astrocytoma

 An astrocytoma is a type of glioma, a tumor that develops from star-shaped brain cells called astrocytes. These tumors can be benign (non-cancerous) or malignant (cancerous) and can occur in both children and adults. Astrocytomas can vary in their growth rate and aggressiveness, ranging from slow-growing to rapidly growing, and are classified into grades 1 through 4, with grade 4 being the most aggressive. 

🧑‍⚕️ Nursing & Monitoring

• Head must stay aligned and at the correct level (usually 0°–30° angle)

• The drainage system must stay level with the child’s head to prevent over- or underdrainage

• Regular monitoring for CSF output, ICP values, and signs of infection

📤 When is it removed?

• When the underlying issue is resolved (e.g., tumor removed, swelling gone)

• Or when a permanent solution like a VP shunt is placed

1. EVD Placement (External Ventricular Drain)

What is it?

An External Ventricular Drain (EVD) is a temporary catheter (tube) surgically inserted into the ventricles of the brain to:

• Drain cerebrospinal fluid (CSF)

• Relieve intracranial pressure (ICP)

• Monitor pressure within the brain 

  ✅ Normal ICP:

  • 3 to 7 mmHg (millimeters of mercury)

  • 📈 Elevated ICP in children:

    • > 15 mmHg is concerning

    • > 20 mmHg is generally considered pathologic and may require intervention

    • > 40 mmHg is severe and life-threatening

    • 🎯 ICP Management Goals (in critical care):

      For children with brain injury, hydrocephalus, or post-op care:

    • Keep ICP < 20 mmHg

    • Maintain cerebral perfusion pressure (CPP) to avoid brain ischemia

    • 📈 How is ICP monitored?

      • The EVD system is connected to a pressure transducer

      • Normal ICP in a 6-year-old = 3–7 mmHg

      • Readings are continuously monitored in the ICU

      • If ICP rises (e.g., > 15–20 mmHg), doctors may adjust drainage or give medications

• Remove blood or infection (in some cases)

Why is it placed?

EVD is placed when there's:

• Hydrocephalus (too much CSF in the brain)

• Increased ICP from trauma, tumor, hemorrhage, or infection

• Need for CSF diversion while waiting for a permanent solution (e.g., VP shunt)

How is it placed?

1. Preparation:

   • The patient is sedated or under general anesthesia.

   • Head is shaved and sterilized.

2. Burr Hole:

   • A small hole is drilled in the skull (usually in the frontal bone).

3. Catheter Insertion:

   • A soft catheter is inserted through the brain tissue into a lateral ventricle.

   • CSF flows through the catheter and is collected in an external drainage system.

4. System Setup:

• The drainage system is calibrated to drain at a specific pressure level.

• The EVD height relative to the patient’s head determines the drainage rate.

Risks

1. Infection (especially after 5–7 days)

2. Hemorrhage

3. Overdrainage → collapsed ventricles

4. Misplacement or clogging of the catheter

What is SEGA?

SEGA stands for Subependymal Giant Cell Astrocytoma:

• A benign brain tumor

• Often associated with Tuberous Sclerosis Complex (TSC)

• Usually located near the foramen of Monro (the passage between ventricles)

Why is resection needed?

• Tumor blocks CSF flow → causes obstructive hydrocephalus

• Can lead to increased ICP, headaches, nausea, vision changes, seizures

• Though slow-growing, it can become life-threatening due to location

Surgical Resection Procedure:

1. Pre-op Imaging:

   • MRI/CT to visualize the tumor and plan surgery

2. Craniotomy:

   • The skull is opened to access the tumor.

   • Usually done via interhemispheric transcallosal or transcortical approach.

3. Tumor Removal:

   • The surgeon carefully dissects the tumor from surrounding brain tissue.

   • Aim: Total resection, while preserving surrounding structures

4. Post-op Monitoring:

• Watch for CSF leaks, infections, hydrocephalus, seizures, or neurologic deficits

5. \

Alternative Treatment (if surgery is risky):

• mTOR inhibitors like everolimus (Afinitor) may shrink the tumor in patients with TSC.

  • Especially helpful when surgery is not safe or tumor is small.

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Recovery & Follow-up:

• ICU monitoring post-surgery

• Neurologic assessments

• MRI follow-ups to check for residual tumor or recurrence

• Consideration of VP shunt if hydrocephalus persists

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Summary Table:

Topic	Description
EVD	Catheter to drain CSF and reduce ICP
Reason for EVD	Hydrocephalus, increased pressure from SEGA tumor
SEGA Tumor	Benign brain tumor near foramen of Monro, common in TSC
Why Remove SEGA	Blocks CSF flow → hydrocephalus, symptoms, pressure
Surgical Risk	Bleeding, infection, damage to brain tissue
Post-op Care	ICU monitoring, imaging, neurologic checks