What is the appropriate management for a 6-year-old male patient with persistent fever, respiratory symptoms, and abdominal pain, following initial negative dengue tests?

Management of Pediatric Patient with Persistent Fever and Suspected Dengue

This 6-year-old requires immediate aggressive fluid resuscitation, continued dengue workup with repeat serology, chest imaging to evaluate the respiratory findings, and close monitoring for dengue warning signs given the concerning clinical trajectory despite initial negative testing.

Immediate Priorities

Fluid Management

• Initiate isotonic crystalloid bolus at 20 mL/kg (350 mL for this 17.5 kg child) with careful reassessment afterward, as this patient shows warning signs of potential dengue shock syndrome 1
• The current PLR at 55 mL/hr is appropriate for maintenance but may be insufficient if shock develops 1
• Target fluid intake exceeding 2500 mL daily for suspected dengue cases 1
• Monitor continuously for persistent tissue hypoperfusion; prepare vasopressors (dopamine or epinephrine) if fluid resuscitation proves inadequate 1

Fever and Pain Control

• Continue acetaminophen exclusively at the prescribed dose (4 mL of 250 mg/5 mL = 200 mg Q4 hours, approximately 11 mg/kg/dose), which is appropriate and safe 1
• Absolutely avoid aspirin and NSAIDs due to increased bleeding risk and platelet dysfunction in dengue 1
• Implement tepid water sponging for high fevers 2

Diagnostic Workup Rationale

Dengue Evaluation

The initial negative NS1 does not exclude dengue, as this patient is now on day 4-5 of illness 1:

• Repeat dengue NS1 AND obtain dengue IgM/IgG serology, as nucleic acid tests are most useful ≤7 days from symptom onset, while IgM capture ELISA becomes positive after 5-7 days 1
• The presence of nosebleeding (mucosal bleeding) and vomiting are concerning warning signs for dengue progression 1
• Abdominal pain, particularly LLQ tenderness, is a recognized warning sign in dengue 1

Respiratory Assessment

• Obtain chest X-ray AP/lateral immediately to evaluate the decreased breath sounds at left base, as this could represent pneumonia, pleural effusion (parapneumonic or dengue-related), or other complications 2
• Pleural effusion in dengue can indicate more severe disease and plasma leakage 3
• The combination of fever, productive cough, and decreased breath sounds suggests possible bacterial pneumonia as a concurrent or alternative diagnosis 2

Laboratory Monitoring

The ordered tests are appropriate 2, 1:

• Daily CBC with platelet count and hematocrit to track for thrombocytopenia and hemoconcentration (rising hematocrit with falling platelets is a dengue warning sign) 1
• Electrolytes (Na, Cl), renal function (BUN, Creatinine) to assess hydration status and organ function 2
• Urinalysis to evaluate for UTI as alternative diagnosis 2

Critical Monitoring Parameters

Warning Signs Requiring Intensive Surveillance

Monitor continuously for 1:

• Persistent vomiting (already present - 3 episodes)
• Severe abdominal pain (present - LLQ tenderness)
• Lethargy/restlessness (decreased activity and irritability noted)
• Mucosal bleeding (epistaxis already occurred)
• Rising hematocrit with falling platelet count
• Hepatomegaly or ascites development

Hemodynamic Monitoring

• Continuous assessment of blood pressure, heart rate (currently tachycardic at 122), capillary refill time (currently normal at <2 sec), and urine output 1
• Current BP 90/60 is at lower limit for age (normal pediatric SBP = 70 + (2 × age in years) = 82 mmHg minimum) 2
• Oliguria defined as <0.5 mL/kg/hour for 8 hours in this age group 2

Differential Diagnosis Considerations

Beyond Dengue

Given the clinical presentation, consider 2:

• Bacterial pneumonia with parapneumonic effusion - supported by productive cough, decreased breath sounds, fever >3 days 2
• Intra-abdominal infection - LLQ tenderness, vomiting, fever warrant consideration 2
• Typhoid fever - persistent fever, abdominal pain, relative bradycardia absent but still possible 3
• Other viral infections - influenza, other arboviruses 2

Imaging for Abdominal Pain

• If dengue workup remains negative and abdominal symptoms persist, ultrasound of abdomen is the initial imaging of choice in pediatrics to evaluate for appendicitis, intussusception, or other pathology 2
• CT scan is reserved for adults or when ultrasound is inconclusive 2

Antibiotic Considerations

Do not initiate empiric antibiotics immediately unless bacterial pneumonia or sepsis is strongly suspected, as this could mask concurrent bacterial infection while dengue workup is pending 2:

• If chest X-ray confirms pneumonia, initiate appropriate antibiotics (ceftriaxone or ampicillin-sulbactam for community-acquired pneumonia) 2
• For suspected intra-abdominal infection with fever and peritoneal signs, broad-spectrum coverage should begin once diagnosis is established 2
• Blood and urine cultures should be obtained before antibiotics if bacterial infection is suspected 2

Disposition and Follow-up

Admission Criteria (Already Met)

This patient requires hospitalization given 2, 1:

• Persistent fever >3 days
• Warning signs of dengue (mucosal bleeding, vomiting, abdominal pain)
• Respiratory compromise (decreased breath sounds)
• Need for IV fluid resuscitation

Discharge Criteria (For Future Reference)

Patient can be discharged only when 1:

• Afebrile ≥48 hours without antipyretics
• Resolution or significant improvement of symptoms
• Laboratory parameters returning to normal
• Stable hemodynamics ≥24 hours without support
• Adequate urine output (>0.5 mL/kg/hour)

Common Pitfalls to Avoid

• Do not dismiss dengue based on single negative NS1 test early in illness - serology timing is critical 1
• Do not delay fluid resuscitation while awaiting test results - dengue shock can develop rapidly 1
• Do not use NSAIDs or aspirin for fever control - increases bleeding risk 1
• Do not overlook concurrent bacterial infections - pneumonia can coexist with dengue 2
• Do not assume abdominal pain is solely dengue-related - maintain broad differential 2

2, 3, 1