FAT EMBOLISM SYNDROME

FAT EMBOLISM SYNDROME (FES)

DEFINITION- FES occurs when embolic fat macroglobules pass into the small vessels of the lung and other sites, producing endothelial damage and resulting respiratory complication, cerebral dysfunction and petechial rashes.

ETIOPATHOGENESIS –

2 theories:

1)      Mechanical theory
– initial symptoms- caused by mechanical occlusion of multiple blood vessels with fat globules, too large to pass through capillaries.

2)      Biomechanical theory – late presentation-a result of hydrolysis of fat→ free fatty acids (more irritating &toxic) →migrate to other organs in systemic circulation.
 

CAUSES –

1)    Fracture –more often long bone- closed #

2)    Orthopaedic procedures –most common- intramedullary nailing, hip or knee replacement.

3)    Massive soft tissue Injury, Severe Burns

4)    Bone marrow biopsy,

5)    Non-traumatic setting: - Liposuction,

- Fatty liver,

- Osteomyelitis,

-Sickle cell disease,

-Acute pancreatitis,

- Prolonged corticosteroid.

DIFFERENTIAL DIAGNOSIS –

1.     Bronco pneumonia

2.     Pulmonary Embolism

3.     Septicemia

4.     Head injury

5.     Diabetic coma

6.     Shock

GERD’S CRITERIA:-

Ø Mazor(M):       1.  Respiratory Insufficiency

2. Cerebral Involvement

3. Petechial Rash

Ø Minor(m):   

1)    Pyrexia

2)    Tachycardia

3)    Retinal Changes

4)    Liver Changes(Jaundice)

5)    Renal Changes

Ø Lab Features(L):

a)     Fat macroglobulinemia

b)    Anemia

c)     Thrombocytopenia

d)    Raised ESR

                       

DIAGNOSIS— 1M + 4m + 1L

FES vs Cerebral/Head Injury:

	FES	Cerebral Injury
Lucid Interval	18-24 hr	6-10 hr
Confusion	Severe	Moderate
Pulse Rate	Rapid(140-160)	Slow
Onset of Coma	Rapid	Slow
Localizing Sign	Absent	Present
Decerebrate rigidity	Early	Terminal

(Mnemonics- OLD LCP)

INVESTIGATIONS:  

1.     Cytological examination of urine, blood, sputum, & BAL (bronchoalveolar lavage) -may detect fat globules.

2.     CXR- “Snow-storm Appearance”

                              -B/L fluffy appearance

3.     Blood Gas Analysis- p_aO₂ ˂60 mm Hg

4.      Reduced Platelets, ↑_ed Lipase

5.     Brain MRI.

SEVITT CLASSIFICATION:

3 types-

                                               I.            Subclinical- fat-emboli +^nt in blood & lung

      -no clinical symptoms

                                           II.            Non-fulminant- respiratory insufficiency

-cerebral changes

-petechiae

-lab changes

                                           III.            Fulminant- rare

     -develop within hours

     -respiratory failure

     -altered mental status

MANAGEMENT:

                             Supportive:-

·        Ensure good arterial oxygenation

·        High flow O₂

·     Restriction of fluid intake & use of diuretics-minimize fluid accumulation in lung

·   Volume resuscitation with albumin & balanced electrolyte solution

·        Albumin- restore blood volume

-         binds fatty acids & decrease the extent of lung injury.

·        Mechanical ventilation & PEEP (positive end expiratory pressure).