【Learning Key Points】
- Normal intracranial pressure (ICP) is generally
less than 10–15 mmHg or 135–200
mmH₂O. Persistent ICP above 15 mmHg or 200 mmH₂O is considered elevated intracranial pressure
(intracranial hypertension).
- Increased intracranial pressure may result from
an increase in brain tissue
volume, cerebrospinal fluid (CSF) volume, or intracranial blood volume.
- Avoid activities that require straining or
breath-holding, such as straining
during bowel movements, forceful nose blowing, and excessive coughing,
to reduce the risk of increasing intracranial pressure.
I. What Is Increased Intracranial Pressure?
The skull is
essentially a rigid structure. Because the contents of the skull—including brain tissue, blood, and cerebrospinal fluid
(CSF)—are relatively incompressible, any increase in intracranial
contents can result in an increase in intracranial pressure.
Intracranial
pressure (ICP) refers to the pressure exerted by the brain tissue, blood, and cerebrospinal fluid within the cranial cavity.
ICP may vary with changes in blood
pressure, venous pressure, intrathoracic and intra-abdominal pressure, body
position, blood gas levels, and body temperature.
Normal ICP is
generally less than 10–15 mmHg or
135–200 mmH₂O. Persistent ICP above 15 mmHg or 200 mmH₂O is considered intracranial hypertension. Severe or sustained elevation of
ICP may cause brain injury and can become life-threatening if not treated
promptly.
II. Causes of Increased Intracranial Pressure
- Increased brain
tissue volume: such as brain tumors or cerebral edema.
- Increased
cerebrospinal fluid (CSF) volume:
caused by excessive CSF production, impaired CSF circulation, or decreased
CSF absorption.
- Increased
intracranial blood volume: such as hemorrhagic stroke or bleeding caused by
rupture of a cerebral aneurysm.
III. Symptoms of Increased Intracranial Pressure
- Increased blood
pressure, decreased pulse rate, and slow or irregular breathing.
- Persistent dizziness,
projectile vomiting, severe headache, or worsening headache.
- Changes in level of
consciousness, such as drowsiness,
difficulty awakening, slurred speech, or abnormal behavior.
- Unsteady gait or
progressive weakness of the limbs.
- Seizures or
convulsions.
- Blurred vision or
double vision.
IV. How to Prevent an Increase in Intracranial
Pressure
- When lying in bed, elevate the head of the bed as recommended by the healthcare team.
Keep the head in a neutral midline position with the neck aligned in a
straight line. Avoid excessive neck flexion caused by turning the head to
the side (Figure 1).
- Avoid activities that require straining or breath-holding, such
as straining during bowel movements, forceful nose blowing, or excessive
coughing, to reduce the risk of increased intracranial pressure (Figure
2).
- Consume adequate high-fiber foods, such as black beans, broccoli, and guava.
Take stool softeners as prescribed
by the physician to maintain regular bowel movements and prevent
constipation.
- Minimize noise and
maintain a calm environment as much
as possible. If you experience pain, take analgesics as prescribed by your
physician to reduce painful or unpleasant stimulation that may contribute
to increased intracranial pressure.
- If you develop symptoms of increased intracranial pressure or any change in your
level of consciousness, seek medical assistance immediately.
V. Conclusion
Increased
intracranial pressure is an important and potentially life-threatening
neurological condition. If not recognized and treated promptly, it may result
in brain injury and potentially
threaten the patient's life.
Pay attention
to symptoms such as headache, vomiting,
changes in consciousness, and limb weakness. Follow the instructions
provided by the healthcare team, maintain proper positioning while in bed,
avoid straining during bowel movements, and minimize excessive stimulation to
reduce the risk of increased intracranial pressure and promote brain health and
safety.
VI. References
- Hoh, B. L., Ko, N. U., Amin-Hanjani, S., Chou,
S. H.-Y., Cruz-Flores, S., Dangayach, N. S., Derdeyn, C. P., Du, R.,
Hänggi, D., Hetts, S. W., Ifejika, N. L., Johnson, R., Keigher, K. M.,
Leslie-Mazwi, T. M., Lucke-Wold, B., Rabinstein, A. A., Robicsek, S. A.,
Stapleton, C. J., Suarez, J. I., … Welch, B. G. (2023). 2023 guideline for
the management of patients with aneurysmal subarachnoid hemorrhage: A
guideline from the American Heart Association/American Stroke Association.
Stroke, 54(7), e314–e370.
- Kareemi, H., Pratte, M., English, S., &
Hendin, A. (2023). Initial diagnosis and management of acutely elevated
intracranial pressure. Journal of Intensive Care Medicine, 38(7),
643–650. https://doi.org/10.1177/08850666231156589