Case definition for dengue shock syndrome
All of the above four criteria for DHF must be present, plus evidence of circulatory failure manifested by:

• Rapid and weak pulse, and
  
• Narrow pulse pressure (<20 mmHg (2.7 kPa) )
  Or manifested by:
  
• Hypotension for age,1 and
  
• Cold, clammy skin and restlessness.
  The spectrum of dengue haemorrhagic fever is shown in Figure 2.2.
  Fig. 2.2
  The spectrum of dengue haemorrhagic fever

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1 see p. 21, bottom, for the definition of hypotension.

Guidance for diagnosis of DHF/DSS
The following manifestations have been selected as indicating a provisional diagnosis of DHF/DSS. They are not intended to be substitutes for the above case definitions. The use of these criteria may help clinicians to establish an early diagnosis, ideally before the onset of shock, as well as to avoid overdiagnosis.

Clinical

The following clinical observations are important indicators of DHF/DSS:

• High fever of acute onset
  
• Haemorrhagic manifestations (at least a positive tourniquet test)
  
• Hepatomegaly (observed in 90 - 96% of Thai and 67% of Cuban children with DHF)
  
• Shock