Information
Editors
Olli-PekkaKämäräinen
MaaritLång
TimoKoivisto
JuhaE.Jääskeläinen
Increased Intracranial Pressure
Essentials
- 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.
Aetiology
- Intracranial space occupying process
- Traumatic haemorrhage Traumatic Cerebral Haemorrhages
- Acute epidural haematoma
- Acute subdural haematoma
- Acute brain contusion and bleeding inside the brain tissue (also in the subarachnoid space)
- Chronic subdural haematoma: elderly people, alcoholics, patients with shunts, anticoagulant treatment
- Spontaneous haemorrhage
- Intracranial abscess
- Epidural or subdural abscess
- Brain abscess(es)
- Intracranial tumour
- Primary or metastatic
- Mechanisms: large size of the tumour, cerebral oedema or obstructive hydrocephalus
- High-pressure hydrocephalus
- Obstructive hydrocephalus
- The circulation of cerebrospinal fluid in the ventricles is obstructed.
- Tumours, aqueduct stenosis or other obstruction to the flow
- Delayed oedema following a cerebellar infarction and obstruction of the fourth ventricle
- Cerebellar haemorrhage and obstruction of the fourth ventricle
- Resorptive hydrocephalus
- The absorption of cerebrospinal fluid into the venous blood is disturbed.
- Bacterial meningitis or its sequelae
- Acute haemorrhage (ICH, IVH, SAH) or its sequelae
- Sequelae of acute brain contusion
- Leptomeningeal tumour
- Normal-pressure hydrocephalus (NPH)
- Blocked shunt in a patient with hydrocephalus Shunt Complications in Children
- Sinus thrombosis and obstruction of venous return
- Cerebral oedema
- Cytotoxic cerebral oedema
- Brain cells are damaged.
- Brain infarction, cerebral haemorrhage, brain contusion, SAH
- Inflammation and many other causes
- 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.
- Lumbar puncture is contraindicatedLumbar Puncture.
- 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
- Intense and/or long-term hyperventilation causes cerebral ischaemia
- Osmotic diuretics reduce the pressure quickly but the effect is only temporary
- Mannitol 15% 300-500 ml i.v. during transport (urinary catheter inserted because there will be a significant increase in urine output)
- Glucocorticoid therapy
- For example, dexamethasone initial dose 10 mg p.o. or i.m.
- Will relieve brain oedema (tumour, abscess or obstructive hydrocephalus) - but only after 12 hours.
- Of no benefit in an acute brain injury, cerebral infarction, cerebral bleeding and SAH.
- Upright position of the upper body
- Treatment of hydrocephalus
- Ventriculostomy, shunt or endoscopic puncture of the floor of the third ventricle
- Emergency repair of a blocked shunt in patients carrying a shunt Shunt Complications in Children
- Removal of a flow obstruction (e.g. tumour)
- Removal of intracranial expansion
- Evacuation of a haematoma, excision of a tumour, puncture of an abscess
- Decompressive craniectomy if a swelling cerebral infarction increases intracranial pressure
- Microsurgical resection of a cerebellar infarction or haematoma if the fourth ventricle becomes blocked or brain stem is compressed
- Fluid and electrolyte management
- Treatment and preventive care of epileptic seizures
- Treatment of infection affecting the central nervous system
- Papilloedema endangers eyesight if treatment is delayed.