What Is Intracranial Hypotension? Symptoms, Causes and Treatment
Intracranial hypotension is a neurological syndrome associated with a decrease in the normal pressure inside the encephalic cavity. In general, it’s the result of a reduction in cerebrospinal fluid (CSF). Are you interested in the symptoms, causes, and treatment of intracranial hypotension? Read on, and we’ll tell you all about it.
Cerebrospinal fluid is a translucent, odorless, aseptic substance, similar to distilled water. It’s produced mainly in the choroid plexus and lateral ventricles of the brain. Studies state that the total volume of CSF in adults ranges from 90 to 159 milliliters. Its functions include encephalic protection and the elimination of waste products.
The reduction in CSF volume causes negative pressure within the cranial vault resulting in intracranial hypotension. Headache is one of the most common symptoms, as well as the appearance of neurological disturbances. Prompt treatment improves the long-term prognosis.
Intracranial hypotension classically manifests as a severe headache that spreads throughout the skull. It’s usually worse when standing and improves or subsides when lying down, hence it’s called orthostatic headache. Other symptoms associated with this condition are as follows:
- Vomiting and nausea
- Neck pain and stiffness
- Double or blurred vision
- Hearing alterations
- Sensitivity to light and sound
- Dizziness and confusion
- Alteration of motor skills and balance
On the other hand, there are cases of intracranial hypotension associated with fistulas that occur with CSF outflow through the nose or rhinorrhea. Similarly, there may be fluid leakage through a surgical wound due to a rupture of the meninges.
Causes of intracranial hypotension
Research suggests that the triggering phenomenon of intracranial hypotension is the loss and reduction in the concentration of CSF at the encephalic level. This decrease appears as a result of CSF leakage through the meningeal layers of the brain.
The three layers of membranes collectively called meninges are the dura mater, the subarachnoid layer and the pia mater, from the outside in. The dura is responsible for surrounding and protecting the brain and spinal cord. Injuries at this level are the most frequent cause of intracranial hypotension. Causes of this condition include the following:
- Lumbar puncture
- Trauma or injury to the skull or spinal cord
- Acquired defect or congenital weakness in the dura
- Spinal surgery
- Epidural anesthesia
- Calcified discs or bone spurs in the spine
- Hydrocephalus shunts
Read more here: 4 Solutions for a Sinus Headache
How is intracranial hypotension diagnosed?
Thorough medical examination and detailed neurological examination are key in the diagnosis of intracranial hypotension. The characteristics of headache and cerebral focal symptoms are helpful in the suspicion of possible CSF leakage.
Similarly, imaging studies are essential for the definitive diagnosis of this disease. Magnetic resonance imaging (MRI) of the brain with contrast may show thickened meninges with bright pachymeningeal enhancement. In addition, this test can highlight the descent of the thalamus and cerebellar tonsils.
Occasionally, a computed tomography (CT) scan can reveal 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 encephalic pressures. Other tests useful in the diagnosis of intracranial hypotension include:
- Dynamic myelography with fluoroscopy
- Spinal magnetic resonance imaging
- Radioisotope cisternography
- CT with intrathecal iodinated contrast
Treatment of intracranial hypotension
In most cases, intracranial hypotension resolves spontaneously, according to studies. However, there are severe cases in which it doesn’t cure itself; this is more serious, and requires professional intervention. Epidural patches and surgery are the most common treatments.
Epidural blood patch
This procedure involves the injection of a small amount of blood at the epidural level, around the spinal canal, close to the site of CSF leakage. As the blood clots, a patch, or plug is created that stops the flow of fluid leakage.
Find out more: What’s an Intracerebral Hemorrhage and Why Might it Occur?
Surgery is a treatment option when the above-mentioned epidural patches fail to work at least twice. Surgical intervention plans include the following:
- Repair of tears in the dura mater
- Clipping of meningeal diverticula
- Duroplasty to strengthen the dura
In certain cases, the resolution of postural hypotension may be associated with rebound intracranial hypertension. As encephalic pressure increases, the treatment of choice is aacetazolamide 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 cerebrospinal fluid leakage and consequent negative pressure in the brain. The prognosis for this condition improves with timely professional care.
Fortunately, most people improve spontaneously. However, some patients require more complex interventions, with the prognosis depending on the severity of the meningeal injury and the volume of fluid lost.
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