Clinical Correlations

Cranium, Meninges, and Ventricles: Clinical Correlations

• Intracranial masses, like hydrocephalus, tumors, hemorrhages, abscesses, or edema, take up space in the cranial vault.
• Mass effect from these masses leads to local tissue compression and damage.
• Symptoms (S/Sx) depend on the damaged area.
• These masses can increase intracranial pressure (ICP).
• Midline shift or herniation can occur, where a part of the central nervous system (CNS) moves to another compartment.

Types of Herniation

• The diagram shows different types of herniation: subfalcine, central, uncal transtentorial, and tonsillar.

Intracranial Pressure

• Compensated: small lesions cause a decrease in cerebrospinal fluid (CSF) or blood volume.
• Uncompensated: large lesions cause an increase in ICP.
• Symptoms include headache, nausea, vomiting, altered mental status, visual loss, and papilledema.

Papilledema

• Papilledema is swelling of the optic disc.
• It is a symptom of increased intracranial pressure.

Intracranial Hemorrhage

• Epidural hematoma: rapidly expands and is associated with arterial blood. It is often caused by skull fractures.
• Subdural hematoma: expands more slowly and is linked to venous blood; it results from torn bridging veins.
• Subarachnoid hematoma: results from bleeding into the subarachnoid space.
• Intracerebral hematoma: bleeding within the brain tissue.
• Causes include trauma (coup/contrecoup), hypertension, and vascular malformations.

Subarachnoid Hemorrhage

• Nontraumatic causes: usually from an aneurysm (a weakened area in an artery).
• Traumatic causes: results from brain contusion/trauma leading to ruptured vessels.
• Symptoms can include a "worst headache of my life."

Hydrocephalus

• Causes:
  • Excessive CSF production
  • Obstruction of CSF flow
  • Reduced CSF reabsorption through arachnoid granulations.
• Different outcomes exist in infants/toddlers compared to adults.

Craniotomy

• Burr holes are drilled without penetrating the dura mater.
• Bone between these holes is cut with a saw (bone flap).
• Dura mater can be carefully cut for surgery.
• The bone flap is saved and replaced afterward.