A 32-year-old woman from Mumbai presents to the emergency department on day 5 of illness with sudden onset of severe abdominal pain, persistent vomiting, and a petechial rash over the lower extremities. Her vital signs show: BP 92/58 mmHg, HR 118/min, RR 24/min, temperature 37.8°C. Laboratory investigations reveal: Hb 14.2 g/dL, WBC 3,200/μL, platelets 45,000/μL, AST 320 U/L, ALT 240 U/L, albumin 2.8 g/dL. Dengue NS1 antigen is positive. What is the most likely clinical diagnosis?

Explanation

## Clinical Diagnosis: Dengue Hemorrhagic Fever (DHF) with Plasma Leakage ### Key Clinical Features Present **Day 5 of illness (Critical Phase):** This patient has entered the critical phase of dengue, which typically occurs on days 3–7 when fever subsides but plasma leakage begins. **Plasma Leakage Indicators:** - Hypotension (BP 92/58) with tachycardia (118/min) - Severe abdominal pain and persistent vomiting (signs of plasma leakage into peritoneal cavity) - Petechial rash (hemorrhagic manifestation) - Hypoalbuminemia (2.8 g/dL) — reflects protein loss from vascular leak **Hematologic Findings:** - Thrombocytopenia (45,000/μL) — hallmark of DHF - Leukopenia (3,200/μL) — typical in dengue - Hb normal/elevated (14.2 g/dL) — suggests hemoconcentration from plasma loss **Hepatic Involvement:** - Elevated transaminases (AST > ALT) — characteristic dengue hepatitis pattern ### Dengue Hemorrhagic Fever vs. Dengue Fever: Diagnostic Criteria | Feature | Dengue Fever | Dengue Hemorrhagic Fever | |---------|--------------|-------------------------| | Fever | Present | Present (may defervescence by day 5) | | Hemorrhagic manifestations | Rare | Present (petechiae, purpura, bleeding) | | Plasma leakage | Absent | Present (hypotension, ascites, pleural effusion) | | Thrombocytopenia | Mild (>100,000) | Moderate–severe (<100,000) | | Hemoconcentration | Absent | Present (Hct rise >20%) | | Shock | No | Yes (DHF Grade III–IV) | **Key Point:** DHF is defined by the **combination of fever + hemorrhagic manifestations + thrombocytopenia + evidence of plasma leakage** (hypotension, ascites, hypoalbuminemia, hemoconcentration). This patient meets all criteria. ### Why This Is NOT Dengue Fever Alone Dengue fever (DF) is self-limited viral illness without plasma leakage or hemorrhagic manifestations. This patient has **hemorrhagic manifestations (petechiae), hypotension, and ascites** — all absent in uncomplicated DF. **High-Yield:** The critical phase (days 3–7) is when DF progresses to DHF. Fever defervescence paradoxically marks the onset of plasma leakage and shock risk — a common NEET PG trap. **Clinical Pearl:** Severe abdominal pain in dengue on day 5 with hypotension is **ascites from plasma leakage**, not peritonitis. Absence of fever does not rule out DHF; it actually marks the critical phase. ### Management Implications This patient requires: 1. **IV fluid resuscitation** (Ringer's lactate or normal saline) — target urine output 0.5 mL/kg/hr 2. **Platelet transfusion** if spontaneous bleeding occurs or platelets <20,000/μL with bleeding risk 3. **Close monitoring** of vital signs, urine output, and serial hematocrit 4. **Avoid NSAIDs** (increased hemorrhage risk) [cite:Harrison 21e Ch 189]