Graves' disease (Graves)
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Thyrotoxic crisis (or thyroid storm) is a rare but potentially fatal complication of untreated or decompensated Graves' disease. It manifests as high fever, severe tachycardia, extreme agitation, confusion and vomiting. This situation constitutes an absolute medical emergency.
Call 911 immediately.
Autoimmune mechanism
In Graves' disease, the immune system produces thyroid stimulating immunoglobulins (TSI), also known as TSH receptor antibodies (TRAK). These antibodies bind to thyroid follicular receptors and activate them autonomously, independently of the usual pituitary signals. The thyroid, constantly stimulated, increases in volume (goiter) and excessively secretes thyroid hormones. This immune dysfunction is often triggered or exacerbated by stress, infection, pregnancy or excessive iodine intake.
Symptoms and clinical manifestations
Manifestations result from excess circulating thyroid hormones and, in some cases, specific autoimmune involvement of eye and skin tissues.
| System | Common manifestations |
|---|---|
| General and metabolism | Weight loss despite preserved or increased appetite, heat intolerance, excessive sweating, fatigue |
| Cardiovascular | Palpitations, resting tachycardia, systolic hypertension, risk of atrial fibrillation |
| Neuropsychiatric | Nervousness, irritability, insomnia, fine hand tremors, emotional lability |
| Muscular and bone | Proximal muscle weakness, amyotrophy, accelerated bone remodelling (risk of osteoporosis) |
| Ocular (Graves' ophthalmopathy) | Exophthalmos, palpebral retraction, diplopia, lacrimation, photophobia, foreign body sensation |
| Thyroid | Diffuse, soft, painless goiter, sometimes vascular murmur on auscultation |
| Skin and appendages | Hot, clammy skin, fine, brittle hair, onycholysis, pretibial myxedema (rare). |
| Menstrual cycle | Menstrual irregularities, oligomenorrhea, impact on fertility |
Diagnosis
The diagnosis of Graves' disease is based on a combination of clinical, biological and, in some cases, thyroid imaging data.
- Measurement of TSH (collapsed), free T4 and free T3 (elevated)
- Determination of TRAK antibodies (anti-TSH receptors): a specific marker for Graves' disease
- Anti-TPO and anti-thyroglobulin antibody tests (frequently positive)
- Thyroid ultrasound: diffuse goiter, hypervascularization on color Doppler
- Thyroid scintigraphy if diagnostic doubt: diffuse, homogeneous hyperfixation
- Lipid profile, blood glucose, CBC (systemic effects of hyperthyroidism)
- ECG in case of palpitations or tachycardia
- Ophthalmological evaluation in the presence of ocular signs
Treatment options
Three main treatment modalities are available. The choice depends on the patient's age, the severity of the hyperthyroidism, the presence of ophthalmopathy, the desire for pregnancy and the individual's informed preferences.
| Treatment | Principle | Remarks |
|---|---|---|
| Synthetic antithyroid drugs (ATS) | Methimazole (Tapazole) or propylthiouracil (PTU): reduce hormone production | First-line treatment; usually lasts 12 to 18 months; risk of relapse on discontinuation in 40 to 60 % of cases |
| Radioactive iodine (iodine-131) | Selective destruction of hyperfunctional thyroid tissue by internal irradiation | Definitive treatment; often leads to permanent hypothyroidism requiring levothyroxine supplementation; contraindicated in pregnancy and severe active ophthalmopathy |
| Total thyroidectomy | Surgical removal of the thyroid gland under general anesthesia | Fast, definitive option; indicated in cases of large goitre, suspected associated neoplasia or contraindication to other treatments; definitive post-operative hypothyroidism |
| Beta-blockers | Propranolol or atenolol: rapid symptomatic control (palpitations, tremors, anxiety) | Adjuvant treatment only, with no effect on the autoimmune cause |
Graves' disease and pregnancy
Graves' disease presents specific challenges in pregnancy. Maternal TRAKs cross the placenta and can induce transient neonatal hyperthyroidism. Propylthiouracil (PTU) is preferred to methimazole in the first trimester, due to its more favorable teratogenic profile. Close monitoring by the general practitioner, endocrinologist and obstetrician is recommended throughout pregnancy and in the post-partum period, when relapse is likely.
Long-term monitoring and development
Biological monitoring (TSH, free T4) is carried out regularly, more frequently at the start of treatment, then at intervals depending on clinical stability. Bone mineral density monitoring is indicated in cases of prolonged hyperthyroidism. After definitive treatment with radioactive iodine or thyroidectomy, levothyroxine substitution (Synthroid) is initiated and adjusted according to the results of the thyroid work-up.
Consult at Clinique Omicron
Clinique Omicron dispose de médecins et d'infirmières praticiennes spécialisées (IPS) formés au dépistage et à la prise en charge des dysfonctions thyroïdiennes, dont la maladie de Basedow. Un bilan initial comprenant le dosage de la TSH, de la T4 libre et des anticorps TRAK peut être prescrit et interprété rapidement dans ses points de service au Québec. En cas de diagnostic confirmé, une orientation vers l'endocrinologie est facilitée selon les besoins cliniques. Prenez rendez-vous en ligne ou par téléphone à l'un des points de service de Clinique Omicron au Québec.
The content of this page is provided for informational purposes only and is not intended to replace the advice of a qualified healthcare professional. Consult a physician for any symptoms, questions or decisions you may have regarding your health.
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