CEREBRAL MENINGITIS. Acute inflammation of the pia mater of the brain occurs chiefly in two forms—tubercular. and simple or purulent. The arachnoid takes part, to a greater or less extent, in the inflammatory process.
Tubercular meningitis occurs at all ages, hut is more common in children than in adults. The disease is caused bytheLacillus tuberculosisand is usually secondary to a tuberculous process in some other portion of the body, for example, pul monary phthisis, hip-joint disease, or caries of the spine. Primary cases are said to occur, but it is usually found after death that eascous tubercular glands, or other latent. or previously unrecognized forms of tubercular in feet ion. are present. The characteristic lesions of the dis ease are found in the pia mater at the base of the brain. or over the optic ehiasm, crura. or pons. Tubercles are deposited along the vessels of the pia, which becomes thickened. opaque, and studded with grayish white granules. There is an exuda tion of lymph, gray or grayish yellow, but rare ly purulent, into the meshes of the membrane in the same portions in which the tubercles exist and extending along the fissure of Sylvins and the middle cerebral artery. The upper surface of the hemispheres is only slightly affected, so that the disease is sometimes called basilar meningitis. The ventricles are generally distended with fluid (whence the old name, acute hydrocephalus), clear, milky, or even bloody. The symptoms of tubercular meningitis are very complex, and a ease fully developed presents a painful clinical picture, particularly in children. The onset of the disease is often preceded by a period of gen eral ill health. The child is peevish. irritable, and experiences a complete change of disposition, together with loss of appetite and constipation. The first or irritative stage then sets in sud denly, with a convulsion, or more commonly with vomiting, headache, and fever. The headache is severe and continuous, and the child moans and occasionally utters a sharp cry—the so-called 'hydrocephalic cry.' Sometimes the patient
screams until utterly exhausted and has to be kept under the influence of powerful sedatives all the time. There is moderate fever and exces sive sensitiveness to light and sound. In the second period of the disease, the stage of de pression, the irritative symptoms subside. The child no longer complains of headache, but is dull and apathetic, drowsy or slightly delirious. Pulse and respiration are irregular, and fever continues. The head is retracted and the neck stiff. If the fingernail is drawn across the skin of the forehead or abdomen a broad red streak appears, the hiche e(Wbrule, which may last for five minutes. In the last or paralytic stage. all these symptoms are intensified; the drowsiness increases to coma; paralysis of various parts of the body occurs, and death takes place in from ten days to three weeks after the onset of pronounced symptoms. Few eases recover. Treatment is entirely symptomatic and palliative. An ice cap is put upon the head, and sedatives are given in ternally.
Simple acute meningitis is as a rule purulent or suppurative. It may be caused by inflamma tion of neighboring tissues, e.g. otitis, suppura tive phlebitis, or abscess of the brain; or may occur as a complication of pyemia, septicaemia, malignant endocarditis, or the specific fevers, par ticularly smallpox, typhoid, and scarlatina. The pia mater and arachnoid become infiltrated with purulent material, and the brain beneath them is commonly softened. The symptoms resemble in a. general way those of the tubercular form just de scribed, but the onset and course of the malady are much more rapid. When simple meningitis occurs in the course of other acute illnesses, its features may be masked to a certain extent, but in other eases the symptoms begin acutely with a chill, severe pain in the head, and vomiting, and the ease passes on to convulsions, paralysis, coma, and death, as in the tubercular form. A fatal termination is the rule, but some recoveries occur after a long period of convalescence.