Spontaneous intracranial hypotension is a neurological condition that the fluid pressure inside the skull is lower than normal. It is secondary to a cerebrospinal fluid leak (CSF) at the level of the spine.
Normally, the CSF circulates inside the dura, gradually drains, and is constantly replenished with new fluid. But a leak in the dura can allow too much CSF to escape too quickly, which reduces the amount of CSF in circulation and further decreases the fluid pressure and leads to intracranial hypotension. It may cause a headache when sitting upright, nausea, and vomiting.
Men and women of all ages are possibly affected but it is more common in women. It is a rare condition, estimated to occur in 1 in 50,000 people.
The underlying cause of spontaneous intracranial hypotension is a loss of cerebrospinal fluid volume through a hole or tear in the spinal dura. However, the exact causes of the spontaneous spinal fluid leak are not completely understood.
Statistics show that spontaneous intracranial hypotension occurs twice as frequently in women than in men. People with genetic disorders of connective tissue or Chiari malformation are at increased risk of getting spontaneous intracranial hypotension.
is thought that spontaneous intracranial hypotension can occur after a minor
trauma when there is already a slight weakness in the dura, such as a hard hit
to the spine during athletic activity or during a car accident.
In addition, many cases are associated with calcified discs and bone spurs of the spine that can tear the dura on the front side of the spinal cord. In rare instances, the condition can be caused by dehydration or a diabetic coma.
The most common symptom of spontaneous intracranial hypotension is a positional headache that gets worse with upright posture and improves with horizontal positioning. The headache is a consequence of the low CSF pressure producing a displacement of pain-sensitive structures and varies a great deal in severity and characteristics. Besides, other possible symptoms associated with spontaneous intracranial hypotension include:
- Double vision
- Sensitivity to light
- Neck or spinal pain
- Hearing problems
- Taste changes
To diagnose spontaneous intracranial hypotension, several diagnostic procedures are recommended to take.
- Magnetic resonance (MR) imaging
Due to the lower pressure inside the skull, the brain may “sag” toward, or even partially sag out of, the skull base. These certain signs shown by an MR may lead a physician to suspect intracranial hypotension.
- Computed tomography plus myelogram (myelo-CT)
Like a plain CT scan, it uses a computer and a series of X-rays to construct images of structures inside the body. A myelo-CT uses an opaque dye that is injected into the CSF. Since the dye is visible to the CT scan, it can often reveal where the CSF and dye are escaping from the dura.
Spontaneous intracranial hypotension can be treated by both non-operative and operative measures. For patients with mild symptoms, the condition can be successfully managed with non-operative methods, such as:
- Bed rest
- Increased fluid intake
- Increased salt intake
- Intravenous or oral theophylline
- Steroid therapy
- Injection of treated blood or fibrin sealant at the site of the leak
In other cases, when the condition does not respond to these measures or patients have significant or persistent symptoms, a surgical repair is a good option to manually address the leak site. The neurosurgeon will perform a laminectomy to expose the problematic area. Then the surgeon will patch the dura, ensuring a watertight seal.
Before taking any treatment options, make sure you consult with a doctor first for your best treating plan.
Keywords: spontaneous intracranial hypotension.