Intracranial Pressure (ICP)
What Is It?
Intracranial pressure (ICP) is the pressure within the head. Normally, in the cranial vault there are only a few things that take up significant space, brain, blood inside blood vessels and cerebrospinal fluid. Because the skull in an adult is a fixed space, if any additional mass is introduced inside the head, the pressure within the cranium will increase.
Normally, ICP is low and varies somewhat with changes in position and blood pressure. It normally increases with some movements such as straining, coughing, or laughing. The pressure in the head can be measured in several ways. Most commonly, either a pressure transducer probe or a ventricular catheter are placed in the head, allowing the accurate measurement of pressure in patients.
In some pathological conditions, the ICP can be increased. The nervous system does not tolerate high intracranial pressure for long. It compromises the normal function of the brain and can lead to permanent damage if not reversed quickly. Symptoms of high pressure include headache and nausea and vomiting. As the pressure gets more severe it leads to impairment in the level of consciousness, initially lethargy and later coma and death if not corrected.
Some examples where pressure
may be elevated include:
Head Trauma: Hemorrhage and/or swelling of the brain after traumatic injury can lead to very high pressures. Physicians often aggressively attempt to lower the high ICP. Some of the common treatments used to lower ICP after trauma include:
- Surgical evacuation of any intracranial hematomas
- Placement of a ventriculostomy to measure ICP and drain cerebrospinal fluid
- Intravenous mannitol or sodium to draw fluid from the brain into the blood by osmosis
- Sedation and chemical paralytic medications
- Craniectomy - removal of a portion of the skull to allow the brain to expand
Massive Stroke: Very large infarctions of the brain can lead to massive swelling of the damaged brain. This can lead to increased ICP which may require treatment such as a craniectomy (see above).
Hydrocephalus: Many forms of hydrocephalus lead to increased intracranial pressure. The typical treatment is a shunting procedure to drain the excess cerebrospinal fluid into another part of the body where it can be re-absorbed.
Brain Tumors: Any mass inside the head can lead to increased pressure. While smaller tumors only cause pressure on the structures just adjacent to them, very large tumors can lead to increase in ICP. Usually the treatment consists of removing the mass surgically, but other treatments are sometimes used as well.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.