DEFINITION An enlarged thyroid gland. -Clinically palpable gland.-Gland enlargement more than twice of the normal size.
OVERVIEW• Geography: Worldwide, the most common cause of goiter is iodine deficiency.Approximately 800million people subsist on iodine-deficient diet.In industrialized countries,goiter is more often due to Hashimoto’s thyroiditis.
OVERVIEW• Sex: The female-to-male ratio is 4:1.Thyroid nodules are more likely to be malignant in menThe frequency of goiters decreases with advancing age. although the incidence of thyroid nodules increases with advancing age.• Race: No racial predilection exists.
BACKGROUND• TRH:Produced by Hypothalamus. Release is pulsatile,circadian. Downregulated only by T3. Travels through portal venous system to adenohypophysis. Stimulates TSH formation.• TSH: Produced by Adenohypophysis Thyrotrophs.Up regulated by TRH .Down regulated by T4, T3.
BACKGROUND Travels through portal venous system to cavernous sinus, then thyroid gland. Stimulates several processes Iodine uptake Colloid endocytosis Growth of thyroid gland.• Thyroid Hormone: Majority of circulating hormone is T4 98.5% T4 1.5% T3
BACKGROUNDTotal Hormone load is influenced by serum binding proteins Albumin 15% Thyroid Binding Globulin 70% Transthyretin 10%Regulation is based on the free component ofthyroid hormone
PRESENTATION• History:Anterior neck swellingPain: Haemorrhage, inflammation, necrosis, or Malignant transformationCompressive symptoms: Dysphagia, dyspnea, stridor, plethora or hoarsenessSymptoms of hyperthyroidism or hypothyroidism
PRESENTATION• Physical ExaminationCharacterisation of thyroid swellingCheck for signs of hyperthyroidism/hypothyroidismCheck for signs of compression(Pemberton manoeuvre).Check for signs of malignancy
PRESENTATIONHyperthyroidism versus Hypothyroidism
INVESTIGATIONS• Imaging Studies:Ultrasonography:Evaluate goiter size, consistency, and nodularity. Localize nodules for ultrasonographically guided biopsy.X Rays:Usually AP and Lateral with thoracic inlet.Retrosternal goitre extension.Presence of calcification.
INVESTIGATIONSComputed tomography (CT) scanning: Delineate the relationship of the thyroid gland to nearby structures.CT-guided biopsies.Radionuclide isotope scanning are used to assess thyroid function and anatomy in hyperthyroidism, as shown below.
TREATMENT• Observation Small goiter Euthyroid Asymptomatic• Medications: Hypothyroidism: Thyroid hormone replacement with levothyroxine. Hyperthyroidism:May require medications to normalize hormone levels for example propylthiouacil,Methimazole Inflamed thyroid gland, aspirin or a corticosteroid
TREATMENT• Surgery: Removing all or part of the thyroid gland-Thyroidectomy.Large goiters with compressionMalignancyWhen other forms of therapy are not practical or ineffective• Radioactive iodine: Treatment results in diminished size of goiter, but eventually may also cause a hypothyroid state.
TREATMENT• Minimally-invasive modalitiesEndoscopic subtotal thyroidectomyEmbolization of thyroid arteriesPlasmaphoresisPercutaneous ethanol injection into toxic noduleL-Carnitine supplementation may improve symptoms and may prevent bone loss
PROGNOSIS• Complications of thyroidectomy:• Thyrotoxic storm• Bleeding• Infection• Hypoparathyroidism• Injury to recurrent laryngeal nerve• Injury to superior laryngeal nerve• Hypothyroidism
PROGNOSIS• A small percentage of multinodular goiters do lead to hyperthyroidism.• Benign goiters have a good prognosis,furthermore,the risk of malignant transformation is low.