Dengue (Adults) – House Officer Guide

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Last Updated on August 20, 2026

“Dengue is a bread and butter. Every doctor must know dengue from front till the end”

Table of Contents

Introduction

• Dengue must be identified and risk-stratified early
• Dengue is a notifiable disease

Pathogen

• Dengue virus (single-stranded RNA virus, from Flavivirus genus)
• Intrinsic incubation: 4 – 7 days, up to 14 days (viraemic period, may be asymptomatic)

Warning signs of dengue

Warning signs suggest high possibility of complications in dengue infection / rapid progression into severe dengue

(unprovoked) Mucosal bleeding
Persistent vomiting (≥3 times over 24 hours)
Abdominal pain / tenderness
Tender liver
Persistent diarrhoea (≥3 times over 24 hours)
Lethargy / confusion / restlessness
Laboratory: ↑HCT with rapid ↓Platelet count

Diagnosis of dengue

(A) Probable dengue

Live in dengue area
Fever with ≥2 other

(B) Laboratory-confirmed dengue

e.g. Dengue rapid combo test / Dengue serology

Classification of dengue

Dengue ± warning signs
Severe dengue

Pathophysiology

• Dengue virus impairs endothelial cell adhesion and tight junction → vascular hyperpermeability → leakage of plasma into extravascular compartment (i.e. 3rd space loss) → haemoconcentration, hypovolaemic shock
• Abnormal haemostasis (thrombocytopenia / coagulopathy)
• Stimulation of cytokines and other inflammatory mediators →

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Further reading
1. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008603

Phases in dengue

Febrile phase

High grade fever lasting 2 – 7 days + facial flushing, rash, generalised body ache, vomiting, headache, sore throat, eye redness
Mild haemorrhagic manifestation e.g. petechiae / mucosal membrane bleeding
May have liver tenderness

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Change in blood parameters

Earliest FBC change: progressive decreasing WCC and low platelet count

Critical phase

Onset: Often occurs after 3rd day of fever OR indicated by rapid drop in temperature
Duration: 24 – 48 hours
In
severe dengue
infection, patient may deteriorate
Most patients recover spontaneously or require short period of fluid and electrolyte therapy; but some patients may develop compensated / decompensated shock due to plasma leakage
Organ dysfunction usually but not exclusively occurring in this phase

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Changes in blood parameters that are usually observed:

FBC: haemoconcentration, thrombocytopenia, leucopenia with relative lymphocytosis
LFT: elevation of transaminases (typically AST > ALT), hypoproteinaemia, hypoalbuminaemia

Recovery phase

Onset: after 24 – 48 hours of critical phase
Plasma leakage stops, followed by reabsorption of extravascular fluid → haemodilution
Patient’s general wellbeing improves — appetite returns, GI symptoms improve, diuresis ensues
Haemodynamics stabilise
May have classical rash — ‘isles of white in the sea of red’
In some condition, organ dysfunctions may worsen

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Changes in blood parameters that are usually observed:

FBC: Haematocrit stabilises, then drops further due to haemodilution ; WCC recovery followed by platelet count recovery

Plasma leakage

Plasma leakage → hypovolaemia → reflex tachycardia & generalized vasoconstriction

Manifestations of vasoconstriction

Differential Diagnoses

• Malaria
• Leptospirosis
• Typhoid fever
• COVID 19

Physical Examination

Haemodynamics

Brain, cardiovascular, lungs, kidney, skin

	Normal Circulation	Compensated Shock	Decompensated / Hypotensive Shock
Consciousness level	Clear & alert	Clear (may be missed if you do not touch patient)	Change of mental state - restless / drowsy
Temperature of extremities	Warm & pink	Cold	Cold clammy extremities
Capillary refill time (CRT)	Brisk (<2 seconds)	Prolonged (>2 seconds)	Mottled skin, very prolonged CRT
Peripheral pulse volume	Good volume	Weak & thready pulses	Feeble / Absent
Heart rate	Normal	Tachycardia	Severe tachycardia // bradycardia in late shock
Blood pressure	Normal	- Normal SBP with rising DBP - Postural hypotension	Hypotension / Unrecordable BP
Pulse pressure	Normal	Narrowing pulse pressure	Narrowed (≤20 mmHg) / Unrecordable
Respiratory rate	Normal	Tachypnoea	Metabolic acidosis / Hypernoea
Urine output	Normal	Reducing trend	Oliguria / Anuria

Investigations

Full blood count (FBC)

Progressive decrease in WCC followed by platelet reduction is

White cell count
• Leucopenia with relative lymphocytosis can be usually observed during critical phase
• Leucocytosis + dengue shock may suggest plasma leakage / bleeding, rather than secondary bacterial infection

Haematocrit
Median normal values :
• Female — 40%
• Male — >60 years old = 42%; ≤60 years old = 46%

Notes:
• Correlates well with plasma volume loss & severity
• Confounding factors: haemorrhage, excessive fluid replacement, haemodilutional state

Management

Does this patient require fluid?

Algorithm A — Fluid management in compensated shock

Algorithm B — Fluid management in decompensated shock

Algorithm C — Fluid management in decompensated shock (with presence of bleeding u0026amp; leaking or other causes of shock)

Common Q&A

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Take Home Message
1. Remember to analyse the severity and anticipate the complications of dengue fever
2. CCTVR : shock can be missed if you do not touch the patient