Intracranial hypotension is a neurological syndrome associated with a decrease in normal pressure within the brain cavity. Find out more about it!
In general, it is the result of a reduction in the volume of cerebrospinal fluid (CSF). Are you interested in learning about the symptoms, causes, and treatment of intracranial hypotension? Next, we tell you everything about it.
Cerebrospinal fluid is a translucent, odorless, and aseptic substance, similar to distilled water. This occurs mainly in the choroid plexuses and the lateral ventricles of the brain. Studies affirm that the total volume of CSF in the adult ranges from 90 to 159 milliliters. Its functions include brain protection and elimination of waste products.
The reduction in CSF volume causes a negative pressure within the cranial vault that results in intracranial hypotension. Headache is one of the most common symptoms, as well as the appearance of neurological disorders. Timely treatment improves the long-term prognosis.
Common symptoms of intracranial hypotension
Intracranial hypotension classically manifests as a severe headache that spreads throughout the skull. It usually worsens when standing and improves or subsides when lying down, which is why it is called orthostatic headache. Other symptoms associated with this condition are the following:
- Vomiting and nausea.
- Neck pain and stiffness.
- Double or cloudy vision.
- Hearing changes.
- Sensitivity to light and sound.
- Dizziness and confusion.
- Impaired motor skills and balance.
On the other hand, there are cases of intracranial hypotension associated with fistulas that present with CSF leakage through the nose or rhinorrhea. Similarly, there may be fluid leakage through a surgical wound due to a rupture of the meninges.
Research suggests that the triggering phenomenon of intracranial hypotension is the loss and reduction in CSF concentration at the brain level. This decrease appears as a result of its leakage through the meningeal layers of the brain.
The three layers of membranes collectively called the meninges are the dura mater, the subarachnoid layer, and the pia mater, from the outside in. The dura mater is responsible for surrounding and protecting the brain and spinal cord. Lesions at this level are the most common reason for intracranial hypotension. The causes of this condition include the following:
- Lumbar puncture.
- Injury to the skull or spinal cord.
- Acquired defect or congenital weakness in the dura mater.
- Colon surgery.
- Epidural anesthesia.
- Calcified discs or bone spurs in the spine.
- Referrals for hydrocephalus.
Thorough medical examination and detailed neurological examination are key in the diagnosis of intracranial hypotension. The characteristics of the headache and the symptoms of cerebral focalization are very useful for the suspicion of a possible CSF leak.
Similarly, imaging studies are essential for the definitive diagnosis of this disease. Contrast-enhanced magnetic resonance imaging (MRI) of the brain may show thickened meninges with bright pachymeningeal enhancement. Additionally, this test can highlight descent of the thalamus and cerebellar tonsils.
Sometimes a computerized axial tomography (CT) allows to show encephaloceles and bone defects that are triggering the pathology. Similarly, the detection and monitoring of intracranial pressure is crucial for the determination of abnormally negative brain pressures. Other useful tests in the diagnosis of intracranial hypotension include:
- Dynamic myelography with fluoroscopy.
- Spinal MRI.
- Radioisotope cisternography.
- CT with intrathecal iodinated contrast.
In most cases, intracranial hypotension resolves spontaneously, according to studies. However, there are serious cases in which it does not heal on its own, it is more serious and requires professional intervention. Epidural patches and surgery are the most common treatments.
Epidural blood patch
This procedure consists of injecting a small amount of blood at the epidural level, around the spinal canal, close to the CSF leak site. As the blood clots, it creates a patch or plug that stops the flow of fluid from escaping.
Surgery is a treatment option when there is a failure to use at least two epidural patches. Surgical intervention plans include the following:
- Repair of tears in the dura.
- Clipping of meningeal diverticula.
- Duroplasty to strengthen the dura.
In certain cases, resolution of postural hypotension may be associated with rebound intracranial hypertension. By increasing brain pressure, the treatment of choice is acetalozamide, a diuretic that reduces fluid retention in the body.
Early medical attention and supervision determine a better prognosis
As you can see, intracranial hypotension is a rare condition related to the loss of cerebrospinal fluid and the consequent negative pressure in the brain. The prognosis of this condition improves with timely professional care.
Fortunately, most people get better on their own. However, some patients require more complex interventions, the prognosis of which will depend on the severity of the meningeal lesion and the volume of fluid lost.
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