COMPLICATIONS OF SINUSITIS 83 any localizing phenomena from abscess formation and diagnosis is conse- quently difficult to make. There may be evidence of progressive cerebral compression in that there is a complaint of headache sometimes accompanied by vomiting. The temperature is subnormal and the pulse is slow. There are slowly developing personality changes such as delayed cerebration and defective memory. The pupil may be contracted and react sluggishly but a large abscess may result in the pupil being in a state of stable mydriasis. The Fig, 39. Cavernous sinus thrombosis. frontal sinus should be explored and its posterior wall examined for evidence of erosion. Enlargement of the defect will drain an extradural abscess into the sinus* A frontal lobe abscess may be drained via a burr hole, but the help of the neurosurgeon is frequently sought to localize and deal with the abscess, Cavernous sinus thrombosis is a serious and frequently fatal complication of ethmoidal sinusitis which is now rarely seen as a result of antibiotic therapy foTtffe original infection. A thrombophlebitis of the ophthalmic vein causes oedema of the eyelids, chemosis of the conjunctiva and proptosis of the eyeball with blurring of the optic disc, while paralysis of the ocular muscles leads to fixation of the eyeball. The thrombosis spreads from one cavernous sinus to the other so that similar signs appear in the other eye either simul- taneously or after a brief interval (Fig. 39). Treatment by broad-spectrum antibiotics and anticoagulants must be vigorous.