How the Wet beriberi Developed Rapidly?

Oedema is the significant feature of wet beriberi. It may develop rapidly and involve not only the legs but also the face, trunk and serous cavities.  Palpitation and breathlessness are present. The calf muscles are frequently tense, slightly swollen and tender on pressure. The veins of the neck are distended and show visible pulsations. The diastolic blood pressure is low and systolic is high. The pulse is fast and bouncing. The heart becomes weak and death occurs because of heart failure.