Subdural hygromas refer to a cerebrospinal fluid (CSF) accumulation in the subdural space. In many cases it is considered an epiphenomenon of head injury when it is called a traumatic subdural hygroma.
They generally occur along the supratentorial cerebral convexities; occurrence in the posterior fossa is generally rare 4.
- idiopathic: in paediatric patients
- trauma: secondary to tear in the arachnoid mater
- post surgical, e.g. haematoma evacuation, ventricular drainage
- Spontaneous intracranial hypotension
Crescentic CSF density/signal accumulation of CSF in subdural space that does not extend into the sulci. Vessels may cross through the lesion in contrast enhanced studies.
Imaging differential considerations include
- chronic subdural haematoma: MRI may required to differentiate as they can have an identical appearance on CT
- atrophy/involutional change with enlargement of the subarachnoid space
- 1. Mccluney KW, Yeakley JW, Fenstermacher MJ et-al. Subdural hygroma versus atrophy on MR brain scans: "the cortical vein sign". AJNR Am J Neuroradiol. 13 (5): 1335-9. AJNR Am J Neuroradiol (citation) - Pubmed citation
- 2. Deltour P, Lemmerling M, Bauters W et-al. Posttraumatic subdural hygroma: CT findings and differential diagnosis. JBR-BTR. 1999;82 (4): 155-6. - Pubmed citation
- 3. Zanini MA, De lima resende LA, De souza faleiros AT et-al. Traumatic subdural hygromas: proposed pathogenesis based classification. J Trauma. 2008;64 (3): 705-13. doi:10.1097/TA.0b013e3180485cfc - Pubmed citation
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- 6. Hosten N, Liebig T. CT of the Head and Spine. TIS. ISBN:B005R1PB8S. Read it at Google Books - Find it at Amazon