Neurology: Increased Intracranial Pressure (ICP)

Study Notes

Normal ICP is 10 to 20 mm Hg, measured in the lateral ventricles.
The rigid cranial vault contains brain tissue, blood, and cerebrospinal fluid (CSF), which are in equilibrium, producing the ICP.

Elevated ICP is associated with head injury, brain tumors, and hemorrhage.
Increased ICP decreases cerebral perfusion, stimulates further swelling (edema), and shifts brain tissue, resulting in herniation (a frequently fatal event).

Monitoring ICP, decreasing cerebral edema, maintaining cerebral perfusion, reducing CSF and intracranial blood volume, controlling fever, maintaining oxygenation, and reducing metabolic demands are key to managing increased ICP.
Decreasing cerebral edema can be achieved through osmotic diuretics (mannitol), corticosteroids, avoiding overhydration, and monitoring fluid and electrolyte balance.
Reducing CSF and intracranial blood volume can be achieved through CSF drainage, maintaining the PaCO2 at 30 to 35 mm Hg, and hyperventilation (in patients whose ICP is unresponsive to conventional therapies).
Maintaining oxygenation involves systemic oxygenation, maintaining a patent airway, and suctioning with care.

Restlessness, confusion, increasing drowsiness, changes in level of consciousness (LOC), abnormal respiratory and vasomotor responses, motor or sensory disturbances, stupor, coma, and pupillary changes are all clinical manifestations of increased ICP.
The earliest sign of increasing ICP is a change in LOC, with slowing of speech and delay in response to verbal suggestions as other early indicators.

Evaluation of mental status, LOC, motor and sensory function, pupil checks, and vital signs are all part of a neurologic examination.
The Glasgow Coma Scale may be used to evaluate LOC.

Paresis is a condition characterized by weakness of voluntary movement, while plegia is paralysis in which all voluntary movement is lost.
Hypoesthesia refers to a reduced sense of touch or sensation, while paresthesia is an abnormal sensation such as tingling, numbness, or burning of skin.
Abnormal motor responses can also occur.