Synopsis
Confirm excess circulating thyroid hormone, grade clinical urgency, distinguish increased synthesis from destructive or exogenous release, and begin safe cause-directed assessment.
- Thyrotoxicosis means tissue exposure to excess thyroid hormone; hyperthyroidism specifically means increased gland synthesis, so the terms are not interchangeable.
- Typical features include weight loss despite appetite, heat intolerance, sweating, tremor, anxiety, proximal weakness, frequent stools, menstrual change and tachycardia.
- Suppressed TSH with raised free T4 and/or free T3 confirms overt biochemical thyrotoxicosis after assay and medicine confounders are considered.
Key red flags
Atrial fibrillation, systolic hypertension, high-output failure, worsening angina or unexplained dyspnoea may dominate, especially in older people; establish haemodynamic stability before outpatient planning.
Investigation priorities
Confirm overt thyrotoxicosis and identify T3-predominant disease.
Management branches
A new thyroid profile or presentation suggests thyrotoxicosis.
- Perform ABCDE and document temperature, pulse rhythm, blood pressure, oxygenation, hydration, cognition, heart failure, chest pain and gastrointestinal or hepatic features.
- Escalate fever plus organ dysfunction, unstable arrhythmia, pulmonary oedema or delirium to the thyroid-storm and critical-care pathway immediately.
Key medicines
Propranolol for adrenergic symptomsA common adult BNF range is 10 to 40 mg by mouth three or four times daily, adjusted to pulse, symptoms and comorbidity while the underlying cause is treated.
Carbimazole for hormone synthesisInitial adult dosing is severity-dependent and commonly totals 15 to 40 mg daily in the BNF; use the specialist plan, then reduce or block-and-replace only under the agreed protocol.