Introduction
A subdural hygroma is an injury to the brain caused by the accumulation of cerebrospinal fluid between the outermost layer of the meninges, the dura mater, the middle layer, and the arachnoid layer. The accumulation of cerebrospinal fluid in this space can cause an increase in pressure within the skull and lead to a wide range of symptoms, including headache, confusion, drowsiness, and seizures. In severe cases, subdural hygroma can cause loss of consciousness, paralysis, and death.
What Is the Study of the Distribution and Determinants of Subdural Hygroma in Populations Called?
Subdural hygromas can occur in individuals of all ages, with a higher prevalence in the elderly. The demographic affected will vary depending on the underlying cause, which may include:
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Idiopathic, which is commonly found in pediatric patients.
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Trauma can be either an acute or chronic event.
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Post-surgical, such as after hematoma evacuation or ventricular drainage procedures.
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Spontaneous intracranial hypotension.
What Are the Causes of Subdural Hygroma?
The exact mechanism behind the formation of subdural hygromas has yet to be well understood. The most commonly accepted theory is that a tear in the arachnoid layer creates a one-way valve that allows cerebrospinal fluid (CSF) to flow into the subdural space. However, this theory may not accurately reflect the underlying processes involved. According to some research, subdural hygromas could be caused by prominent subdural effusions, which occur when the dural border cell layer is separated and a buildup of fluid. In many cases, there is a relationship between subdural hygromas, subdural hematoma hygromas, and other conditions, such as acute on chronic and chronic subdural hematomas.
The causes of subdural hygroma also include traumatic brain injury, bleeding disorders, infections, and certain medical conditions, such as those that lead to an accumulation of cerebrospinal fluid in the brain, such as hydrocephalus. In some cases, subdural hygroma may also develop due to post-surgical procedures, such as hematoma evacuation or ventricular drainage.
What Are the Symptoms of Subdural Hygroma?
Most patients with subdural hygroma do not experience any symptoms. However, some rare symptoms that have been reported include:
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Headaches.
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Changes in mental status.
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Nausea and vomiting.
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Focal neurological impairments.
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Dizziness.
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Confusion.
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Memory loss.
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Difficulty speaking.
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Seizures.
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Weakness or numbness in the limbs.
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Changes in vision or hearing.
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Unusual behavior or personality changes.
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Loss of consciousness.
A subdural hygroma can pressure the brain in severe cases, leading to neurological problems and potential long-term complications.
What Are DIagnostic Methods for Diagnosing Subdural Hygroma?
Subdural hygroma can be diagnosed through various medical imaging techniques. These imaging tests can help determine the size, location, and cause of the fluid accumulation and help rule out other potential causes of symptoms. These imaging tests include:
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Computed Tomography (CT) Scans: A CT scan utilizes X-rays and computer technology to generate comprehensive images of the brain and nearby tissues. A subdural hygroma is a type of brain condition that shows up as a crescent-shaped buildup of fluid or signals near the cerebrospinal fluid (CSF) in imaging tests. It does not spread into nearby areas and does not usually cause major problems. In tests with contrast, the blood vessels do not usually go through the area, and the buildup does not always look the same as the CSF in certain types of imaging. It may appear brighter in the images.
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Magnetic Resonance Imaging (MRI) Scans: MRI is a medical imaging technique that utilizes a powerful magnetic field, radio waves, and computer technology to generate intricate images of the brain and its surrounding tissues.
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Ultrasound: Ultrasound imaging employs high-frequency sound waves to generate images of the brain and adjacent tissues.
A fluid biopsy may sometimes be needed for a definitive diagnosis. In addition, a neurological examination and a review of the patient's medical history may also be part of the diagnostic process.
What Conditions Need to Be Considered for Differential Diagnosis of a Subdural Hygroma?
When identifying a subdural hygroma in imaging tests, it is important to consider other conditions that could be mistaken for it. Some possible conditions to keep in mind are:
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Chronic Subdural Hematoma: The relationship between subdural hygromas and chronic subdural hematomas is not fully understood, but it is believed that some collections thought to be chronic subdural hematomas are subdural hygromas. A magnetic resonance imaging (MRI) test may be necessary to tell the difference between the two, as they can appear the same in computed tomography (CT) scans. However, subdural hygromas usually do not look the same as cerebrospinal fluid (CSF) in fluid-attenuated inversion recovery (FLAIR) scans.
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Cerebral Atrophy: This is a condition in which the brain shrinks or wastes away.
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Enlargement of the Subarachnoid Spaces in Old Age: As people age, their subarachnoid spaces can enlarge. A positive cortical vein sign can indicate this instead of a subdural hygroma.
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Arachnoid Cyst: This type of cyst can develop in the brain. It is rounded, circumscribed, has a localized mass effect, and looks the same as CSF in all scans.
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Benign Enlargement of the Subarachnoid Spaces in Infancy: In some infants, the subarachnoid spaces can enlarge without causing problems. A positive cortical vein sign can indicate this instead of a subdural hygroma.
What Are the Treatment Plans for This Condition?
Treatment for subdural hygromas typically involves a surgical intervention to remove the fluid buildup and prevent it from reaccumulating. The most common surgical method is a subdural hematoma evacuation, in which a neurosurgeon incurs the skull and drains the fluid. This can often be done using minimally invasive techniques, such as burr holes or endoscopies.
In some cases, a subdural hygroma may resolve independently without surgical intervention, but this is less common and typically occurs in younger patients with milder conditions. In general, surgical intervention is recommended for patients with symptomatic subdural hygromas, as the fluid buildup can lead to increased pressure on the brain and other complications if left untreated.
The prognosis for subdural hygroma depends on several factors, including the size of the fluid buildup, the location of the hygroma, and the patient's overall health. However, patients who undergo surgical intervention for a subdural hygroma generally have a good prognosis, as the procedure is typically effective in removing the fluid and reducing symptoms.
Conclusion
A subdural hygroma is a type of brain injury caused by an accumulation of cerebrospinal fluid between the dura mater and the arachnoid layer of the meninges. The exact cause of this condition needs to be better understood. Still, theories suggest a tear in the arachnoid layer, traumatic brain injury, and medical conditions leading to an accumulation of cerebrospinal fluid. Most patients do not experience any symptoms, but when present, they can range from headaches to loss of consciousness. A subdural hygroma is diagnosed through medical imaging techniques such as CT scans, MRI scans, and ultrasound; sometimes, a fluid biopsy may be necessary. Differential diagnoses should consider conditions such as chronic subdural hematoma and brain tumors.
