There may be some venous congestion of the meninges, but the brain itself shows no important vascular, or naked-eye, changes. The intestinal mucosa, as well as that of the stomach, is swollen and exhibits patches of congestion.
Pathology.—As may be gathered from the remarks on etiology, the pathology of siriasis, so far, is in a very unsettled state, and will continue to be so until the essential cause of the disease has been finally determined.
Diagnosis.—The presence of high fever is sufficient to differentiate siriasis from sudden insensibility caused by uraemia, by diabetic coma, by alcoholic and opium poisoning, and by all similar toxic conditions. Cerebral haemorrhage, particularly pontine, may, after some hours, be followed by high temperature; but here the febrile condition follows the insensibility, whereas in heat-stroke the febrile condition precedes insensibility. The diagnosis from a cerebral malarial attack may be very difficult; chief reliance has to be placed on the history—if obtainable, on the condition of the spleen, and, especially, on the result of microscopical examination of the blood. Malarial fevers, and the early stages of the eruptive fevers in children, are very apt to be regarded as heat-stroke, particularly if there has been recent exposure to a hot sun. Cerebro-spinal fever, so often mistaken for siriasis, may be recognized by the occipital retraction, the irregular pupils, the frequent occurrence of strabismus, the comparatively low and fluctuating temperature, the associated herpes, the initial rigor, and its long duration.
Treatment.—In all fulminating fevers, including siriasis, occurring in warm climates, if malaria be suspected, particularly if the parasite be discovered in the blood, quinine should be injected intravenously or intramuscularly at once (7 to 10 grains of the bihydrochloride), or given by enema as directed under Malaria (p. 125); this dose should bo repeated three or four times at intervals of four hours. In every case of siriasis, whether it has been deemed advisable to administer quinine or not, attention must at once be
