The spontaneous venous echo contrast: a sonographic sign allowing suspicion of superior vena cava syndrome

Dear editor

The superior vena cava syndrome (SVCS) is defined as a cluster of symptoms resulting from a vascular flow decrease within the superior vena cava caused by compression, thrombosis, or invasion of the vein, and that depends on its extent and how rapidly it develops. Prompt diagnosis is essential not only to control the development of symptoms and to avoid clinical deterioration but also so that the proper treatment can be initiated. We describe 2 cases of patients in which Point-of-Care-Ultrasound (PoCUS) had led to a faster diagnosis of this syndrome allowing early initiation of the underlying diseases’ treatment.

The first case, a 42-year-old man, without relevant past medical history or chronic medication, presented to the emergency department (ED) with a chief complaint of facial and cervical swelling over the past 3 weeks. Upon initial examination, the patient presented with cervical edema and bilateral jugular venous distension (Fig. 1A). He had evidence of cyanosis of his head and upper torso, with a demarcation line below the nipples, and presented superficial collateral circulation upon his chest. The pulmonary and abdomen exams showed no significant alterations and there were no signs of profound venous thrombosis on the lower extremities. To clarify the findings chest radiography was performed, which revealed a right paratracheal hipotransparency suggestive of being a mass, and PoCUS showed a superior vena cava with diminished compressibility, spontaneous echo contrast and a slow velocity flux (Fig. 1B), compatible with the diagnosis of stenosis but without thrombus evidence. The Computed Tomography (CT) scan revealed a heterogeneous mass in the anterosuperior thorax region, which invaded the superior vena cava causing a complete obliteration of the venous left brachiocephalic trunk. A fine-needle aspiration biopsy was performed and revealed a mediastinal seminoma for which appropriate chemotherapy was initiated.

Fig. 1.

Bilateral internal jugular venous distension (A); Superior vena cava slow velocity flux (B)

The second patient, a 69-year-old man with a history of renal carcinoma, treated with total nephrectomy, and a thyroid metastasis diagnosed 7 years later, presented to the ED due to facial and upper limb edema associated with dyspnea. Clinical examination revealed facial plethora, upper limb edema, voice hoarseness, and cervical and chest distended vessels (Fig. 2A). A cervical PoCUS showed bilateral internal jugular venous enhanced echo contrast and associated thrombosis (Fig. 2B). Thus, prompting anticoagulation initiation. Later, a CT-angiography was also performed and confirmed vein thrombosis with superior vena cava extension.

Fig. 2.

Chest vessels distension with associated plethora (A); Internal jugular venous thrombosis (B)

The superior vena cava syndrome is the clinical manifestation of gradual obstruction of blood flow in the superior vena cava [1, 2]. Approximately 70% of these cases are in the context of malignancies [3, 4]. In fact, SVCS is caused by a yet undiagnosed malignancy in up to 60% of the patients [3].

Although patients with malignant SVCS have a median life expectancy of about 6 months, the greatest predictor of survival is the underlying cancer. Consequently, the aetiology and histologic grade of the neoplasm must be determined to help guide therapy and aid in prognosis [3].

Contrast-enhanced CT remains the main choice for imaging of SVCS, as it has high sensitivity and specificity, and allows to clarify the underlying pathology [2]. However, this is an exam that is not always immediately available and that can be dangerous to execute on unstable patients.

Blood echogenicity is attributed to ultrasonic waves reflected by blood cell aggregates. Accordingly to Fatkin et al. and Bakalli et al., spontaneous echo contrast is a usual sign of reduced flow velocity associated with thromboembolic events. However, this sign is not reduced by anticoagulants, which is consistent with the red cell rouleaux formation mechanism since these drugs inhibit the coagulation cascade to prevent thrombus formation but do not alter red cells aggregation [5, 6].

Having in mind that, by using PoCUS, in the presence of a low flow we can find a vein echogenic enhanced signal but with conserved compressibility, whereas in the presence of a thrombus there is evidence of an echogenic vein content with associated diminished compressibility, PoCUS make it possible to distinguish these two diagnoses.

Consequently, since PoCUS can detect a spontaneous venous echo contrast in the jugular veins, in the presence of clinical symptoms suggestive of a superior vena cava syndrome, it reinforces the presence of flow disturbance allowing to confidently order additional tests to image the underlying cause even before there is evidence of a thrombus formation. Therefore, this is a fast, cost-effective and safe tool, that can be performed before thorax CT is available and that can improve the management of these patients, allowing to initiate the proper treatment, as demonstrated by the two cases reported.

Author contributions

All authors have contributed to this work. All authors read and approved the final manuscript.

Funding

This work has not been supported by public grants or financial support. No sources of funding were used to assist in the preparation of this study.

Declarations

Conflict of interest

Each author certifies that he has no commercial associations that might pose a conflict of interest in connection with the submitted article. We certify that this research was conducted in conformity with ethical principles of our institution. This work and figures have not been previously published and reproduced from another source.

Informed consent

Informed consent was obtained from the patient. A case report is a medical/educational activity that does not meet the definition of “research”, which is: “a systematic investigation, including research development, testing and evaluation, designed to develop or contribute to generalizable knowledge.” Therefore, the activity does not have to be reviewed by an IRB.