Thyroid Diseases (Management)

Nota:

• Heat intolerance Tremor Nervousness Goiter Weakness/ Insomnia Frequent bowel movement; diarrhea

1. Increased Radioactive Iodine Units(RAIU)

   Nota:

   • TSH related Reistance to Pitutiary TH secretion
   1. TSH related

      Nota:

      • TSH causes the overprod of T3, T4
   2. non TSH related

      Nota:

      • Meds Pituitary resists Thyroid hormone Various thyroid cancers Goiter(due to "fooled gland" thinking that there is  too little T3/T4; there is more than enough).
      1. Graves Disease

         Nota:

         • This is an autoimmune disease and a common cause of increased RAIU--hyperthyroidism!
         1. Thyroid Storm

            Nota:

            •    —high fever (often >103°F), tachycardia, tachypnea, dehydration, delirium, coma, nausea, vomiting, and diarrhea    
2. Decreased Radioactive Iodine Units

   Nota:

   • Cancer Inflammatory thyroid Too much outside thyroid intake Meds Food
   1. Inflammatory/related to inflammation
   2. Cancers
   3. Food and medications
      1. Amiodarone

         Nota:

         • Iodine makes up 37% of the weight. Can cause Type I or Type II  thyroid disease!
         1. Type I

            Nota:

            • This is known as thyrotoxicosis:hyperthyroidism!
            1. De-iodinization is lowered-->more t4 and t3 remaining

               Nota:

               • See MedScape Article; but  Amiodarone blocks T4 and T3 from entering the cell and ALSO stops conversion of T4 to T3 in the peripheral/other organ tissues
            2. (THYROID DISEASE)
         2. Type II
            1. (NO THYROID DISEASE)

1. SURGERY
   1. Meds used pre-surgery

      Nota:

      • For 6 to 8 weeks Iodine is used for 1 to 2 weeks
2. Radioactive Iodine(I-131)
   1. 1st Line Conditions

      Nota:

      • Graves' disease Nodules Goiters
   2. Contraindications

      Nota:

      • Pregnancy and nursing mothers.
   3. Adverse Effects
      1. related to disease Risk Increasing

         Nota:

         • Thyroid Cancer Cardiovascular Disease Death (Got it? Yes, but sad nevertheless!!)
      2. related to thyroid

         Nota:

         • radiation thyroiditis  hypothyroidism
3. Antithyroid Medications
   1. Thioamides
      1. Propylthiouracil(PTU)
         1. Preferred Scenarios

            Nota:

            • Phrase that helps you remember when this should be used  Peter ran a LaP in Th(ialand) La-Lactation P-Pregnancy Th-Thyroid Storm
      2. Methimazole
         1. Advantages over PTU

            Nota:

            • Less liver issues and works faster.  Top recommended thioamide (The article on Thyroid function testing also made reference to use in patient...saw Real world application )
      3. Benefits
      4. Disadvantages
         1. Side Effects
            1. SEVERE
               1. Agranulocytosis
               2. Hepatitis
            2. BENIGN
               1. Joint Pain
               2. Fever and Rash
               3. leukopenia
      5. USED for 1 (12 months)to 2 YEARS(24 months)
   2. Iodides
      1. Conditions /Indications of Use
         1. Thyroid Storm
         2. Severe Thyroidtoxicosis
         3. Surgery
      2. Contraindications
         1. Pregnancy
         2. Before use of Radioactive Iodine(RAI)
         3. Nodular Goiters and Adenomas
4. Beta Blockers

   Nota:

   • Should be used until the more specific anti-thyroid medication effect takes place  The  peripheral T4 to T3 conversion (propranolol, nadolol)   is inhibited.
   1. Reasons to Use

      Nota:

      • AKA indications and Uses/Conditions
      1. management of symptoms
      2. Works within hours
   2. Reasons not to use

      Nota:

      • Also known as contraindications and precautions
      1. Bronchospasm (severe)
      2. Heart issues

         Nota:

         • 2nd or 3rd degree heart block Decompensated heart failure
      3. Alternatives

         Nota:

         • CCBs, beta 2 antagonists and other sympatholytics CAN be used.

1. Levothyroxine

   Nota:

   • Synthetic T4(AKA thyroxine)! Multiple brands are available  but these may not be therapeutic equivalent to each other.
   1. Drug Interactions
      1. Decrease T4 absorption

         Nota:

         •    ¡Cholestyramine- Brand Name (Questran) and associated products   ¡Calcium- Brand Names(Phoslo, Eliphos, Phoslyra, and Calphron)   ¡Ferrous sulfate ¡Aluminum hydroxide  ¡Sucralfate- Carafate, Orafate, and ProThelial  
      2. Increase T4 metabolism

         Nota:

         •    ¡Rifampin- Rifadin  ¡Phenytoin- Dilantin, Phenytek and others ¡Phenobarbital- Lumina  ¡Sertraline-Zoloft
      3. Pharmacodynamic effects
         1. Warfarin

            Nota:

            • Elevated INR and bleeding risk
         2. Digoxin

            Nota:

            • More digoxin may be needed if using levothyroxine
   2. Side Effects
2. Liothyronine (Cytomel)

   Nota:

   • Not first line Synthetic T3/TriiodothyronineAdvantageous against myxedema coma
3. Armour Thyroid

   Nota:

   • Think "it varies": -Ratio of hormones varies -The products vary in potency among the brands
   1. High allergy potential
4. Liotrix(Thyrolar)

   Nota:

   • Combination of  Synthetic T4 AND T3 It is predictable and stable NOT dispensed often though
   • Adverse reactions: Rare but clinical pharmacology does note itching, hypersensitivity and a skin rash

Nota:

• TSH is high T4 and T3 are low. Note Radioactive Iodide Uptake is not used in diagnosis.

1. Primary
2. Secondary

1. high T34 or t4--> negative feedback