What Is Cerebral Edema?

Cerebral edema is a pathological accumulation of fluid in the brain tissue.This swelling causes an increase in intracranial pressure, which can severely limit brain function and cause herniation.Ultimately, the brain will no longer receive enough oxygen, which in the worst case can lead to permanent tissue damage.

Does Brain Swelling Only Occur in Traumatic Cerebral Edema?

The most frequent cause of generalized brain swelling is not a mild concussion, but a severe craniocerebral trauma.Such cerebral trauma initially causes an increase in fluid outside the brain cells. This is caused by an increase in capillary permeability and a disruption of the blood-brain barrier.

A secondary effect of a lack of oxygen can be cytotoxic edema, which is characterized by the build-up of excess intracellular fluid.Another potential cause of cerebral edema are rapid electrolyte shifts such as hyponatremia.This leads to an increase in volume, which, due to the limited space inside the skull, exerts pressure on the brain, thus causing damage to the brain tissue.

However, increased intracranial pressure can also be caused by other pathological mechanisms, which may be of vasogenic or inflammatory origin, such as encephalitis or meningitis.Severe hemorrhage or a tumor also cause an increase in volume and localized swelling.Furthermore, the accumulation of cerebrospinal fluid resulting from an impaired drainage of cerebrospinal fluid or an impeded reabsorption (e.g. after subarachnoid hemorrhage) can also lead to a volume increase.

What Are the Symptoms of Cerebral Edema?

When intracranial pressure builds up slowly, the symptoms can also appear gradually.

A slow-growing tumor can exert pressure on the surrounding brain tissue, resulting in functional loss in the corresponding regions.This can in turn lead to impaired motor skills, speech, vision, or even seizures.

If the pressure increase is caused by an accumulation of cerebrospinal fluid, a CT scan can be used to diagnose hydrocephalus.Concomitant symptoms often include headaches, regardless of where the fluid is located, as well as nausea and vomiting.

If the build-up of cerebrospinal fluid is a chronic, an ophthalmologist performing an external examination of the eye may discern a papilloedema as a sign of the increased intracranial pressure.In such cases, either the cause of the accumulation will be treated and/or the cerebrospinal fluid will be drained using a ventriculoperitoneal shunt.This thin tube equipped with a control valve is placed under the skin and transports the cerebrospinal fluid from the cerebral ventricles into the abdominal cavity, thus causing pressure relief.

A rapid increase in intracranial pressure, as is the case with acute hydrocephalus, e.g. in the context of a subarachnoid hemorrhage, must always be treated as an emergency. It usually leads to impairments that can range from cognitive clouding to coma.

A fulminant inflammation or a space-occupying hemorrhage can also develop rapidly and require emergency treatment to improve the chances of survival and avoid complications.

What Is the Prognosis for Cerebral Edema?

The prognosis for cerebral edema depends greatly on its severity and on effective treatment.This requires a specialized infrastructure with suitable equipment and qualified staff.Treatment usually takes place in a hospital setting.Comatose patients with a life-threatening condition are treated in an intensive care unit.A CT scan is indispensable in emergency situations. An MRI scan is usually carried out at a later stage to assess the exact damage to the brain tissue.In an intensive care unit, physicians and nurses cannot perform an external assessment of the intracranial pressure in comatose patients. Therefore, a probe is inserted into the brain tissue to allow continuous monitoring.

In the event of increased intracranial pressure, countermeasures include a slight upright position of the upper body, mild hyperventilation, drug administration and the drainage of cerebral fluid via an external ventricular drain applied beforehand.This treatment requires close cooperation between nursing and medical staff.Even though this treatment is very laborious and intense, minimal handling may be indicated from time to time. This involves refraining from any manipulation of the patient in order to avoid an increase in intracranial pressure.

If these measures do not result in a lasting reduction of intracranial pressure to under 25 mmH2O, surgery is indicated.In this case, decompressive craniotomy is performed, where the skullcap is removed on the affected side and the meninges are expanded. The first step of this surgical procedure involves drilling a hole, e.g. using the evoDrill from

evonos.Then the skull bone is opened using a craniotome to give the swollen brain space to expand.If the intracranial pressure cannot be reduced and the swelling does not respond to treatment, herniation cannot be prevented. Many scientific papers and articles deal with the treatment of increased intracranial pressure and cerebral edema, and can be found in international journals of neurosurgery and neurology.

Parenthesis: Does a Swelling of the Meninges Lead to Cerebral Edema?

A swelling of the meninges is a very rare phenomenon which can occur in the context of pachymeningitis.It is characterized by a swelling of the dura mater, the outermost protective layer of the brain, and may be associated with an underlying inflammatory condition such as rheumatism, tuberculosis, syphilis, or a generalized inflammation of the paranasal sinuses and the mastoid process.The literature also describes idiopathic cases without signs of infection.

The swelling typically leads to a mechanical compression of nerves and vascular structures.This pressure causes headaches, but patients can also experience ataxia and cranial nerve deficits, resulting in visual or hearing impairments. A swelling of the meninges in the form of pachymeningitis can also occur in the spinal region and lead to symptoms of paraplegia.

Meningitis caused by bacteria and viruses often occurs during childhood – in 70% of cases in children under 5 years of age.Vaccines recommended by Germany’s Standing Committee on Vaccination (STIKO) are available for some of these infections.

A fast diagnosis and initiation of antibiotic or antiviral treatment is required while the vital signs are monitored in a hospital setting.Cognitive clouding can occur following initial symptoms like fever, a stiff neck and headaches.Cerebral swelling caused by fulminant bacterial meningitis can be treated with causal antibiotics and cortisone.Surgical treatment is indicated in exceptional cases only.

Inflammatory conditions involving the meninges are often associated with severe headaches.However, irritation caused by blood, as occurs in cases of subarachnoid hemorrhage, can also lead to what is known as a “destructive headache”.