Severe dengue shock — DTM&H MCQ

Correct answer: A — Severe dengue with compensated shock

The correct answer is A, severe dengue with compensated shock. By day 5 to 7 of dengue illness, defervescence marks the critical phase, when increased vascular permeability causes plasma leakage into the extravascular space. A pulse pressure of 16 mmHg (below the 20 mmHg threshold), delayed capillary refill, restlessness and clamminess, together with a rising haematocrit reflecting haemoconcentration from plasma loss, are the WHO-defined criteria for dengue shock syndrome at the compensated stage, where systolic pressure is still maintained by peripheral vasoconstriction. This combination of warning signs and shock parameters defines severe dengue and mandates immediate fluid resuscitation before decompensation (hypotension) occurs. Why the other options are wrong: C. Leptospirosis without organ dysfunction: this does not cause plasma leakage or haemoconcentration, and the illness day and haematocrit pattern described are specific to dengue's critical phase, not leptospiral disease. D. Zika virus infection: typically produces a mild, self-limiting illness with rash and conjunctivitis, and does not cause shock, capillary leak or rising haematocrit. B. Uncomplicated chikungunya: characterised by severe polyarthralgia without plasma leakage, shock or haemoconcentration; by definition it excludes the haemodynamic compromise seen here. E. Enteric fever with ileus: presents with prolonged fever, abdominal distension and relative bradycardia, not narrowed pulse pressure with rising haematocrit, which are haemoconcentration markers specific to capillary leak syndromes. Key point: in a patient with confirmed dengue, a narrowing pulse pressure (≤20 mmHg) with delayed capillary refill and rising haematocrit around the time of defervescence signals plasma leakage and compensated dengue shock, requiring urgent fluid resuscitation.

Reference: World Health Organization, Dengue Guidelines for Diagnosis, Treatment, Prevention and Control (2009), section on Dengue Haemorrhagic Fever/Dengue Shock Syndrome grading and management, https://www.who.int/publications/i/item/9789241547871