Dengue is one of the most prevalent vector-borne diseases with no medical treatment for cure. Sometimes, dengue infection develops hemorrhagic shock which is life-threatening and urges emergency medical support. At this stage, the infusion of intravenous fluid of an adequate amount is a must for the survival of the patient. However, unsystematic fluid infusion may lead to fluid overload and bring adverse outcomes. With an aim to quantify required amount of fluid infusion I extend minimal within-host dengue model to incorporate plasma dynamics as well as the intravenous fluid infusion. I experimented type I and type II functional response to model the impact of cytokines on plasma leakage, where Type II model showed better fit with published data. Optimal control theory has been used to establish the existence of a time-dependent optimal fluid infusion strategy. The forward-backward sweep method was used to solve the model numerically and deduce the optimal fluid infusion rate. The optimal strategy recommends fluid infusion initiation at a slower rate, which should be kept increasing for about 24 hours. Then the rate should be decreased gradually. The infusion requires about 4000 ml to 5000 ml within an interval of 2 to 3 days. Delay of a few hours in fluid support after initiation of leakage could be compensated. But a delay of more than one day could be life-threatening.