Teaching Case

We retrospectively evaluated the imaging findings of young patients (below 50 years of age) affected by COVID-19 infection.

Six patients in the 27-46 age range were admitted to the Emergency Room (ER) of our institution in the first half of March 2020 with the main complaint of fever (5/6) and/or cough (5/6), and with unremarkable clinical history. The results of laboratory tests were in range, except for respiratory alkalosis (3/6) and reduced leukocyte count (1/6). Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) for the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was found positive on nasopharyngeal swab (5/6) or bronchoalveolar lavage (1/6). None of the patients required intubation; only 3 of them required respiratory support with low flow oxygen supplementation through nasal cannula (2/6), or CPAP (1/6).

Chest X-Rays (CXR) and Computed Tomography (CT) were performed in all patients. CXR did not show typical findings for Coronavirus Disease-19 (COVID-19) and was reported as negative (3/6) or arising question of bilateral lung consolidations (3/6). The chest CT showed typical findings for interstitial pneumonia in all patients. The main finding was the presence of pulmonary areas of increased attenuation with a “ground-glass” appearance (6/6). These areas were mainly localised in subpleural peripheral areas of the basal segments of lower lobes and sometimes associated to thickened interstitium in a “crazy-paving” pattern (2/6). Pleural effusion was absent in all patients and mediastinal lymphadenopathy was present in 2 out of 6 cases. Only one patient performed a follow-up CT on the 5^th day of hospitalisation that showed an increased number of hyperattenuating areas, compatible with lung consolidations. (Figure 1 and Figure 7d-7e)

1. Background:

The purpose of this study is to collect, analyse and report clinical data, imaging findings and prognostic assessment of COVID-19 in young adults.

The outbreak of SARS-CoV2 has diffused rapidly all around the world, starting from its epicentre in Hubei province. On 11^th March 2020, COVID-19 was declared a pandemic. Considering its high infectivity and the human-to-human transmission pattern through infected droplets, the main applied containment measure was the complete lockdown. [1] From the pathogenetic point of view, the viral receptor is the receptor for the angiotensin converting enzyme 2 (ACE2), mainly expressed at the level of lower respiratory tract, explaining why pneumonia represents the principal clinical feature.

2. Clinical Perspective:

The clinical presentation of SARS-CoV2 infection is extremely variable, ranging from asymptomatic patients to Acute Respiratory Distress Syndrome (ARDS) or Multi-organ Failure (MOF). Similarly, the incubation period is very variable, ranging from 1 to 14 days with a faster progression in elderly people.

Clinically, it is often difficult to distinguish the COVID-19 pneumonia from other common respiratory infections because the main presenting symptoms are the same, such as fever, malaise, cough and dyspnoea. The diagnosis of COVID-19 is performed with RT-PCR on a nasopharyngeal swab or bronchoalveolar lavage. Common non-specific laboratory findings are leukopenia, especially lymphocytopenia as marker of disease severity, and an increase in inflammatory markers, such as CRP, SSA, IL-6. Recent studies demonstrated that adolescents and young adults presented less severe symptoms and fewer abnormal laboratory test results at admission: our study confirmed these results. [1, 2]

3. Imaging Perspective:

In all our cases CRX was non-diagnostic for COVID-19 infection, while typical findings were observed on the chest CT in all patient.

It has been reported that CXR has relatively low sensitivity in the early stages of the infection due to its intrinsic limitation in the detection of GGOs, while it can show bilateral multifocal consolidation in more advanced stages. [3]

One of the main advantages of performing a chest CT is the possibility of an obtain an early diagnosis, considering also the relatively low sensitivity of RT-PCR tests during the initial phase of disease: patients may show typical lung anomalies at CT scan, despite a negative RT-PCR. [4]

The characteristic findings at chest CT were already described. [5]

 The CT pattern changes consistently during the disease course. The most common early CT findings are round areas of subpleural ground-glass opacities (GGOs), usually bilateral and predominantly in the lower lobes, associated with consolidations that increase in number with the progression of the disease. In advanced phases, other signs may appear, such as linear opacities, “crazy-paving” pattern and a “reverse halo” sign. Pleural effusion, nodules and lymphadenopathy are uncommon. [6]

Even if the role of chest CT has not clearly defined yet, our imaging findings confirmed its high sensitivity in diagnosing COVID-19 [7]. Moreover, CT scan is the most direct and rapid examination test for a quick confirmation of the diagnosis and to properly adjust the treatment plan. [1]

Therefore, we suggest to perform chest CT also on young patients that show symptoms and signs compatible with COVID-19.

4. Outcome:

The prognosis of COVID-19 in the young population is generally good, leading to complete resolution by supportive treatments (antibiotic therapy, IV fluids and electrolytes). Worst clinical outcome is found in elderly and in patients with chronic diseases due to the development of complications, sometimes fatal, such as ARDS. The cornerstone of therapy for pneumonia is respiratory support with both non-invasive (NIV) or invasive (IV) ventilation, or extracorporeal membrane oxygenation (ECMO). Our study confirmed that younger patients have better outcome [2]: none of the 6 patients included in the report required IV or developed complications during treatment. So far, no specific treatment has been discovered, even if chloroquine/hydroxychloroquine and some antiviral drugs, such as lopinavir-ritonavir, seems to improve the clinical course. After receiving antiviral and antibiotic therapy, along with oxygen support in some cases (2/6), all the patients were discharged in stable clinical conditions (range of hospitalization: 3-11 days) with the indication to continue quarantine at home for 14 days.  

5. Teaching Points: 

Even in young patients, chest CT can disclose typical findings of COVID-19 and thus support the diagnosis of Sars-Cov-2 infection. On the contrary, CRX has a low sensitivity and is of limited diagnostic value.

Patients of all ages are at risk of developing a severe form of COVID-19 pneumonia and ARDS. These life-threatening conditions require intensive care unit admission and invasive ventilation. Fortunately, invasive treatment is not always necessary: its need is directly related to age, comorbidities and extent of the disease. 

Written informed patient consent for publication has been obtained.