In a recent study published in the Radiology journal, German researchers assessed lung dysfunction seen after pediatric coronavirus disease 2019 (COVID-19).
Children and adolescents infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have a milder course than adults and recover within weeks. The definition of a symptom varies; therefore, there are inconsistent reports of persistent symptoms, which can last for several months after infection and range from 0% to 66%. The fact that there are more unbiased results on sequelae and post-acute symptoms in younger patients further complicates these conclusions. The nature, frequency and definition of post-acute sequelae in children and adolescents are still unknown and there is a gap between the clinical aspect and the objective results.
Study: Pulmonary dysfunction after pediatric COVID-19. Image Credit: MarcinWojc/Shutterstock
About the study
In the current study, researchers described morphological and functional changes in lung parenchyma on low-field magnetic resonance imaging (MRI) in post-COVID-19 children and adolescents compared to healthy controls.
The team conducted a cross-sectional experiment initiated by an investigator between August 2021 and December 2021 at a single academic medical institution to examine lung parenchymal abnormalities in adolescents and children after SARS-CoV-2 infection. From a nationwide search, the study recruited consecutive patients with COVID-19. A blood sample was taken and all subjects with COVID-19 and healthy controls underwent low-field MRI after being assessed against clinical criteria. Imaging data were compared to clinical features before and after infection, time since a positive reverse transcription-polymerase chain reaction (RT-PCR) test, and laboratory values.
The conditions for inclusion of the COVID-19 group included the requirement to be between five and 18 years old. RT-PCR testing for SARS-CoV-2 was required for all eligible patients, regardless of the time between positive test and trial enrollment. The inclusion conditions for the healthy control group included a specified age range of five and 18 years.
In the study, long COVID was defined as having symptoms that persisted for at least 12 weeks and met one of four criteria listed below: (1) Symptoms that persisted after the acute phase of COVID-19 or its treatment, (2) symptoms that triggered a new health restriction, (3) new symptoms that arose after the acute phase but were recognized as a result of COVID-19 illness, and (4) worsening of a pre-existing comorbidity.
Using low-field proton MRI, the primary outcome found was the frequency of morphological alterations in the lung parenchyma. Secondary outcomes included laboratory assessments, reported clinical complaints, functional lung changes including ventilation defects, perfusion defects, and match and failure of both.
The medical history of participants in the COVID-19 group and their symptoms during and after infection with COVID-19 were assessed. Each person measured their blood pressure and heart rate. Blood was drawn to measure blood count, interleukin (IL)-6, C-reactive protein (CRP), and antibodies to SARS-CoV-2 spike protein and nucleocapsid antibodies.
Free-breathing phase-resolved (PREFUL) functional lung low-field MRI at 0.55 T with parameters calculated in an axial plane after automatic registration at a mid-expiratory position and segmentation of the lung parenchyma. From left to right, representative color-coded images of functional ventilation defects (VDP, blue), perfusion defects (QDP, red), ventilation/perfusion (V/Q match, green), ventilation defects /perfusion (V/Q defect, purple) in a healthy control (top row, 7-year-old male), a recovered COVID-19 participant (middle row, 10-year-old male), and a participant with long COVID ( 15 year old male).
Nearly 91 RT-PCR positive SARS-CoV-2 infected pediatric patients and a total of 17 healthy controls were screened. After exclusions, clinical, laboratory and low-field MRI examinations were performed by 54 people with post-acute COVID-19 and nine controls.
Individuals in both groups had many of the same traits. Participants with post-acute COVID-19 had a mean age of 123 years, a mean weight of 4818 kg, a mean height of 15617 cm, and 44% of them were female. A total of 54 people received RT-PCR results for SARS-CoV-2 infection. Of these, 54% had recovered and 46% were classified as having long COVID.
In addition to shortness of breath, 9% of participants had headaches, 28% dyspnea, 2% pneumonia, 7% anosmia, 2% ageusia, 7% fatigue, 11% attention and 2% limbic pain. In 22% of healthy volunteers, 5% of recovered patients and 10% of long COVID-19 patients, pre-existing diseases were found. During the acute phase of infection, four RT-PCR-positive SARS-CoV-2 infected subjects showed no symptoms.
Only one participant in the recovered group out of the 54 people in the post-acute COVID-19 group and the nine healthy controls who underwent low-field MRI showed morphological alterations. Using in-press low-field functional MRI, greater ventilation, perfusion, and combination deficits were found in diseased individuals compared to healthy controls. Comparing the post-COVID group to healthy controls, the ventilation/perfusion match (V/Q match) was lower in the post-COVID group.
The overall percentage of ventilation defects (VDP) was higher in the recovered group or in the long COVID-19 group than in healthy controls when the COVID-19 group was divided by clinical characteristics. Like the recovered group, the Percent Perfusion Defect (QDP) of the long-COVID group was higher than that of the healthy controls. Compared to the recovered and long COVID groups, combined V/Q deficiencies were lower in healthy controls. Similar to the V/Q match, the healthy controls had a higher ratio than the recovered and long COVID groups.
Overall, the study reported ongoing lung dysfunction observed on low-field MRI in adolescents and children with long COVID and those who recovered from COVID-19.
- Pulmonary dysfunction after pediatric COVID-19, Rafael Heiss, Lina Tan, Sandy Schmidt, Adrian P. Regensburger, Franziska Ewert, Dilbar Mammadova, Adrian Buehler, Jens Vogel-Claussen, et al, 2022/09/20, Radiology, 221250, Radiology North American Society, DOI: https://www.doi.org/10.1148/radiol.221250;