Fat embolism syndrome (patient information)

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 * Associate Editor(s)-In-Chief: Jinhui Wu, MD

Overview
Fat embolism syndrome (FES) is a rare clinical condition when embolic fat macroglobules pass into the small vessels of the lung and other sites, leading to multisystem dysfunction. Common causes include fracture, blunt trauma, acute pancreatitis, diabetes mellitus and burns. There is usually a latent period of 24 to 72 hours between injury and onset. The onset is then sudden. Usual symptoms include chest pain, tachypnoea, even breathlessness, fever, petechial rash, headache, and any changes of consciousness. Fat embolism syndrome is a clinical diagnosis. Lab tests and images in the chest or head may be helpful. Treatments focus on respiratory support and medication such as corticosteroids. Prognosis of fat embolism syndrome varies from person to person. Mortality occurs in 5-15% of patients.

What are the symptoms of Fat embolism syndrome?
There is usually a latent period of 24 to 72 hours between injury and onset. The onset is then sudden. The usual symptoms include:
 * Chest pain
 * Tachypnoea, even breathlessness
 * Fever
 * Petechial rash
 * Headache
 * Restlessness
 * Disorientation, confusion, seizures, stupor, even coma
 * Renal dysfunction: Oliguria, haematuria, or anuria.

Who is at highest risk?

 * Blunt trauma
 * Acute pancreatitis
 * Diabetes mellitus
 * Burns
 * Fractures
 * Joint reconstruction
 * Liposuction
 * Cardiopulmonary bypass
 * Decompression sickness
 * Parenteral lipid infusion

When to seek urgent medical care?
Fat embolism syndrome is a severe condition. The onset is sudden. If you experience blunt trauma, cardiopulmonary bypass, acute pancreatitis, burns, fractures, joint reconstruction or liposuction, or have the history of diabetes mellitus, tell you doctor as soon as possible when the following symptoms appear:
 * Chest pain
 * Tachypnoea
 * Fever
 * Petechial rash
 * Headache
 * Any change in consciousness such as restlessness, disorientation, confusion, seizures, or stupor
 * Any change in urine, such as oliguria, haematuria, or anuria.

Diagnosis

 * Lab tests: Fat globules free or in macrophages can be detected in urine, blood or sputum in patients with fat embolism. It is a low sensitivity test. A negative result does not exclude fat embolism.
 * Blood gases: This test may demonstrate hypoxia, low pO2 (less than 8 kPa or 60 mmHg), and hypocapnia.
 * Blood tests: Complete blood count (CBC) may show decreased platelets and haematocrit. Lipase level is elevated.
 * Chest x-ray: This image in patients with fat embolism syndrome may show snow storm appearance, increased pulmonary markings and dilatation of the right side of the heart within 24-48 h of onset of clinical findings.
 * Head CT: Diffuse white-matter petechial hemorrhages may be shown in patients with fat embolism. A normal CT finding can not exclude this disease. CT scan can also be used to rule out other causes for deterioration in consciousness level.
 * Brain MRI scan: This test may help diagnose fat embolism in brain. It is more sensitive than CT scan and can diagnose earlier. This image may show typical white matter changes in the area of damaged vasculars.
 * Transoesophageal echocardiography (TEE): This procedure may be used to assess intraoperative release of marrow contents into the bloodstream during intramedullary reaming and nailing.

Treatment options

 * General treatment
 * Oxygenation, mechanical ventilation and positive end-expiratory pressure (PEEP) may be required to maintain arterial oxygenation.
 * Restriction of fluid intake and the use of diuretics
 * Prophylaxis of deep venous thrombosis
 * Prophylaxis of stress-related peptic ulcer
 * Nutrition


 * Medications: The use of drugs such as corticosteroids is dispute. Some trial demonstrate that it can reduce morbidity and prevent complications.
 * Surgery: Early stabilization of long bone fractures is recommended to minimize bone marrow embolization into the venous system.

Diseases with similar symptoms

 * Pulmonary embolism
 * Pneumonia
 * Thrombotic thrombocytopenic purpura
 * Meningitis
 * Stroke

Where to find medical care for Fat embolism syndrome?
Directions to Hospitals Treating Fat embolism syndrome

What to expect (Outlook/Prognosis)?
Prognosis of fat embolism syndrome depends on:
 * Underlying medical problems
 * Patient's general condition such as age, physiologic reserves.
 * Whether the patient is accompanied with complications such as respiratory failure, neurological damages.

Prevention
According to the surgery of fracture, the following measurements may help prevent fat embolism syndrome.
 * Preoperative use of methylprednisolone
 * Early fixation of long-bone fracture
 * External fixation or fixation with plate and screw decreases the possibility of fat embolism than than nailing the medullary cavity and venting the medullary canal during nailing.
 * If nails are needed, smaller-diameter nails and unreamed nailing may be better.