The MRI has been used to clarify the pathophysiology of pseudotumor cerebri in seven children, aged between six months and 13 years, reported from British Columbia’s Children’s Hospital, Vancouver. All had papilledema, three abducens palsies, and six had headache and/or visual impairments. Topical steroid therapy for eczema and mastoiditis were predisposing factors in two. CT head scans were normal. MRIs showed normal signal intensity in the white matter, suggesting that periventricular brain water content was not markedly increased. The authors hypothesize an equilibrium between raised CSF outflow resistance and increased cerebral blood volume and/or mild interstitial cerebral edema. 
COMMENT. Increased cerebral blood volume, confirmed by PET, an abnormal CSF dynamics, demonstrated by decreased arachnoid absorption, and cerebral edema, defined by brain biopsy, are some of the hypotheses proposed in pseudotumor cases. Periventricular edema, the expected consequence of a resistance to CSF outflow, was not demonstrated in this MRI study. Predisposing factors in children have included otitis media, venous sinus thrombosis, mastoiditis, mild head trauma, viral infections, vitamin A intoxication, teracyclines, obesity, menstrual irregularities, nutritional disturbances, and steroid therapy or withdrawal.