CNS cryptococcosis
Updates to Article Attributes
CNS cryptococcosis results from infection of the central nervous system with the yeast like fungus Cryptococcus neoformans. It is the most common fungal infection and second most common opportunistic infection of the central nervous system1,3,10. For a general discussion of infection with this organism, refer to the article cryptococcosis.
Epidemiology
The disease tends to predominant in immunocompromised individuals such as those with AIDS. In immunocompetent patients, there is usually history of close contact with birds.
Clinical presentation
They usually present with meningitis or meningoencephalitis, headache, seizure or blurred vision due to raised intracranial pressure.
Pathology
It typically results from haematogenous spread from the lungs (which is usually the primary site). In HIV/AIDS patients cryptococcal infection of the CNS usually occurs when the CD4+ count drops below 100 cells/µL. The disease can have either meningeal or parenchymal involvement with the former being the primary manifestation 6. With meningeal involvement, a grayish, mucinous exudate accumulates over the involved brain surface.
There are three dominant CNS forms to the disease which are:
- meningitis
- cryptococcomas
- gelatinous pseudocysts
Radiographic features
The disease can have a variety of radiographic presentations.
One of the most common finding is hydrocephalus. There is a tendency for the disease to spread along the perivascular spaces. With parenchymal involvement, there can be often formation of parenchymal cryptococcomas (or torulomas) that commonly involve the midbrain and basal ganglia 2. Gelatinous pseudocysts and choroidal ependymal granulomas may also develop.
CT
CT findings can be often non-specific and with normal scans seen in a significant proportion of patients (reported up to ~40% 3). Diffuse atrophy is usually next most commonly described feature. Hydrocephalus and mass lesions may also each be present in ~10% of cases.
MRI
MRI is better at assessing dilated perivascular spaces, one of the most frequently described feature on MRI, and basal ganglia pseudocysts. These findings are more common in immunocompromised patients. Signal characteristics can vary dependant on the form of infection.
Meningeal disease
- T1 C+ (Gd): can show leptomeningeal enhancement
Cryptococcomas
- T1: low signal
- T2 / FLAIR: high signal
- T1 C+ (Gd): variable, ranging from no enhancement 5 to peripheral nodular enhancement 9
Gelatinous pseudocysts
Tend to give a "soap bubble" appearance.
- T1: low to intermediate (from mucin) signal 9
- T2: high signal
- FLAIR: low signal
Treatment and prognosis
Treated with intravenous amphotericin B or fluconazole. It is fatal if untreated.
Complications
Differential diagnosis
General imaging differential considerations include:
- other types of CNS infection
- CNS toxoplasmosis
- CNS tuberculosis
- pyogenic abscesses
- CNS lymphoma
-<p><strong>CNS cryptococcosis</strong> results from infection of the central nervous system with the yeast like fungus <em><a href="/articles/cryptococcus-neoformans">Cryptococcus neoformans</a></em>. It is the most common fungal infection of the central nervous system <sup>1,3</sup>. For a general discussion of infection with this organism, refer to the article <a href="/articles/cryptococcosis">cryptococcosis</a>.</p><h4>Epidemiology</h4><p>The disease tends to predominant in immunocompromised individuals such as those with <a href="/articles/hivaids">AIDS</a>. In immunocompetent patients, there is usually history of close contact with birds. </p><h4>Clinical presentation</h4><p>They usually present with <a href="/articles/leptomeningitis">meningitis</a> or meningoencephalitis, headache, seizure or blurred vision due to raised intracranial pressure.</p><h4>Pathology</h4><p>It typically results from haematogenous spread from the lungs (which is usually the primary site). In HIV/AIDS patients cryptococcal infection of the CNS usually occurs when the CD4+ count drops below 100 cells/µL. The disease can have either meningeal or parenchymal involvement with the former being the primary manifestation <sup>6</sup>. With meningeal involvement, a grayish, mucinous exudate accumulates over the involved brain surface.</p><p>There are three dominant CNS forms to the disease which are:</p><ul>- +<p><strong>CNS cryptococcosis</strong> results from infection of the central nervous system with the yeast like fungus <em><a href="/articles/cryptococcus-neoformans">Cryptococcus neoformans</a></em>. It is the most common fungal infection and second most common opportunistic infection of the central nervous system<sup>1,3,10</sup>. For a general discussion of infection with this organism, refer to the article <a href="/articles/cryptococcosis">cryptococcosis</a>.</p><h4>Epidemiology</h4><p>The disease tends to predominant in immunocompromised individuals such as those with <a href="/articles/hivaids">AIDS</a>. In immunocompetent patients, there is usually history of close contact with birds. </p><h4>Clinical presentation</h4><p>They usually present with <a href="/articles/leptomeningitis">meningitis</a> or meningoencephalitis, headache, seizure or blurred vision due to raised intracranial pressure.</p><h4>Pathology</h4><p>It typically results from haematogenous spread from the lungs (which is usually the primary site). In HIV/AIDS patients cryptococcal infection of the CNS usually occurs when the CD4+ count drops below 100 cells/µL. The disease can have either meningeal or parenchymal involvement with the former being the primary manifestation <sup>6</sup>. With meningeal involvement, a grayish, mucinous exudate accumulates over the involved brain surface.</p><p>There are three dominant CNS forms to the disease which are:</p><ul>
References changed:
- 10. Grant LA, Grant LA, Griffin N. Grainger and Allison's Diagnostic Radiology Essentials. Elsevier Health Sciences. (2013) ISBN:0702034487. <a href="http://books.google.com/books?vid=ISBN0702034487">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/0702034487">Find it at Amazon</a><span class="auto"></span>
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