Serious complications, in the form of meningitis, cerebral abscess, sinus phlebitis, and general pyæmia, are liable to develop at any time during the progress of the infection, and we have seen pyæmia develop after the suppuration in the skull had been recovered from.
Treatment.—Early, free, and, if necessary, multiple incisions are indicated to admit of disinfection of the affected area, and of the establishment of drainage. If the symptoms point to suppuration having occurred between the bone and the dura, the skull should be trephined and further bone removed with the rongeur forceps as may be required.
Time may be saved by separating the sequestrum with the aid of an elevator or sharp spoon, or by chiselling away the dead part till healthy vascular bone is reached.
Tuberculosis of the cranial vault is usually met with in children. The disease commences in the diploë, and results in the formation of a central sequestrum, around and beneath which the tuberculous process spreads. Granulations form between the skull and the dura, and on the outer aspect lifting up the pericranium. The sequestrum is slowly thrown off, and when separated is circular like a coin and presents worm-eaten edges.
A circumscribed, tender swelling forms, at first yielding an obscure sensation of fluctuation, but later, when the pus is no longer confined under the pericranium, assuming the characters of a cold abscess, which gradually becomes superficial, and eventually bursts through the scalp, forming one or more sinuses.
The abscess should be laid open, all tuberculous granulations scraped away, and the sequestrum removed, with the aid of the chisel if it has not already become loose. On inserting the finger through the opening, it appears to penetrate to an alarming extent; this is due to the accumulation of tuberculous material between the skull and the dura mater, depressing the latter. After healing is completed, a depression or gap in the bone remains.
Syphilis.—Syphilitic affections occur during the tertiary period of the disease, and usually implicate the frontal and parietal bones ([Fig. 202]). They are described in Volume I., p. 462.
Fig. 202.—Skull of woman illustrating the appearances of Tertiary Syphilis of Frontal Bone—Corona Veneris—in the healed condition.