Fat embolism syndrome is a rare complication that can occur following long bone fractures. It is caused by fat globules entering the bloodstream from broken bone marrow and causing mechanical obstruction or toxic effects. Clinically, it presents as a triad of respiratory distress, mental confusion, and petechial rash 12-72 hours after injury. Diagnosis is based on clinical criteria and treatment is supportive to maintain respiratory function. Prognosis is generally good, with most deaths due to pulmonary dysfunction or other injuries.

1. FAT EMBOLISM SYNDROME
By Dr Biplav Sapkota
MS Resident ,NAMS

2. Introduction
 The term ‘fat embolism’ indicates the presence of fat
globules in the peripheral circulation and lung parenchyma
after fracture of long bones, pelvis or other major trauma

3.  ‘Fat embolism syndrome’ is a serious manifestation of fat
embolism phenomenon characterized clinically by triad of
dyspnoea, petechiae and mental confusion.
 In 1873, EVon Bergmann was first to establish the clinical
diagnosis of fat embolism syndrome.

4.  Although fat and marrow embolism occurs in some 90% of
individuals with severe skeletal injuries, less than 10% show
any clinical findings..

5. Incidence
 Fat Embolism Syndrome (FES) most commonly is associated
with long bone and pelvic fractures, and is more frequent in
closed.
 Patients with a single long bone fracture have a 1 to 3%
chance of developing the syndrome
 FES has been noted in up to 33 percent of patients with
bilateral femoral fractures.

6.  Incidence is also higher in young men
 rarely in children, as in children, the bone marrow contain
more of hematopoietic tissue and less of fat.

7. Causes
 FES is most common after skeletal injury and it is most likely
to occur in patients with multiple long bone and pelvic
fractures.

8.  Trauma related
 Long bone fractures
 Pelvic fractures
 Fractures of other marrow-containing bones
 Orthopaedic procedures
 Soft tissue injuries (e.g. chest compression with or
without rib fractures)
 Burns
 Bone marrow transplant

9.  Non trauma related
• Pancreatitis
• Diabetes mellitus
• Osteomyelitis
• Steroid therapy
• Sickle cell haemoglobinopathies
• Alcoholic (fatty) liver diseases

10. Pathophysiology
 There is considerable controversy over both the source of fat
emboli and their mode of action.Three major theories have
been proposed.
1. The mechanical theory
2. The biochemical theory
3. Coagulation theory

11. The MechanicalTheory
 proposed by Gauss in 1924

12. trauma to long bones
releases fat droplets
Disrupting fat cell in the fractured
bone or in adipose tissue
enter the torn veins near long
bone
when the intramedullary press >
the venous press
transported to
pulmonary vascular bed
large fat globules result
in mechanical obstruction and
are trapped as emboli
in the lung capillaries.
Small fat droplets of 7 – 10 ¼m
size may pass via lung & reaches systemic
circulation causing embolisation to brain,
skin, kidney and retina

13.  However, this theory does not sufficiently explain the 24-72
hr delay in development after the acute injury.

14. The BiomechanicalTheory
 given by Lehmann and Moore in 1927

15. embolized fat is degraded in plasma to free fatty acids
it is hydrolysed over the course of hours to several
products,including free fatty acids
cardiac contractile
dysfunction
affectthe pneumocytes,
producing abnormalities in
gas exchange

16. Coagulation theory
long bone fractures
thromboplastin is released with
marrow elements
activates the complement
system and extrinsic
coagulation cascade
FactorVII
Products of Intravascular
coagulation
fibrin and fibrin degradation
products
increase pulmonary vascular
permeability
leukocytes, platelets and fat
globules

17. Clinical Features
 presents 12-72 hrs after the initial injury.
 Patients present with a classic triad of :
 respiratory manifestations (95%)
 cerebral effects (60%) and
 petechiae (33%).
Bulger EM, Smith DG, Maier RV, et al. Fat embolism.A 10-year
review. Arch Surg 1997;132:435-39.
P Glover, L.I.GWorthley. Fat embolism. Critical care and
Resuscitation 1999;1:275-84

18. Pulmonary manifestations
 Respiratory changes are often the first clinical feature to
present.They include
• Dyspnoea,
• tachypnoea and
• hypoxaemia
May progress to respiratory failure and ARDS.
Half of the patient of FES requires mechanical ventilation.

19. CNS manifestations
 Occur after the development of respiratory distress
 Acute confusional state is the most common symptom
 Focal neurological sign include hemiplegia, aphasia,, visual
field disturbances and anisocoria may be present.
Fortunately, almost all neurological deficits are transient and fully reversible.

20. Petechial rash
 It is the only pathognomic feature of fat embolism syndrome
and usually appears within the first 36 hrs
 Due to embolization of small dermal capillaries leading to
extravasation of erythrocytes
 Selflimiting,disappearing completely within 7 days.

21. Ocular manifestation:
 In fundoscopy
 cotton wool exudates,
 macular oedema and
 macular haemorrhage.

22. CVS involvement
 Early persistent tachycardia

23. Systemic fever:
 Low grade fever

24. Diagnosis
 Diagnosis is usually made on the basis of clinical findings
 The most commonly used set of major and minor diagnostic
criteria are those published by Gurd

25. Gurd &Wilson criteria
Major criteria
1. Axillary or subconjunctival
petechiae
2. Hypoxaemia PaO2 <60 mm Hg,
FIO2 = 0.4
3. Central nervous system
depression disproportionate to
hypoxaemia
4. Pulmonary oedema
Minor criteria
1. Tachycardia >110 bpm
2. Pyrexia >38.5°C
3. Emboli present in the retina on
fundoscopy
4. Fat globules present in urine
5. A sudden inexplicable drop in
haematocrit or platelet values
6. Increasing ESR
7. Fat globules present in the
sputum
requires at least 1 major and 4 minor criteria

26. Lindeque’s Criteria
 Sustained Pao2 <8 kPa
 Sustained PCO2 of >7.3 kPa or a pH <7.3
 Sustained respiratory rate >35 breaths min, despite sedation
 Increased work of breathing: dyspnoea, accessory muscle
use,tachycardia, and anxiety
based on respiratory features

27.  More recently, a fat embolism index has been proposed
Schonfeld’s criteria
 Petechiae 5
 Chest X-ray changes (diffuse alveolar infiltrates) 4
 Hypoxaemia (Pao2 < 9.3 kPa) 3
 Fever (>38°C) 1
 Tachycardia (>120 beats min–1) 1
 Tachypnoea (>30 bpm) 1
Cumulative score >5 required for diagnosis

28. Investigations
 no laboratory test is sufficiently sensitive or specific

29. Hematology & Biochemistry
 anemia (70% of patients) and
 thrombocytopenia ( up to 50% of patients)
 Hycocalcemia
 Elevated serum lipase
 Hypofibrinogenemia, raised ESR and increased Prothrombin
time may be seen.
circulating fat concentrations
do not correlate with the severity of the syndrome

30. Arterial blood gases
 Decreased PaO2
 Decreased PaCO2
 Respiratory Alkalosis

31. Chest x-ray
 Normal initailly
 Classical multi flocculent shadows(snow storm appearance)
 Diffuse or patchy consolidation-prominent in periphery and
base
 Radiological sign remain for up to 3 wks

32. CT Scan chest
 ground glass opacification
 Interlobular septal thickening
 ill-defined centrilobular and subpleural nodules

33. MRI
Source:http://www.ispub.com/journal/the_internet_journal_of_anesthesiology/volume_19_number_2/article/acute_fatal_fat_embolism_syndrome_in_bilateral_total_knee_arthroplasty_a_review_of_the_fat_embolism_syndrome.html
showing foci of ischemia(starfield appearance) suggestive of fat embolism syndrome
post op day 2 showing multiple hyperintense areas
consistent with multiple emboli
post operative day 14 and shows
evolving cortical infarctions

34. Treatment
Prophylaxis
 Immobilization and early internal fixation of fracture
 High doses of corticosteroids
 Albumin

35. Medical
 Medical care includes
 adequate oxygenation and ventilation,
 stable hemodynamics,blood products
 hydration,
 prophylaxis of deep venous thrombosis and
 stress related gastrointestinal bleeding and nutrition.
Various drugs have been tried but with inconclusive results

36.  Corticosteroids as an anti-inflammatory agent, reducing
the perivascular haemorrhage and oedema.
 Aspirin resulted in significant normalization of blood
gases, coagulation proteins, and platelet numbers when
compared with controls
 Heparin : clear lipaemic serum by stimulating lipase activity

37. Prognosis
 Severe trauma mortality from FES is usually between 5-15%,
other are due to other injury or secondary infection.
 Most deaths attributed to pulmonary dysfunction

38. At Last……
 Fat embolism syndrome is a rare complication occurring in
0.5 to 2% of patients following a long bone fracture.
 It is believed to be caused by the toxic effects of free fatty
acids.
 Diagnosis is clinical, based on respiratory, cerebral and
dermal manifestations.
 Treatment is only supportive, directed mainly at maintaining
respiratory functions.

39. References
 Campbell’s Orthopaedics 12th ed
 Apleys orthopaedics 9th ed
 Bailley & Love’s short practice of surgery 24th ed
 Robbins basic pathology,9th edition
 Orthopaedic pathology,5th edition