BENIGN THYROID DISORDERS

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BENIGN THYROID DISORDERS

• Regional SpR Teaching
• Woo-Young Yang
• ST5

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CLASSIFICATION

• Simple Non-Toxic
• Toxic
• Inflammatory
• Neoplastic
• Rare

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CLASSIFICATION

• Simple Non-Toxic
• Iodine Difficiency
• Multinodular Goitre
• Solitary Nodule
• Physiological
• Toxic
• Graves Disease
• Plummers Disease
• Inflammatory
• Hashimotos Thyroiditis
• De Quervains Thyroiditis
• Riedels Thyroiditis

• Neoplastic
• Follicular
• Papillary
• Medullary
• Anaplastic
• Lymphoma
• Metastatic
• Rare
• Infective
• Iatrogenic

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IODINE DIFFICIENCY

• Epidemiology
• Commonest cause of goitre and hypothyroidism
  world wide
• Not common in the western world
• Pathophysiology
• Insufficient iodination of thyroglobulin
• Decrease in Thyroid Hormone
• Increase in TSH
• Diffuse hyperplasia(/- multinodular appearance)
• Pregnancy
• Increased demand on maternal iodine
• Worsening features with subsequent pregnancies
• Treatment
• Iodine Replacement

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EUTHYROID MNG

• Epidemiology
• Incidence by Palpation 10
• Incidence by Imaging up to 50
• Aetiology
• Benign
• Colloid cyst
• Simple cyst
• Adenoma
• Infection
• Malignant

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INVESTIGATIONS

• Serological
• TFT
• Serum Calcitonin?
• FNAC
• USS ((useful in looking for malignant features
  such as microcalcification and capsular
  invasion/increased vascularity))
• CT/MRI for retrosternal component
• Tc99/I123 Scintigraphy NOT useful in MNG/SN
  ((BTA and ATA, incidence of cancer 10 in cold
  nodules))

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TREATMENT

• Surgery
• Cosmetic
• Compressive symptom
• Suspicion for cancer
• Radioiodine
• Indicated if unfit for surgery
• Regression of the goitre size

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SOLITARY NODULES

• Mx is broadly similar to MNG
• Cystic nodules
• Many resolve spontaneously
• Larger cysts tend to recur
• Treatment
• Simple aspiration and expectant approach with
  small cysts(lt3ml)
• Surgery for the larger ones(10 cancer risk)

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CLASSIFICATION

• Simple Non-Toxic
• Iodine Difficiency
• Multinodular Goitre
• Solitary Nodule
• Physiological
• Toxic
• Graves Disease
• Plummers Disease
• Inflammatory
• Hashimotos Thyroiditis
• De Quervains Thyroiditis
• Riedels Thyroiditis

• Neoplastic
• Follicular
• Papillary
• Medullary
• Anaplastic
• Lymphoma
• Rare
• Infective
• Iatrogenic

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HYPERTHYROIDISM CLINICAL FEATURES

• Cardiac
• Tachycardia, AF
• High output congestive heart failure
• Thermoregulatory
• Heat intolerance
• Metabolic
• Weight loss
• Increased appetite
• GI
• Diarrhoea

• Neuopsychiatric
• Irritability
• Anxiety
• Dermatological
• Hair loss and brittle nails
• Hormonal
• Irregular menstruation
• Misc
• Fine tremor
• Thyroid bruit

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HYPOTHYROIDISM CLINICAL FEATURES

• Cardiac
• Bradycardia
• Thermoregulatory
• Cold intolerance
• Metabolic
• Weight gain
• Decreased appetite
• Glucose intolerance
• GI
• Constipation

• Neuopsychiatric
• Depression
• Mental impairment
• Dermatological
• Dry skin
• Myxoedema
• Hormonal
• Irregular menstruation
• Misc
• Hoarseness

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GRAVES DISEASE

• Epidemiology
• Commonest cause of hyperthyroidism(60)
• UK incidence 80/100,000
• Pathophysiology
• Autoantibodies against TSH receptor
• Stimulation of thyroid gland hyperplasia
• Autonomous production of T3 and T4
• Association with other organ-specific autoimmune
  diseases
• Pernicious anaemia, DM, Addison Disease,
  Myesthenia Gravis
• HLA-DR3, B8

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GRAVES DISEASE CLINICAL PRESENTATION

• Thyroid Manifestations
• Diffuse symmetrical goitre /- bruits
• Hyperthyroidism
• Extrathyroid Manifestations
• Acropachy
• Myxoedema
• Graves ophthalmopathy

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GRAVES OPHTHALMOPATHY

• Pathophysiology
• Lymphocytic infiltration and glycosaminoglycan
  deposition
• Extraocular muscle swelling
• Periorbital fat proliferation

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GRAVES OPHTHALMOPATHY

• Clinical Features
• Proptosis greater than 22 mm
• Lid retraction and lid lag
• Conjunctival oedema and corneal ulceration
• Oculomotor problem
• Decreasing visual acuity
• Rx options
• High dose steroids
• Radiotherapy
• Surgical alignment/decompression

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TOXIC MULTINODULAR GOITRE

• Epidemiology
• Commonly found in the elderly
• Pathophysiology
• Jod-Baselow Phenomenon ((exact mechanism is
  obscure. Background iodine deficiency, followed
  by iodine Xs, leading to unmasking
  hyperthyroidism. Normal follicular architecture
  becomes disrupted, leading to inefficient iodine
  trapping))
• T3 toxicosis subclinical hyperthyroidism
  ((importance of T3 measurement))

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TOXIC ADENOMA

• Plummers Disease
• Epidemiology
• Rare 2 of hyperthyroidism
• Younger than Toxic MNG
• Pathophysiology
• Somatic, non-inherited TSH receptor mutation
• Autonomous TSHR activation and

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TOXIC GOITRE - INVESTIGATIONS

• TFT
• Thyroid Autoantibodies
• TPO ((actually the most senstive marker of
  graves disease 45 for TSH R))
• Thyroglobulin
• TSH receptor
• Scintigraphy
• Distinction between toxic nodule and Graves
  disease

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TOXIC GOITRE - TREATMENT

• Difference between Graves disease and Toxic
  MNG/Adenoma
• Graves disease may go into remission(30)
• Toxic MNG/Adenoma does not go into remission
• Treatment Options
• Antithyroid Drugs
• Radioiodine
• Surgery

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ANTITHYROID DRUGS

• Thionamides
• Carbimazole, Methimazole, Popylthiouracile(PTU)
• Pharmacophysiology
• Inhibition of the organification and oxidation of
  iodine
• T4/T3 synthesis inhibition
• ? Immunomodulation effect for Graves disease?
• Side effects
• Deranged LFT - rarely drug-induced hepatitis
• Agranulocytosis(1/1,000)

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OTHER DRUGS

• Beta-blocker
• Propranolol
• Anticoagulants
• AF management

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RADIOIODINE 131

• First treatment of choice for Graves Disease and
  MNG
• PO administration
• Pharmacophysiology
• Beta radiation DNA damage and apoptosis
• (different from I 123, which emits gamma rays)
• Dose
• ? Titration
• 400 600 MBq sufficient for both Graves and
  Toxic MNG

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RADIOIODINE 131

• Side effect
• Hypothyroidism
• Thyroiditis
• Safety?
• Outpatient treatment
• Avoid contact with children ((sleep alone/no
  sharing utensils))
• Contraindication
• Pregnancy
• Breast feeding

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TOXIC GOITRE - SURGERY

• Indications
• Refractory to radioiodine
• Patients rejection of radioiodine
• Severe ophthalmopathy
• Pregnancy with uncontrolled disease
• Cosmetic
• Pre-op Preparation
• Antithyroid treatment
• Potassium Iodide if antithyroid drug not
  tolerated ((saturates the thyroid with iodine,
  then the gland turns off the absorption
  mechanism))

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TOXIC GOITRE - SURGERY

• Graves Disease
• Total thyroidectomy
• Toxic Adenoma
• Thyroid Lobectomy
• Toxic SMG
• ? Subtotal thyroidectomy

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HYPERTHYROIDISM IN PREGNANCY

• Graves Disease
• Thionamides are safe in pregnancy
• PTU is preferred as less drug is delivered to
  foetus
• Intra-partum Transient Hyperthyroidism of
  hyperemesis gravidarum ((betaHCG and TSH share
  the same subunit))
• Post-partum Thyroiditis ((distinction by autoAb,
  clinical signs, iodine uptake(postpartum)))

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INFLAMMATORY GOITRES - HASHIMOTOS THYROIDITIS

• Anti-TPO/Thyroglobulin/TSHR autoAb
• Initial transient hyperthyroidism due to cellular
  destruction and release of the preformed thyroid
  hormones
• Subsequent hypothyroidism
• Rubbery diffuse thyroid enlargement
• Treatment
• Thyroid replacement
• Surgery if necessary

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INFAMMATORY GOITRES DE QUERVAINS SUBACUTE
THYROIDITIS

• Granulomatous inflammation of the thyroid gland ?
  2y to viral infection
• Subacute course over weeks/months
• Tender symmetrical diffusely enlarged goitre
• Phases
• hyperthyroid hypothyroid euthyroid(recovery)
• Treatment
• Thyroid status control
• NSAIDs

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INFLAMMATORY GOITRES RIEDELS FIBROSING
THYROIDITIS

• Chronic Inflammation and Fibrosis of Thyroid
  Gland
• Very rare 1.6/100,000
• Uncertain Pathophysiology
• ? Autoimmune
• ? Part of systemic fibrosis
• Spread of the fibrosis outside the thyroid gland
  can cause RLN dysfunction/tracheal
  compression/hypoparathyroidism

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RIEDELS FIBROSING THYROIDITIS

• Clinical features
• Extent of hypothyroidism depends on extent of
  fibrosis of the gland
• Hard wooden goitre WITHOUT cervical
  lymphadenopathy
• May have extra-cervical involvements
  retroperitoneal fibrosis/mediastinal fibrosis
• Investigation
• Neither FNAC nor Imaging can reliably distinguish
  Riedels Fibrosing Thyroiditis from malignancy
• ? PET-CT?
• Open surgical biopsy is required by wedge
  resection

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RIEDELS THYROIDITIS

• Medical Treatment
• Steroid
• Tamoxifen ((not by oe inhibition but by grow
  factor level decrease therefore fibroblasts
  down))
• Thyroid hormone replacement
• Surgical Treatment
• Wedge Resection
• Further surgical Rx not recommended due to the
  extensive fibrosis
• Prognosis
• self-limiting, good prognosis

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THANK YOU