In normal gas exchange, carbon dioxide diffuses across the endothelium of the capillaries, the interstitial space, and across the alveolar epithelium; oxygen diffuses in the other direction. Fluid accumulation interferes with gas exchange, and can cause the alveoli to fill with proteins and collapse due to edema and bleeding. The larger the area of the injury, the more severe respiratory compromise will be. Consolidation and collapse
Pulmonary contusion can cause parts of the lung to consolidate, alveoli to collapse, and atelectasis (partial or total lung collapse) to occur. Consolidation occurs when the parts of the lung that are normally filled with air fill with material from the pathological condition, such as blood. Over a period of hours after the injury, the alveoli in the injured area thicken and may become consolidated. A decrease in the amount of surfactant produced also contributes to the collapse and consolidation of alveoli; inactivation of surfactant increases their surface tension. Reduced production of surfactant can also occur in surrounding tissue that was not originally injured.Inflammation of the lungs, which can result when components of blood enter the tissue due to contusion, can also cause parts of the lung to collapse. Macrophages, neutrophils, and other inflammatory cells and blood components can enter the lung tissue and release factors that lead to inflammation, increasing the likelihood of respiratory failure. In response to inflammation, excess mucus is produced, potentially plugging parts of the lung and leading to their collapse.
Some available genetic tests for metachondromatosis are sequence analysis of the entire coding region, targeted variant analysis, deletion/duplication analysis, and a sequence analysis of select exons associated with the disorder. Treatment
Osteochondromas are usually painless, and in many cases, they spontaneously regress after the first or second decade of life. Most patients are asymptomatic, making medical intervention unnecessary. However, in extreme cases such as severe malalignment of the fingers and toes, surgery can be used to remove the osteochondromas. Epidemiology
Metachondromatosis is very rare, occurring in less than 1 in 1,000,000 people. Fewer than 40 cases have been reported around the world to date. References


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