Hyperthyroidism

Hyperthyroidism

1. Cause

   • Common
     • Grave's Disease (Autoimmune)
       • Investigations
         • TSH-Ab Specific
       • Possible Infection - Initiation
       • Thyroid Eye disease
       • Fluctuation - Relapse and Remission
         • Hypothyroidism Eventually
     • Toxic Multinodular Goitre
       • Anti-thyroid Drugs Unsuccessful
         • But can control Hyperthyroidism
     • Adenoma
       • Anti-thyroid drugs unsuccessful
   • Uncommon
     • Thyroiditis
       • Viral
         • DeQuervain's
           • Acute Inflammation
           • Fever
           • Malaise
           • Neck Pain
           • Tachycardia
           • Local thyroid Tenderness
           • Investigations
             • TFTs
               • Hyperthyroidism
             • ESR elevated
             • Plasma viscosity High
             • Thyroid Uptake Scan
               • Uptake suppression
           • Treatment
             • Aspirin (Acute)
             • Severe Symptoms
               • Prednisolone
       • Autoimmune
       • Post-irradiation
       • Postpartum
     • Gestational Thyrotoxicosis
     • Neonatal Thyrotoxicosis
     • EXOGENOUS IODINE
       • DRUGS
         • Amidarone
           • Type 1 Amiodarone-induced Thyrotoxicosis
             • Associated with Pre-existing Graves' disease or MultiNodular goitre
             • High Iodine Content of Amiodarone
           • Type II - AIT
             • Not associated with previous thyroid disease
               • Direct effect of the drug on follicular cells
                 • Destructive thyroiditis
                   • T4 and T3 Release
             • Initial Hypothyroid phase
         • Lithium
   • Rare
     • Pituitary Tumor (TSH secreting)
     • Thyroid Mets
     • HCG-producing Tumors
     • Hyperfunctioning Ovarian Teratoma

2. Clinical Feature

   • Symptoms
     • Weight Loss
     • Increased Appetite
     • Irritability
     • Tremor
     • Heat Intolerance
     • Eye Complaints
   • Signs
     • Eyes
       • Lid Lag & Stare
     • Graves' dermopathy (rare)
       • Pretibial Myxoedema
     • AF / Tachycardias / HF
       • TFTs mandatory in all AF
     • Tremor
     • Exophthalmos
       • Graves' disease

3. Investigations

   • TSH is suppressed
     • T4 raised
   • TPO & Thyroglobulin Ab
     • Graves'

4. Management

   • Antithyroid Drugs
     • Inhibit Thyroid Hormone Formation
       • Carbimazole
         • Also an Immunosuppressive
         • Complications
           • Agranulocytosis
             • High Risk of Infection / Septic
               • Unexplained fever or sore throat requires urgent help
         • Regimen
           • 20-40mg / Day
             • Review 4-6 wks
               • Reduce Dose depending on Clinical state and fT4 / fT3
                 • TSH may remain suppressed for several months and NOT helpful at this stage
                 • Review 18 months
                   • Reduce Carbimazole if fT4 or fT3 fall below normal or TSH raises above normal
                   • Increase Carbimazole if fT4 or fT3 are above normal. Or if TSH remains suppressed after several months.
                   • STOP Carbimazole at end of course or if patient is euthyroid on 5mg daily.
               • When clinically Euthyroid STOP Beta-Blockers
       • Propylthiouracil (PTU)
         • Complications
       • Clinically not apparent for 10-20 days
   • Beta-Blockers (Propanolol)
     • Rapid partial Sympathetic Control
     • Decrease T4-T3 conversion
     • Avoid in Asthma
     • Do not use alone
       • Unless Cause self-limiting
         • Subacute Thyroiditis
   • 'Block and Replace'
     • Carbimazole 40 daily to suppress thyroid AND Levothyroxine 100ug daily to replace till EUTHYROID
       • For 18 months
       • avoidance of over or under treatment
       • Better use of Immunosuppressant action
     • Contraindicated In Pregnancy
   • Relapse
     • RadioIodine
       • Contraindicated in pregnancy & Breast Feeding
       • Destroys the Gland
       • Patient must be euthyroid before treatment
         • Stop anti-thyroid drugs 4 days before
       • Worsening can occur
         • Treat with Propanolol
         • If necessary, Carbimazole can be restarted
       • Eye disease is contraindicated
         • Steroids are then used.
       • Long-term Surveillance is needed
     • Surgery
       • Only in Euthyroid patients.
       • Stop anti-thyroid Drugs 10-14 days pre-op
         • Give Potassium Iodine 60mg TDS
           • Reduced vascularity of gland
       • Complications
         • Early Post-Op bleeding
           • Tracheal compression
           • Aphyxia
         • Laryngeal Nerve Palsy
         • Hypocalcaemia
         • Hypothyrodism
     • Most hyperthyroid pts with goitre
       • large single or multinodular goitre unlikely to remit after anti-thyroid drugs
         • Require definitive Treatment