Thyroid Bruit and the Underlying ‘Inferno’
The normal thyroid has the most abundant blood flow of any tissue in the body. Early descriptions of color-flow Doppler ultrasonography in pathologic states of hyperthyroidism referred to the dramatic picture of elevated blood supply to the gland as the “thyroid inferno.”(1) Systolic-diastolic or systolic thyroid bruits have been reported in thyrotoxicosis for some time. Although historical references to thyroid bruit before the 1900s are few, Osler commented that “a thrill may be felt on palpation and on auscultation a loud systolic murmur, or more commonly a bruit de diable.”(2) Bruits are especially characteristic of Graves’ disease, being detectable in up to 85% of cases by auscultation and up to 95% by phonocardiogram.(3) They are often continuous in nature with systolic accentuation and are thought to be secondary to arteriovenous fistulae or accelerated blood flow.(3) Thus, thyroid surgery in its early days, especially for Graves’ disease and goiter, had a high mortality rate predominantly because of perioperative hemorrhage. Samuel Gross wrote in 1866 that “every stroke of his knife will be followed by a torrent of blood, and lucky will it be for him if his victim lives long enough to enable him to finish his horrid butchery.”(4)
Case Presentation
A 34-year-old woman presented to the emergency department because she thought that her thyroid was “acting up” again. She had increased shakiness, difficulty sleeping, hair loss, a 15-lb weight loss, polyuria, and polydipsia. She was taking metoprolol for symptomatic treatment. One month earlier, her methimazole dose had been reduced in preparation for radioactive iodine I131 ablative therapy. She had been diagnosed with diabetes during an emergency department visit 2 years ago, but she did not use pharmacologic therapy. Her blood pressure was 168/98 mm Hg, pulse was 88 beats/min, and temperature was 97.8°F. On physical examination, she had dry mucous membranes, overt exophthalmos, and a large goiter with a continuous loud bruit without a thrill (Figure 1).
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–Elizabeth Williams, BS, Shawn Chillag, MDemail, Ali Rizvi, MD
This article originally appeared in the June 2014 issue of The American Journal of Medicine.
