Graves' disease

Useful indicator of general health and underlying disease. 

Normocytic normochromic anaemia and eosinophilia may be seen with glucocorticoid deficiency.

B12 deficiency may indicate associated pernicious anaemia or coeliac disease.

Hypokalaemia may occur in association with Grave's thyrotoxicosis with hypokalaemic periodic paralysis. This is more common in people of Chinese ethnic origin.

Hyperkalaemia and hyponatraemia may occur in Addison's disease which may be associated with auto-immune thyrotoxicosis.

Liver function should be tested at baseline before starting medical treatments.

Useful indicator of general health and underlying disease.

Hypercalcaemia may occur with thyrotoxicosis and glucocorticoid deficiency.

Ensure patients have stopped sex steroid therapy, for example HRT or the combined oral contraceptive pill for six weeks prior to test.

A synacthen test is required to formally exclude Addison’s, however, a 9am cortisol can be a useful screen. Levels below 250nmol/l demand thorough assessment, levels above 590nmol/l exclude glucocorticoid deficiency.

A low thyroid stimulating hormone (TSH) confirms hyperthyroidism in suspected Graves' disease.

TSH levels within the normal range imply normal thyroid function, except in those with potential pituitary disease, in whom a normal TSH may be seen with hypothyroidism.

Ideal treatment of thyroid disease is reflected by control of symptoms and a serum TSH in the middle of the reference range approximately 1mU/L.

TSH and free thyroxine should be tested together in all patients suspected of having thyroid dysfunction.

Elevated thyroxine implies hyperthyroidism of any cause. Elevated thyroxine with suppressed TSH confirms this to be due to primary hyperthyroidism.

ECG should be performed in all patients at baseline, to document and confirm any arrhythmias or other changes.

There are multiple different tests available for thyroid auto-antibodies, with varying levels of sensitivity.

Thyroid peroxidise antibodies are commonly used as an initial screen and may be positive in patients with any autoimmune thyroid condition, with higher titres occurring in patients with Hashimoto’s thyroiditis and hypothyroidism.

TSH receptor stimulating antibodies occur specifically in Graves' disease, and may be particularly helpful in the assessment of pregnant patients.

Free liothyronine levels are not usually necessary for the assessment and treatment of Graves' disease.

Patients with auto-immune thyroid dysfunction are at increased risk of developing diabetes mellitus.

Falling insulin requirements or hypoglycaemia in established diabetes, may be an early sign of thyrotoxicosis.

Ultrasound scan is not usually required in the assessment of Graves' disease, though may be helpful where the aetiology of thyroid dysfunction is unclear, for example between nodular goitre and Graves' disease, or if a nodule is palpated within the gland.

Bone mineral density should be assessed where there is clinical suspicion of osteoporosis, for example in some older patients with biochemical thyrotoxicosis.

Patients with coeliac disease may well have low serum vitamin D levels.

In patients with known or suspected osteoporosis, serum vitamin D levels will guide whether routine calcium and vitamin D supplementation is enough, or whether specific high dose vitamin D replacement is required.

This is useful in patients with acute thyrotoxicosis to help distinguish between Graves' disease, in which case the whole gland will have increased uptake, or viral or other forms of thyroiditis, in which case the gland will not take up iodine.

Tissue transglutaminase and anti gliadin antibodies should be checked if there is clinical suspicion of Coeliac disease.

This must be performed if there is clinical or biochemical suspicion of Addison’s disease.