ct, mri, and assays are the most common types of csf leak instrumental tests. many csf leaks do not show up on imaging and chemical assays, thus such diagnostic tools are not definitive to rule out csf leaks. a clinician may often depend upon patient history and exam to diagnose, for example: discharge of excessive amount of clear fluid from the nose upon bending over, the increase in headache following a valsalva maneuver or the reduction of headache when the patient takes a prone position are positive indicators. a clinical exam is often used as a means to diagnose csf leaks. improved patient response to conservative treatment may further define a positive diagnosis. the lack of clinician awareness of the signs -symptoms and ailments- of a csf leak is the greatest challenge to proper diagnosis and treatment, in particular: the loss of the orthostatic characteristic of headache and that every chronic csf leaker will have a unique symptom set that as a whole contributes to the underlying condition, and diagnosis of, a csf leak. the primary place of first complaint to a physician is a hospital emergency room. up to 94% of those with scsfls are initially misdiagnosed. incorrect diagnoses include migraines, meningitis, chiari malformation, and psychiatric disorders. the average time from onset of symptoms until definitive diagnosis is 13 months. a 2007 study found a 0% success rate for proper diagnosis in the emergency department. ct main article: computed tomography of the head diagnosis of a cerebrospinal fluid leak is performed through a combination of measurement of the csf pressure and a computed tomography myelogram (ctm) scan of the spinal column for fluid leaks. 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, a radiocontrast agent is injected into the spinal fluid. the contrast then diffuses out through the dura sac before leaking through dural holes. this allows for a ctm with fluoroscopy to locate and image any sites of dura rupture via contrast seen outside the dura sac in the imagery. mri main article: magnetic resonance imaging of the brain there is disagreement over whether mri should be the diagnostic tool of choice. magnetic resonance imaging is less effective than ct at directly imaging sites of csf leak. mri studies may show pachymeningeal enhancement (when the dura mater looks thick and inflamed), sagging of the brain, pituitary enlargement, subdural hygromas, engorgement of cerebral venous sinuses, and other abnormalities. for 20% of patients, mris present as completely normal. mris performed with the patient seated upright (vs. laying supine) are not better for diagnosing csf leaks, but are more than twice as effective at diagnosing cerebellar tonsillar ectopia, also known as chiari malformation. cerebellar tonsillar ectopia shares many of the same symptoms as csf leak, but originates either congenitally or from trauma, including whiplash strain to the dura. an alternate method of locating the site of a csf leak is to use heavily t2-weighted mr myelography. this has been effective in identifying the sites of a csf leak without the need for a ct scan, lumbar puncture, and contrast and at locating fluid collections such as csf pooling. another highly successful method of locating a csf leak is intrathecal contrast and mr myelography. contrast-enhanced brain mri with sagittal reformats can assess for the following: subdural fluid collections enhancement of the meninges engorgement of venous structures pituitary swelling sagging of the brain for suspected spinal csf leaks, spine imaging can be used to guide treatment. assay fluid dripping from the nose (csf rhinorrhoea) or ears (csf otorrhea) should be collected and tested for the protein beta-2 transferrin which would be highly accurate in identifying cs fluid and diagnosing a cranial csf leak. csf analysis spinal needles used in lumbar puncture and introduction of contrast into the spine patients with csf leaks have been noted to have very low or even negative opening pressures during lumbar puncture. however, patients with confirmed csf leaks may also demonstrate completely normal opening pressures. in 18–46% of cases, the csf pressure is measured within the normal range. analysis of spinal fluid may demonstrate lymphocytic pleocytosis and elevated protein content or xanthochromia. this is hypothesized to be due to increased permeability of dilated meningeal blood vessels and a decrease of csf flow in the lumbar subarachnoid space. myelography a myelogram can be used to more precisely identify the location of a csf leak by injecting a dye to further enhance the imaging. however, csf leaks are frequently not visible on imaging. for patients with recalcitrant spontaneous intracranial hypotension and no leak found on conventional spinal imaging, digital subtraction myelography, ct myelography and dynamic myelography (a modified conventional myelography technique) should be considered to rule out a csf-venous fistula. in addition, presence of a hyperdense paraspinal vein should be investigated in imaging as it is highly suggestive of a csf venous fistula. treatment symptomatic treatment usually involves analgesics for both cranial and spinal csf leaks. initial measures can include rest, caffeine intake (via coffee or intravenous infusion), and hydration. corticosteroids may provide transient relief for some patients. an abdominal binder, which increases intracranial pressure by compressing the abdomen, can temporarily relieve symptoms for some people. sometimes a csf leak will heal on its own. otherwise, symptoms may last months or even years. epidural blood patch main article: epidural blood patch 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 the surgical application of epidural blood patches, which has a higher success rate than conservative treatments of bed rest and hydration. through the injection of a person's own blood into the area of the hole in the dura, an epidural blood patch uses blood's clotting factors to clot the sites of holes. the volume of autologous blood and number of patch attempts for patients is highly variable. one-quarter to one-third of scsfls patients do not have relief of symptoms from epidural blood patching. finding the location of a cerebrospinal fluid leak is not required prior to using an epidural blood patch as initial lumbar epidural blood patches often provide relief of symptoms and resolve the leak without further intervention. fibrin glue sealant if blood patches alone do not succeed in closing the dural tears, placement of percutaneous fibrin glue can be used in place of blood patching, raising the effectiveness of forming a clot and arresting csf leakage. surgical drain technique in extreme cases of intractable csf leak, a surgical lumbar drain has been used. this procedure is believed to decrease spinal csf volume while increasing intracranial csf pressure and volume. this procedure restores normal intracranial csf volume and pressure while promoting the healing of dural tears by lowering the pressure and volume in the dura. this procedure has led to positive results leading to relief of symptoms for up to one year. neurosurgical repair surgery to treat a csf-venous fistula in csf leak patients is highly effective. neurosurgery is available to directly repair leaking meningeal diverticula. the areas of dura leak can be tied together in a process called ligation and then a metal clip can be placed in order to hold the ligation closed. alternatively, a small compress called a pledget can be placed over the dura leak and then sealed with gel foam and fibrin glue. primary suturing is rarely able to repair a csf leak, and in some patients exploration of the dura may be required to properly locate all sites of csf leak. adjunct measures the use of antibiotics to prevent meningitis in those with a csf leak due to a skull fracture is of unclear benefit. prognosis long-term outcomes for people with scsfls remain poorly studied. symptoms may resolve in as little as two weeks, or persist for months. less commonly, patients may have unremitting symptoms for many years. people with chronic scsfls may be disabled and unable to work. recurrent csf leak at an alternate site after recent repair is common. epidemiology a 1994 community-based study indicated that two out of every 100,000 people with scsfls, while a 2004 emergency room-based study indicated five per 100,000. scsfls generally affects the young and middle aged; the average age for onset is 42.3 years, but onset can range from ages 22 to 61. in an 11-year study, women were found to be twice as likely to be affected as men. studies have shown that scsfls runs in families. it is suspected that genetic similarity in families includes weakness in the dura mater which leads to scsfls. large scale population-based studies have not yet been conducted. while a majority of scsfls cases continue to be undiagnosed or misdiagnosed, an actual increase in occurrence is unlikely. history spontaneous csf leaks have been described by notable physicians and reported in medical journals dating back to the early 1900s. german neurologist georg schaltenbrand reported in 1938 and 1953 what he termed "aliquorrhea", a condition marked by very low, unobtainable, or even negative csf pressures. the symptoms included orthostatic headaches and other features that are now recognized as spontaneous intracranial hypotension. a few decades earlier, the same syndrome had been described in french literature as "hypotension of spinal fluid" and "ventricular collapse". in 1940, henry woltman of the mayo clinic wrote about "headaches associated with decreased intracranial pressure". the full clinical manifestations of intracranial hypotension and csf leaks were described in several publications reported between the 1960s and early 1990s. modern reports of spontaneous csf leak have been reported to medical journals since the late 1980s. research tetracosactide is a corticosteroid that causes the brain to produce additional spinal fluid to replace the volume of the lost csf and alleviate symptoms, and has been given intravenously to treat csf leaks. in three small studies of 1-2 patients with recurrent csf leaks where repeated blood patches failed to form clots and relieve symptoms, the patients received temporary but complete resolution of symptoms with an epidural saline infusion. the saline infusion temporarily restores the volume necessary for a patient to avoid sih until the leak can be repaired properly. intrathecal saline infusion is used in urgent cases such as intractable pain or decreased consciousness. the gene tgfbr2 has been implicated in several connective tissue disorders including marfan syndrome, arterial tortuosity, and thoracic aortic aneurysm. a study of patients with scsfls demonstrated no mutations in this gene. minor features of marfan syndrome have been found in 20% of csf leak patients. abnormal findings of fibrillin-1 have been documented in these csf leak patients, but only one patient demonstrated a fibrillin-1 defect consistent with marfan syndrome.