Neuro 1: Intracranial Pressure Flashcards

Intracranial Pressure (ICP)

• ICP refers to the pressure from total brain volume within the skull, composed of brain tissue (80%), blood (10%), and cerebrospinal fluid (CSF) (10%).
• Normal ICP ranges from 5-15 mmHg.
• The body can adapt to changes in component volume, but excessive increases (e.g., due to injury) lead to elevated ICP.

Increased Intracranial Pressure

• Increased ICP compensates through decreased CSF production and displacement of CSF.
• If elevated ICP persists, blood volume helps compensate, potentially resulting in intracranial hypertension.

Four Stages of Increased Intracranial Pressure

• Stage 1: Vasoconstriction and external compression of the venous system occur.
• Stage 2: ICP surpasses compensatory capacity, leading to compromised oxygenation and arterial vasoconstriction.
• Stage 3: Arterial constriction develops as ICP nears arterial pressure; brain experiences hypoxia and hypercapnia, losing autoregulation, resulting in decreased blood pressure and increased ICP.
• Stage 4: Brain tissue herniates due to extreme pressure, compressing the brainstem and inducing further oxygen deprivation.

Clinical Manifestations of Increased Cranial Pressure

• Early indicator: Change in level of consciousness (LOC) reflects poor mental status.
• Late signs include vital sign changes known as Cushing's triad: increased systolic blood pressure (SBP), bradycardia, and irregular respiratory patterns.
• Ocular signs: Compression of the ocular nerve leads to fixed and dilated pupils on the injured side.
• Decreased motor function: Hemiparesis and abnormal posturing, including:
  • Decorticate: Flexion of arms, wrists, and fingers, with adduction of upper extremities.
  • Decerebrate: Extension and internal rotation of upper extremities with wrist flexion.
• Additional symptoms: Headache and vomiting.

Treatment of Increased Intracranial Pressure

• Address and manage the underlying cause of elevated ICP.
• Diuretics: Reduce fluid volume and ICP.
• Corticosteroids: Decrease brain inflammation, eliminate excess fluid, and restore normal autoregulation of blood vessel size.
• Mechanical ventilation may be necessary to protect the airway.

This quiz focuses on the concept of intracranial pressure (ICP) and its implications. It covers definitions and key information related to normal and increased ICP, essential for understanding neurological conditions. Perfect for students or professionals in the field of neuroscience.