BY BY DR. MOUSA EL-SHAMLYDR. MOUSA EL-SHAMLY

Consultant, PulmonologyConsultant, PulmonologyKing Saud HospitalKing Saud Hospital

•Fat embolism syndrome is a Fat embolism syndrome is a well-known cause of pulmonary well-known cause of pulmonary and neurologic dysfunction and neurologic dysfunction secondary to a variety of secondary to a variety of injuries.injuries.•Its presentation vary from a sub Its presentation vary from a sub clinical state to fulminant clinical state to fulminant respiratory failure.respiratory failure.

•The amount of manipulation of The amount of manipulation of injured tissue and degree of injured tissue and degree of hypovolemia or hypoperfusion hypovolemia or hypoperfusion are thought to be factors that are thought to be factors that predispose the patient to fat predispose the patient to fat embolism syndrome.embolism syndrome.•Overall mortality range from 5 to Overall mortality range from 5 to 15 %.15 %.

PathophysiologyPathophysiology•FES most commonly associated FES most commonly associated with long bone and pelvic with long bone and pelvic fractures, and most common in fractures, and most common in closed rather than open fracture.closed rather than open fracture.•Patients with a single long bone Patients with a single long bone fracture have 1-3 % chance of fracture have 1-3 % chance of developing the syndrome .developing the syndrome .

Pathophysiology (Cont’d.)Pathophysiology (Cont’d.)•The incidence increase to 33 % The incidence increase to 33 % with bilateral femoral fractures.with bilateral femoral fractures.•Other less common causes include Other less common causes include liposuction thrombolytic therapy liposuction thrombolytic therapy and orthopedic reconstructive and orthopedic reconstructive surgery. surgery. •

Pathophysiology Cont’d.Pathophysiology Cont’d.•Theories about the origin of fat Theories about the origin of fat deposition in the pulmonary deposition in the pulmonary vasculature include venous fat vasculature include venous fat embolization originating from embolization originating from traumatized bone marrow or traumatized bone marrow or excessive mobilization of free fatty excessive mobilization of free fatty acid from peripheral tissue secondary acid from peripheral tissue secondary to stress hormones.to stress hormones.

Pathophysiology Cont’d.Pathophysiology Cont’d.•Those acids coalesce in the blood Those acids coalesce in the blood and form fat aggregates.and form fat aggregates.•Regardless of the site of origin of fat Regardless of the site of origin of fat emboli the pulmonary capillaries act emboli the pulmonary capillaries act as filters and the emboli are carried as filters and the emboli are carried to the lung where they lodge in to the lung where they lodge in pulmonary capillaries and increase pulmonary capillaries and increase resistance to blood flow.resistance to blood flow.

Pathophysiology Cont’d.Pathophysiology Cont’d.•The lung parenchymal produce The lung parenchymal produce lipase to remove emboli.lipase to remove emboli.•Hydrolysis of the triglycerides to Hydrolysis of the triglycerides to glycerol and fatty acid occur glycerol and fatty acid occur and chemical pneumonitis and chemical pneumonitis results.results.

Pathophysiology Cont’d.Pathophysiology Cont’d.•This inflammatory response is This inflammatory response is mediated by complement mediated by complement activation platelet aggregation activation platelet aggregation and leukocyt enzymatic action.and leukocyt enzymatic action.

Pathophysiology Cont’d.Pathophysiology Cont’d.•Morphologically there is increase Morphologically there is increase in the permeability of the in the permeability of the capillaries and alveolar cell capillaries and alveolar cell With leakage of fluid and protein With leakage of fluid and protein into the alveolar wall and into into the alveolar wall and into alveolar space.alveolar space.

Pathophysiology Cont’d.Pathophysiology Cont’d.•Lung surfactant activity is decreased, Lung surfactant activity is decreased, functional residual capacity is functional residual capacity is reduced and there is diffusion barrier.reduced and there is diffusion barrier.•This cascade of events is seen This cascade of events is seen clinically as decreased pulmonary clinically as decreased pulmonary compliance, increase a work of compliance, increase a work of breathing and hypoxia.breathing and hypoxia.

Pathophysiology Cont’d.Pathophysiology Cont’d.•Other studies demonstrate presents of Other studies demonstrate presents of echogenic material passing into right echogenic material passing into right heart during orthopedic and spinal heart during orthopedic and spinal surgery, with continued emoblization surgery, with continued emoblization ,pulmonary artery and right pressure ,pulmonary artery and right pressure rise and material can pass through rise and material can pass through patent foramen ovale into systemic patent foramen ovale into systemic circulation resulating in paradoxical circulation resulating in paradoxical embolism.embolism.

Pathophysiology Cont’d.Pathophysiology Cont’d.•Serum from acutely ill patients Serum from acutely ill patients has the capacity to agglutinate has the capacity to agglutinate chylomicrons, low density chylomicrons, low density lipoprotein and liposomes of lipoprotein and liposomes of nutritional fat emulsions.nutritional fat emulsions.

Pathophysiology Cont’d.Pathophysiology Cont’d.•C reactive protein which appear C reactive protein which appear to be elevated in these patient to be elevated in these patient appear to be responsible for the appear to be responsible for the lipid agglutination and may also lipid agglutination and may also participate in the mechanism for participate in the mechanism for non traumatic fat embolism .non traumatic fat embolism .

Clinical ManifestationClinical Manifestation•FES typically manifest 24 to 72 FES typically manifest 24 to 72 hours after the initial insult hours after the initial insult rarely occur as early as 12 hours rarely occur as early as 12 hours or as later 2 weeks after the or as later 2 weeks after the inciting events.inciting events.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)1.1. Pulmonary abnormalitiesPulmonary abnormalities

- Tachypnea- Tachypnea- Dyspnea- Dyspnea- Hypoxemia- Hypoxemia

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)1.1. Pulmonary abnormalitiesPulmonary abnormalities

- Diffuse bilateral inspiratory - Diffuse bilateral inspiratory crepitationcrepitation- Approximately one half of the - Approximately one half of the patients with FES develop patients with FES develop severe hypoxemia and require severe hypoxemia and require mechanical ventilationmechanical ventilation

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• Neurological abnormalities Neurological abnormalities

occur in majority of patient with occur in majority of patient with FES and often occur after FES and often occur after development of respiratory development of respiratory distress.distress.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• Affected patients usually Affected patients usually

develop a confusional state develop a confusional state followed by an altered level of followed by an altered level of consciousness.consciousness.

• Seizures and focal deficits also Seizures and focal deficits also have been described.have been described.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• In severe injured patients it In severe injured patients it

may difficult to separate may difficult to separate changes caused by fat changes caused by fat embolism from these caused embolism from these caused by head injury.by head injury.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)

2. Neurological abnormalities2. Neurological abnormalities

In general changes caused In general changes caused by fat embolism are diffuse by fat embolism are diffuse without localization and may without localization and may change quickly.change quickly.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• The etiology of these mental The etiology of these mental

changes may related to changes may related to hypoxia or direct fat embolism hypoxia or direct fat embolism to the brain.to the brain.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• The duration and severity of The duration and severity of

the neurological disturbances the neurological disturbances are directly related to the are directly related to the degree of hypoxemia.degree of hypoxemia.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)2. Neurological abnormalities2. Neurological abnormalities• There is no relation between There is no relation between

the severity of neurological the severity of neurological signs and the prognosis for signs and the prognosis for recovery.recovery.

• The neurological finding are The neurological finding are reversible in most cases.reversible in most cases.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)3. Petechial haemorrhage3. Petechial haemorrhage• The classic clinical finding in patients The classic clinical finding in patients

with fat emnbolism is petechial with fat emnbolism is petechial haemorrhage which may appear as haemorrhage which may appear as early as 12 hours after injury or late early as 12 hours after injury or late as 3 to 4 days. as 3 to 4 days.

• The petechiae occur in 40 % of The petechiae occur in 40 % of patient with FES.patient with FES.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)3. Petechial haemorrhage3. Petechial haemorrhage• They can be seen most easily in They can be seen most easily in

the head, neck, anterior thorax, the head, neck, anterior thorax, axilla and subconjunctiva, axilla and subconjunctiva, over the sclera and may over the sclera and may accompanied by haemorrhages accompanied by haemorrhages in the eye ground.in the eye ground.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)3. Petechial haemorrhage3. Petechial haemorrhage• The petechiae come in crops The petechiae come in crops

and feed over 48 hours.and feed over 48 hours.• The presence of 6 to 12 classic The presence of 6 to 12 classic

petechiae firmly establishes the petechiae firmly establishes the clinical diagnosis of fat clinical diagnosis of fat embolism.embolism.

Clinical Manifestation (Cont’d.)Clinical Manifestation (Cont’d.)3. Petechial haemorrhage3. Petechial haemorrhage• The petechial rash result from The petechial rash result from

occlusion of dermal capillaries by occlusion of dermal capillaries by fat globules loading to fat globules loading to extravasation of erythrocyte or may extravasation of erythrocyte or may due to increase capillary fragility.due to increase capillary fragility.

• The rash usually resolve in 5 to 7 The rash usually resolve in 5 to 7 days.days.

DiagnosisDiagnosis• FES clinical diagnosis FES clinical diagnosis

usually characterized by usually characterized by presence of respiratory presence of respiratory insufficiency, neurological insufficiency, neurological impairment and petechial impairment and petechial rash.rash.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• Chest X-Ray normal in majority Chest X-Ray normal in majority

of patientsof patients• Minority have diffuse or patchy Minority have diffuse or patchy

air space consolidation, these air space consolidation, these changes are due to oedema or changes are due to oedema or alveolar haemorrhage and are alveolar haemorrhage and are most prominent in the periphery most prominent in the periphery and bases.and bases.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• Ventilation/perfusion scans Ventilation/perfusion scans

may demonstrate mottled may demonstrate mottled pattern of subsegmental pattern of subsegmental perfusion defects with normal perfusion defects with normal ventilatory pattern.ventilatory pattern.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• Focal areas of ground glass Focal areas of ground glass

opacification with interlobar opacification with interlobar septal thickening are septal thickening are generally seen on chest CT.generally seen on chest CT.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• MRI of the brain may reveal MRI of the brain may reveal

high intensity T2 signal which high intensity T2 signal which correlate with the degree of correlate with the degree of clinical neurological clinical neurological impairment.impairment.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• It is a comoon misconception It is a comoon misconception

that the presence of fat that the presence of fat globule either in sputum globule either in sputum ,urine or a wedged PA ,urine or a wedged PA catheter is necessary to catheter is necessary to confirm the diagnosis of FES.confirm the diagnosis of FES.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• In one study presence of fat In one study presence of fat

was demonstrated in the was demonstrated in the serum of more than 50 % of serum of more than 50 % of fracture patients without fracture patients without symptom suggestive of FES.symptom suggestive of FES.

Diagnosis (Cont’d.)Diagnosis (Cont’d.)• There is growing literature on There is growing literature on

the use of bronchoscopy with the use of bronchoscopy with BAL to detect fat globules in BAL to detect fat globules in the alveolar macrophage as the alveolar macrophage as mean to diagnose fat mean to diagnose fat embolism.embolism.

Treatment and PreventionTreatment and Prevention1. Early immoblization of the 1. Early immoblization of the

fractures reduce the incidence fractures reduce the incidence of FES. The risk further of FES. The risk further reduce by operative correction reduce by operative correction rather than conservative rather than conservative management (i.e. traction management (i.e. traction alone).alone).

Treatment and PreventionTreatment and Prevention2. Supportive care is the 2. Supportive care is the

mainstay of therapy for FES.mainstay of therapy for FES.3. Mortality is estimated to be 3. Mortality is estimated to be

between 5 and 15 %.between 5 and 15 %.

Treatment and PreventionTreatment and Prevention• Use of corticosteroid Use of corticosteroid

prophylaxis. There is number prophylaxis. There is number of study report decrease of study report decrease incidence of FES by use of incidence of FES by use of prophylactic steroid.prophylactic steroid.

Treatment and PreventionTreatment and Prevention• Methyl Prednisolone 7.5 Methyl Prednisolone 7.5

mg/kg every 6 hours for 12 mg/kg every 6 hours for 12 doses. No complication doses. No complication related to steroid treatment related to steroid treatment was observed.was observed.

Treatment and PreventionTreatment and Prevention• One rational, conservative approach One rational, conservative approach

would be to give prophylactic steroid would be to give prophylactic steroid therapy only to those patient at high risk therapy only to those patient at high risk for FES as those with long bone or for FES as those with long bone or pelvic fractures especially closed pelvic fractures especially closed fractures. Give methyl Prednisolone 1.5 fractures. Give methyl Prednisolone 1.5 mg/kg every 8 hours for six doses.mg/kg every 8 hours for six doses.

Treatment and PreventionTreatment and Prevention• Because hypoxemia is the Because hypoxemia is the

fundamental physiological fundamental physiological defect, its prevention by early defect, its prevention by early administration of oxygen is administration of oxygen is reasonable.reasonable.

Treatment and PreventionTreatment and Prevention• If it becomes impossible to If it becomes impossible to

maintain Pa02 above 60 maintain Pa02 above 60 mmHg with 40 % oxygen mmHg with 40 % oxygen inhalation, intubation and use inhalation, intubation and use of mechanical ventilation of mechanical ventilation must be considered.must be considered.

Treatment and PreventionTreatment and Prevention• The use of positive end The use of positive end

expiratory pressure is helpful to expiratory pressure is helpful to maintaining adequate maintaining adequate oxygenation with lower oxygenation with lower concentration of oxygen.concentration of oxygen.

• There is no benefit to raising There is no benefit to raising Pa02 above 100 mmHg.Pa02 above 100 mmHg.