Nervous System.—Very characteristic for plague is the intense and early disturbance of the mental condition. The patient presents the characteristics of alcoholic intoxication, thick speech, lack of mental concentration and giddiness which causes a staggering gait. Later on an apathetic or stuporous stage may ensue or there may be delirium.
Rarely a case of bubonic plague may show marked involvement of the meninges, giving the clinical picture of meningitis.
Circulatory System.—The pulse is at first soft, dicrotic and rapid, 110 to 120 beats per minute. Later on, as the heart begins to show the toxic effects of the disease, the pulse becomes thready and irregular, to be followed by cardiac failure. There is a marked tendency to congestion of various internal organs and to haemorrhages from the capillaries.
Respiratory System.—Pulmonary congestion and even broncho-pneumonia may supervene in bubonic plague. In pneumonic plague, however, the lungs seem to be the primary seat of the bacterial development. Plague pneumonia is characterized by intense toxaemia and few physical signs. The abundant, watery sanguineous sputum is loaded with plague bacilli. Dyspnoea and cyanosis appear early.
Fig. 69.—Plague Carbuncle. (Reproduced from Simpson’s Treatise on Plague 1905.) From Jackson’s Tropical Medicine.
The Lymphatic System.—It is the presence of the plague bubo which differentiates bubonic plague. There is no relation between the size of the bubo and the severity of the attack. Axillary buboes are the most fatal. A characteristic of these buboes is their extreme tenderness, the pain causing the patient to draw up the legs or assume any attitude which will relieve tension upon the bubo. The size is mainly due to the periglandular infiltration or oedema, which causes the glands of a group to be matted together.
The elevation of a plague bubo is rather diffuse, not pointed as with venereal buboes. Femoro-inguinal buboes are about 6 times as frequent as cervico-maxillary ones. There may be lymphangitis as well as lymphadenitis.
Cutaneous System.—The skin over the buboes often tends to become necrotic and slough off. This however may occur elsewhere and such lesions are termed “carbuncles.” Capillary haemorrhages of the skin may cause petechiae and when the area is large they have been designated “tokens.” In about 5% of cases there is a small vesicle or pustule at the site of the flea bite as an indication of reaction. The contents teem with plague bacilli. It is often termed the primary lesion.
The Liver, Spleen and Alimentary Tract.—The spleen may show enlargement and tenderness on deep pressure, as may also the liver, these organs being markedly congested. The tongue at first is coated, with clean tip and sides. Nausea and vomiting frequently occur and, as a rule, there is constipation. Haemorrhages from the bowel may occur.