Download Benign Thyroid Disorders

BENIGN THYROID
DISORDERS
Regional SpR Teaching
Woo-Young Yang
ST5
CLASSIFICATION
Simple Non-Toxic
 Toxic
 Inflammatory
 Neoplastic
 Rare

CLASSIFICATION

Simple Non-Toxic

Iodine Difficiency
 Multinodular Goitre
 Solitary Nodule
 Physiological






Toxic
Grave’s Disease
 Plummer’s Disease




Inflammatory
Hashimoto’s Thyroiditis
 De Quervain’s
Thyroiditis
 Riedel’s Thyroiditis

Neoplastic

Follicular
Papillary
Medullary
Anaplastic
Lymphoma
Metastatic
Rare
Infective
 Iatrogenic

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
EUTHYROID MNG

Epidemiology
Incidence by Palpation – 10%
 Incidence by Imaging – up to 50%


Aetiology

Benign
Colloid cyst
 Simple cyst
 Adenoma
 Infection


Malignant
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))
TREATMENT

Surgery
Cosmetic
 Compressive symptom
 Suspicion for cancer


Radioiodine
Indicated if unfit for surgery
 Regression of the goitre size

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(<3ml)
 Surgery for the larger ones(10% cancer risk)

CLASSIFICATION

Simple Non-Toxic

Iodine Difficiency
 Multinodular Goitre
 Solitary Nodule
 Physiological


Grave’s Disease
 Plummer’s Disease





Toxic

Inflammatory
Hashimoto’s Thyroiditis
 De Quervain’s
Thyroiditis
 Riedel’s Thyroiditis

Neoplastic


Follicular
Papillary
Medullary
Anaplastic
Lymphoma
Rare
Infective
 Iatrogenic

HYPERTHYROIDISM – CLINICAL
FEATURES

Cardiac
Tachycardia, AF
 High output
congestive heart
failure

Irritability
 Anxiety





Heat intolerance
Metabolic
Weight loss
 Increased appetite
Dermatological

Thermoregulatory

Neuopsychiatric

Hormonal



GI


Irregular
menstruation
Misc
Fine tremor
 Thyroid bruit

Diarrhoea
Hair loss and brittle
nails
HYPOTHYROIDISM – CLINICAL
FEATURES

Cardiac


Bradycardia
Cold intolerance
Depression
 Mental impairment





Constipation
Hormonal

GI

Dermatological
Dry skin
 Myxoedema
Metabolic
Weight gain
 Decreased appetite
 Glucose intolerance
Neuopsychiatric

Thermoregulatory




Irregular
menstruation
Misc

Hoarseness
GRAVE’S 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

GRAVE’S DISEASE – CLINICAL
PRESENTATION

Thyroid
Manifestations
Diffuse symmetrical
goitre +/- bruits
 Hyperthyroidism


Extrathyroid
Manifestations
Acropachy
 Myxoedema
 Grave’s
ophthalmopathy

GRAVE’S OPHTHALMOPATHY

Pathophysiology
Lymphocytic
infiltration and
glycosaminoglycan
deposition
 Extraocular muscle
swelling
 Periorbital fat
proliferation

GRAVE’S 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

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))
TOXIC ADENOMA
Plummer’s Disease
 Epidemiology

Rare – 2 % of hyperthyroidism
 Younger than Toxic MNG


Pathophysiology
Somatic, non-inherited TSH receptor mutation
 Autonomous TSHR activation and

TOXIC GOITRE - INVESTIGATIONS


TFT
Thyroid Autoantibodies

TPO ((actually the most senstive
marker of grave’s disease – 45% for
TSH R))
Thyroglobulin
 TSH receptor


Scintigraphy

Distinction between toxic
nodule and Grave’s
disease
TOXIC GOITRE - TREATMENT

Difference between Grave’s disease and Toxic
MNG/Adenoma
Grave’s disease may go into remission(30%)
 Toxic MNG/Adenoma does not go into remission


Treatment Options
Antithyroid Drugs
 Radioiodine
 Surgery

ANTITHYROID DRUGS

Thionamides


Carbimazole, Methimazole, Popylthiouracile(PTU)
Pharmacophysiology
Inhibition of the organification and oxidation of iodine
 T4/T3 synthesis inhibition
 ? Immunomodulation effect for Grave’s disease?


Side effects
Deranged LFT - rarely drug-induced hepatitis
 Agranulocytosis(1/1,000)

OTHER DRUGS

Beta-blocker


Propranolol
Anticoagulants

AF management
RADIOIODINE 131



First treatment of choice for Grave’s 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 Grave’s and Toxic MNG

RADIOIODINE 131

Side effect



Hypothyroidism
Thyroiditis
Safety?
Outpatient treatment
 Avoid contact with children ((sleep alone/no sharing utensils))


Contraindication
Pregnancy
 Breast feeding

TOXIC GOITRE - SURGERY

Indications
Refractory to radioiodine
 Patient’s 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))
TOXIC GOITRE - SURGERY

Grave’s Disease


Toxic Adenoma


Total thyroidectomy
Thyroid Lobectomy
Toxic SMG

? Subtotal thyroidectomy
HYPERTHYROIDISM IN PREGNANCY

Grave’s 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)))
INFLAMMATORY GOITRES HASHIMOTO’S 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

INFAMMATORY GOITRES – DE
QUERVAIN’S 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

INFLAMMATORY GOITRES – RIEDEL’S
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

RIEDEL’S 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 Riedel’s
Fibrosing Thyroiditis from malignancy
 ? PET-CT?
 Open surgical biopsy is required by wedge resection

RIEDEL’S THYROIDITIS


Medical Treatment


Steroid
Tamoxifen ((not by oe inhibition but by grow factor level decrease therefore fibroblasts

Thyroid hormone replacement
Surgical Treatment



down))
Wedge Resection
Further surgical Rx not recommended due to the extensive
fibrosis
Prognosis

self-limiting, good prognosis
THANK YOU