Graves’s disease

By | 15th May 2012

 

Definition:

This is the commonest cause of hyperthyroidism and is due to autoimmune process in which serum IgG antibodies bind to the thyroid TSH receptors and produce stimulation of thyroid hormone production, behaving like TSH.

 

Clinical features

Increased size and secretion of thyroid gland

GIT features include weight loss despite normal or increased appetite

Diarrhea

Anorexia

Vomiting

 

CVS

Palpitation

Sins tachycardia

Atrial fibrillation

 

Respiratory features

 

Increased pulse pressure

Dyspnea on exertion

 

Neuromuscular features

 

Nervousness

Irritability

Emotional liability

Tremor of hand

Muscle weakness

 

Dermatological features

 

Increased sweating

Palmar erythema

Pigmentation

Finger clubbing periorbital myxedema

 

 

Ocular

Exophthalmos

Corneal ulceration

Excessive lacrimation

Grittiness

Lid retraction

Lid lag

Chemosis

Ophthalmoplegia

Diplopia

Papilledema

Loss of visual acuity

 

Other

 

Heat intolerance

Fatigue

Thirst

Lymphadenopathy

 

Treatment

 

  1. Antithyroid drugs
  2. Subtotal thyroidectomy
  3. Radioactive iodine

 

Methimazole

 

An active derivative metabolite of carbimazole and propylthiouracil .these drugs act by reducing the synthesis thyroid hormone by inhibiting the iodinization of thyroxin.

Dose: 30-40 mg of methimazole or 300-400 mg of PTU are given until patient is euthyroid.

Improvement occurs in few weeks to months and then lower the dose that maintain euthyroidism and drug should be continued for 12-18 months.

 

Adverse effects:

Skin rash, agranlocytosis

 

Subtotal thyroidectomy

 

Peoperatve preparation

 

Operation in a thyrotoxic patient risk the thyroid storm so first treat the patient with antithyroid drugs to return them to euthyroid state before surgery.

Pros

Increase success rate

Rapid cure of hyperthyroid state

 

Cons

Hospitalization

Surgical and anesthesia side effects

 

Complications

Hypothyroidism

Recurrent laryngeal nerve paralysis

Postoperative bleeding

 

Radioactive iodine

 

A singe dose of iodine 131 I cause a decrease function and size of thyroid gland in 6-12 weeks.

Approx 75 % of patients are made euthyroid by a single dose. Eventually, almost all patients cured in this way.

 

Cons

Multiple doses may be needed

Hypothyroidism