Increased Pressure inside the Cranium

Increased Intracranial Pressure - For Nurses & Nursing Students!

Concept of Intracranial Pressure

The pressure normally exerted by the cerebrospinal fluid is known as intracranial pressure. Cerebrospinal fluid (CSF) is generated in the cerebral ventricles and it circulates around the brain and spinal cord. The human skull contains brain matter, blood supplying nutrients and oxygen to the brain and cerebrospinal fluid which protects the brain. Monroe Kelly hypothesis states that the volume of these components is in dynamic equilibrium.

The normal intracranial pressure ranges from 0 to 10 mm of Hg although 15 mm of Hg is considered the upper limit of normal. If the intracranial pressure increases due to any reason, the body will try to bring it back to normal by some compensatory mechanisms like displacing CSF to the spinal and perioptic subarachnoid space, compressing the venous system, decreasing the production of CSF and vasoconstriction of the cerebral vasculature

Intracranial hypertension

A sustained elevation of Intra Cranial Pressure beyond 15 mm of Hg or higher is known as intracranial hypertension

Causes of Intracranial hypertension.

Conditions that increase the brain volume like brain tumors, cerebral edema due to different reasons.

Conditions that increase blood volume like obstruction to venous outflow from brain, increased arterial blood supply to the brain as in infections and increase in the level of CO2 in the arterial blood.

Conditions that increase the production of CSF like tumors of the choroid plexus, communicating hydrocephalus and subarachnoid hemorrhage.

Increased Intracranial Pressure

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Consequences of intracranial hypertension

Decreased Cerebral Blood Flow

Decreased Cerebral Perfusion Pressure

Increased CO2

Decreased O2

Increased acidosis


Vasodilatation

Increased Cerebral Blood Flow

Increased Cerebral Blood Volume

Increased Intra Cranial Pressure

Impairment of auto regulation

Cerebral herniation and death

Signs and symptoms of intracranial hypertension

Transient pressure signs include

Decreased level of consciousness: The person may become drowsy or not oriented to time, place or person.

Pupillary abnormalities: Normally pupils constrict briskly on flashing bright light. This response may be delayed or impaired in people with intracranial hypertension.

Visual disturbances, motor dysfunction, headache, vomiting, aphasia, changes in respiratory pattern and changes in vital signs are other signs.

Cushing’s response

This is a compensatory response of the body in an attempt to provide adequate cerebral perfusion pressure [(Mean arterial pressure (MAP) – Intracranial pressure (ICP)] in the presence of rising intra cranial pressure. It is indicated by a rising systolic pressure, a widening pulse pressure and bradycardia

Management of Intracranial hypertension

Neurological assessment should be done frequently i.e., every 15 mins to 1 hr.

It includes assessment of the level of consciousness using Glasgow Coma Scale (GCS). GCS assesses the response of the patient to call, touch and painful stimulation in terms of eye opening, verbal response and motor response.

Pupillary size and reaction to direct light are assessed to detect the early signs of increasing intracranial pressure and its effect on the optic nerve.

Assessment of respiratory pattern, pulse and blood pressure are done on a regular basis.

Elevation of the head of the bed to 300 will help in improving the venous drainage.

Hyperventilation (increasing the respiratory rate will help in reducing hypercapnoea and thereby reducing intracranial pressure.

Blood pressure is maintained above 90 mm of Hg and below 150 mm of Hg at all times to maintain an effective cerebral perfusion pressure.

CSF drained using a tube put into the cerebral ventricles (ventriculostomy) can be used as a temporary method to reduce intracranial pressure.

Drugs like Mannitol, corticosteroids and diuretics help in reducing intracranial pressure.

Fluid management aims at preventing hypotension and maintaining serum osmolality and electrolyte levels.

Hyperthermia should be treated aggressively because it can increase the cerebral blood flow and result in increased intracranial pressure.

Seizures should be prevented by giving anticonvulsants as it will increase intracranial pressure.

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Comments 4 comments

thumbi7 profile image

thumbi7 4 years ago from India Author

Hi Pamela,

Don't worry. This serious condition occurs with brain tumor, head injury etc.

Herniation does not happen in migraine

Thanks for the visit

Have a great day


Pamela Kinnaird W profile image

Pamela Kinnaird W 4 years ago from Maui and Arizona

Cerebral herniation and death! Wow. That is a serious condition to have. I read this twice in case I was missing something because I wondered if it could be the cause of the really serious migraines that most of us have the experience of having a few times in our life. But it looks like it is not in any way related. I think I've read that doctors still don't really know what caused migraines.

Voting up and interesting.


thumbi7 profile image

thumbi7 4 years ago from India Author

Thank you KoffeeKlatch Gals. I am glad that you enjoyed reading this.


KoffeeKlatch Gals profile image

KoffeeKlatch Gals 4 years ago from Sunny Florida

Great information and research. I learned a lot I didn't know.

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