Endocrine System >
Hyperthyroidism
“The clinical effect of excess thyroid hormone, usually from gland hyperfunction”
Aetiology & Pathogenesis
- Graves’ Disease (2/3 cases of Hyperthyroidism):
- IgG autoantibody binds Thyrotropin Receptors -> Smooth thyroid enlargement + Increased thyroid hormone production + React with orbital autoantigens
- Toxic Multinodular Goitre:
- Elderly + in iodine-deficient areas
- Nodules which secrete thyroid hormones
- Toxic Adenoma:
- Solitary nodule producing T3 + T4
- Ectopic Thyroid Tissue:
- Metastatic follicular thyroid cancer
- Struma Ovarii (Ovarian teratoma with thyroid tissue)
- Exogenous:
- Iodine excess e.g. food contamination, contrast media
- Others
Clinical Presentation
- Symptoms:
- Heat intolerance
- Diarrhoea
- Weight loss
- Increased appetite (may cause paradoxical weight gain)
- Overactive
- Palpitations
- Sweat
- Tremor
- Irritability
- Labile emotions
- Oligomenorrhoea +/- Infertility
- Signs:
- Fast / Irregular Pulse (AF or SVT)
- Warm moist skin
- Fine tremor
- Palmar Erythema
- Thin hair
- Lid lag & Lid retraction
- Signs of Graves Disease:
- Thyroid Eye Disease
- Pretibial Myxoedema
- Thyroid Acropachy
Investigations
- Bloods:
- Low TSH
- Low T4
- High T3
- May be mild normocytic anaemia
- Mild neutropenia (in Graves)
- Elevated ESR
- Ca2+
- LFTs
- Thyroid Autoantibodies
- Imaging: n/a
- Special:
- Isotope Scan – If the cause is unclear, to detect nodular disease or subacute thyroiditis
- Visual Fields, Acuity + Eye Movements – If ophthalmopathy present
Management
- Conservative:
- Medical:
- Medication
- Beta-Blockers e.g. Propanolol 40mg/6h
- Antithyroids e.g. Carbimazole
- Radioiodine Treatment
- Medication
- Surgical:
- Thyroidectomy
- Risk of recurrent laryngeal nerve damage and hypoparathyroidism
- Patients become hypothyroid post-surgery, so thyroid replacement needed
- Thyroidectomy
Complications
- Thyroid Storm
- Heart Failure (Thyrotoxic Cardiomyopathy)
- Angina
- Atrial Fibrillation
- Osteoporosis
- Ophthalmopathy
- Gynaecomastia