Aside from papilledema, there is remarkably little to be found on neurologic examination, perhaps slight unilateral or bilateral abducens palsy, fine nystagmus on far lateral gaze, or minor sensory change on the face or trunk. Visual field testing usually shows minor peripheral constriction with enlargement of the blind spots. As the process continues, more severe constriction of the fields, with greater nasal or inferior nasal loss, is found, often inevident to the patient. These issues are elaborated below. Enlargement of the blind spot is the result of displacement of the retina from the edges of the swollen disc. Central acuity is spared initially and the patient, in advanced cases, is left with an island of preserved central vision. These patients are at particular risk of visual loss. A study of 66 men with pseudotumor (9 percent of a larger cohort) by Bruce and colleagues suggested that there is a higher risk of vision loss than in women. Profound disc edema, significant early visual loss and perhaps being of African-American descent are other risks for visual loss.
Exceptionally, particularly in children, an otherwise typical Bell’s palsy may occur (Chutorian et al). Mentation and alertness are preserved, and the patient seems surprisingly well aside from the headaches, which infrequently become severe enough to limit daily activity.
Examinations by CT and MRI show the ventricles to be normal in size or small. The sella may be enlarged and filled with CSF (see “empty sella” in Chap. 30), the posterior globes may be compressed and the perioptic subarachnoid spaces, expanded. Variable attenuation of the transverse sinuses has also been pointed out (see Friedman and colleagues). These are helpful but not indispensible features of the syndrome. There is no MRI evidence of change in the density of the brain, but edema may be seen in the optic nerves.
In recent years, attention has been called to the ostensibly high rate of overdiagnosis of pseudotumor, for example, by Fisayo and colleagues in a large neuro-ophthalmology clinic. Almost 40 percent of cases referred to them probably had other diagnoses and the main sources of error included poor or misinterpreted ophthalmoscopic examination of the optic nerve. Benign headaches in obese women were responsible for many of their reported cases when strict criteria for the diagnosis of pseudotumor were applied.
As remarked above, most affected patients are overweight young women of short stature, often with menstrual irregularities, but the condition also occurs in children or adolescents, in whom there is no clear sex predominance, and in men (Digre and Corbett). We have had experience with several familial instances of pseudotumor, for example, affecting mother and daughter. In obese women without the pseudotumor syndrome, CSF pressure usually does not differ from that of normal individuals (Corbett and Mehta).
Several endocrine and menstrual abnormalities (particularly amenorrhea), as well as the use of oral contraceptives, have been postulated as causative factors, but none has been substantiated. Cases have been reported during pregnancy, both those who have symptoms for the first time during pregnancy and a larger group with ongoing pseudotumor who become pregnant. Despite the theoretical appeal of relating the endocrine and other changes of pregnancy to the increased ICP, no suitable connection has been found, and there is no evidence that premature delivery or termination of the pregnancy ameliorates the pseudotumor. Nevertheless, our obstetric colleagues have often recommended delivery when safe for the fetus if the mother’s vision is threatened. Most of the standard medical treatments detailed below have been used with some benefit during pregnancy, as in the series reported by Huna-Baron and Kupersmith.