Lung ultrasound may help in the differential diagnosis of suspected oligosymptomatic COVID-19 patients on hemodialysis: A case report

Abstract

Introduction: Considering that patients on dialysis showed a poor outcome during COVID-19 pandemic, and that COVID-19 symptoms in dialysis patients are often mild or absent, each dialysis unit should implement local strategies to early recognize patients affected by COVID-19. However, many available SARS-CoV-2 diagnostic tests demonstrated a moderate sensitivity, 70%-80% is probably a reasonable estimate. Consequently, having useful tools for differential diagnosis becomes essential. In this scenario, lung ultrasound (LUS) may have an important role in the evaluation of lung involvement in hemodialysis patients during COVID-19 pandemic.

Methods: We present two cases of hemodialysis patients with COVID-19 pneumonia in whom LUS had a central role in the diagnostic process. Ultrasound images of COVID-19 pneumonia show a typical bilateral pattern characterized by multiple or confluent B-lines with spared areas, thickened and irregular pleural line, and rare subpleural consolidations. LUS showed high accuracy in diagnosing COVID-19 pneumonia.

Findings: Despite both patients appeared clinically euvolemic and afebrile, they presented with acute diarrhea and oxygen saturation level of 92%-93%. Although clinical manifestations were mild and not specific in both patients, LUS raised suspicion on the possible COVID-19 diagnosis which was confirmed by a positive nasopharyngeal RT-PCR.

Discussion: There are many reasons for a patient on dialysis to present shortness of breath, fever, and multiple B-lines at LUS assessment (such as heart failure, fluid overload, vascular access infection, interstitial pneumonia) but the recognition of typical ultrasound patterns of the COVID-19 pneumonia is helpful for differential diagnosis. LUS may have an important role in the screening process of hemodialysis patients during the COVID-19 pandemic, especially in oligosymptomatic patients before the SARS-CoV-2 diagnostic tests, and in those with suspected symptoms and/or known exposure with unexpected negative SARS-CoV-2 diagnostic tests.

Keywords: COVID-19; SARS-CoV-2; dialysis; lung ultrasound.

FIGURE 1

A proposed flow‐chart on the management of hemodialysis patients to control COVID‐19 in dialysis centers

FIGURE 2

Ultrasonographic features of lung ultrasound in a hemodialysis patient with mild hypervolemia: (a) normal sonographic lung appearance with the pleural line (hyperechoic horizontal line) and multiple horizontal reverberations of the pleural line (A‐lines); (b) short reverberation artifact which start from the pleural line and move with lung sliding, but its appearance is obviously different from B‐lines (white arrow); (c) a single comet‐shaped B‐line, with a triple line converging in a single point on the pleural line, considered as a single B‐line (white arrow); (d) two single thin B‐lines (white arrows)

FIGURE 3

Ultrasonographic features of COVID‐19 pneumonia: (a) a subpleural consolidation (yellow asterisk); (b) irregular pleural line (green arrow) with multiple blurred B‐lines (yellow asterisks)