From the Guidelines
A subdural hygroma is essentially a collection of cerebrospinal fluid (CSF) in the subdural space, often associated with conditions like spontaneous intracranial hypotension, which may require investigation for spinal CSF leaks, especially in the absence of trauma, coagulopathy, or alcohol misuse, as suggested by the multidisciplinary consensus guideline for the diagnosis and management of spontaneous intracranial hypotension 1.
Key Characteristics and Management
- Subdural hygromas can be asymptomatic or present with symptoms such as orthostatic headache, indicating a possible spinal CSF leak.
- The management of subdural hygromas, particularly those associated with spontaneous intracranial hypotension, involves treating the underlying cause, such as the CSF leak, rather than just the hygroma itself.
- Diagnostic imaging, including MRI of the brain with contrast and whole spine, is crucial for investigating the possibility of a spinal CSF leak in patients with subdural hygromas or hematomas, especially when there's a high index of suspicion based on clinical history 1.
- Small or asymptomatic hygromas are typically managed conservatively, focusing on treating the CSF leak, while symptomatic hygromas with significant mass effect may require more invasive interventions like burr hole drainage, in conjunction with leak treatment.
Diagnostic Approach
- The use of MRI with contrast and whole spine imaging is recommended to investigate spinal CSF leaks in the context of subdural hygromas or hematomas, particularly when clinical suspicion is high due to symptoms like orthostatic headache or in the absence of other explanatory factors like trauma, coagulopathy, or alcohol misuse 1.
- Imaging characteristics, such as a crescent-shaped, low-density collection along the inner surface of the skull on CT scans or MRI, are crucial for diagnosing subdural hygromas.
Clinical Considerations
- The distinction between subdural hygromas and hematomas is important, as their management strategies can differ, with hygromas typically containing clear, xanthochromic fluid and hematomas containing blood.
- The potential for subdural hygromas to evolve into chronic subdural hematomas, due to the stretching and tearing of small blood vessels in the expanded subdural space, underscores the importance of follow-up imaging for monitoring patients with this condition.
From the Research
Definition of Subdural Hygroma
- A subdural hygroma is an accumulation of cerebrospinal fluid (CSF) in the subdural space, which can occur after head injury, trauma, or as a result of other medical procedures 2, 3, 4.
- It is considered a relatively common complication, but its onset time and natural history are not well defined 2.
Causes and Risk Factors
- Subdural hygroma can occur as a result of head trauma, external hydrocephalus, or as a treatment complication of CSF shunting and craniotomies 3.
- Risk factors for developing subdural hygroma include midline shift, subarachnoid hemorrhage, delayed hydrocephalus, compression of basal cisterns, and tearing of the arachnoid membrane 5.
- Male sex, older age, basal cistern hemorrhage, diffuse injury, and swelling are also independently associated with the development of subdural hygroma in patients without decompressive craniectomy 6.
Clinical Features and Classification
- Subdural hygromas can be classified into different types based on their pathogenesis, including simple hygroma, external hydrocephalus, and hygroma with mass effect 2.
- Clinical features of subdural hygroma include accumulation of CSF in the subdural space, which can be detected by CT scan or other imaging modalities 2, 3.
- The management and prediction of subdural hygroma should be performed according to the type of hygroma and the patient's characteristics 6.