Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download presentation source
Document related concepts
Transcript
‘All in the I of the beholder’ Amy Joyce, Fiona Boyle, Sobana Anandarajah, Aamir Iqbal, Philip McGlone, Gareth Bowen-Perkins Presenting Complaint Free T4 > 100 TSH < 0.01 History of Presenting Complaint Diarrhoea 8-10 x /day Tremor, increased sweating SOB – could walk ~ 100m on a flat surface Dizzy, light-headed and weak Hearing and visual disturbances ~ 3.5 stones wt. loss Past Medical History Dilated cardiomyopathy Dec 1999 ICD Sep 2000 Family History Nil of note Drug History Warfarin 6/7 mg – alternate doses Amiodarone 200 mg od Spironolactone 26 mg od Frusemide 40 mg od Ramipril 5 mg od Carvedilol 15 mg bd Zopiclone 3.75 mg od Carbimazole 20 mg bd Allergies - amoxycillin Social History Occupation – Surveyor Married with one seven month old son Non-smoker Alcohol – 6-8 units/week Examination Pt appeared comfortable at rest with an obvious tremor, and sweating. P 86 reg; BP 112/59; T 36.6; sats 96%; RR 14 CVS – normal HS, JVP, no murmur Resp – lung fields clear Abdo – soft, non-tender, bowel sounds present, striae ++ Thyroid – not enlarged, no nodules, no goitre What next? Impression – Amoidarone induced thyrotoxicosis Plan: Bloods: FBC, U+E, CRP, TFT, LFT, Thyroid AB’s CXR, ECG, Echo, 24 hour tape Iodine uptake scan Stop amiodarone Increase CBZ INR Dilated Cardiomyopathy Characterized by ventricular dilatation + depressed myocardial contractility largest gp of myopathic disorders responsible for systolic HF prevalence: 0.2% in UK (inc in developing countries) Unknown aetiology Associations: Alcohol Hypertension Haemochromotosis Viral infection Autoimmune Peri/post partum Congenital (x-linked) Thyrotoxicosis Pathophysiology Relative degree of L + R ventricular impairment is variable Compensatory in sympathetic activity: – maintains systolic function –central redistribution of flow: ventricular filling inotropic responsiveness of failing heart CO + renal perfusion- 2º aldosteronism Na+ and H2O retention–progressive systemic + pulmonary congestion – ventricular filling- progressive dilation/ hypertrophy Clinical Features Often asymptomatic in early stages Symptoms/signs of CHF develop Later, peripheral oedema and orthopnoea develop Tachycardia and signs of cardiac enlargement are present JVP: elevated often giant ‘v’ wave Auscultation: 3rd heart sound pansystolic mumurs of MR/TR Complications Cardiac arrhythmias are common (esp AF, ventricular premature beats) Sig incidence of sudden death due to more complex ventricular arrhythmias Systemic and pulmomary thromboembolism from dilated R/L cardiac chambers Investigations CXR: cardiomegaly, pulmonary oedema ECG: tachycardia, non-specific T-wave changes, poor R wave progression Echo: globally dilated hypokinetic heart with low ejection fraction Also- look for MR, TR, LV mural thrombus Management Treat any known aetiological cause As for heart failure bed rest ACE-inhibitor diuretics digoxin Amiodarone (if arrhythmias) Anticoagulation (if AF/ prev thromboembolic event) Consider transplant AMIODARONE Amiodarone in tx of dilative cardiomyopathy: Class III antiarrhythmic drug- prolongs a.p. Less -vely inotropic than other drugs in its class Effective in treating tachyarrythmias: supraventricular (eg. AF) ventricular (eg. VT, VF) nb. High iodine content => propensity to cause hypo/hyperthyroidism (hyperthyroidism being associated with dilative cardiomyopathy) AMIODARONE Amiodarone Class 3 anti-arrhythmic drug Used in the treatment of SVT and ventricular arrhythmia Long half-life, 13-103 days If toxicity occurs, it may persist long after drug administration is discontinued 15-30 days or more are required to load the body stores with sufficient Amiodarone for full efficacy Loading doses are 0.8-1.2g daily for about 2 wks, maintenance dose is 200-400mg daily Side Effects Cardiac effects: symptomatic bradycardia heart block heart failure in susceptible patients Extra-cardiac effects: pulmonary fibrosis corneal/skin deposits neurological effects thyroid dysfunction gastrointestinal tract liver involvement drug interactions Amiodarone and The Thyroid Contains 30% by weight of iodine Causes thyrotoxicosis in 3% of patients who use it Inhibits type 1 5’ deiodinase enzyme activity peripheral conversion of T4 to T3 Also clearance of T4 and rT3 and acts as a competitive antagonist of T3 Two types, types 1 and 2, based on pre-existing thyroid disorder Thyroid Hormone Metabolism Find picture Amiodarone induced thyrotoxicosis Type 1 Affects patients with latent/pre-existing thyroid disorders Due to excessive, uncontrolled synthesis of thyroid hormone in response to the iodine Type 2 Patients with previously N thyroid Due to destructive inflammatory thyroiditis induced by Amiodarone Investigations Specific Serum TSH – Suppressed Serum T4 – Increased Serum T3 - Increased Technetium Scan – will show little or no uptake Fine Needle Aspiration Non- Specific CRP/ESR – Raised in type 2 ECG – Atrial fibrillation? Treatment Options Medical Antithyroid Drugs Potassium percholate? Beta blockers – for control of symptoms Steroids Radioactive iodine Surgery Subtotal/total thyroidectomy Medical Treatment If possible withdraw amiodarone treatment Amidarone will remain in the blood following cessation due to its long half life. In type 1 AIT Antityhroid drugs Potassium percholate In type 2 AIT Steroids Type 1 AIT 1st 6 weeks Carbimazole 45mg/day for 6 weeks – I/c with Potassium percholate? 0.6-1.2g/day. > 6 weeks Carbimazole ~ 30-45mg/day for 12-18 months Radioactive iodine Subtotal thyroidectomy/total thyroidectomy Type 2 AIT Steroids Prednisolone 30-40 mg/day for 1-2 weeks Gradually weaned off of steroids following normalisation of serum T3 and serum T4 levels. If required antithyroid drugs can also be used Mixed Type 1 and Type 2 AIT In these types of case of AIT both treatment regimes are combined. Therefore treatment is Antityroid drugs/potassium percholate and steroids. Radioactive iodine Usually NOT FEASIBLE In AIT: Low thyroid radioactive iodine uptake High stable iodine content in the gland This reduces the efficacy of radioactive iodine Radioactive iodine can be used to treat underlying graves disease following medical treatment of AIT. Surgery Normally want patient euthyroid pre-op Subtotal/Total thyroidectomy Patient is started on thyroxine replacement due to hypothyroid state following subtotal or total thyroidectomy. Patient can then remain on Amiodarone to treat cardiac arrythmia
