When once present, the swelling of the disk may increase rapidly. In a case of cerebellar abscess recently under my care the swelling reached 6D. in three days. Whatever the localizing value of unilateral neuritis in tumour formation (see [p. 216]), I am strongly of opinion that in the cases under discussion, optic neuritis, when confined to or more marked on the one side, implies that the abscess is situated on that side.
The pulse and temperature. It is commonly stated that, in typical cases of brain abscess, the pulse-rate is slowed—40 to 60 per minute—and that the temperature is subnormal. Slowing of the pulse results from stimulation of the medullary centre, the lowering of temperature to less determinate causes. In the consideration of pulse and temperature—and the two must invariably be considered together—it will, however, frequently be found that the temperature is raised and the pulse-rate but little altered. Thus, in one case the pulse was 88 and the temperature 103·4 degrees, in another the pulse was 74 and the temperature 102, in a third case the pulse was 89 and the temperature 102·8 degrees. These cases are very significant, and show that the greatest attention should be paid to a comparison between pulse-rate and temperature, a relative slowing of the pulse being more constant than an actual retardation.
The elevation of temperature results from the fact that the great majority of cases of brain abscess are secondary to some highly infective purulent collection, as, for instance, a mastoid empyema. In such a case, if the mastoid region be cleared out, the temperature will fall and the typical clinical picture of subnormal temperature and slowed pulse-rate will be depicted.
The respiration. The increase of intracranial pressure may lead to some slowing and deepening of respiration. Irregularity is, however, the more common condition, deepening, in the later stages, to definite Cheyne-Stokes respiration. Under anæsthesia—more especially in cerebellar cases—there is considerable risk of respiratory failure (see [foot-note], [p. 238]).
Vaso-motor changes. Vaso-motor changes are fairly constant, evidenced by sweats and flushings, tache cérébrale, &c.
Reflexes. In the earlier stages of the trouble the reflexes may be increased and Babinski’s sign present. In the later stages, all reflexes are abolished.
Fig. 75. A Large Right-sided Temporo-sphenoidal Abscess.
Other more general symptoms. Obstinate constipation, foul tongue and breath, anorexia, deficient urine, loss of bladder and rectal control, are all noticeable features. A well-marked leucocytosis is generally to be observed.
Symptoms dependent on the localization of the abscess