SAN DIEGO—A headache that does not respond to treatment could result from a problem with a patient’s CSF pressure, said Linda Gray-Leithe, MD, at the 65th Annual Meeting of the American Academy of Neurology. Even if the patient’s pressure falls within the normal range, he or she may have a headache related to a CSF pressure abnormality. Specific techniques can be used to determine whether the headache is CSF pressure related. Low CSF pressure may indicate a leak that can be treated with targeted blood or fibrin glue patching. If the CSF pressure is high, however, CSF can be removed to relieve the headache, and the patient can begin to take a CSF lowering medication.
Techniques for Evaluating a Patient’s CSF Pressure
During an evaluation, the patient lies on the examination table in the lateral decubitus position with legs extended. A lumbar puncture is performed with a 24-gauge, noncutting, atraumatic needle to measure the patient’s CSF pressure. If a patient has refractory headache and CSF pressures in the normal range, artificial CSF can be added. “If it makes [the patient] feel better, the implication would be that the pressure is too low for this patient. Then it might be appropriate to do a myelogram, look for a leak, and perform blood or fibrin glue patching,” said Dr. Gray-Leithe, Associate Professor of Radiology at Duke University School of Medicine in Durham, North Carolina. If the headache worsens with the addition of artificial CSF, CSF can be removed. At that point, if the patient’s headache is relieved, a trial of CSF pressure lowering medications can be initiated.
If a myelogram is indicated, it can be performed on the CT scanner table. Contrast is introduced through the same needle used for the lumbar puncture. The contrast is distributed by lifting the patient’s hips and rotating the patient around on the table. In this way, “we get an immediate myelogram and can immediately check the images” and plan the treatment approach, said Dr. Gray-Leithe.
Causes and Consequences of Intracranial Hypotension
Intracranial hypotension and subsequent headache can result from sports-related trauma, motor vehicle accidents, bicycle accidents, or trivial trauma. Falling, moving furniture, working out at a gym, heavy lifting, and severe coughing and sneezing also can cause intracranial hypotension.
The condition can cause chronic daily headaches that may worsen later in the day with upright posture or with coughing or bending over. Blurred, dim, or double vision; ringing or fullness in the ears and decreased hearing; facial pain or weakness; swallowing or speech difficulties; and occipital or neck pain are other symptoms of intracranial hypotension. Autonomic dysfunction, diabetes insipidus, and other neuroendocrine abnormalities may accompany the problem.
Dural enhancement, which may involve the tentorium, is one of “the classic imaging findings of intracranial hypotension,” said Dr. Gray-Leithe. Other distinctive findings include swelling of the pituitary fossa, loss or effacement of the prepontine cistern, rounding of the transverse sinus, subdural effusions, and mammillary bodies that rest on the pons. A patient with intracranial hypotension may have an acquired Chiari I malformation, “which is probably related to a CSF pressure leak,” said Dr. Gray-Leithe. The Chiari malformation also may result in a syrinx in the spinal cord.
Atypical Imaging and Clinical Presentations
Patients with CSF pressure problems do not always have typical imaging and clinical findings and may not have headache. One patient presented to Dr. Gray-Leithe with left-hand tremor, weakness, left leg stumbling, and no headaches. Several years later, the patient developed brain herniation, a swollen pituitary gland, a Chiari I malformation, and dural enhancement.
“His opening pressure was 3 mm Hg. He had multiple diverticula off of almost every single nerve root, with no extravasation of contrast,” said Dr. Gray-Leithe. “In patients like this, we have to start treating the diverticula that we think are most likely to be causing the problem.” After several years of treatment, the patient’s pressure increased to 10 cm H20 and subsequently 17.5 cm H20, his brain herniation subsided, and his arm and leg symptoms improved.
“No single symptom or imaging finding is necessarily reliable for identifying low-pressure headaches,” said Dr. Gray-Leithe. “We need more encompassing diagnostic criteria to make the diagnosis of low CSF pressure. We need better imaging strategies to make the diagnosis if imaging is unclear. We also have to figure out what the best treatment is if the source [of the pressure problem] is not known,” she concluded.
—Erik Greb
Senior Associate Editor
Suggested Reading
Schievink WI, Dodick DW, Mokri B, et al. Diagnostic criteria for headache due to spontaneous intracranial hypotension: a perspective. Headache. 2011;51(9):1442-1444.
Sinclair AJ, Kuruvath S, Sen D, et al. Is cerebrospinal fluid shunting in idiopathic intracranial hypertension worthwhile? A 10-year review. Cephalalgia. 2011;31(16):1627-1633.