A 1996 study published in the British Medical Journal found that mortality in type III OI is significantly higher, with many patients dying in their 20s, 30s, and 40s; patients who survive to the age of 10 were further found to have longer life expectancy than newborns. Mobility
People with mild (type I) OI as adults need few pieces of adaptive equipment, although in infancy they reach motor milestones at a significant delay compared to the general population. : 477 With adaptive equipment such as crutches, motorized wheelchairs, splints, reach extenders, and/or modifications to the home, many individuals with moderate to severe OI can achieve or maintain a significant degree of independence. : 488  With treatment and physical therapy, the maximum levels of mobility are expected to be unassisted community walking for type I, household or exercise walking for type III, and household or community walking for type IV; due to the variability of OI between individuals, mobility achieved varies and may be below this expected maximum. : 476

Epidemiology
In the United States, the incidence of osteogenesis imperfecta is estimated to be one per 20,000 live births. An estimated 20,000 to 50,000 people are affected by OI in the United States.The most common types are I, II, III, and IV, while the rest are very rare. Type I is the most common and has been reported to be around three times more common than type II. The prevalence of types III and IV is less certain.
Constrictive pericarditis is a medical condition characterized by a thickened, fibrotic pericardium, limiting the hearts ability to function normally. In many cases, the condition continues to be difficult to diagnose and therefore benefits from a good understanding of the underlying cause. Signs and symptoms
Signs and symptoms of constrictive pericarditis are consistent with the following: fatigue, swollen abdomen, difficulty breathing (dyspnea), swelling of legs and general weakness. Related conditions are bacterial pericarditis, pericarditis and pericarditis after a heart attack. Causes
The cause of constrictive pericarditis in the developing world are idiopathic in origin, though likely infectious in nature. In regions where tuberculosis is common, it is the cause in a large portion of cases. Causes of constrictive pericarditis include:

Tuberculosis
Incomplete drainage of purulent pericarditis
Fungal and parasitic infections
Chronic pericarditis
Postviral pericarditis
Postsurgical
Following MI, post-myocardial infarction
In association with pulmonary asbestos

Pathophysiology
The pathophysiological characteristics of constrictive pericarditis are due to a thickened, fibrotic pericardium that forms a non-compliant shell around the heart. This shell prevents the heart from expanding when blood enters it. This results in significant respiratory variation in blood flow in the chambers of the heart.During inspiration, pressure in the thoracic cavity decreases but is not relayed to the left atrium, subsequently a reduction in flow to the left atrium and ventricle happens.