Manual of Surgery Volume Second: Extremities—Head—Neck. Sixth Edition.

by Alexis Thomson; Alexander Miles

At first the symptoms of irritation of the brain predominate: severe headache, photophobia, inequality of the pupils, stiffness of the neck, cutaneous hyperæsthesia, vomiting and convulsions. Kernig's sign—pain on flexing the hip while the knee is extended, and inability to extend the knee while in the sitting posture—is present. There is usually obstinate constipation, and the abdomen is retracted. Later, signs of increased intra-cranial tension develop: unconsciousness deepening into coma, paralysis of ocular muscles, rapid pulse, Cheyne-Stokes respiration, and sometimes hyperpyrexia. An excess of mono-nuclear lymphocytes and, sometimes, tubercle bacilli may be discovered in the cerebro-spinal fluid withdrawn by lumbar puncture. The absence of the diplococcus intracellularis helps to differentiate the disease from cerebro-spinal meningitis, which it may closely simulate.

The only surgical measure that is justifiable is lumbar puncture, which often affords marked relief of symptoms, although the benefit is only temporary.

Localised tuberculous nodules sometimes develop in the brain and form definite tumours. They vary in size from a pea to a hen's egg, are rounded and encapsulated. Sometimes the centre is caseous, sometimes fibrinous or calcified. In children they are usually multiple; in adults they may be single—the so-called “solitary tubercle.” They are most common in the pons, basal ganglia, and cerebellum, but occur also in the cerebral cortex and sometimes in the centrum ovale. They usually originate in the pia and invade the brain substance, but do not as a rule involve the dura. The membranes in the vicinity of the growth are often the seat of tuberculous disease.

As these nodules give rise to the same symptoms as other forms of cerebral tumour, and as their nature can be diagnosed only in exceptional cases, their clinical features and treatment are described with tumours of the brain.

Intra-cranial Syphilis.—Syphilitic meningitis is usually secondary to cario-necrosis of the bones of the vault or to a localised gumma of the brain. When primary, it usually affects the inter-peduncular region of the base, and takes the form of a diffuse gummatous infiltration of the membranes which gives rise to symptoms referable to the parts pressed upon, and especially paralysis of one or other of the cranial nerves. As in other intra-cranial syphilitic lesions, the symptoms show a variability in intensity which is characteristic. The diagnosis is made by the history, and the treatment is carried out on the same lines as in other syphilitic lesions.

Localised gummata are described with tumours of the brain.

Cephaloceles

The term “cephalocele” is applied to a protrusion of a portion of the cranial contents through a congenital deficiency in the bones of the skull. This malformation is believed to be due to an irregularity in development, whereby a portion of the primary cerebral vesicle remains outside the mesoblastic layer of the embryo. It is usually associated with adhesion of the membranes in the region of the fourth ventricle, and with internal hydrocephalus. Cephaloceles are covered by the scalp, and are most commonly met with in the occipital region and at the root of the nose; less frequently at the anterior inferior angle of the parietal bone, and in the line of the sagittal suture. Very rarely they occur at the base of the skull and project into the pharynx, the mouth, or the nose, where they are liable to be mistaken for polypi. Cephaloceles vary greatly in size, some being so small as almost to escape detection, while others are larger than a child's head. In many cases the condition is incompatible with life.

Several varieties are recognised. They are known as (1) meningocele, which consists of a protrusion of a cul-de-sac of the arachno-pial membrane, containing cerebro-spinal fluid; (2) encephalocele, in which a portion of the brain is protruded in addition to the membranes; and (3) hydrencephalocele, in which the protruded portion of brain includes a part of one of the ventricles.

Clinical Features.—The meningocele is commonest in the occipital region, where it escapes through a cleft in the bone between the foramen magnum and the occipital protuberance ([Fig. 197]). It forms a tense, smooth, translucent globular swelling, which may be sessile or pedunculated, and is usually covered by thin, smooth skin in which the vessels are dilated and nævoid. The tumour does not pulsate, but increases in size and tension when the child cries or coughs. It may be diminished in size or even made to disappear by pressure, and so permit of the opening in the bone being felt. This manipulation, however, may be followed by slowing of the pulse, vomiting, loss of consciousness, or convulsions.