Makindo Medical Notes

Related Subjects: |Thyrotoxicosis and Hyperthyroidism |Thyroid Storm - Thyrotoxic crisis |Graves' Disease (Thyrotoxicosis) |Amiodarone and Thyroid disease |Thyroid Surgery (Thyroidectomy) |Hypothyroidism |Hashimoto's thyroiditis |DeQuervain's thyroiditis |Subacute Thyroiditis |Thyroid nodule |Congenital Hypothyroidism |Thyroid Function Tests and antibodies |Post partum thyroiditis |Sick Euthyroid Syndrome |Thyroid Exam (OSCE) |Thyroid Gland anatomy and Physiology |Thyroid Cancer

Smokers with Graves' Disease are at increased risk of thyroid eye disease and must stop smoking.

About

• Autoimmune disease: Grave's disease is the most common cause of hyperthyroidism, responsible for 60-80% of cases.

Risk Factors

• Gender: More prevalent in women than men, at a 10:1 ratio.
• Age: Typically affects individuals aged 30-50.
• Postpartum increase: Higher incidence following childbirth.
• Smoking: Major risk factor, particularly for eye disease associated with Grave's.
• Leading cause of thyrotoxicosis.

Aetiology

• Genetic associations: Higher prevalence in individuals with HLA B8 and DR3 markers.
• Thyroid-stimulating immunoglobulin (TSI): Causes follicular hyperplasia and can cross the placenta.
• Thyroid peroxidase (TPO) antibodies: Present in 80% of cases.
• Eye disease: Characterized by fibroblast activation and glycosaminoglycan production.
• Autoimmune basis: Involves antibodies against TSH receptor in 80-90% of cases.

Clinical Presentation

• Common symptoms: Weight loss, anxiety, tachycardia, heat intolerance, and palpitations.
• Thyrotoxicosis: May present as apathetic thyrotoxicosis in elderly patients.
• Thyroid examination: Diffuse enlargement with thrill or bruit.

Grave's Disease-Specific Manifestations

• Thyroid Acropachy and Onycholysis: A form of clubbing unique to Grave's disease.
• Pretibial Myxoedema: Pink, purple, or orange discoloration on the shins, affecting around 5% of cases.
• Eye Disease (40% of cases): Includes lid retraction, lid lag, proptosis, diplopia, and possible corneal damage.

Investigations

• Thyroid hormone levels: High T4/T3 and low TSH (< 0.05 mIU/L).
• TSH receptor antibodies: More specific than TPO antibodies.
• Radionuclide scan: Shows diffuse increased activity in the goitre.

Differential Diagnosis

• Nodular goitre
• Toxic adenoma
• Iatrogenic causes (excess thyroxine intake)

Management

• Beta-blockers: Propranolol to manage symptoms.
• Antithyroid medications: Propylthiouracil or carbimazole (20-40 mg daily).
• Radioactive iodine: For patients who need further control.
• Surgery: Subtotal thyroidectomy for severe cases.
• AF management: Anticoagulate if atrial fibrillation is present.

Eye Disease Management

• Inferior rectus involvement: First affected, leading to restricted upgaze and compensatory eyelid retraction.
• Sympathetic activity in thyrotoxicosis: Leads to bilateral eyelid retraction, improving with beta-blockade and thyrotoxicosis treatment.
• Smoking cessation: Essential, as smoking worsens eye disease and radioiodine treatment side effects.
• Ophthalmology care: Regular visual acuity checks and specialist management.
• Symptomatic treatment for eye discomfort: Eye drops, patching, or tarsorrhaphy for gritty eyes.
• Immunosuppression: Options include prednisolone (60 mg daily), ciclosporin, PLEX, or rituximab.
• Advanced therapies: Orbital irradiation or decompression if necessary.

Grave's disease is a significant cause of hyperthyroidism and may present with unique clinical and ocular manifestations, requiring a multidisciplinary approach for optimal management.