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The COVID-19 pandemic has introduced new terms to physicians that were previously unfamiliar to patients. So, when describing radiographs obtained after computed tomography of the lungs, doctors drew attention to one feature – the ground glass effect that occurs in lung tissue affected by inflammation. But what is it and how dangerous is such an effect, what does it mean for the patient and the doctor?
What is ground glass in the lungs
The term refers to the blurry white-speckled pattern seen on a CT scan of the lungs, indicative of their increased density. This effect is not as dense as the “cobblestone” pattern (also typical of pneumonias) and which looks like a mosaic or paving stone and is not the same as typical microbial pneumonias. Essentially, the “ground glass effect” describes the “shades of gray” between a normal lung scan and a scan of an extremely diseased lung that is almost completely white because it is full of pus or fluid.
The term comes from old films where scenes were shot through a glass lens that made the film look hazy. It was adopted by radiologists in the 1980s and is still used today in descriptions of x-rays.
Radiologists often see ground glass on chest x-rays. The patches come in many shapes, sizes, numbers, and locations, and they can indicate many different underlying pathologies, including coronavirus and other viral infections, chronic lung disease, fibrosis, other inflammatory conditions, and cancer. To establish the diagnosis, in addition to describing the CT scan of the lungs, clinical symptoms and examination data are also needed.
However, according to radiologists, the “ground glass effect” is unlikely to be found in healthy lungs and will not be the result of exposures such as air pollution or smoking. It is safe to say that if you are a healthy person, you should not have ground glass opacities.
Causes of ground glass in the lungs in adults
Given that the ground glass effect can be associated with various diseases, researchers have carefully studied the clinical features of this symptom in COVID-19. There are many diseases that can cause ground glass opacities, but COVID-19 has a distinct distribution, a preference in certain parts of the lungs, mainly the lower lobes and the periphery, and it appears multifocal and bilateral. Ground glass opacities associated with COVID are also very round in shape, which is unusual compared to other ground glass pathologies.
Influenza or other pneumonias do not often have this pattern. Flu patients may have ground glass cloudiness, but more in the middle parts of the lungs. And the flu doesn’t have those round, crisp shapes. However, chest CT is not an official diagnostic tool for COVID-19.
Opacity or ground glass effect is a descriptive term referring to an area of increased obscuration in the lungs on computed tomography (CT) with preserved bronchial and vascular markings. It is a nonspecific sign of inflammation with a wide etiology, including infections, chronic interstitial disease, and acute alveolar lesions.
Ground glass opacity is also used in chest x-ray to indicate an area of cloudy lung radiopacity, often quite diffuse, in which the edges of the pulmonary vessels are difficult to distinguish.
Ground glass opacities have a wide etiology:
- partial filling of air spaces;
- partial collapse of the alveoli;
- interstitial thickening;
- inflammation;
- edema;
- fibrosis;
- neoplasm growth.
Ground glass symptoms in the lungs in adults
Since this is one of the radiological signs of the disease, the symptoms can be different, up to asymptomatic pneumonia. But for this condition there are a number of special signs and descriptions that doctors use.
There are so-called morphological forms:
- focal opacity of ground glass (i.e. nodule with ground glass effect);
- diffuse opacification with a similar effect (all lung tissue is affected);
- isolated diffuse dull opacity (in one lobe or segment of the lung).
All ground glass opacity can be divided into groups:
- infectious processes (opportunistic or non-opportunistic);
- chronic interstitial diseases;
- acute alveolar diseases;
- other reasons.
Among the infections of the opportunistic group (that is, those occurring against the background of severe immunodeficiencies, including AIDS), such a picture is given by pneumocystis pneumonia, cytomegalovirus (CMV) pneumonia and caused by the herpes simplex virus (HSV), respiratory syncytial viral (RSV) bronchiolitis.
If it is viral pneumonia in people with normal immunity, it is provoked by human coronaviruses COVID-19, Middle East respiratory syndrome coronavirus, severe acute respiratory syndrome (ARVI), herpesviruses.
Ground glass opacity can be seen in many eosinophilic pneumonias, but is most commonly seen in simple pulmonary eosinophilia (there are nodules with turbidity) and idiopathic hypereosinophilic syndrome (there are nodules with a halo of ground glass), in acute eosinophilic pneumonia bilateral patchy ground glass areas with interlobular thickening are seen. partitions. Sarcoidosis (pulmonary manifestations of sarcoidosis), acute alveolar disease, pulmonary edema, cardiogenic pulmonary edema, adult respiratory distress syndrome, and some lung tissue tumors can give a similar picture.
Treatment of ground glass in the lungs in adults
Given the fact that such a picture is typical of CT scans, it is important to treat not the effects themselves, but the causes that cause them. Therefore, it is important to evaluate complaints, the clinical picture and additional examinations.
Diagnostics
The effect of ground glass can be detected by conducting a series of CT scans of the chest with a layered examination of the lung tissue.
Modern treatments
The main goals of treatment are to prevent exposure to the pathogen, suppress the inflammatory component of the disease (alveolitis), and treat complications. The first task is achievable only when the etiology of the disease is known. The drugs used are corticosteroids and additional therapy depending on the cause. Indications and duration of treatment vary depending on the form of pneumonia. Patients with secondary pulmonary hypertension may benefit from oxygen therapy and vasodilators.
Prevention of ground glass in the lungs in adults at home
The basis of prevention is protection against infections. It is important to wear a protective mask, vaccinate, wash your hands frequently and avoid contact with sick people.
Popular questions and answers
We asked questions about the frosted glass effect pathologist, junior researcher, National Research Center for Pediatric Hematology, Oncology and Immunology named after N.N. Dmitry Rogachev to Dmitry Abramov.
● respiratory failure, which is the cause of death in 40% of cases – patients may have a clinical picture characterized by shortness of breath, fever and rapidly progressive acute respiratory failure;
● secondary respiratory infections – lung changes make patients susceptible to respiratory infection caused by common or opportunistic pathogens;
● pulmonary hypertension;
● pulmonary thromboembolism – predisposing factors are lack of activity due to shortness of breath, heart failure and the presence of concomitant pathologies;
● pneumothorax, which is accompanied by rapid clinical deterioration and respiratory failure – this is usually not solved by chest drainage due to the rigidity of the lung parenchyma, which prevents the lung from re-expanding.