Treatment of TOXIC GOITRE

Highlights :

Treatment of TOXIC GOITRE

Written by Administrator

Friday, 11 December 2009 08:53

Treatment:
A) Medical treatment B) Radio-active iodine therapy
C) Surgical Management
A) Medical Treatment:
Ä Indications:
1- Mild cases or during periods of stress e.g. pregnancy.
2- Decompensated thyrocardiacs.
3- Recurrent cases esp. the 2nd recurrence "difficult" op.
4- Progressive exophthalmos as operation ® Malig. exophth. Medical treatment is given untill exophthalmos become stable for 6 months.
Ä Drugs used:
1- Anti thyroid drugs: Thiocyanate and perchlorates interfers with iodide trapping. Carbimazole (Neomercazol) 10 mg/8 hs "the best" and thiouracil prevent oxidation of iodide and iodination of tyrosine. Carbimazole also has an immunosuppressive effect.
2- b-blockers: ® Inderal / 10-40 mg twice daily to control the cardiac manifestations
3- Sedatives ® to control neurological symptoms
4- Lugol's iodine drops 10-15 drop tds for pre-operative preparation to decrease the vascularity of the thyroid.
· It decrease TSH by direct feed back through inhibition of pituitary.
· It decrase thyroxin formation through inhibition if oxidation of iodide and depression of protease enzyme.
· Mental and physical rest with good nutrient diet are necessary with the above drugs.
Ä Scheme of treatment:
- Neomercazol is given for one month
- If no response ® prepare for surgery
- If there is good response continue for 3 ms.
- Then halved for another 3 months
- The 1/4 of the original dose is given for 1 year
ÄComplications of anti thyroid drugs:
1- Allergy causing itching and vomiting.
2- Bone marrow depression. Stop the drug if sore throat developed and give penicilline.
3- Increased vsacularity how? (T.S.H hyperplasia)
4- Persistent tachycardia Why (A.V.shunts)
5- Critinoid goitre: for the infant in case of pregnancy .so we stop the drug 3 weeks before labour and reduce the dose and stop lactation as the drug secreted in milk.
6- Myxoedema due to over dosage.
B) Radio-active iodine therapy:
ÄIndications:
1- Patient is not fit for surgery or refuse surgery.
2- Recurrence after surgery but the dose can't be adjusted.
3- Malignant thyrotoxicosis.
ÄContraindications or complications:
1- During pregnancy and lactation ® cretinism of the baby.
2- Under the age of 40 ys. as irradiation is carcinogenic within 20 ys.
ÄDosage: 4-8 millicuries or according to the size of the gland.
ÄDisadvantages:
1- The exact dose is difficult to be estimated.
2- Delayed action: after 2-3 months.
3- Coplications of irradiations e.g. bone marrow depression, foetal anomalies, cancer thyroid.
C) Surgical Management:
ÄIndications:
1- Moderate and severe cases.
2- Pressure symptoms.
3- Retrosternal or intrathoracic as medical treatment increases the size and causes pressure symptoms.
4- Secondary toxic goitre.
5- Suspicion of malignancy.
6- Failure of medical treatment or relapse after medical treament.
ÄTechnique of Surgical Treatment:
a) Preoperative investigation:
1. Indirect laryngoscopy, to detect symptomless cord paralysis .(3% of cases)
2. Thyroid antibodies for:
i) LATSH antibody titre ( High titre may postpone surgery)
ii) Diagnosis of Hashimoto's disease.
3. Serum calcium estimation.
4. Thyroid scan in patient with solitary nodule and toxic nodular goitre.
b) Preoperative preparation:
1) Mental and physical rest.
2) Sedation (Luminal & Serpasil).
3) Antithyroid drugs. ( Carbimazol 30-40 mg/day for 8-12 weeks.)
4) Beta- blockers (Inderal: 10-40 mg t.d.s.).
5) Lugol's iodine (5% iodine in 10% potassium iodide): is given instead of antithyroid drugs 15 drops tds for 10:15 days before operation to decrease the size and vascularity of the gland.

F N.B.In cases of toxic retrosternal goiter the preparation should not include antithyroid drugs (only Inderal) as it may increase size of the gland within closed area causing aggressive pressure manifestations.

c) Operation (Subtotal thyroidectomy):
1- Anaesthesia: General endo-tracheal.
2- Position: Supine with extended neck.
3- Incision: Kocher's collar incision:
One inch above the manubrium from posterior border of sternomastoid m. to the posterior border of the other.
The incision involves skin and platysma m.
Dissect the upper flap to the upper border of thyroid cartilageand the lower flap to the manubrium.
The pretracheal muscles splitted and retracted laterally or incised near its upper pole.
* Indications of cutting pretracheal muscles:
a- Toxic goitre: ¯ manipulation to avoid toxic crisis
b- Malignant goitre. c- Huge Nodular goitre.
* Why near to its upper pole ? being innervated by ansa cervicalis (C1, C2) coming from its lower pole ® to leave a good part of muscles innervated.
4- Devascularisation:
a) Ligation of the middle thyroid vein at first with its division, for easier mobilization and it is weak liable to be torn easily.
b) Ligation of the superior thyroid artery & vein near to upper pole why? to avoid injury of ext. laryngeal nerve.
c) Ligation of the inf. thyroid artery as far as possible from the gland WHY? to avoid injury of the recurrent laryngeal nerve.
d) Ligation of the vessels supplying the lower pole [Inf. thyroid vein & thyroida ema].
5- Cut the thyroid leaving the posteromedial part of thyroid of the size of normal thyroid. why posteromedial part?
a) To leave parathyroids intact.
b) Avoid injury of recurrent laryngeal nerve.
6- Put a drain in both sides.
7- Closure.
m Complications of Operation:
1- Haemorrhage
1ry: during operation.
Reactionary: within 24 hs. after operation due to increase of bl.pr (which was hypertensive intraoperative.)
2ry: 7-10 days after operation due to infection ® erosion of bl. vessels.
The blood may accumulate behind the infrahyoid muscle ¯suffocation. Rapid cutting of sutures and transportation of the patient to the theatre is necessary.
2- Injury to recurrent laryngeal nerve:
a) Unilateral injury: causes hoarseness of voice which improves within few weeks. WHY?
b) Bilateral injury:
* Incomplete ® suffocation.
* Complete®aphonia as cords lies in the cadaveric position.
3- Injury to external laryngeal nerve ®Low pitched voice and shocking & usually improves spontaneously.
4- Thyrotoxic crisis: It is rare now after good preoperative preparation.
Ä Definition: Rapid flushing of circulation with T3 & T4.
ÄAetiology: Inadequate preparation or excessive manipulation during operation.
Ä Clinical Picture:
Ÿ Marked irritability Ÿ Marked sweating
Ÿ Severe tachycardia Ÿ Hyperthermia.
Ÿ If neglected heart failure will occur.
Ä Treatment of thyrotoxic crisis:
Ÿ Sedatives as Morphia and Chloral hydrate. ŸCold compresses.
Ÿ 500 cc glucose 5% . Ÿ Digoxine for AF.
Ÿ Diuretics to prevent heart failure.
Ÿ Specific treatment:
a) Carbimazol 15-20 mg / 6 hs.
b) Lugol's iodine 10 drops/8 hs by mouth or sodium 1 gm intravenous.
c) Propranolol 40 mg / 6 hs orally to block beta adrenergic effect .
5- Tetany:Usually 2-5 days postoperative.
ÄPermanent ® due to accidental removal of parathyroid. glands.
ÄTemporary ® due to ischaemia of the glands.
ÄTreatment:ŸCalcium gluconate 10 % 10 cc/day till improvement.
Ÿ If permanent oral Dihydrotachysterol for long term.
6- Myxoedema: Usually 2 years postoperative due to removal of all thyroid tissue. It may be present 5 years postoperative due to change in the effect of the antibodies to destruction instead of stimulation.
Ä Treatment: thyroid extract is given for life.
7- Rare complications:
a) Heart failure.
b) Surgical emphysema.
c) Tracheomalacia.
d) Keloid formation: especially if incision is low near the sternum.
m Treatment of Progressive Exophthalmos:
1- Dark glasses.
2- Diuretics & corticosteroids ® reduce retrobulbar oedema.
3- If no response:
ÄTarsorraphy
ÄOrbital decompression
SOURCE: Prof. AYMAN SALEM'S BOOK
Copyright: (Vascular Society of Egypt ) & (Medical Educational web)
Not to be reproduced without permission of Vascular Society of Egypt

Comments

Add New