CT-Morphological Characterization of Respiratory Syncytial Virus (RSV) Pneumonia in Immune-Compromised Adults

Abstract

Purpose: Characterization and follow-up evaluation of chest CT of RSV pneumonia in immune-compromised adults during a seasonal epidemic.

Materials and Methods: Retrospective analysis of 132 chest CT examinations of 51 adult immune-compromised patients (29 m/22f, Ø58 years) with clinical signs of pneumonia and positive RSV test in winter 2011/2012. Two experienced chest radiologists evaluated the morphology (bronchial wall thickening, tree-in-bud, nodules, halo, ground-glass opacities, consolidations, pleural fluid) of the CT scans by consensus.

Results: Pathological findings were in 86 % of the chest CT scans: Areas of ground-glass attenuation in 64 %, consolidations in 56 %, nodules in 55 % (Ø 8 mm in maximal diameter, with halo in 71 %), pleural fluid in 44 % (Ø 2 cm), tree-in-bud in 36 %, bronchial wall thickening in 27 % and more than one morphological finding in 72 %. There were no pathological CT findings in 14 % of patients with clinical symptoms of pneumonia because these patients did not undergo follow-up. Radiological progression was found in 45 % of patients and regression in 33 % in follow-up examinations. In 37 % an additional examination of the paranasal sinuses was performed and showed sinusitis in 63 % of cases. 90 % of the patients had sinusitis as well as pneumonia. In addition to RSV, a further pathogenic agent was found in bronchoalveolar lavage of five patients (Aspergillus spec., herpes simplex virus, Pseudomonas aeruginosa). Conclusion: The most characteristic signs in chest CT scans were at the beginning of pneumonia with nodules and tree-in-bud often combined with bronchial wall thickening. The following CT scans showed characteristic but not pathognomonic chest CT findings of RSV pneumonia. These morphological findings should be recognized seasonally (winter) especially at the beginning of the case of pneumonia. RSV-associated additional sinusitis is probably common and should be noticed.

Key Points:

• The most characteristic signs in chest CT scans were at the beginning of RSV pneumonia with nodules and tree-in-bud; we suppose that the pneumonia is run through different CT morphological phases.

• The following CT scans showed less characteristic and multiple CT variations most frequently ground glass and nodules.

• Negative thoracic CT were seen only in a little part of RSV positive patients with symptoms of pneumonia.

• An additional RSV-associated sinusitis should be in mind.

Citation Format:

• Mayer JL, Lehners N, Egerer G et al. CT-Morphological Characterization of Respiratory Syncytial Virus (RSV) Pneumonia in Immune-Compromised Adults. Fortschr Röntgenstr 2014; 186: 686 – 692

Zusammenfassung

Ziel: Radiomorphologische Charakterisierung und Verlaufsbeurteilung der Thorax-CT-Befunde bei Ausbruch einer saisonalen Epidemie von RSV-Infektionen in einem immunsupprimierten Patientenkollektiv.

Material und Methoden: Retrospektive Analyse von 132 Thorax-CT-Untersuchungen bei 51 erwachsenen immunsupprimierten Patienten (29 m/22 w, Ø 58 Jahre) mit klinisch nachgewiesenem Infekt der Atemwege und positivem RSV-Nachweis im Winter 2011/2012. Musterbasierte Auswertung (Bronchialwandverdickungen, tree-in-bud, Noduli, Halo, Milchglas, Konsolidierungen, Pleuraerguss) der radiologischen Bilder durch zwei erfahrene Thoraxradiologen im Konsens.

Ergebnisse: 86 % der CT-Untersuchungen wiesen einen relevanten Befund auf: 64 % milchglasartige Dichteanhebungen, 56 % Konsolidierungen, 55 % Noduli (Ø 8 mm, davon 71 % mit Halo), 44 % Pleuraerguss (Ø 2 cm), 36 % tree-in-bud, 27 % Bronchialwandverdickungen, 72 % mit mehreren morphologischen Veränderungen. Bei 14 % der Patienten mit klinischen Symptomen einer Pneumonie wurden keine relevanten morphologischen Veränderungen in der CT festgestellt. Im Verlauf kam es bei 45 % der Patienten zur radiologischen Progression (33 % Regression) in den Folgeuntersuchungen. Zusätzliche Untersuchungen der Nasennebenhöhlen (NNH) bei 37 % der Patienten erbrachten in 63 % eine Sinusitis, davon 90 % bei gleichzeitigem Vorliegen radiologischer Zeichen einer Pneumonie. Im Verlauf konnte bei fünf Patienten ein weiterer Keim in der BAL (Aspergillus spec., HSV [Herpes simplex virus], Pseudomonas aeruginosa) nachgewiesen werden.

Schlussfolgerung: Am charakteristischsten waren die Thorax-CTs zum mutmaßlichen Beginn der Erkrankung mit Noduli bzw. tree-in-bud häufig in Kombination mit Bronchialwandverdickungen. In den CTs bei zeitlich weiter fortgeschrittener Erkrankung finden sich auch noch, jedoch weniger charakteristische Lungenparenchymveränderungen. Diese RSV-Charakteristika, v. a. zum mutmaßlichen Beginn der Erkrankung, sollten gerade im Winter als verdächtig bewertet und ein Keimnachweis angestrebt werden. Bei positivem RSV Nachweis sollte zusätzlich an eine begleitende Sinusitis gedacht werden.

Key words

thorax - CT - infection - sinusitis - pneumonia - respiratory syncytial virus (RSV)

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