loses the power to contract altogether. The blood then rapidly accumulates in the great veins, the right auricle and ventricle are distended almost to bursting, and death is inevitable. The result is often contributed to by the coexistence of pleural effusion, hydropericardium, paresis of the diaphragm, over-distension of the stomach by food or gas, "and, above all, by oedema of the lungs. It can readily be understood how the establishment of any additional obstruction of this description would still further tax the dilated, enfeebled heart and determine the fatal issue.
When we come to make a post-mortem in these cases we may find a heart slightly hypertrophied and enormously dilated, the right cavities distended with blood, the lungs and liver full of dark blood, and all the great veins engorged.
Prognosis.— This tendency to dilatation of the heart is the dangerous element in beriberi; it should always be before our eyes, and dominate our plans of treatment. It is wonderful how rapidly it may come on, and how rapidly it may prove fatal. These sudden deaths, occurring sometimes from syncope—from instantaneous failure, as well as from the somewhat slower process of increasing over-distension— are constantly sprung on one in this disease. An absolutely favourable prognosis, therefore, ought never to be ventured on in even the mildest-looking case of beriberi, or so long as the patient is exposed to the conditions causing the disease, or so long as the neuritis appears to be active. That is a lesson which is often, and sometimes painfully, borne in on the practitioner in beriberi districts.
Evidences of grave heart implication, such as pulsating cervical vessels, equal spacing of the intervals audible on auscultation, enlargement of cardiac dullness especially to the right, epigastric pulsation, a rapid feeble pulse, a distended stomach, cold extremities, cyanosis, dyspnœa, and a disproportion in the strength of the heart- and wrist-beats, are significant of danger. Paralysis of the diaphragm, of the intercostal muscles, extensive serous effusions, very scanty urine are also unfavourable signs.
