Loss of the fluid that cushions and protects the brain may lead to intracranial hypotension, intense headaches
The most common cause of intracranial hypotension, or low cerebrospinal fluid (CSF) pressure in the brain, is CSF Leak. CSF cushions and protects the brain and spinal cord. It is held in place by a sac-like covering called the meninges. The thickest outer layer of the meninges is the dura. Normally, the brain floats in this fluid.
A CSF leak is when a hole or tear in the dura allows this fluid to leak out. When the volume of CSF becomes low, the brain will sag inside the skull, causing headaches that worsen when the patient is in an upright position (sitting or standing up). CSF leaks can happen after medical procedures, such as lumbar puncture (spinal tap), epidural injections or spine surgery. When it happens in these situations, however, it usually is easily found.
Sometimes, though, this type of headache occurs spontaneously, making diagnosis more difficult. Fortunately, the past decade has led to much better awareness of spontaneous spinal CSF leaks, resulting in faster diagnosis and treatment. In most cases, a weakened dura is suspected or observed. In two-thirds of cases, patients report no history of a triggering event, such as lifting, straining, stretching, sporting activities, roller coaster rides and falls.
Genetic disorders of the connective tissue, such as Marfan syndrome, Ehlers-Danlos syndrome, and polycystic kidney disease are more common in these patients. These disorders make it more likely that a patient's dura will be weaker or thinner than normal.
CSF Leak Symptoms
The main symptom of intracranial hypotension, and of a CSF leak that may be the cause, is a headache that gets worse when upright and better when lying down. This is known as a positional headache. Headaches usually start within 15 minutes of sitting or standing up, and get better after 15-30 minutes of lying down. However, sometimes the headaches take hours to worsen or improve with change of position. Over time, the positional trait of the headache may lessen or disappear.
The headache usually is in the back of the head or base of the skull, but can also occur in the front, sides or all over the head. It is rarely on just one side of the head, and often is described as a “pulling sensation” from the head to the neck. The severity of the headache can range from mild to very severe and disabling.
Other common symptoms include neck pain, neck stiffness, nausea, vomiting, sensitivity to light and/or sound, sense of imbalance, ringing in the ears and changes in hearing. Patients may also experience visual changes, dizziness or vertigo, facial numbness or pain, or changes in taste. Pain between the shoulder blades and into upper arms is commonly reported. Less frequently, there may be pain at the site of the spinal CSF leak.
CSF Leak Diagnosis
While a computed tomography (CT) scan of the head often is performed to rule out bleeding, a magnetic resonance imaging (MRI) scan of the brain, with and without contrast, is important to look for common specific findings, complications and to rule out other causes of the patient's symptoms.
In 80 percent of cases, the brain MRI shows a series of findings known as SEEPS:
- Subdural fluid collections
- Enhancement of the meninges
- Engorgement of venous structures
- Pituitary swelling
- Sagging of the brain
A lumbar puncture (spinal tap) may be performed to measure the CSF pressure within the brain and to analyze the fluid. If the pressure is low, it supports the diagnosis of CSF leak, although a normal pressure reading does not totally rule out a spinal CSF leak.
Spinal imaging using CT, MRI and digital subtraction is used to identify the location a suspected spinal CSF leak. Cedars-Sinai uses a range of specialized diagnostic imaging techniques to provide the best information possible for treatment planning.
CSF Leak Treatment
If the cause of the patient's headache intracranial hypertension is a CSF leak, treatment is available. For many patients, symptoms go away without any specific treatment. Initial treatment may include bed rest, good hydration and increased caffeine intake to reduce symptoms. An abdominal binder can reduce symptom severity by increasing fluid pressure in the head.
If these conservative treatments do not work, the most common treatment is epidural blood patching. In this procedure, some of the patient's own blood is injected into the spinal canal outside the dura. Epidural blood patching may be successful even when the leak location is unknown and can be repeated several times. Another type of patching involves injecting a fibrin glue at the specific location of the leak or tear.
In some cases, surgery may be recommended when simpler treatments do not work. Surgery focuses on the specific location and anatomy of the leak, and may use sutures, clips, synthetic sealants or artificial materials to repair it. These surgeries often are very successful at correcting the problem.
CSF Leak Prognosis
Some patients with spontaneous CSF leaks and intracranial hypotension have symptoms that resolve without ever needing medical attention. For patients who are correctly diagnosed after they seek medical attention, the majority do very well with appropriate testing and treatment.
CSF Leak Scientific References
For more information, see our experts' scientific publications on the topic of spontaneous intracranial hypotension secondary to spinal CSF leaks.