What are the symptoms and management of dengue fever?

Dengue Fever: Clinical Presentation and Management

Primary Symptoms

Dengue fever presents with acute-onset high fever, severe headache, retro-orbital (behind the eyes) pain, muscle and joint pain (often called "breakbone fever"), and a characteristic rash, typically appearing 4-8 days after mosquito exposure. 1

Classic Symptom Complex

• Fever: Acute onset, high-grade temperature 1
• Headache: Frontal headache with retro-orbital pain (pain behind the eyes) 1, 2
• Musculoskeletal pain: Severe myalgia (muscle pain) and arthralgia (joint pain), particularly affecting the back 1, 3
• Rash: Maculopapular rash similar to measles, typically appearing during days 3-7 of illness when fever subsides, often pruritic (itchy) 3, 4
• Gastrointestinal symptoms: Vomiting and diarrhea may occur 5

Disease Spectrum and Phases

Dengue follows a characteristic triphasic course consisting of febrile phase, critical phase, and recovery phase. 6 The disease ranges from mild febrile illness (>90% of cases) to life-threatening severe dengue. 1, 6

Warning Signs Requiring Immediate Medical Attention

Critical warning signs typically appear around day 3-7 of illness, coinciding with defervescence (when fever subsides), and include: 2

• Persistent vomiting 1, 2
• Severe abdominal pain or tenderness (particularly right upper quadrant due to liver involvement) 1, 2
• Clinical fluid accumulation (pleural effusion, ascites) 2
• Mucosal bleeding (nose, gums, gastrointestinal) 1, 2
• Lethargy or restlessness 1, 2
• Hepatomegaly (enlarged liver) 2
• Rising hematocrit with concurrent rapid platelet decline 1, 2

Early recognition of these warning signs can reduce case-fatality rate to <0.5%. 2

Severe Dengue Manifestations

Dengue Hemorrhagic Fever (DHF)

DHF is defined by minor or major bleeding phenomena, thrombocytopenia (platelet count ≤100,000/mm³), and evidence of plasma leakage. 1, 2 The increased vascular permeability results in fluid leakage from intravascular to extravascular space. 7

Dengue Shock Syndrome (DSS)

DSS includes all DHF criteria plus hemodynamic instability: 1, 2

• Narrow pulse pressure ≤20 mmHg (earlier and more sensitive indicator than absolute hypotension) 2
• Systolic blood pressure <90 mmHg for >30 minutes 2
• Signs of end-organ hypoperfusion: cold/clammy extremities, capillary refill time ≥3 seconds, elevated lactate >2 mmol/L 2

Severe dengue carries a mortality of 1-5% but is rare. 6

Diagnostic Approach

Timing-Based Testing Strategy

• Days 1-7 of symptoms: Order dengue PCR/NAAT (nucleic acid amplification test) on serum, as PCR is most effective during viremia 1, 2
• After day 5-7 of symptoms: Order IgM capture ELISA if PCR unavailable or negative 1, 2
• Acute phase (days 1-10): NS1 antigen detection is useful and detectable throughout this period 2
• Rapid diagnostic tests: Combined NS1 antigen and IgG tests have very high positive likelihood ratios and can optimize management 1

Special Testing Considerations

• Pregnant women: Test by NAAT for both dengue and Zika virus regardless of outbreak patterns due to risk of adverse outcomes 1
• Cross-reactivity: Document vaccination history for yellow fever, Japanese encephalitis, and tick-borne encephalitis to avoid false positives 1

Management Strategy

Risk Stratification and Disposition

Outpatient Management Criteria (Dengue Without Warning Signs): 1

• No warning signs present
• Platelet count >100,000/mm³ without rapid decline
• Stable hematocrit without hemoconcentration
• Hemodynamically stable
• Able to maintain adequate oral intake

Hospitalization Indications: 1

• Any warning signs present
• Severe plasma leakage, severe bleeding, or organ failure
• Dengue shock syndrome (narrow pulse pressure ≤20 mmHg or hypotension)
• Rising hematocrit (>20% increase from baseline)
• Thrombocytopenia ≤100,000/mm³, particularly if declining rapidly
• Pregnant women with confirmed or suspected dengue

Outpatient Management

• Aggressive oral hydration: Aim for >2500 mL daily using oral rehydration solutions 1
• Pain and fever management: Acetaminophen at standard doses 1
• Daily monitoring: Complete blood count to track platelet counts and hematocrit levels 1
• Patient education: Monitor for warning signs and return immediately if they develop 1

Inpatient Fluid Management

For Dengue Shock Syndrome: 1, 2

• Initial bolus: Administer 20 mL/kg isotonic crystalloid over 5-10 minutes 1, 2
• Immediate reassessment: After bolus completion, evaluate response 1
• Additional boluses: Consider if inadequate response 1
• Severe shock: For pulse pressure <10 mmHg, consider colloid solutions (show benefit for time to resolution of shock compared to crystalloids alone) 1
• Vasopressors: For persistent tissue hypoperfusion despite adequate fluid resuscitation, use dopamine or epinephrine 1

Critical caveat: In resource-limited settings without mechanical ventilation and inotropic support, aggressive fluid boluses may increase mortality, but for dengue shock specifically, colloids show benefit. 1 Avoid over-resuscitation as excessive fluids can worsen outcomes given the underlying plasma leakage pathophysiology. 2

Management of Complications

• Significant bleeding: Blood transfusion may be necessary 1, 4
• Persistent fever: Common and typically resolves within 5 days; obtain blood/urine cultures and chest radiograph if fever persists to rule out secondary bacterial infections 1
• Severe cases: Continuous cardiac telemetry and pulse oximetry monitoring 1

Critical Pitfalls to Avoid

• Never use aspirin or NSAIDs: These increase bleeding risk significantly and should be avoided under any circumstances when dengue cannot be excluded 1
• Do not delay fluid resuscitation: In patients showing signs of shock, immediate intervention is essential 1
• Do not change antibiotics based solely on persistent fever: Without clinical deterioration or new findings, this is inappropriate 1
• Monitor narrow pulse pressure closely: This is an earlier and more sensitive indicator of dengue shock than absolute hypotension 2

Special Populations

Pregnant Women

• Acetaminophen remains the safest analgesic option 1
• Hospitalization recommended due to risk of maternal death, hemorrhage, preeclampsia, and vertical transmission 1
• Test for both dengue and Zika virus by NAAT regardless of outbreak patterns 1

Children

• Acetaminophen dosing should be carefully calculated based on weight 1

Discharge Criteria

Patients can be safely discharged when ALL of the following are met: 1

• Afebrile for ≥48 hours without antipyretics 1
• Resolution or significant improvement of symptoms (including respiratory symptoms if present) 1
• Stable hemodynamic parameters for ≥24 hours without support (normal heart rate, stable blood pressure, normal capillary refill time) 1
• Adequate oral intake 1
• Adequate urine output (>0.5 mL/kg/hour in adults) 1
• Laboratory parameters returning to normal ranges 1
• Improved general condition and return to baseline mental status 1

Post-Discharge Instructions

• Monitor temperature twice daily 1
• Return immediately if: Temperature rises to ≥38°C on two consecutive readings or any warning signs develop 1

Prevention

• Vector control: Day-biting mosquitoes of the genus Aedes (particularly Aedes aegypti) are the primary vectors 1, 6
• Vaccination: Consider after documented initial infection 6
• Mosquito bite avoidance: Meticulous prevention measures 6