Most DHF patients do not go into shock. Observations of many patients with DHF have shown that many of those who progress to shock present with certain danger signs prior to manifesting circulatory failure. These danger signs include:

1. Abdominal pain that is intense and sustained;
2. Persistent vomiting;
3. Abrupt change from fever to hypothermia, with sweating and prostration; and
4. Change in the mental status of the patient, going to be restlessness or somnolence.

All of these are signs of impending shock and should alert clinicians that the patient needs close observation and fluids.