Fat embolism f

Fat Emboli Fat Emboli SyndromeSyndrome

Samir el ansarySamir el ansary

HistoryHistory

First diagnosed in 1873 by Dr Von First diagnosed in 1873 by Dr Von BergmannBergmann

1879 Fenger and Salisbury 1879 Fenger and Salisbury published description of FES.published description of FES.

FE vs. FESFE vs. FESFat emboli vs Fat emboli syndromeFat emboli vs Fat emboli syndrome

FE: FE: fat in the vascular circulation, can cause fat in the vascular circulation, can cause embolic phenomenon, more common 90% pts embolic phenomenon, more common 90% pts with traumatic injury (ECHO and BAL have with traumatic injury (ECHO and BAL have shown high incidence of FE after fractures and shown high incidence of FE after fractures and orthopedic surgery)orthopedic surgery)

FES: FES: FE with pattern of sxs. Incidence 1-3% FE with pattern of sxs. Incidence 1-3% femur fx, 5-10% if bilateral or multiple.femur fx, 5-10% if bilateral or multiple.

Fat Emboli SyndromeFat Emboli Syndrome

Mortality: 5-15%Mortality: 5-15% Clinical diagnosis, No specific laboratory test is Clinical diagnosis, No specific laboratory test is

diagnosticdiagnostic Mostly associated with long bone and pelvic fxs, Mostly associated with long bone and pelvic fxs,

and more frequent in closed fracturesand more frequent in closed fractures Single long bone fracture 1-3% chance of Single long bone fracture 1-3% chance of

developing FES, and increases with number of developing FES, and increases with number of fxsfxs

Onset is 24-72 hours from initial insultOnset is 24-72 hours from initial insult

Sickle Cell DiseaseSickle Cell Disease

FES can occur in SC FES can occur in SC crisiscrisis

Bone marrow necrosis as Bone marrow necrosis as a result of hypoxia may a result of hypoxia may release fatrelease fat

PLA2 has been seen to PLA2 has been seen to increase 100x normal in increase 100x normal in SC crisis. SC crisis.

Diagnostic CriteriaDiagnostic Criteria

Gurd criteria most commonly Gurd criteria most commonly usedused

1 major, plus 4 minor1 major, plus 4 minor

Gurd CriteriaGurd Criteria

Pathogenesis- FEPathogenesis- FE

Direct entry of fat globules (fat enters Direct entry of fat globules (fat enters torn venules) torn venules)

1.1. torn vessels torn vessels 2.2. free fat present free fat present 3.3. temporary rise in marrow pressure temporary rise in marrow pressure

above venous pressure. above venous pressure.

Pathogenesis- FEPathogenesis- FE

In orthopedic surgery echogenic In orthopedic surgery echogenic material can be seen in material can be seen in R heart R heart circulation. circulation.

Paradoxical embolism: fat Paradoxical embolism: fat embolism in arterial system, eg embolism in arterial system, eg PFOPFO

Pathogenesis- FESPathogenesis- FES

Production of toxic byproducts from Production of toxic byproducts from TG/chylomicrons (lipase)TG/chylomicrons (lipase)

FES theorized to result from FES theorized to result from degradation of degradation of fat from FE to free fatty acids fat from FE to free fatty acids cause cause vasculitis/ARDS). (inflammatory mediated). vasculitis/ARDS). (inflammatory mediated).

CRP also shown to be elevated in FE and causes CRP also shown to be elevated in FE and causes fat agglutination. fat agglutination.

Pathogenesis of ARDS in FEPathogenesis of ARDS in FE

fat emboli obstructs lung vessel fat emboli obstructs lung vessel (20 microns) platelets and fibrin (20 microns) platelets and fibrin adhereadhere

Lipase creases FFALipase creases FFA

Inflammatory changesInflammatory changes

endothelial damage ARDS endothelial damage ARDS

Triad of FESTriad of FES

HypoxemiaHypoxemiaNeurological abnormalitiesNeurological abnormalitiesPetechial rashPetechial rash

Early SignsEarly Signs

Dyspnea, Dyspnea, TachypneaTachypneaHypoxemiaHypoxemia

PulmonaryPulmonary

Hypoxia, rales, pleural friction rubHypoxia, rales, pleural friction rub ARDS may developARDS may develop ½ of pts with FES require mechanical ½ of pts with FES require mechanical

ventilationventilation CXR usually normal early on, later may show CXR usually normal early on, later may show

‘snowstorm’ ‘snowstorm’ pattern- pattern- diffuse bilateral infiltratesdiffuse bilateral infiltrates CT chest: CT chest: ground glass opacification with ground glass opacification with

interlobular septal thickeninginterlobular septal thickening

Neurological findingsNeurological findings Usually occur after respiratory symptomsUsually occur after respiratory symptoms Incidence 80% patients with FESIncidence 80% patients with FES Minor global dysfunction most common, but ranges Minor global dysfunction most common, but ranges

from mild delirium to coma. from mild delirium to coma. Seizures/focal deficits not common but can occurSeizures/focal deficits not common but can occur Transient and reversible in most casesTransient and reversible in most cases CT Head: CT Head: general edemageneral edema MRI brain: MRI brain: Low density on T1, and high intensity T2 Low density on T1, and high intensity T2

signal, correlates to degree of impairmentsignal, correlates to degree of impairment

RashRash PetechialPetechial Usually on conjuntiva, MM, neck, axillaeUsually on conjuntiva, MM, neck, axillae Results from occlusion of dermal capillaries Results from occlusion of dermal capillaries

by fat globules and then extravasations of by fat globules and then extravasations of RBCRBC

Resolves in 5-7 daysResolves in 5-7 days Pathognomonic, but only present in Pathognomonic, but only present in 20-50%20-50% of of

patientspatients

Other findingsOther findings

Retinopathy (exudates, cotton wool Retinopathy (exudates, cotton wool spots, hemorrhage)spots, hemorrhage)

LipiduriaLipiduria FeverFever

DICDIC Myocardial depression (R heart strain)Myocardial depression (R heart strain) Thrombocytopenia/AnemiaThrombocytopenia/Anemia HypocalcemiaHypocalcemia

TreatmentTreatment

Supportive careSupportive care Early immobilization of fx reduces Early immobilization of fx reduces

incident of FESincident of FES Conservative tx also reduces risk. Conservative tx also reduces risk. Higher incidence when fixation Higher incidence when fixation

delayed greater than 24 hours.delayed greater than 24 hours.

SteroidsSteroids

Steroid prophylaxis is controversial Steroid prophylaxis is controversial to prevent FESto prevent FES

Theorized blunting of inflammatory Theorized blunting of inflammatory response and complement response and complement activationactivation

SteroidsSteroids

Few studies and small study size, so Few studies and small study size, so remains controversial. remains controversial.

Prospective studies suggests prophylactic Prospective studies suggests prophylactic steroids benefit high risk patientssteroids benefit high risk patients

Once FES established, steroids have not Once FES established, steroids have not shown improved outcomes.shown improved outcomes.

Heparin and ASAHeparin and ASA

Have also been proposed for tx as Have also been proposed for tx as they activate lipase and block they activate lipase and block

thromboxane respectively, but no thromboxane respectively, but no evidence exists for either use in evidence exists for either use in

FES. FES.

Prevalence of PFO in the general Prevalence of PFO in the general population = 25%population = 25%

Good luckGood luck

Samir el Samir el ansaryansary