Cerebral fat embolism

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Cerebral fat embolism is one manifestation of fat embolism syndrome.

Epidemiology

Cerebral fat embolism typically occurs in patients with bony fractures (usually long bones of the lower limb). Rarely it has been described as part of a sickle cell crisis with bone marrow fat necrosis and subsequent embolism 4.

Pathology

Fat emboli usually reach the brain through either right-to-left cardiac shunt or through an intact pulmonary circulation in those without a shunt 3.

Clinical presentation

Cerebral manifestations of fat embolism syndrome can be highly variable and non-specific: the symptoms spectrum includes headache, lethargy, irritability, delirium, stupor, convulsions, or coma. Most cases can occur as subclinical events. Concurrent pulmonary or cutaneous features may aid in diagnosis.

Pathology

Fat emboli usually reach the brain through either right-to-left cardiac shunt or through an intact pulmonary circulation in those without a shunt 3.

Radiographic features

CT brain

The CT brain can be normal in most cases 8. TheThere may be evidence of diffuse oedema with scattered low-attenuating areas and haemorrhage in some situations.

MRI brain
  • T2: may show multiple non-confluent areas of high signal intensity
  • DWI: may show bright spots on a dark background (starfield pattern) corresponding to the region of T2 signal abnormality. 
  • SWI: may distinctly demonstrate multiple minute hypointense foci in the brain 12-13
  • T1: corresponding focal regions may show low T1 signal 9

Differential diagnosis

A differential to consider for the starfield pattern on MRI includes many other causes of multiple small foci of infarction or haemorrhage, although generally, only fat emboli will result in the very large number of tiny lesions characteristic of a starfield appearance. Other diagnoses to consider 6:

  • -<p><strong>Cerebral fat embolism </strong>is one manifestation of <a href="/articles/fat-embolism-syndrome">fat embolism syndrome</a>.</p><h4>Epidemiology</h4><p>Cerebral fat embolism typically occurs in patients with bony fractures (usually long bones of the lower limb). Rarely it has been described as part of a <a href="/articles/sickle-cell-disease-cerebral-manifestations-1">sickle cell crisis</a> with bone marrow fat necrosis and subsequent embolism <sup>4</sup>.</p><h4>Pathology</h4><p>Fat emboli usually reach the brain through either right-to-left cardiac shunt or through an intact pulmonary circulation in those without a shunt <sup>3</sup>.</p><h4>Clinical presentation</h4><p>Cerebral manifestations of fat embolism syndrome can be highly variable and non-specific: the symptoms spectrum includes headache, lethargy, irritability, delirium, stupor, convulsions, or coma. Most cases can occur as subclinical events. Concurrent pulmonary or cutaneous features may aid in diagnosis.</p><h4>Radiographic features</h4><h5>CT brain</h5><p>The CT brain can be normal in most cases <sup>8</sup>. The may be evidence of diffuse oedema with scattered low-attenuating areas and haemorrhage in some situations.</p><h5>MRI brain</h5><ul>
  • +<p><strong>Cerebral fat embolism </strong>is one manifestation of <a href="/articles/fat-embolism-syndrome">fat embolism syndrome</a>.</p><h4>Epidemiology</h4><p>Cerebral fat embolism typically occurs in patients with bony fractures (usually long bones of the lower limb). Rarely it has been described as part of a <a href="/articles/sickle-cell-disease-cerebral-manifestations-1">sickle cell crisis</a> with bone marrow fat necrosis and subsequent embolism <sup>4</sup>.</p><h4>Clinical presentation</h4><p>Cerebral manifestations of fat embolism syndrome can be highly variable and non-specific: the symptoms spectrum includes headache, lethargy, irritability, delirium, stupor, convulsions, or coma. Most cases can occur as subclinical events. Concurrent pulmonary or cutaneous features may aid in diagnosis.</p><h4>Pathology</h4><p>Fat emboli usually reach the brain through either right-to-left cardiac shunt or through an intact pulmonary circulation in those without a shunt <sup>3</sup>.</p><h4>Radiographic features</h4><h5>CT </h5><p>The CT brain can be normal in most cases <sup>8</sup>. There may be evidence of diffuse oedema with scattered low-attenuating areas and haemorrhage in some situations.</p><h5>MRI </h5><ul>
  • -<strong>DWI:</strong> may show bright spots on a dark background (<a title="Starfield pattern (fat embolism)" href="/articles/starfield-pattern-fat-embolism">starfield pattern</a>) corresponding to the region of T2 signal abnormality. </li>
  • +<strong>DWI:</strong> may show bright spots on a dark background (<a href="/articles/starfield-pattern-fat-embolism">starfield pattern</a>) corresponding to the region of T2 signal abnormality. </li>

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