Cerebral fat embolism
Updates to Article Attributes
Body
was changed:
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.
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
The CT of the brain can beis normal in most cases 8. There may be evidence of diffuse oedema with scattered low-attenuating areas and haemorrhage in some situations.
MRI
The distribution of changes in the brain is primarilybilaterally symmetric and predominantly in a border-zone pattern (both superficial/corticalthe subcortical and deep/internal zones) which is similar to other non-fat microemboli white matter, including subcortical U-fibers, corpus callosum, and internal capsule. SWI and DWI are the most sensitive sequences 14,1517.
-
DWI:
- early (most common at 1-4 days): scattered punctate foci of cytotoxic edema (starfield pattern) 17
- later (most common at 5-14 days): confluent areas of cytotoxic edema in the white matter 17
- SWI: profuse microhemorrhages in the white matter (walnut kernel pattern) 12,13,16,17
-
T2/FLAIR:
maymay showmultiple non-confluentsmall 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 brain12-13, 16indicating vasogenic edema - T1: corresponding focal regions may show low T1 signal 9
- T1 C+: some of the areas of vasogenic may enhance 17
Differential diagnosis
AThe imaging differential to consider for the starfield pattern on MRIcharacteristic of a starfield appearanceon both SWI and DWI. Other diagnoses to consider 6:
- disseminated intravascular coagulation due to systemic causes other than fat embolism, such as infection/sepsis
- watershed infarction
- diffuse axonal injury
- cardiogenic cerebral emboli or septic cerebral emboli
- cerebral vasculitis
- minute haemorrhagic cerebral metastases
See also
-<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, <a href="/articles/delirium">delirium</a>, 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><p>The distribution of changes in the brain is primarily in a border-zone pattern (both superficial/cortical and deep/internal zones) which is similar to other non-fat microemboli<sup> 14,15</sup>. </p><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, <a href="/articles/delirium">delirium</a>, 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 of the brain is 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><p>The distribution of changes in the brain is bilaterally symmetric and predominantly in the subcortical and deep white matter, including subcortical U-fibers, corpus callosum, and internal capsule. SWI and DWI are the most sensitive sequences <sup>17</sup>. </p><ul>
-<strong>T2:</strong> may show multiple non-confluent areas of high signal intensity</li>-<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>- +<strong>DWI: </strong><ul>
- +<li>early (most common at 1-4 days): scattered punctate foci of cytotoxic edema (<a href="/articles/starfield-pattern-fat-embolism">starfield pattern</a>) <sup>17</sup>
- +</li>
- +<li>later (most common at 5-14 days): confluent areas of cytotoxic edema in the white matter <sup>17</sup>
- +</li>
- +</ul>
- +</li>
-<strong>SWI: </strong>may distinctly demonstrate multiple minute hypointense foci in the brain <sup>12-13, 16</sup>- +<strong>SWI: </strong>profuse microhemorrhages in the white matter (<a title="Walnut kernel microbleed pattern" href="/articles/walnut-kernel-microbleed-pattern">walnut kernel pattern</a>) <sup>12,13,16,17</sup>
- +<strong>T2/FLAIR:</strong> may show small areas of high signal intensity indicating vasogenic edema</li>
- +<li>
-</ul><h4>Differential diagnosis</h4><p>A differential to consider for the <a href="/articles/starfield-pattern">starfield pattern</a> 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 <sup>6</sup>:</p><ul>- +<li>
- +<strong>T1 C+: </strong>some of the areas of vasogenic may enhance <sup>17</sup>
- +</li>
- +</ul><h4>Differential diagnosis</h4><p>The imaging differential to consider 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 on both SWI and DWI. Other diagnoses to consider <sup>6</sup>:</p><ul>
- +<li>
- +<a title="Disseminated intravascular coagulation" href="/articles/disseminated-intravascular-coagulation">disseminated intravascular coagulation</a> due to systemic causes other than fat embolism, such as infection/sepsis</li>
-</ul><h4>See also</h4><ul>-<li><a title="Walnut kernel microbleed pattern" href="/articles/walnut-kernel-microbleed-pattern">Walnut kernel microbleed pattern</a></li>-<li><a title="Starfield pattern (fat embolism)" href="/articles/starfield-pattern-fat-embolism">Starfield pattern (cerebral fat embolism)</a></li>
References changed:
- 17. Kuo KH, Pan YJ, Lai YJ, Cheung WK, Chang FC, Jarosz J. Dynamic MR imaging patterns of cerebral fat embolism: a systematic review with illustrative cases. (2014) AJNR. American journal of neuroradiology. 35 (6): 1052-7. <a href="https://doi.org/10.3174/ajnr.A3605">doi:10.3174/ajnr.A3605</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23639561">Pubmed</a> <span class="ref_v4"></span>
Unable to process the form. Check for errors and try again.