Download Thyroid Disease - Dorridge Surgery

Thyroid Disease
Dr Andrew S Bates
Heart of England Foundation Trust
Outline




What and where is it?
What does it do?
How is it controlled?
What can go wrong with it?

Functional disorders


Hyper- and Hypothyroidism
Goitre, nodules and tumours
The normal thyroid
What does the thyroid do?

Secretes thyroid hormones (T4 and T3)

Control basal metabolic rate

Burn fat

Increase heart rate

Increase bone turnover
Thyroid Physiology





Heavily dependent on iodine
Iodination of thyroglobulin resulting in
formation of mono- and di-iodotyrosines
Iodotyrosines combine to form T4 (100%)
and T3 (20%) - released into circulation
80% of T3 is formed outside the thyroid
Deiodinases play important role in thyroid
metabolism
How is it controlled?
What do we measure?


TSH-most important

Low or ‘turned off’ if overactive

High if underactive
FT4 and FT3


Occasionally useful in addition to TSH
Thyroid antibodies

Non-diagnostic but useful as a pointer to
autoimmune thyroid disease
What can go wrong?

Overactive


Underactive


High free T4 low or suppressed TSH
Low free T4 and high TSH
Thyroid growths

Goitre, nodules, cancer
Overactive thyroid
Thyroid Hormone Excess
Clinical Features

General


Cardiovascular


Tachycardia, heart failure.
Gastrointestinal


Heat intolerance, fatigue, tremor.
Weight loss, diarrhoea
Ophthalmological

Lid lag, ophthalmopathy
Thyroid Hormone Excess
Clinical Features

Genitourinary


Neuromuscular


Proximal muscle weakness, HPP, MG
Psychiatric


Amenorrhea, infertility.
Irritability, agitation, anxiety, psychosis
Dermatological

Pruritus, hair thinning, onycholysis, vitiligo.
Causes of Thyroid Hormone
Excess

Increased iodine uptake

Graves

Toxic Multinodular Goitre

Toxic solitary adenoma
Causes of Thyroid Hormone
Excess

Reduced iodine uptake

Thyroiditis

Iodine induced (Amiodarone)

Factitious
Increased iodine uptake
Selective iodine uptake
No iodine uptake
Graves Disease






Most common cause in UK
Diffuse Goitre
Hyperthyroidism
Ophthalmopathy
Dermopathy
Autoimmune.
Toxic Multinodular Goitre




Older
Usually less severe hyperthyroidism
May have subclinical
hyperthyroidism(normal thyroid
hormones, low TSH)
May have long history of goitre
Toxic Solitary Adenoma




Rare cause (< 2% of patients with
hyperthyroidism)
Younger people 30’s and 40’s
Isotope scan useful
Benign follicular adenomas
Thyroiditis




Painful (subacute, de Quervain’s)
Painless (post partum)
Hyperthyroid, hypothyroid and
euthyroid phases
Anti thyroid drug therapy does not work
Treatment of hyperthyroidism

Antithyroid drugs




Carbimazole 10 mg tid
Reduce to maintenance after 4 weeks
Rash, GI, agranulocytosis
Graves – withdraw drugs after course of
treatment
Treatment of hyperthyroidism

Radio-iodine





Inflammatory response followed by fibrosis
May be used for Graves, TMG or TA
? Need for drug treatment before and after
May need retreatment
Long term risk of hypothyroidism
Treatment of Hyperthyroidism

Surgery



Rarely used nowadays
Need to be rendered euthyroid before
surgery
Lugol’s iodine 0.1-0.3 mls tid for 10 days
before surgery
Graves Eye Disease



Onset relative to hyperthyroidism is
variable.
Pain, watering, photophobia, blurred
vision, double vision
Usually mild – Tx, protective glasses,
elevate head of bed, conjunctival
lubricants
Graves Eye Disease



High dose steroids
External radiotherapy
Orbital decompression
Thyroid Eye Disease
Hypothyroidism





Autoimmune
Hashimoto’s
Iatrogenic
Congenital
Hypopituitarism
Treatment



Thyroxine – variable doses.
Aim to normalize TSH
In patients with heart disease start with
lower dose e.g. 25ug once daily.
Multinodular Goitre
Simple non-toxic goitre



Normal TFT’s
No treatment required
Surgery if obstructive symptoms
Nodular Thyroid Disease

Prevalence 5-50%




Depending on age and methods used
Clinically apparent nodules in 4-7% UK
population
Four times more common in women
<5% are cancerous
Factors Favouring Benign
Disease






Age
Family history of benign thyroid nodule
Presence of hyperthyroidism
Associated pain or tenderness
Soft, smooth, mobile nodule
Multinodular goitre without a dominant
nodule
Management





Clinical history and examination
Thyroid function tests
Ultrasound
Fine Needle Aspiration
Surgery
Conclusion


A small but very important gland with
many vital functions
Commonly develops faults, but
fortunately most are easily sorted out