Spontaneous cerebrospinal fluid leak
Classification and external resources
The spinal meninges
ICD-10	G96.0, G97.0
MedlinePlus	001068

A spontaneous cerebrospinal fluid leak is a medical condition in which the cerebrospinal fluid (CSF) held in and around a human brain and spinal cord leaks out of the surrounding protective sac called the dura mater for no apparent reason.^[1][2] The dura mater, usually just referred to as the dura, is a tough, inflexible tissue which is the outermost of the three layers of the meninges, the system of membranes surrounding the brain and spinal cord. The other two meningeal layers are the pia mater and the arachnoid mater.

Abbreviated SCSFLS (Spontaneous Cerebrospinal Fluid Leak Syndrome), this condition is one of several types of cerebrospinal fluid leaks, and occurs due to one or more holes appearing in the spinal dura. A spontaneous CSF leak, as opposed to other forms of CSF leaks, arises idiopathically, that is without any obvious cause such as a head trauma. The loss of CSF due to the leak leads to a decreased pressure inside the skull (intracranial hypotension). SCSFLS is characterized by a severe and disabling headache, dizziness, metallic taste in the mouth and facial weakness. The site of the cerebrospinal fluid leakage on the spine can be identified by CT scan. Once identified the leak can often be repaired by epidural blood patch, an injection of the patient's own blood at the site of the leak.^[3][4]

SCSFLS afflicts 5 out of every 100,000 people, at an average age of 42, with women being twice as likely to develop the condition. Some people with SCSFLS chronically leak cerebrospinal fluid despite repeated attempts at patching, leading to long-term disability due to pain and nerve damage.

[edit] Signs and symptoms

Symptoms of cerebrospinal fluid leaks include an orthostatic headache^[5] (pain is worse when the patient is vertical and better when horizontal), a metallic taste in the mouth, severe dizziness and vertigo, facial numbness or weakness, diplopia (double vision), nausea and vomiting.^[2] Due to these symptoms, many people suffering from the condition are disabled and unable to work.^[6] Orthostatic headaches can be incapacitating ^[7] and disabling.^[6] Lack of CSF pressure and volume allows the brain to descend through the foramen magnum, or occipital bone, the large opening at the base of the skull. The descend portion of the brain is believed to stretch or impact one or more nerve complexes, thereby causing a variety of sensory symptoms. Nerve complexes that can be affected and the related symptoms include:

• the vestibulocochlear nerve, the eighth cranial nerve, causing hearing problems or vertigo;
• the optic nerve, the second cranial nerve which transmits visual information to the brain, or the Optic chiasm, where the optic nerves partially cross, causing visual blurring;
• the facial nerve, the seventh cranial nerve, causing facial numbness and weakness, and
• the chorda tympani, a branch off the seventh facial nerve, or the glossopharyngeal nerve, the ninth cranial nerve, causing taste distortion.^[8]

As holes form in the dura mater, CSF leaks out into the surrounding space. The CSF is then absorbed into the vascular system. CSF leak can can sometimes be observed coming from the nose or ear.^[9]

[edit] Causes and epidemiology

Spontaneous CSF leak is idiopathic, meaning it arises spontaneously or from an obscure or unknown cause. It has been suggested by various scientists and physicians that this condition may be the result of an underlying connective tissue disorder affecting the spinal dura.^{[10][11][2][12]} Alternatively, some studies have proposed involvement of the spinal venous drainage system as the cause of CSF leak.^[13]

The average age for onset of SCSFLS is 42.3 years, ranging from 22 to 61 years,^[14] generally representing the young and middle age.^[15] In an 11 year study, from 1992 to 2003, of patients with SCSFLS, women were found to be affected more than men at a ratio of 2:1.^[16] A 1994 community-based study indicated that SCSFSL occurred in 1 out of every 50,000 people, while a 2004 emergency room-based study demonstrated 5 per 100,000 people.^[17]

[edit] Diagnosis

Spinal needles used in lumbar puncture and introduction of contrast into the spine

A typical CT scan machine used in the imaging and diagnosis of spinal fluid leak by using non-ionic contrast

Diagnosis of a cerebrospinal fluid leak is done by measuring the CSF pressure and scanning the spinal column for fluid leak. The opening fluid pressure in the spinal canal is obtained by performing a lumbar puncture, also known as a spinal tap. Once the pressure is measured, radioactive contrast material is infused into the spinal fluid. This allows for a computed tomography myelogram with fluoroscopy to locate and image any sites of dura rupture.^[18]

Magnetic resonance imaging studies may show pachymeningeal enhancement and an Arnold-Chiari malformation, but this may not be seen in every case. MRIs can be completely normal, however, and are not the study of choice.^[10] In addition, in 18-46% of cases the CSF pressure has been measured as normal.^[19] An alternate method of locating the site of CSF leak is to use heavily T2-weighted MR myelography. This has been shown to be effective in identifying the sites of CSF leak without the need for CT scan, lumbar puncture and contrast.^[20]

[edit] Treatment

The epidural syringe is filled with autologous blood and injected in the epidural space in order to close holes in the dura mater.

The treatment of choice for this condition is bedrest and surgical epidural blood patches.^[21][7] The volume of autologous blood and number of patch attempts for patients is highly variable.^[7] When repeated blood patches fail, some patients have experienced complete resolution of symptoms with epidural saline infusion.^[22] IV Cosyntropin has also been used to treat CSF leak.^[23]

In extreme cases of intractable CSF leak, a surgical lumbar drain has been utilized. Dura resection is believed to decrease spinal CSF volume while increasing intracranial CSF pressure and volume. This procedure has lead to positive results and relief of symptoms for many patients.^[15]

[edit] Complications

Arnold-Chiari malformation is a complication of spontaneous CSF leak, where brain tissue moves down through the opening at the base of the skull due to low volume and pressure of CSF

Several complications may be present in cases of CSF leak. Patients can develop a Arnold-Chiari malformation, a downward displacement of lower parts of the brain through the skull opening due to lack of CSF volume and pressure. Infection from repeated epidural blood patches may occur. Orthostatic hypotension, when blood pressure drops significantly, can also occur, likely due to an autonomic dysfunction.

There are documented cases of reversible dementia and coma.^[19] Coma due to CSF leak has been successfully treated using blood patches and by placing the patient in the Trendelenburg position—flat on their back with their feet higher than their head.^[24]

[edit] Prognosis

Outcomes for people with SCSFLS remains poorly studied.^[8] Some of those afflicted continue to leak CSF from one or more sites and may suffer from symptoms for many years. Patients with chronic SCSFLS may be disabled and unable to work.^[6]

[edit] History

Spontaneous CSF leaks have been described by notable physicians and reported in medical journals dating back to the 1800s. Among them were Georges Schaltenbrand and a French medical journal.^[25][26]

"George Schalten-brand, a German neurologist, in a German-language article in 1938 and in an English-language article in 1953 emphasized the term “aliquorrhea,” a condition marked by very low, unobtainable, or even negative CSF pressures that were clinically manifested by orthostatic headaches and other features that later came to be recognized as spontaneous intracranial hypotension. A few decades earlier the same syndrome had been described in the French literature as “hypotension of spinal fluid” or “ventricular collapse.”...In the United States, as early as 1940, Henry Woltman of the Mayo Clinic wrote about “headaches associated with decreased intracranial pressure”...The full clinical manifestations of intracranial hypotension or CSF leak were described in several publications reported between the 1960s and early 1990s.^[26]

Additional medical research is ongoing.

SCSFLS was featured on Discovery Health's Mystery Diagnosis on April 4, 2008.^[27][28]

[edit] See also

• Intracranial hypotension
• Subdural effusion
• Cerebrospinal fluid leak

[edit] References