Hyperthyroidism

Hyperthyroidism

Aetiology

1. Graves Disease

   • TSH receptor antibodies (TRABs) positive

   • Thyroid eye disease

2. Thyroiditis

   • Post infective hyper then hypothyroidism

3. Toxic Multinodular (TMN) Goitre 

4. Adenoma: toxic thyroid nodule

5. TSH pituitary adenoma

6. Post-partum thyroiditis

   • beta-HCG has thyroid action

   • Presents within couple months of birth

   • Tender thyroid gland

   • Nil TPO but 40% progress to Hashimoto's

7. Drug induced

   • Amiodarone

     • Management: steroids

8. Neuroendocrine tumour secreting TSH

General symptoms

• Weight loss despite increased appetite

• Heat intolerance

• Excessive sweating

• Fatigue and weakness

• Reduced exercise tolerance

• Increased thirst

• Increased frequency of bowel movements or diarrhoea

• Difficulty sleeping

Cardiovascular features

• Palpitations

• Tachycardia

• Increased pulse pressure

• Atrial fibrillation (especially in older adults)

• Shortness of breath on exertion

Neurological and psychological features

• Anxiety and irritability

• Restlessness

• Tremor (fine, rapid tremor of the hands)

• Difficulty concentrating

• Hyperactivity

• Mood changes

Gastrointestinal and muscle features

• Increased bowel frequency

• Muscle weakness (especially proximal muscles, e.g., difficulty climbing stairs)

• Reduced muscle mass

Reproductive features

• Menstrual irregularities (often lighter or less frequent periods)

• Reduced fertility

• Reduced libido

• Erectile dysfunction in men

Eye features (especially in Graves' disease)

• Lid retraction (“staring” appearance)

• Lid lag

• Exophthalmos/proptosis

• Eye irritation or dryness

• Double vision in more severe cases

Thyroid and neck findings

• Diffuse goitre (common in Graves’ disease)

• Thyroid bruit (from increased blood flow)

• Thyroid nodules (in toxic multinodular goitre or toxic adenoma)

Skin and hair changes

• Warm, moist skin

• Fine hair and hair thinning

• Increased hair shedding

• Pretibial myxoedema (specific to Graves’ disease)

Severe presentation: Thyroid storm (medical emergency)

Features may include:

• High fever

• Severe tachycardia

• Heart failure

• Delirium, agitation, or coma

• Vomiting and diarrhoea

Typical examination findings: tachycardia, fine tremor, brisk reflexes, warm sweaty skin, goitre, and possible eye signs depending on the cause.

Assessment

Presentation

• Weight loss, heat intolerance, sweating, weakness, diarrhoea

• Palpitations, Anxiety, difficulty concentrating

• Irregular light periods, reduced libido, erectile dysfunction; agitation

Examination

• Fine Tremor, Myopathy (proximal), AF, 

• Tachycardia, Fever

• Graves: thyroid eye disease- lid retraction, lid lag, exophthalmos, proptosis

Investigations

• TFT: raised T3 & T4 - TSH appropriately low,

• Thyroid iodine uptake scan

• Thyroid US

Diagnosis

Diagnostic Criteria: raised T3

Management

MDT

• Endocrinologist, General Surgeon

Medical

• Betablockers: reduce adrenergic symptoms & burden (propranolol)

• Anti-thyroid medications (agranulocytosis)

  • Carbimazole- rash

  • Propanuricil- used in pregnancy & thyroid storm, liver toxicity

Procedural

• Radioactive iodine therapy- requires isolation due to radiation risk

• Thyroidectomy

Thyrotoxicosis (Thyroid Storm)

Presentation

• Coma

• Myoxodema

• Delirium

• Tachycardia, Fever

Management

• Betablockers- propranolol

• Suppress T3: Propylthiouracil, Iodine (after anti-thyroid drug) & Corticosteroids

• Supportive care: IVF, cooling, 

• Treat underlying cause e.g. infection

Subclinical Hyperthyroidism

Presentation

• Incidental finding

Investigations

• T3/4 within normal range, low TSH (TSH compensating to reduce T4)

• TPO antibodies: negative

Management

• Repeat thyroid function tests every 3 years (nil management required)

Links

Resources

1. https://cks.nice.org.uk/topics/hyperthyroidism/background-information/causes/

Written in 2025