Intracranial pressure may increase slowly or rapidly.
The possibility of slowly increased intracranial pressure must be considered in a patient whose symptoms include headache, nausea and vomiting, problems with memory, vision and balance, or impaired level or loss of consciousness.
In a catastrophic brain event (brain injury, cerebral haemorrhage, subarachnoid haemorrhage, brain infarction, status epilecticus), the increasing intracranial pressure does not immediately cause papillary stasis.
Direct ophthalmoscopy should be performed for the presence of papilloedema; normal optic discs do not, however, rule out rapidly increasing intracranial pressure in brain emergencies (e.g. brain injury).
Increased intracranial pressure warrants immediate imaging of the head (CT, MRI) in order to establish the cause and the correct acute treatment.
In the neurointensive care of an acute catastropic brain event, the management of intracranial pressure is a central challenge, and uncontrolled pressure may lead to brain death.
General
An adult brain is enclosed within a rigid skull. Expansion of any type within the cranial cavity will initially lead to the reduction in the volume of cerebrospinal fluid and venous blood. Later on, intracranial pressure will increase (normal pressure 10 cmH2O).
Intracranial pressure may increase within hours to a life-threatening level and cause brain herniation.
The process of intracranial pressure increasing may also be slow and take several months to develop.
Difficult to treat - acute glucocorticoid therapy is useless.
Vasogenic cerebral oedema
The blood brain barrier is disrupted and fluid is transferred into the intracellular space in brain tissue.
Tumour, hydrocephalus, brain abscess, meningitis or other cause
Administration of dexamethasone starts to alleviate symptoms after 12 hours.
E.g. first 10 mg initial dose and then 3 mg 3 times daily p.o.
Signs and symptoms
Headache, nausea and vomiting (particularly in the mornings)
Problems with memory, concentration, initiative, balance and vision
Slowness, somnolence and impaired level of consciousness
Papilloedema takes some time to develop
Acute presentation
Rapidly expanding intracranial process (e.g. haemorrhage) or acute worsening when the pressure is already elevated
Risk of brain herniation and ischaemia of the brain tissue
Impaired level of consciousness
Transtentorial herniation - the medial portion of the temporal lobe pushed through the tentorial orifice
Dilated pupil unresponsive to light (oculomotor nerve entrapment)
Unconsciousness
Tonsillar herniation - inferior parts of the cerebellum pushed through the foramen magnum
Regulation of breathing and circulation under threat, tetraparesis
Possible complication following a lumbar puncture carried out when intracranial pressure increased
Diagnosis
The diagnosis is based on medical history, neurological findings as well as neuroradiological and any other appropriate investigations.
CT or MRI scan (as necessary with contrast medium) performed at an acute stage will often be highly suggestive of the cause of increased intracranial pressure.
Invasive monitoring of intracranial pressure is possible in a neurointensive care unit by a ventricular catheter or a fibre sensor inserted in the brain tissue.
Treatment of the acute phase and patient transfer
Acute presentation - decreasing level of consciousness and signs of herniation - is a medical emergency requiring immediate intervention and transportation to a secondary or tertiary level hospital where immediate CT scan is performed.
CT or MRI findings may call for immediate transfer to neurointensive care and neurosurgical treatment in hospital with appropriate expertise.
Acute epidural haematoma may call for life-saving immediate craniotomy and evacuation of the heamatoma performed by an on-call surgeon in any central hospital (after consulting an on-call neurosurgeon of a unit with appropriate special expertise, e.g. in a university hospital).
Scan images should immediately be sent forward electronically and an on-call neurosurgeon should be consulted by telephone.
An emergency medicine consultant or the ICU anesthesiologist of the receiving hospital should be consulted regarding the care of the patient during transportation. This is especially important if the level of consciousness is impaired or the patient is unconscious.
The person accompanying the patient during transportation must be qualified in emergency medicine.
Threatening situations
Decreasing level of consciousness
Haemodynamic instability
Hypoxia and hypoventilation
Brain herniation
Epileptic seizures
Goals of emergency care
Secure airways, if level of consciousness is decreasing (GCS < 8)
Prevent hypoxia (oxygen saturation < 95%) and hypoventilation
Support circulation (systolic arterial pressure > 120-140 mmHg)
Treatment of brain oedema
Intubation of an unconscious patient, mild hyperventilation and normal oxygenation