Thyroid Disease

Prof T O’Brien

Thyroid Hormone ExcessClinical Features General

Heat intolerance, fatigue, tremor. Cardiovascular

Tachycardia, heart failure. Gastrointestinal

Weight loss, diarrhoea Ophthalmological

Lid lag, ophthalmopathy

Thyroid Hormone ExcessClinical Features Genitourinary

Amenorrhea, infertility. Neuromuscular

Proximal muscle weakness, HPP, MG Psychiatric

Irritability, agitation, anxiety, psychosis Dermatological

Pruritus, hair thinning, onycholysis, vitiligo.

Diagnosis High Free T4, T3 and supressed sTSH

If sTSH is high suspect pituitary tumour or rare cases of thyroid hormone resistance

Causes of Thyroid Hormone Excess Increased radioactive iodine

uptake Graves TMG Toxic solitary adenoma Pituitary tumour

Causes of Thyroid Hormone Excess Reduced radioactive iodine uptake

Thyroiditis Iodine induced (amiodarone) Factitious Struma ovarii Thyroid carcinoma

Graves Disease Most common cause in Ireland Diffuse Goitre Hyperthyroidism Ophthalmopathy Dermopathy Autoimmune. TSI.

TMG Older Usually less severe

hyperthyroidism May have subclinical

hyperthyroidism May have long history of goitre

Toxic Solitary Adenoma Rare cause (< 2% of patients with

hyperthyroidism) Younger people 30’s and 40’s Scan 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

Treatment of Hyperthyroidism Patient presents with

hyperthryoidism Make diagnosis, get RAI uptake. Beta block (inderal 40-80 mg tid). If RAI uptake is high – treat with

RAI. If RAI is low - symptomatic

Thyroid Storm Carbimazole (or PTU) Inderal, 80mg qid Iodine (Lugols 5 drops q6) Dexamethasone 2mg q6 Other supportive measures

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

Hypothyroidism Hashimoto’s Iatrogenic Congenital Hypopituitarism

Treatment Thyroxine 100-150ug daily. Aim to normalize sTSH In patients with CAD start with

lower dose e.g. 25ug qd.

Simple non-toxic goitre Normal TFT’s No treatment required Surgery if obstructive symptoms

Non-thyroidal illness Ill patients may have low T3 and/or

T4 usually with a normal sTSH Psychotic patients may have

elevated T3 and/or T4.

Thyroid Nodule FNA Benign no further intervention Malignant or suspicious– papillary

or follicular.

Papillary Cancer Controversies

Extent of surgery (near total thyroidectomy). Follow up with sTSH, thyroglobulin exam and US.

Radioactive iodine ablation for high risk tumours. Follow up with RAI scans plus the above.

Follicular cancer Less common than papillary Total thyroidectomy (or near total). Routine remnant ablation with RAI

due to increased risk of metastatic disease.