Summarize this article:

To treat severe cases of dengue fever at a hospital, doctors will begin by introducing intravenous (IV) fluids and electrolytes (salts) into the patient's body. This treatment works to replace the fluids lost through vomiting or diarrhea. This step will only be taken if the patient is not able to take fluids orally (e.g., because of severe vomiting) or is in shock.  Intravenous means "within a vein." In other words, liquid substances will be infused directly into one of the patient's veins via a syringe or intravenous catheter.  The recommended first-line IV fluid is crystalloids (0.9% saline).  Doctors will monitor the patient's fluid intake through IV due to newer guidelines recommending a more cautious intake of IV fluids than in the past. This is because overhydration can cause adverse effects, including intravascular fluid overload, or a flooding of the capillaries. For this reason, in most cases, doctors will administer fluid in increments, rather than a constant flow. In more advanced and severe cases cases of dengue, doctors may have to perform a transfusion to replace lost blood. This is often the required treatment for patients whose dengue has escalated to DHF. A transfusion can entail transfer of fresh blood into the patient's system or just platelets, which are parts of the blood that help the blood clot and are smaller than red or white blood cells. Corticosteroids are man-made drugs that closely resemble cortisol, a hormone produced naturally by your adrenal glands. These drugs work by decreasing inflammation and reducing the activity of the immune system. The effects of corticosteroids on dengue infection are still undergoing medical trials and are as yet inconclusive.

Summary:
Deliver intravenous fluids. Do a blood transfusion. Administer corticosteroid injections.