A 28-year-old previously healthy man presents on day 4 of dengue fever with severe abdominal pain, persistent vomiting, and clinical warning signs. BP is 100/70 mmHg, pulse 108 bpm. Hematocrit has risen from 38% to 48% (rise >20%). Platelets are 58,000/μL. What phase of dengue is he in and what does the hemoconcentration indicate?

• A Febrile phase; dengue hemorrhagic fever
• B Recovery phase; reabsorption of leaked plasma
• C Febrile phase; secondary dengue infection
• D Critical phase; plasma leakage causing hemoconcentration ✓

Explanation

Dengue has three phases: febrile (days 1–3), critical (days 4–6), and recovery (days 7–9). The critical phase, beginning around day 4–5, is characterized by plasma leakage from capillaries into extravascular compartments due to increased vascular permeability. Hemoconcentration (hematocrit rise ≥20%) is the cardinal marker of significant plasma leakage. Severe abdominal pain, persistent vomiting, and rapid hematocrit rise are WHO warning signs mandating close monitoring with IV fluid therapy. Failure to manage this phase can lead to dengue shock syndrome.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.