In summary, the clinician is left with only incomplete guidance as to the course of treatment of pseudotumor cerebri. In cases with no visual impairment and with moderate headaches, we have favored aggressive weight reduction, acetazolamide, and repeated lumbar punctures. For more severe cases, we perform careful vascular imaging and correction of venous sinus occlusions as noted above. Failing this, we have advised lumbar drainage to the peritoneum. If vision is imminently threatened, optic sheath fenestration is probably the best course.
We have been impressed with the persistence of a complex migraineor tension-like headache in some patients whose CSF pressure has been adequately reduced by repeated lumbar punctures, shunting, or optic nerve fenestration. After it has been confirmed that the pressure is not elevated, these headaches may be treated in a manner similar to the usual types of chronic headaches, as outlined in Chap. 9, especially with topiramate, which has the potential benefit of facilitating weight reduction. A recent review of the subject of surgical treatment, extensively referenced, has been given by Brazis. He was unable to conclude that any one approach was superior.
These disorders, in which air enters the ventricular system or the subarachnoid spaces, are discussed in relation to cranial injury, and the postoperative state (see Chap. 34). In the case of pneumocranium, the collection of air may act as a mass that compresses adjacent brain tissue, and requires relief by aspiration.
INTRACRANIAL HYPOTENSION (SEE ALSO “LOW-PRESSURE AND SPINAL PUNCTURE HEADACHE” IN CHAP. 9)
After lumbar puncture, this syndrome is usually attributable to a lowering of ICP by leakage of CSF through the needle track into the paravertebral muscles. The headache may last for days or, rarely, weeks. Most characteristic is the relation of the cranial pain to upright posture, and its relief within moments after assuming the recumbent position. Actually, the syndrome includes more than headache. There may be pain at the base of the skull posteriorly and in the back of the neck and upper thoracic spine, mild stiffness of the neck and shoulders, and nausea and vomiting. At times, the signs of meningeal irritation are so prominent as to raise the question of postlumbar puncture meningitis, although lack of fever usually excludes this possibility. In addition to a low or unmeasurable CSF pressure if another spinal tap is performed (the CSF pressure is found to be in the range of 0 to 60 mm H2O), there are occasionally a few to a dozen white cells in the CSF, which may further raise concern of meningitis. In the infant or young child, stiffness of the neck may be accompanied by irritability, unwillingness to move, and refusal of food. If the headache is protracted, recumbency still reduces it, but a feeling of dull pressure may remain, which the patient continues to report as pain. Many patients also report that shaking the head produces a cephalic pain. Occasionally, there will be unilateral or bilateral sixth nerve palsy or a self-audible bruit from turbulence in the intracranial venous system. Hearing loss is a far less common complication (see Chap. 2). A rare syndrome that has been attributed to sagging of the frontal lobes in low CSF pressure situations (“brain-sagging syndrome”) has been described by Wicklund and coworkers. Patients are apathetic and disinhibited and have prominent daytime somnolence, which the authors liken to frontotemporal dementia.
It has been recognized that low CSF pressure is associated on the MRI with variable dural enhancement by gadolinium (Fig. 29-6) and, when the syndrome is protracted and severe, there may be small subdural effusions (see in the following text). In older patients taking warfarin, a subdural hematoma may be found.