What occurs during the critical phase of dengue after 48-72 hours?

During the critical phase of dengue, which typically occurs 48-72 hours after the onset of fever, the patient's condition can become significantly more serious. It is in this phase that a dramatic drop in hematocrit levels may be observed due to plasma leakage caused by increased vascular permeability. This can lead to shock and potentially severe complications if not managed properly.

The correct response highlights that fluid levels return to normal, which typically occurs after management interventions such as fluid resuscitation. In this phase, medical interventions are crucial to stabilize the patient's fluid balance and prevent complications related to plasma leakage.

Other options mention symptoms or conditions such as fever spikes, rashes, or severe abdominal pain, which may be observed during different phases of dengue, particularly in the febrile phase or in cases of complications. However, they do not accurately reflect the characteristic changes in fluid status that define the critical phase in management of the disease.