Anti-inflammatory treatments have been used, with good responses being recorded for intravenous immunoglobulin (IVIG), with or without corticosteroids. Oxygen is often needed. Supportive care is key for treating clinical complications. Most children who receive expert hospital care survive.Knowledge of this newly described syndrome is evolving rapidly. Its clinical features may appear somewhat similar to Kawasaki disease, a rare disease of unknown origin that typically affects young children, in which blood vessels become inflamed throughout the body. It can also show features of other serious inflammatory conditions of childhood, including toxic shock and macrophage activation syndromes. Nevertheless, it appears to be a separate syndrome. Older children tend to be affected.This emerging condition has been defined slightly differently (using different names), by the World Health Organization (WHO), the Royal College of Paediatrics and Child Health (RCPCH), and the Centers for Disease Control and Prevention (CDC). Although the condition is thought to follow SARS-CoV-2 viral infection, antigen or antibody tests are not always positive. Exclusion of alternative causes, including bacterial and other infections, is essential for differential diagnosis. Some general clinical guidance has been provided by the RCPCH, the National Institutes of Health, the American College of Rheumatology, and the American Academy of Pediatrics.Clusters of new cases have been reported two to six weeks after local peaks in viral transmission. The disease is thought to be driven by a delayed biological mechanism in certain predisposed children.
Pneumatosis is the abnormal presence of air or other gas within tissues.In the lungs, emphysema involves enlargement of the distal airspaces, and is a major feature of chronic obstructive pulmonary disease (COPD). Other pneumatoses in the lungs are focal (localized) blebs and bullae, pulmonary cysts and cavities. Pneumoperitoneum (or peritoneal emphysema) is air or gas in the abdominal cavity, and is most commonly caused by gastrointestinal perforation, often the result of surgery. Pneumarthrosis, the presence of air in a joint, is rarely a serious sign. Lung cysts
A lung cyst, or pulmonary cyst, encloses a small volume of air,  and has a wall thickness of up to 4 mm. A minimum wall thickness of 1 mm has been suggested, but thin-walled pockets may be included in the definition as well. Pulmonary cysts are not associated with either smoking or emphysema.A lung cavity has a wall thickness of more than 4 mm. Other thoracic
Pneumothorax, air or gas in the pleural space
Pneumomediastinum, air or gas in the mediastinum
Also called mediastinal emphysema or pneumatosis/emphysema of the mediastinum

Abdominal
Pneumoperitoneum (or peritoneal emphysema), air or gas in the abdominal cavity. The most common cause is a perforated abdominal viscus, generally a perforated peptic ulcer, although any part of the bowel may perforate from a benign ulcer, tumor or abdominal trauma. Pneumatosis intestinalis, air or gas cysts in the bowel wall
Gastric pneumatosis (or gastric emphysema) is air or gas cysts in the stomach wall

Joints
Pneumarthrosis is the presence of air in a joint.