Question 29

College Answer

Symptoms ie   dyspnoea, confusion,

Signs               Respiratory, CNS, cutaneous,

Causes            Long Bone #s, smaller bones, sickle cell, compression liposuction etc

Treatment:      Supportive ie O2, CPAP, Ventilation.

Discussion

For a ten mark question, the college answer - though technically hitting all the correct notes- appears a little austere.

A more generously expanded answer could be constructed using the various published review literature on the subject. It would resemble something like the following:

Symptoms of fat embolism

• Confusion is usually the earliest symptom
• Dyspnoea
• Tachypnoea
• Haemoptysis
• Usually, with a latent period (say, some days after the manipulation of a fracture).

Signs of fat embolism

• • Respiratory features: moist crepitations over all lung fields, hypoxia, cyanosis
  • Characteristic petechial rash, usually over the anterior axillary fold and at the root of the neck, as well as on the buccal mucosa and the conjunctiva. This distribution can be explained by fat droplets accumulating in the aortic arch prior to embolisation to nondependent skin via the subclavian and carotid vessels.

• • Fever
  • Tachycarda
  • Retinal haemorrhages
  • Visible fat droplets on ophthalmoscopy
  • Jaundice
  • Renal impairment
  • Anaesthetists often note a sudden drop in end-tidal CO₂ concentration during a stable steady state.

Laboratory features

• • Thrombocytopenia
  • Anaemia (sudden decrease)
  • High ESR
  • Fat macroglobulinaemia

Causes of fat embolism

• • Long bone fractures
  • Liposuction
  • Bone marrow harvest
  • Lymphography
  • Acute pancreatitis
  • Necrosis of a fatty liver
  • Acute sickle cell crisis (with marrow necrosis)

Management of fat embolism

• Boring, non-specific treatment:
  • O₂ supplementation
  • Positive pressure ventilation
  • Correction of coagulopathy
  • Replacement of platelets
  • Correction of the source problem (i.e. reduction of fractures)

Weird management strategies have been advanced, such as heparin (which supposedly encourage lipase activity and discourages the formation of pletelt aggregates). Alcohol intoxication seems to be somehow protective against fat embolism.

Mellor, A., and N. Soni. "Fat embolism." Anaesthesia 56.2 (2001): 145-154.

 

Gurd, Alan R., and R. I. Wilson. "The fat embolism syndrome." Journal of Bone & Joint Surgery, British Volume 56.3 (1974): 408-416.

 

Myers, R., and J. J. Taljaard. "Blood alcohol and fat embolism syndrome." J Bone Joint Surg Am 59.7 (1977): 878-880.

 

Hofmann, S., G. Huemer, and M. Salzer. "Pathophysiology and management of the fat embolism syndrome." Anaesthesia 53.S2 (1998): 35-37.