Toxic adenoma is one of the causes of thyrotoxicosis. It also known as Plummer disease. It is characterized by a solitary nodule that produces T3 and T4.
Isotope scan will show the nodule is ‘hot’. Isotope scan is a useful technique to determine causes of hyperthyroidism. It uses Iodine (123) or Technetium pertechnetate (99). “Hot” means that there is increase uptake of isotope while “cold” means decrease uptake. About 20% of cold cases are malignant. It is safe to say that there is no hot nodules turn out to be malignant.
The main management is radioiodine. One complication of radioidone is the patient often become hypothyroid after the treatment and patient may need lifelong of thyroid hormone replacement. So far, there is no evidence of increase risk for cancer. In women, there is no long term evidence of evidence that radioiodine cause birth defect or infertility. However, the treatment still contraindicated in pregnancy and lactation. In active hyperthyroidism, caution should be taken for thyroid storm (hyperthyroid crisis).
Other relevant topics:
· Thyrotoxicosis
· Graves’ disease
· Toxic multinodular goiter
· Toxic adenoma
· Thyroid storm
Reference:
1. Oxford handbook of Clinical Medicine. 7th edition. Oxford University Press. 2008.
2. Current medical Diagnosis and Treatment. Lange Mc Graw Hill. 2009.
Thyroid crisis is an emergency. It precipitates by recent surgery of thyroid or radioiodine treatment. Infection, myocardial infarction and trauma may also lead to thyroid storm in active hyperthyroidism patient.
Signs and symptoms:
· Severe hyperthyroidism
· Fever
· Agitation
· Confusion
· Coma
· Tachycardia (heart rate >100 per minute)
· Fast atrial fibrillation
· Diarrhea
· Vomiting
· Goitre
· Thyroid bruit
· Similar symptoms of acute abdomen
Isotope scan is needed to confirm the diagnosis (technetium uptake). However, in urgent or acute case, we shouldn’t wait for the scan before initiation of treatment.
Management:
· IV infusion of 1 pint normal saline over 4 hours
· Nasogastric tube insertion if recurrent vomiting present
· Do blood investigations for TSH/T4/T3, consider blood cultures and sensitivity if there is any suspicion of underlying infection
· In certain cases, sedation is indicated (eg: chlorpromazine)
· Tablet propanolol 40mg 8 hourly should be given if no contraindication (maximum IV dose: 1mg/min, repeated up to 9 times at >2minutes intervals)
· High dose digoxin (eg: IV infusion 1mg/2 hours) – to slow heart rate
· Give antithyroid drugs: tablet carbimazole 15-25mg stat and 6 hourly by oral (or nasogastric tube)
· After 4 hours of first dose, give Lugol’s solution 0.3ml/8 hourly for a week. This is needed to block the thyroid
· Give IV hydrocortisone 100mg/6 hourly or tablet dexamethasone 4mg 6 hourly
· If any suspicion of infection, treat with IV antibiotic
· Reassess the need of fluid infusion and adjust accordingly
· Relief the fever by tepid sponging and paracetamol
· After 5 days, tablet carbimazole dose should be reduce to 15mg/8 hourly
· After 10 days of treatment, stop iodine and propanolol (if heart rate is normal). Carbimazole dose should be adjusted accordingly
Other relevant topics:
· Thyrotoxicosis
· Graves’ disease
· Toxic mutinodular goiter
· Toxic adenoma
· Thyroid storm
Reference:
1. Oxford handbook of Clinical Medicine. 7th edition. Oxford University Press. 2008.
