Autoimmune-mediated inflammation of the thyroid gland with release of thyroid hormone resulting in transient hyperthyroidism, frequently followed by a hypothyroid phase before recovery of normal thyroid function.
Occurs sporadically, postnatally, or during immuno-modulatory or lithium therapy.
Some patients progress to permanent hypothyroidism early, others years or decades later.
The diagnosis can be confirmed by a 4-, 6-, or 24-hour radioiodine uptake of <1% during the hyperthyroid phase of the illness.
Treatment, if needed, includes beta-blockers for the hyperthyroid phase and levothyroxine for the hypothyroid phase of the illness.
The condition is characterised by an autoimmune-mediated lymphocytic inflammation of the thyroid gland resulting in a destructive thyroiditis with release of thyroid hormone and transient thyrotoxicosis (hyperthyroidism). This is frequently followed by a hypothyroid phase and full recovery.
The accepted nomenclature is controversial as many view painless thyroiditis as a variant presentation of chronic lymphocytic (Hashimoto's) thyroiditis, because Hashimoto's thyroiditis results in permanent hypothyroidism and permanent hypothyroidism may occur shortly after the hypothyroid phase of painless thyroiditis or during prolonged follow-up. The condition is particularly common in the postnatal period. However, the term postnatal thyroiditis also includes patients who experience only transient hypothyroidism due to an exacerbation of Hashimoto's thyroiditis. Autoimmune thyroid disease, which includes painless and Hashimoto's thyroiditis and Graves' disease, may arise during immuno-modulatory or lithium therapy. Finally, a destructive thyroiditis may occur in other settings where pathophysiology, evaluation, and treatment differ from painless thyroiditis. These include acute (suppurative), subacute (granulomatous, de Quervain), palpation, radiation-induced, and amiodarone-induced thyroiditis.
History and exam
Key diagnostic factors
- heat intolerance
- small non-tender goitre
Other diagnostic factors
- weight loss
- excessive fatigue
- muscle cramps
- weight gain
- poor concentration
- cold intolerance
- postnatal period
- female sex
- thyroid peroxidase (TPO) antibodies
- immuno-modulatory therapy
- lithium therapy
- type 1 diabetes and other autoimmune conditions
- autoimmune family history
1st investigations to order
- thyroid-stimulating hormone (TSH)
- serum free T4 and T3
- thyroid peroxidase (TPO) antibodies
- TSH-receptor antibodies (TRAb)
- 4-, 6-, or 24-hour radioiodine uptake
- total T3/T4 ratio
Investigations to consider
- technetium-99m pertechnetate scan
- serum thyroglobulin
- thyroid biopsy
- colour-flow Doppler
thyrotoxic phase: mild
thyrotoxic phase: moderate
thyrotoxic phase: severe
hypothyroid phase: mild
hypothyroid phase: moderate to severe
Petros Perros, MD
Department of Endocrinology
Newcastle upon Tyne Hospitals NHS Foundation Trust
Newcastle upon Tyne
PP has been an invited speaker on thyroid topics for the British Endocrine Societies, the American Association of Clinical Endocrinologists Gulf Chapter, Lebanese Society of Endocrinology Diabetes and Lipids, Emirates Thyroid Congress, Cyprus Endocrine Society, European Group On Graves Orbitopathy, European Thyroid Association and Azerbaijan State Advanced Training Institute for Doctors. He has received honoraria for speaking at meetings organised by the American Association of Clinical Endocrinologists Gulf Chapter, the Lebanese Society of Endocrinology Diabetes and Lipids and Azerbaijan State Advanced Training Institute for Doctors and has done consultancy work for IBSA Institut Biochemie SA.
Dr Petros Perros would like to gratefully acknowledge Dr Douglas S. Ross, the previous contributor to this monograph. DSR declares that he has no competing interests.
John Lazarus, MA, MD, FRCP, FACE, FRCOG
Centre for Endocrine and Diabetes Sciences
Cardiff University School of Medicine
University Hospital of Wales
JL declares that he has no competing interests.
Ronald Merrell, MD
Professor of Surgery
Virginia Commonwealth University
RM declares that he has no competing interests.
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