Fat embolism syndrome overview

Jump to navigation Jump to search


Fat embolism syndrome Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Fat embolism syndrome from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

Chest X Ray

CT

MRI

Echocardiography or Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Fat embolism syndrome overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Fat embolism syndrome overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Fat embolism syndrome overview

CDC on Fat embolism syndrome overview

Fat embolism syndrome overview in the news

Blogs on Fat embolism syndrome overview

Directions to Hospitals Treating Fat embolism syndrome

Risk calculators and risk factors for Fat embolism syndrome overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Feham Tariq, MD [2]

Overview

A fat embolism is a type of embolism that is often (but not always) caused by physical trauma. Fat emboli can occur whenever there is a pulmonary embolism. The fat embolism syndrome (FES) is characterized by the triad of hypoxemia, mental status changes and petechiae. The syndrome is usually trauma related and seen with closed fractures of the long bones or pelvis.

Historical Perspective

In 1861, Zenker first discovered fat embolism (FES), after he found pulmonary capillary fat deposition in a patient who suffered from crush injury. In 1873, Bergmann described the first clinical case of FES in a patient who suffered a distal femur fracture. In 1875, Czerny explored cerebralsymptoms associated with FES.

Classification

There is no established system for the classification of fat embolism syndrome.

Pathophysiology

Fat embolism syndrome (FES) is the presence of fat globules in the circulation post traumatic insult which can lodge into the small sized capillaries in the lung, brain and skin leading to devastating clinical manifestations. The two widely accepted theories which explain the pathophysiology of FES are mechanical and biochemical theory. The mechanical theory proposes that there is mechanical obstruction by fat cells from the bone marrow in the end-capillaries after trauma. Biochemical theory attributes the clinical manifestations of FES to the pro inflammatory effect of fat emboli.

Causes

The causes of fat embolism syndrome can be divided into trauma and non-trauma related. The most common cause of fat embolism syndrome is long bone fracture especially the femur. Other causes include orthopedic procedures, liposuction, pelvic fractures and soft tissue injury.

Differentiating Fat Embolism Syndrome from other Diseases

Fat embolism syndrome should be differentiated from other diseases presenting with chest painshortness of breathtachypnea and neurological deficits. FES must be differentiated from meningitispneumoniapulmonary embolismstrokethrombotic thrombocytopenic purpura.

Epidemiology and Demographics

The exact incidence of FES is unknown and is estimated to be of <1% to >30% of all trauma cases. It commonly affects individuals 10-40 years of age. Fat embolism syndrome more commonly affects men more than women.

Risk Factors

The risk factors playing an important role in the development of fat embolism are blunt trauma, acute pancreatitis, diabetes mellitus, long bone fractures and liposuction.

Screening

There is insufficient evidence to recommend routine screening for fat embolism syndrome.

Natural History, Complications and Prognosis

Fat embolism syndrome commonly occurs 12-24 hrs after the inciting event. It can occur as early as 12 hrs and as late as 2 weeks. Patients are often dyspneic, tachypneic and hypoxic. Complications of fat embolism syndrome include disseminated intravascular coagulation, right ventricular dysfunction, acute respiratory distress syndrome and shock. Most patients recover with supportive treatment. Mortality occurs in 5-15% of patients.

Diagnosis

History and Symptoms

A detailed history and early detection of symptoms is vital for the diagnosis of fat embolism (FES). It is entirely a clinical diagnosis. Patients with fat embolism may have a positive history of long bone fracture, orthopedic procedure, plastic surgical procedure or parenteral lipid transfusion. The symptoms may take 24-48 hours to become apparent and can be categorized as pulmonary, neurological and cutaneous symptoms.

Physical Examination

Fat embolism syndrome(FES) is characterized by multisystem dysfunction most commonly presents in 12 to 72 hours after the initial insult. It is a clinical diagnosis and requires high degree of suspicion. The classic triad of clinical manifestations are petechiae, hypoxemia and neurological abnormalities. Pulmonary manifestations are the most common initial signs of FES and include dyspnea, tachypnea, hypoxemia, and respiratory failure of which the hypoxemia is the earliest feature that . Other findings on physical examination are retinal exudates, scotomatas and intravascular fat globules.

Laboratory Findings

Laboratory tests are not done commonly to diagnose fat embolism. However, the most commonly seen findings are anemia, thrombocytopenia and lipiduria.

Electrocardiogram

There are no electrocardiogram(ECG) findings associated with fat embolism syndrome.

Chest X-ray

Chest X-ray in fat embolism syndrome is done in fat embolism to rule out the complications such as acute respiratory distress syndrome and any other possible diagnosis, for example, pulmonary embolism or pulmonary edema. It takes 12-24 hours for the abnormalities to appear on chest X-ray which include bilateral air space opacities, snow-storm appearance, increased pulmonary vascular markings and dilated right heart.

CT Scan

High resolution computed tomopraphy (HRCT) of the lung shows thickening of the interlobular septa, bilateral ground-glass opacities and centrilobular nodular opacities. CT scan of the head is also done in patients with neurological deficits.

MRI

Magnetic resonance imaging (MRI) is performed in patients in patients with neurological deficits and shows the following reversible abnormalilties such as "starfield" pattern of diffuse, punctate, hyperintense lesions

Echocardiogram

Echocardiography may be helpful in the diagnosis of fat embolism syndrome. Findings of fat embolism syndrome include demonstartion of echogenic material passing through the right atrium followed by increased pulmonary pressures and right heart pressures and subsequent paradoxical embolization of this material through a patent foramen ovale (PFO).

Other Imaging Findings

Pulmonary ventilation/perfusion scan may be helpful in the diagnosis of fat embolism syndrome. Findings include demonstration of multiple subsegmental perfusion defects.

Other diagnostic studies

There are no other diagnostic studies done to diagnose fat embolism syndrome.

Treatment

Medical Therapy

The mainstay of treatment of fat embolism syndrome is supportive care, anticoagulation in some cases and corticosteroid therapy in severe respiratory distress. The main steps followed in conservative management include in ICU supportive care, fluid resuscitation, supplemental oxygen, mechanical ventilation and intracranial monitoring.

Surgery

Surgical intervention is not recommended for the management of fat embolism syndrome.

Primary Prevention

Effective measurement for the primary prevention of fat embolism include early fixation of long bone fractures, external fixation with a plate and screw and use of small-diameter nails.

Secondary Prevention

The secondary prevention of fat embolism syndrome is the same as primary prevention.

References