not happen on one side of the body. Respiratory distress can be mild and tends to improve on the third day. Retinal changes similar to Purtscher's retinopathy may also be present. Retinal changes happens in 50% of the patients with FES. These are the cotton wool exudates and small haemorrhages along the retinal vessels and macula. Fulminant FES - This type of FES is much rarer than the above two types. It usually happens within the first few hours of the injury. The three characteristics of FES existed in the most severe form. Cause of death is usually due to acute right heart failure. Causes Orthopaedic injuries especially fractures of the long bones are the most common cause of fat embolism syndrome (FES). The rates of fat embolism in long bone fractures vary from 1% to 30%. The mortality rate of fat-embolism syndrome is approximately 10–20%. However, fat globules have been detected in 67% of those with orthopaedic trauma and can reach as high as 95% if the blood is sampled near the fracture site. As the early operative fixation of long bone fractures became a common practice, the incidence of FES has been reduced to between 0.9% and 11%. Other rare causes of fat embolism syndrome are: Severe burns Liver injury Closed chest cardiac massage (during cardiopulmonary resuscitation) Bone marrow transplantation Liposuction Parenteral lipid infusion Decompression sickness Extracorporeal circulation Acute haemorrhagic pancreatitis Alcoholic liver disease Prolonged corticosteriod therapy Sickle cell disease Carbon tetrachloride poisoning Osteomyelitis Pathophysiology Once fat emboli enter the blood circulation, they can lodge at various sites of the body, most commonly in the lungs (up to 75% of cases). However, it can also enter the brain, skin, eyes, kidneys, liver, and heart circulation, causing capillary damage, and subsequently cause organ damage in these areas. There are two theories that describe the formation of a fat embolus: Mechanical theory - Following trauma, fat is released directly from the bone marrow into the circulation. This is because after trauma, an elevated pressure in the medullary cavity (central cavity of the bone where the bone marrow are stored) causes the release of fat globules into the venous system supplying the bone. Since venous blood returns to the right heart and is pumped to the lungs for reoxygenation, the fat globules often get lodged in the pulmonary circulation. Fat globules may also pass through lung circulation back into the left