April 20, 2017
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Abnormal jugular vein detected during thyroid ultrasound

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Stephanie L. Lee

A 43-year-old woman was referred to the endocrine clinic for a thyroid nodule found on a CT scan of the chest during the evaluation of breast cancer. The patient had been diagnosed 1 year before with stage II estrogen receptor–positive/progesterone receptor–positive, HER-2–negative invasive ductal carcinoma of the left breast metastatic to the axillary nodes. The patient had a tunneled catheter placed in the right subclavian vein for venous access.

The patient had recently been discharged from the hospital on warfarin anticoagulation for a blood clot in her right upper extremity. She had noted swelling under her right chin in the past few days, but reported no food or pill dysphagia, cough, dyspnea or stridor. She had no prior history of head and neck radiation.

Her family history was negative for thyroid disease, including thyroid cancer. Her thyroid function was normal, with thyroid-stimulating hormone 3.65 uIU/mL, free thyroxine index 2.2 and thyroid peroxidase antibody less than 10 IU/mL.

Figure 1. Thyroid ultrasound. Transverse images of the thyroid. (A) Right thyroid lobe. (B) Left thyroid lobe. (C) Right internal jugular vein (IJV) with Doppler. (D) Left IJV with Doppler. Abbreviations: CA = carotid artery; N = nodule; THY = thyroid.

Images reprinted with permission from: Stephanie L. Lee, MD, PhD, ECNU

Ultrasound, CT imaging

An office thyroid ultrasound was performed that showed a thyroid of normal size with an isoechoic nodule with an indistinct border in the left lobe that measured 0.9 cm x 0.8 cm x 0.8 cm (sagittal x anterioposterior x transverse) without microcalcifications or intranodular vascular flow by Doppler (Figure 1B). This nodule did not reach the size threshold for biopsy per the 2015 American Thyroid Association guideline, and the patient was informed that watchful waiting without biopsy was recommended.

Of note, the right thyroid lobe was compressed by an enlarged right interval jugular vein (IJV) and more posterior in position compared with the left lobe in the transverse view (Figure 1A vs. 1B). The left IJV contained a heterogeneous soft tissue with no blood flow by Doppler analysis (Figure 1A) while the diameter of the right IJV was normal with good blood flow (Figure 1C vs. 1D).

Figure 2. CT scan with contrast of the neck. The axial view of the neck shows an enlarged right internal jugular vein (IJV) without blood flow (red arrow) with collateral blood flow resulting in increased flow in the right anterior but not the left anterior jugular vein (blue arrows). Blood flow in the left IJV and bilateral carotid arteries (CA) is normal. Abbreviation: THY = thyroid.
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The right IJV had no blood flow along the entire length within the neck, but the right subclavian vein had flow by Doppler before the junction with the right IJV to form the right innominate vein (Figure 3B). There were no abnormal masses or nodes seen in the bilateral levels II, III, IV, V and VI of the neck.

The patient was referred to the ED, and her hematologist/oncologist was informed of her admission. A CT pulmonary angiogram was performed in the ED that confirmed the ultrasound exam showing that the right IJV was distended with a thrombus (Figure 2). The tunneled catheter entered via the right subclavian vein near the junction of the right IJV with its tip located in the lower superior vena cava (Figure 3). A thrombus completely occluded the right IJV and nearly occluded the right innominate vein and superior vena cava to the cavoatrial junction, but did not involve the right heart atrium. The left IJV was patent, but the left innominate vein and subclavian vein were incompletely evaluated due to mixing of the contrast with blood.

Decision to report or not report

Figure 3. CT pulmonary angiogram. The coronal view of the neck and chest (A) and anatomic diagram (B) demonstrate the location of the tunneled catheter tip (yellow arrow) in the superior vena cava (SVC). There is extensive clot with little or no blood flow in the right internal jugular vein (IJV), right innominate vein and superior vena cava (red arrows). Abbreviations: AO = aorta; CA = carotid artery; LIV = left innominate vein; LV = left ventricle; RA = right atrium; SV = left subclavian vein.

There are many anatomic variations, developmental abnormalities and pathologies that are incidentally found during a thyroid ultrasound exam. Society guidelines and expert recommendations by the American Institute of Ultrasound in Medicine or the ATA do not require that abnormalities of the carotid arteries of IJV be reported during an ultrasound exam of the thyroid, parathyroid or neck nodes, but they are hard to ignore during a thyroid ultrasound exam.

The increase in number and quality of ultrasound imaging means that along with better clarity of the target structures, users are detecting more incidental findings. This opens a Pandora’s box of deciding what to report, how to frame it, whether to recommend further workup, and how best to follow up with the primary care physician or patient on the findings.

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Although endocrinologists are obligated to report and evaluate an abnormal node in the neck detected during a thyroid ultrasound, what should we do if we see obvious carotid artery narrowing or plaques? We have not been trained in vascular ultrasound, and most of us turn a blind eye to changes unless there is a significant obstruction, such as illustrated in this case.

Further, an endocrinologist may not understand the significance of incidental findings on ultrasound. Abnormalities on medical tests, including thyroid, parathyroid and neck node ultrasounds, that physicians are not looking for result in a lot of time, anxiety and money. It is important that we understand what is “normal” in the neck, including vascular structures near the thyroid, and the guidelines for evaluation of these abnormalities, to determine when there is a significant problem that requires immediate investigation or routine notification of the patient’s PCP.

Disclosure: Lee reports no relevant financial disclosures.