Thyroid storm carries a mortality of 10–30% even with treatment. The Burch-Wartofsky scoring system (fever, CNS dysfunction, GI symptoms, HR, heart failure, precipitating history) identifies patients needing immediate ICU-level care — never wait for TFTs to confirm.
Agranulocytosis complicates carbimazole/PTU in ~0.3% of patients, typically in the first 3 months. Untreated sepsis from neutropenia can be fatal. Always counsel patients at initiation and at every review: "Stop the drug and attend A&E same day if you develop a sore throat or fever."
Graves' ophthalmopathy with corneal exposure is a sight-threatening emergency — corneal ulceration can cause permanent visual loss within hours. Refer before trying to manage medically.
TSH alone is misleading. TSH can remain suppressed for weeks after fT4/fT3 normalise (pituitary lag). Monitoring by TSH only risks over-treatment and iatrogenic hypothyroidism. Always check fT4 (and fT3 if TSH suppressed with normal fT4) when adjusting doses.
TRAb antibody status changes management fundamentally: Graves' disease may undergo spontaneous remission (~50% at 18 months of antithyroid therapy), whereas toxic nodular goitre or toxic adenoma will not — they typically require definitive treatment (radioiodine or surgery).
Aetiology fundamentally changes the plan. Starting carbimazole in thyroiditis is a common error — antithyroid drugs do not work in destructive thyroiditis (the gland is releasing pre-formed hormone, not synthesising new hormone) and treatment delays resolution. Beta-blockers for symptom control + watchful waiting is correct.
Toxic nodular goitre has a very low remission rate with antithyroid drugs (<1%). Prolonged drug treatment without a definitive plan exposes patients to unnecessary agranulocytosis risk. These patients should be referred early for definitive discussion.
Apathetic thyrotoxicosis in the elderly presents with weight loss, AF, and fatigue — without the classic anxiety, tremor, or heat intolerance. Without examination, this is easily attributed to malignancy or cardiac disease. Always check TFTs in new AF in the elderly.
Thyroid bruit indicates hypervascular Graves' gland and confirms active autoimmune disease. Its presence (or absence) guides treatment modality — thyroid bruit contraindicates radioiodine in some protocols due to radiation thyroiditis risk in highly vascular glands.
Proximal myopathy indicates significant thyrotoxicosis and needs prompt biochemical control — it is reversible with treatment.
Baseline FBC is critical. If a patient later presents with sore throat on carbimazole and has no baseline WCC, it is impossible to determine whether any neutropenia is drug-induced or pre-existing. Always document the baseline.
LFTs before PTU are mandatory — PTU-induced fulminant hepatic failure has been reported. PTU is reserved for specific circumstances (first trimester, allergy to carbimazole, thyroid storm) precisely because of this hepatotoxicity risk.
TRAb titre at diagnosis predicts remission probability: high TRAb titre correlates with lower remission rate on antithyroid drugs alone, helping counsel patients about definitive treatment options early.
All new Graves' disease should be seen by endocrinology — the decision between antithyroid drugs, radioiodine, and thyroidectomy requires specialist input, isotope scanning, antibody profiling, and patient preference counselling. Starting carbimazole in primary care without a plan for definitive management is a common systems failure.
Agranulocytosis requires the drug to be stopped immediately — before the FBC result is back. The risk of sepsis from neutropenia outweighs the risk of a short period without antithyroid medication. Do not wait for results before stopping.
Graves' ophthalmopathy worsens significantly after radioiodine (in ~25% of patients). This cannot be determined without ophthalmology assessment and CAS scoring first — hence the importance of ophthalmology referral before any definitive treatment.
Block-replace vs titration: Both are equally effective at achieving euthyroidism. Titration uses lower total carbimazole dose (reduces agranulocytosis risk). Block-replace may suit busy patients (fewer dose adjustments) but higher total drug exposure. Either is acceptable — discuss with endocrinology.
Radioiodine and ophthalmopathy: Radioiodine worsens Graves' ophthalmopathy in ~25% of cases (particularly smokers). Patients with active ophthalmopathy (CAS ≥3) should not receive radioiodine without concurrent steroid cover. Ophthalmology assessment is mandatory before choosing definitive therapy.
Remission rates: 40–60% of Graves' patients achieve remission after 12–18 months of carbimazole (higher if TRAb normalises). Relapse is more likely with: large goitre, high TRAb titre, active smoking, younger age. After relapse, definitive treatment is recommended rather than a second antithyroid drug course.
Smoking and ophthalmopathy: The association is dose-dependent and robust. Current smokers have a 7.7× greater risk of developing Graves' ophthalmopathy compared to never-smokers. Smoking cessation is the most effective intervention to prevent orbitopathy progression — more impactful than any drug in this regard.
Bone loss in thyrotoxicosis is clinically significant — thyroid hormones increase bone turnover markers and reduce BMD by 10–20% in prolonged untreated disease. The effect is partially reversible with treatment, but early calcium/vitamin D support and DEXA monitoring prevents long-term fracture risk.
Explaining psychiatric symptoms as thyroid symptoms significantly reduces patient anxiety and medication non-adherence. Many patients are incorrectly labelled with anxiety disorder or depression before thyroid disease is considered.
TSH monitoring error: The commonest monitoring mistake is checking TSH alone during antithyroid drug titration. TSH can remain suppressed for months after fT4 normalises due to pituitary lag. Relying on TSH alone leads to over-treatment and iatrogenic hypothyroidism. Always check fT4 as the primary monitoring marker for the first 6 months.
Agranulocytosis safety-netting must be verbal AND written at every prescription. Most cases occur in the first 3 months, but can occur at any time. In a primary care audit, failure to warn patients was the most common avoidable factor in agranulocytosis deaths on antithyroid drugs.
Pregnancy planning: Poorly controlled hyperthyroidism in pregnancy is associated with miscarriage, pre-term delivery, foetal growth restriction, and neonatal thyrotoxicosis (from transplacental TRAb). Women of childbearing age should be counselled to inform their GP when planning pregnancy so treatment can be optimised in advance.
Relapse surveillance: 50% of Graves' patients who achieve remission relapse within 5 years — most within the first 2 years. Annual TFTs should be lifelong even after successful treatment, with clear patient education to return if symptoms recur.