Causes of hypothyroidism </li></ul><ul><ul><li>Autoimmune (most common Hashimotos) </li></ul></ul><ul><ul><li>Drugs induced (Lithium carbonate- which like iodide inhibits the release of thyroid hormones  goiter and hypothyroidism </li></ul></ul>
    14. 22. Treatment <ul><li>In all cases is thyroxine </li></ul><ul><li>In older patients that present with or has a history of ischemic heart disease sudden increase in T4 levels has been known to cause M.I.s </li></ul><ul><li>Therefore, start on low dose (25ug) and increase very slowly[every 4 – 6 weeks] and should intensify management of anti – anginal therapy </li></ul>
    15. 27. <ul><li>Any questions? </li></ul>
    16. 28. What Are the Parathyroid Glands? <ul><li>The parathyroid glands are four pea-sized glands located on the thyroid gland in the neck . </li></ul><ul><li>The parathyroid glands secrete parathyroid hormone (PTH), a substance that helps maintain the correct balance of calcium and phosphorous in the body. </li></ul><ul><li>PTH regulates release of the calcium from bone, absorption of calcium in the intestine, and excretion of calcium in the urine. </li></ul><ul><li>When the amount of calcium in the blood falls too low, the parathyroid glands secrete just enough PTH to restore the balance. </li></ul>
    17. 29. Hyper-parathyroidism <ul><li>If the glands secrete too much hormone,the balance is disrupted: blood calcium rises. </li></ul><ul><li>This condition of excessive calcium in the blood, called hypercalcemia </li></ul><ul><li>hypercalcemia is what usually signals the doctor that something may be wrong with the parathyroid glands </li></ul>
    18. 30. <ul><li>In 85 percent of people with this disorder, a benign tumor (adenoma) has formed on one of the parathyroid glands, causing it to become overactive. </li></ul><ul><li>In most other cases, the excess hormone comes from two or more enlarged parathyroid glands, a condition called hyperplasia. </li></ul><ul><li>Very rarely, hyperparathyroidism is caused by cancer of a parathyroid gland. </li></ul>
    19. 31. <ul><li>This excess PTH triggers the release of too much calcium into the bloodstream. </li></ul><ul><li>The bones may lose calcium, and too much calcium may be absorbed from food. </li></ul><ul><li>The levels of calcium may increase in the urine, causing kidney stones. </li></ul><ul><li>PTH also acts to lower blood phosphorous levels by increasing excretion of phosphorus in the urine </li></ul>
    20. 32. <ul><li>HPT is most often suspected when a high level of calcium is found in your blood on a routine blood test. </li></ul><ul><li>measuring the amount of PTH in your blood proves the diagnosis </li></ul>
    21. 33. What Are the Symptoms of Hyperparathyroidism? <ul><li>patients have severe symptoms, subtle ones, or none at all </li></ul><ul><li>When symptoms do appear, they are often mild and nonspecific, such as: </li></ul><ul><ul><li>a feeling of weakness and fatigue, </li></ul></ul><ul><ul><li>depression, </li></ul></ul><ul><ul><li>or aches and pains </li></ul></ul><ul><li>With more severe disease, a person may have: </li></ul><ul><ul><li>a loss of appetite, </li></ul></ul><ul><ul><li>nausea, vomiting, </li></ul></ul><ul><ul><li>constipation, </li></ul></ul><ul><ul><li>confusion or impaired thinking and memory, </li></ul></ul><ul><ul><li>and increased thirst and urination </li></ul></ul>
    22. 34. How is HPT treated <ul><li>Surgery to remove the growth in your neck almost always solves the problem. </li></ul><ul><li>The growth doesn't usually come back </li></ul><ul><li>Most of your symptoms will stop in the first month after surgery </li></ul><ul><li>For a short time after surgery, your blood calcium level may be too low </li></ul><ul><li>This problem is easily treated with medicine. </li></ul>
    23. 35. <ul><li>Although surgery is usually recommended for people with HPT (unless they have no symptoms), sometimes other medical problems make surgery too risky </li></ul><ul><li>If you don't have surgery, tests are needed from time to time to see if the disease is hurting your kidneys, bones or other body systems </li></ul><ul><li>Women who take estrogen after menopause are partly protected from the effects of HPT. </li></ul>
    24. 36. Any questions?
    25. 37. Hypoparathyroidism <ul><li>is the clinical condition caused by a lack of parathyroid hormone </li></ul><ul><li>. Calcium levels in the blood fall, and phosphorus levels rise </li></ul><ul><li>The most common cause of hypoparathyroidism is injury to the parathyroid glands during head and neck surgery. </li></ul>
    26. 38. <ul><li>Rarely, hypoparathyroidism is a side effect of radioactive iodine treatment for hyperthyroidism </li></ul><ul><li>PTH secretion may be impaired when blood levels of the element magnesium are low or when blood pH is too high, a condition called metabolic alkalosis. </li></ul><ul><li>DiGeorge syndrome is a childhood disease in which hypoparathyroidism occurs due to congenital absence of the parathyroid glands </li></ul>
    27. 39. <ul><li>The incidence is about 4 out of 100,000 people. </li></ul><ul><li>Symptoms   </li></ul><ul><ul><li>tingling of lips, hands and feet </li></ul></ul><ul><ul><li>muscle cramps </li></ul></ul><ul><ul><li>pain in face , legs and feet </li></ul></ul><ul><ul><li>abdominal pain </li></ul></ul><ul><ul><li>dry hair </li></ul></ul><ul><ul><li>brittle nails </li></ul></ul><ul><ul><li>dry, scaly skin </li></ul></ul><ul><ul><li>cataracts </li></ul></ul><ul><ul><li>weakened tooth enamel in children </li></ul></ul><ul><ul><li>muscle spasms called tetany </li></ul></ul><ul><ul><li>tetany can lead to spasms of the larynx with breathing difficulties </li></ul></ul><ul><ul><li>convulsions or seizures </li></ul></ul>
    28. 40. <ul><li>Additional symptoms that may be associated with this disease: </li></ul><ul><li>menstruation, painful </li></ul><ul><li>hand or foot spasms </li></ul><ul><li>consciousness, decreased </li></ul><ul><li>teeth - delayed or absent formation </li></ul>
    29. 41. Signs and tests     <ul><li>low serum calcium level </li></ul><ul><li>elevated serum phosphorus </li></ul><ul><li>decreased serum parathyroid hormone level </li></ul><ul><li>decreased serum magnesium level (possible) </li></ul><ul><li>occasionally abnormal heart rhythms on ECG </li></ul>
    30. 42. Treatment <ul><li>The goal of treatment is to restore the calcium and associated mineral balance within the body </li></ul><ul><li>Oral calcium carbonate and Vitamin D supplements are usually life-long therapy </li></ul><ul><li>Blood levels require periodic monitoring to ensure proper dosage </li></ul><ul><li>. A high-calcium, low-phosphorous diet is recommended </li></ul><ul><li>Supportive care is necessary for an acute life-threatening attack or hypoparathyroid tetany (prolonged muscle contractions ). </li></ul>
    31. 43. <ul><li>Calcium is administered by intravenous infusion </li></ul><ul><li>Precautions are taken to prevent seizures or larynx spasms </li></ul><ul><li>Heart monitoring for abnormal rhythms is continued until the person is stabilized </li></ul><ul><li>When the life-threatening attack has been controlled, treatment continues with oral preparations. </li></ul>
    32. 44. Complications <ul><li>acute tetany, which can lead to respiratory obstruction requiring a tracheostomy </li></ul><ul><li>growth retardation, malformation of the teeth, and retarded mental development, which can occur if hypoparathyroidism develops in childhood </li></ul><ul><li>over treatment with Vitamin D and calcium, which can cause hypercalcemia (high blood calcium) and sometimes impaired kidney function </li></ul><ul><li>increased risk of pernicious anemia , Addison's disease , cataract development, and Parkinson's disease </li></ul>
    33. 45. Prognosis <ul><li>The probable outcome is good if the diagnosis is made early </li></ul><ul><li>Dental changes, cataracts , and brain calcifications are irreversible changes. </li></ul>

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