What are the causes, complications, and recommended treatment for dengue infection?

Dengue: Karan, Complications, aur Treatment

Dengue ek mosquito-borne viral infection hai jo Aedes aegypti aur Aedes albopictus machhar ke kaatne se failta hai, jisme char serotypes (DENV-1 se DENV-4) hote hain, aur iska treatment purely supportive hai kyunki koi specific antiviral drug available nahi hai 1, 2.

Dengue Ka Karan (Cause)

Dengue virus (Flaviviridae family) char serotypes mein aata hai. Infection tab hota hai jab:

• Infected Aedes machhar (jo din mein kaatte hain) ek infected person ko kaatkar virus ko dusre person mein transfer karte hain 3, 4
• Incubation period: 4-8 din (range: 3-14 din) 4
• Geographic distribution: Tropical aur subtropical areas, especially Asia aur South America - 100+ countries mein present hai with 50-100 million cases annually 4

Important caveat: Agar kisi ko pehle ek serotype se infection ho chuka hai, toh dusre serotype se reinfection hone par severe disease ka risk bahut zyada badh jata hai due to antibody-dependent enhancement 3.

Clinical Phases aur Complications

Disease Phases 1, 2:

1. Febrile phase (7 din tak): High fever, headache, retro-orbital pain, severe myalgia/arthralgia (breakbone fever), rash
2. Critical phase (24-48 hours): Plasma leakage, thrombocytopenia - yeh phase sabse dangerous hai
3. Recovery phase: Gradual improvement

WHO 2009 Classification 3, 2:

• Dengue without warning signs: Mild febrile illness
• Dengue with warning signs: Abdominal pain, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy, liver enlargement >2cm, hematocrit increase with platelet decrease
• Severe dengue: Plasma leakage leading to shock/fluid accumulation with respiratory distress, severe bleeding, organ impairment (liver AST/ALT >1000, altered consciousness, heart/kidney involvement)

Major Complications 3:

Cardiac complications (12-50% hospitalized patients mein):

• Arrhythmias, pericarditis, myocarditis, LV dysfunction
• Myocarditis jo myocardial infarction jaisa lag sakta hai
• Men mein cardiac complications ka risk zyada hai compared to women 3
• Pediatric population mein bhi cardiac complications zyada common hain 3
• ECHO par koi bhi abnormality adverse outcomes se associated hai 3

Hemorrhagic complications:

• Thrombocytopenia, severe mucosal bleeding
• Dengue hemorrhagic fever (DHF) aur dengue shock syndrome (DSS) - mortality 1-5% 1

Other complications 5:

• Hepatitis (liver enzymes >1000)
• Encephalopathy/encephalitis
• Acute kidney injury
• Gastrointestinal bleeding

Diagnosis 4, 6, 1:

Timing-based testing approach:

• Days 0-5 of illness: RT-PCR (reverse transcriptase PCR) ya NS1 antigen detection - yeh preferred hai
• Day 5 ke baad: IgM capture ELISA (serology)
• Convalescent confirmation: IgG ELISA at 3 weeks

Laboratory findings:

• Thrombocytopenia (<100,000/mm³)
• Hemoconcentration (hematocrit increase ≥20%)
• Elevated liver enzymes
• Leukopenia

Important: Flavivirus cross-reactivity ho sakti hai (yellow fever, Japanese encephalitis vaccines ke saath), toh vaccination history zaroori hai 4.

Treatment - Supportive Management

Outpatient Management (Dengue without warning signs) 1, 2:

• Adequate oral hydration: Crystalloid fluids
• Fever control: Paracetamol only - 10-15 mg/kg every 6 hours
• CONTRAINDICATED: Aspirin aur NSAIDs (bleeding risk badhate hain) 7
• Daily monitoring for warning signs
• Complete blood count monitoring

Hospital Management (Warning signs ya severe dengue) 8, 2:

Fluid resuscitation - cornerstone of treatment:

• Crystalloids first-line: Normal saline ya Ringer's lactate
• Initial bolus: 5-10 mL/kg/hour under hematocrit monitoring 8
• Aggressive fluid therapy for 24-48 hours during critical phase 8
• >4 liters may be required in first 24 hours for adults 8

Special consideration:

• Severe dengue shock syndrome (pulse pressure <10 mmHg) mein colloids consider karein, especially children mein 8
• Moderate shock (pulse pressure 10-20 mmHg) mein crystalloids sufficient hain 8

Monitoring endpoints 8:

• Adequate tissue perfusion (warm extremities, normal capillary refill <2-3 seconds, good urine output >0.5 mL/kg/hr adults, >1 mL/kg/hr children)
• Systolic BP >90 mmHg in adults
• Normal heart rate
• Hematocrit levels

Refractory Shock Management 8:

Agar fluid resuscitation ke baad bhi tissue hypoperfusion persist kare:

• Dopamine ya epinephrine (adrenaline) infusion
• Preferably central line se, but peripheral large bore vein ya intraosseous route bhi use kar sakte hain
• Hydrocortisone (up to 300 mg/day) ya prednisolone (up to 75 mg/day) in escalating vasopressor requirements 8

Blood Product Transfusion 2, 5:

• Prophylactic platelet transfusion NOT recommended 2
• Transfuse only for:
  • Active severe bleeding
  • Platelet count <10,000/mm³ with high bleeding risk
  • Invasive procedures planned

Complications Management 2, 5:

• Secondary hemophagocytic lymphohistiocytosis: Steroids ya IVIG consider karein
• Myocarditis/cardiac dysfunction: Supportive care, avoid fluid overload
• Hepatic involvement: Supportive, monitor coagulation
• Bedside ultrasound for early detection of plasma leakage 5

Critical Pitfalls to Avoid:

1. NSAIDs/Aspirin use - bleeding risk dramatically increase hota hai 7
2. Over-aggressive fluid resuscitation - pulmonary edema/cardiac failure cause kar sakta hai, especially cardiac involvement mein 3
3. Ignoring warning signs - critical phase mein rapid deterioration ho sakta hai
4. Prophylactic platelet transfusion - unnecessary aur ineffective 2
5. Cardiac evaluation neglect - especially men aur pediatric patients mein cardiac complications underdiagnosed hain 3

Prevention:

• Dengvaxia vaccine: Live attenuated vaccine, only for documented previous dengue infection 9, 7
• Mosquito bite prevention (repellents, protective clothing, mosquito nets)
• Vector control measures

Note: Koi specific antiviral drug available nahi hai; multiple compounds under study hain but none approved yet 2, 9.