Arachnoid Cyst

An arachnoid cyst is known as a fluid-filled sac, typically non-cancerous, that develops in the brain or spinal cord. It often presents with symptoms such as headaches and seizures. While not all cases require treatment, if symptoms are present, treatment may involve draining or removing the cysts. If left untreated, arachnoid cysts can lead to brain damage or movement issues, affecting the patient’s quality of life.

Arachnoid cysts are fluid-filled sacs that develop within the arachnoid membrane, which is connected to the brain and spinal cord. Often considered the most common type of brain cyst, these growths are typically congenital (present from birth). However, arachnoid cysts in adults may also develop following an infection or head trauma. Since these cysts develop in the cerebrospinal fluid (CSF), they can potentially cause permanent damage to different brain regions. If symptoms arise, diagnosis is usually followed by either surgical intervention or medical treatment.

Causes of Arachnoid Cyst in the Brain

The causes of arachnoid cysts in the brain can be classified into primary (congenital) or secondary (acquired) based on specific findings. Factors that may contribute to the development of an arachnoid cyst include:

1. In the primary type, abnormal development of the arachnoid membrane during the mother’s pregnancy may trigger the condition, potentially resulting in abnormal separation or tearing within the baby’s arachnoid membrane.
2. In some cases, the exact cause of the condition may remain unknown, though genetic predisposition is noted as a contributing factor.
3. Insufficient development or narrowing of the temporal lobe in some individuals may lead to cyst formation in this area.
4. In the secondary type, conditions like meningitis, tumor formation, head trauma, inflammation of the arachnoid membrane, corpus callosum agenesis, or Marfan syndrome may lead to the development of arachnoid cysts.

Arachnoid Cyst Sizes

Arachnoid cysts typically do not tend to grow large compared to other types of masses. The sizes of these cysts generally do not exceed 3 cm. However, if the cysts grow larger than 3 cm, they may pose a significant risk to the patient’s health.

Symptoms of Arachnoid Cyst in the Brain

Common symptoms of an arachnoid cyst in the brain include nausea, vomiting, headaches, and hearing issues. The complications tend to develop more quickly and appear more pronounced in secondary cysts. In contrast, the primary cyst type may take longer to manifest symptoms, given that it is present from birth. The location and timing of the cyst’s development influence the onset and severity of symptoms. Symptoms usually begin to appear before the age of 20, though some individuals may live their entire lives without any symptoms. Common symptoms include:

• Development of hydrocephalus in infants
• Intense morning headaches
• Hearing loss or ringing in the ears, depending on the cyst’s location
• Impaired vision or sudden vision loss
• Confusion, drowsiness, and constant fatigue
• Hormone imbalances and issues with endocrine glands starting from infancy
• Mood disturbances and personality changes
• Loss of balance and coordination
• Muscle weakness leading to involuntary movements
• Seizures and epilepsy attacks
• Paralysis and uncontrolled head nodding
• Nausea and vomiting
• Numbness and fatigue

If the cysts are located near nerve roots, they may press on these areas, leading to nerve loss in the legs, back, or arms, causing significant numbness and tingling.

Treatment of Arachnoid Cyst

Diagnosing the cyst is a prerequisite for creating a treatment plan. The location, characteristics, and size of the cyst can be identified using radiologic imaging techniques. This allows for a tailored treatment approach, either surgical or medical. CT or MRI imaging techniques are often used as diagnostic tools. In many cases, the cyst is incidentally detected on an MRI scan without any prior symptoms. Based on this information, two treatment methods can be applied: medication or surgery.

Surgical Treatment of Arachnoid Cyst

The presence and severity of symptoms can guide the decision for surgical intervention. The patient’s condition is usually monitored, and if the cyst affects brain function or bodily balance, urgent intervention may be required. The following surgical techniques may be applied for the treatment of arachnoid cysts:

• A craniotomy may be performed to remove the cyst wall, creating an opening in the basal cisterns.
• The cyst may be punctured through an endoscopic procedure called fenestration, creating a window in the CSF pathways.
• A burr hole can be drilled into the skull to drain the cyst’s fluid.
• A silicone drain, or ventriculoperitoneal shunt, may be placed within the cyst, allowing fluid to be injected under the skin into the peritoneum, enabling the fluid to be absorbed and lowering intracranial pressure. Minimally invasive surgical techniques have improved the success rate of treatment in recent years.

All these methods may be considered if the cyst poses a risk to surrounding tissues in the brain. Generally, the decision to use surgical methods in treating cysts remains a medical debate, especially if the cyst arises from conditions such as Marfan syndrome. Multidisciplinary approaches are often recommended to address these complex cases.

Medical Treatment of Arachnoid Cyst

Medication is not a definitive treatment method for arachnoid cysts. Medication may be prescribed as supportive therapy during the emergency treatment plan after diagnosis. Even after surgical drainage of the cyst’s fluid, recurrence is possible. If the condition recurs, radiation therapy and radiotherapeutic drugs may be used to minimize the effects of the cyst. Symptoms arising from the cyst, such as slow brain function, severe headaches, or seizures, may disrupt quality of life. Medication may be used to reduce the symptoms affecting the body due to the brain cyst, along with supplements to support brain health, which can be included under a doctor’s supervision.

Frequently Asked Questions about Arachnoid Cyst

• Is an arachnoid cyst harmful? Arachnoid cysts can be primary (congenital) or secondary (acquired). The risk can be assessed based on the symptoms caused by the cyst’s impact on areas such as speech or hearing centers. Additionally, they occur more frequently in men than women, suggesting they may present more risks in men.
• Can an arachnoid cyst disappear on its own? As most cases are asymptomatic, they are often discovered incidentally through MRI. If the cyst causes no symptoms, intervention may not be necessary. However, once detected, the cyst is monitored for growth, as it is not possible for it to resolve on its own.