Patient handout

Dengue (DENV-1/2/3/4) — without warning signs + with warning signs (critical phase) + severe dengue (DSS / bleeding / organ failure) + pregnancy + secondary heterologous infection + returning traveler differential + fluid overload recovery + vaccine decision (Dengvaxia seropositive-only / Qdenga any serostatus where approved)

PRODUCTION

1. Your condition

This handout is for dengue (denv-1/2/3/4) — without warning signs + with warning signs (critical phase) + severe dengue (dss / bleeding / organ failure) + pregnancy + secondary heterologous infection + returning traveler differential + fluid overload recovery + vaccine decision (dengvaxia seropositive-only / qdenga any serostatus where approved). Your care team identified this based on: acute high fever ≥ 39 °c + retro-orbital pain + breakbone myalgia + arthralgia + facial flushing + transient maculopapular rash + headache — classical dengue febrile-phase presentation (who 2009 + 2024; simmons nejm 2012 pmid 22494122).

Other reasons your team may use this plan: warning signs in critical phase (days 4-6, defervescence): abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation (ascites / pleural effusion), mucosal bleed, lethargy / restlessness, hepatomegaly > 2 cm, hct rise concurrent with rapid platelet fall (who 2009 + 2024); severe dengue with shock (dss) — narrow pulse pressure ≤ 20 mmhg, cap refill > 2 s, overt hypotension, cold extremities, tachycardia, decreased uop — life-threatening (who 2009 + 2024; wills nejm 2005 pmid 16135832); severe bleeding — gi bleed, gu bleed, intracranial bleed, mucosal hemorrhage with hemodynamic instability — life-threatening (who 2009 + 2024; lye lancet 2017 pmid 28283286).

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
acetaminophen	Pediatric: 10-15 mg/kg/dose q4-6h PRN (max 60 mg/kg/d in dengue critical phase or hepatitic); adult: 500-1000 mg q6h PRN (max 4 g/d if no hepatitis; 2 g/d if hepatitis)	PO	q4-6h PRN	Paracetamol ONLY in dengue — AVOID aspirin (Reye syndrome + bleeding), NSAIDs (bleeding + AKI), IM injections (hematoma in thrombocytopenia), anticoagulants (bleeding). Max dose reduced to 60 mg/kg/d pediatric / 2 g/d adult if hepatitic (AST/ALT ≥ 1000) per WHO 2009 + 2024 + AAP Red Book 2024

Plan: Dengue supportive care + paracetamol + IV crystalloid (LR / NS) titrated by Hct + UOP + clinical + colloid (dextran 40) for fluid-refractory shock + packed RBC for active bleeding + NO prophylactic platelet transfusion + empiric IV acyclovir for encephalitis differential + furosemide cautious in recovery phase + Dengvaxia (CYD-TDV) seropositive ≥ 9 yo + Qdenga (TAK-003) any serostatus 4-60 yo where approved

3. When to call your provider

Contact your care team if any of the following happen:

Warning signs emerge → urgent ED + CBC + LFT + coags + admit for IV crystalloid maintenance
Severe dengue features (shock, severe bleeding, severe organ failure) → urgent ED + ICU + crystalloid bolus
Pregnancy + active disease → urgent ED + admit regardless of warning-sign status
Dehydration with inability to maintain oral intake → urgent ED + IV fluids
Persistent fever > 7 d → reassess for alternative etiology (bacterial co-infection, atypical course, alternative dx)

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

Severe dengue with shock (DSS — life-threatening) — narrow pulse pressure ≤ 20 mmHg, overt hypotension, cap refill > 2 s, cold extremities, tachycardia, decreased UOP; ICU + IV crystalloid bolus 10-20 mL/kg over 1 h (compensated) or 15-30 min (hypotensive); titrate by Hct + UOP + clinical (NOT MAP alone — over-titration to high MAP can mask under-resuscitation); colloid (dextran 40) 10 mL/kg for fluid-refractory; vasopressor (norepinephrine) for vasopressor-dependent per SSC 2026; avoid blanket 30 mL/kg sepsis bolus per dengue-specific cautious-fluid caveat (WHO 2009 + 2024; Wills NEJM 2005 PMID 16135832; SSC 2026)(life-threatening)
Dengue with warning signs in critical phase (days 4-6, defervescence + plasma leakage window) — abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation (ascites / pleural effusion), mucosal bleed, lethargy / restlessness, hepatomegaly > 2 cm, Hct rise concurrent with rapid platelet fall; admit for IV crystalloid maintenance (LR or NS 5-7 → 3-5 → 2-3 mL/kg/h) + serial Hct + platelets q4-6h; transition to severe dengue within hours possible (WHO 2009 + 2024; PAHO 2022; AAP Red Book 2024)
Severe dengue with severe bleeding (life-threatening) — GI / GU / intracranial / mucosal hemorrhage with hemodynamic instability; packed RBC transfusion for active bleeding (NOT prophylactic regardless of platelet count); cryoprecipitate / FFP if coagulopathy / low fibrinogen; tranexamic acid considered per ID consult for severe bleeding (data emerging, not yet standard); **NO prophylactic platelet transfusion regardless of count per WHO 2009 + Lye Lancet 2017 PMID 28283286** (RCT showed no reduction in bleeding); ICU + correct shock (WHO 2009 + 2024; Lye Lancet 2017 PMID 28283286)(life-threatening)
Dengue in pregnancy (any trimester) — severe; admit for surveillance regardless of warning-sign status; vertical transmission risk peripartum (neonatal dengue surveillance: vesicle / cord blood PCR + serial CBC + LFT for neonate) + PPH risk + maternal-fetal medicine consult; teratogenicity controversial in dengue (less established than rubella, zika); maternal mortality elevated especially with severe disease; MMR equivalent contraindication NOT applicable (Dengvaxia + Qdenga are live attenuated and CONTRAINDICATED in pregnancy); postpartum vaccination planning where approved (ACOG; Paixao Lancet ID 2016 PMID 26949028; WHO 2024)
Suspected secondary heterologous dengue infection (prior documented dengue OR seropositive baseline serology) — severe; antibody-dependent enhancement (ADE) raises severe-dengue risk ~ 7-10× primary infection (Halstead Lancet 2007 PMID 17993365); admit threshold lower; lifetime serology baseline documented + counseling on secondary-heterologous-infection ADE risk for future endemic-area travel; vaccine decision: Dengvaxia (CYD-TDV) appropriate for seropositive ≥ 9 yo + Qdenga (TAK-003) any serostatus 4-60 yo where approved (CDC ACIP 2021 PMID 34978547; EMA 2022)
Severe dengue with severe organ dysfunction (life-threatening) — hepatitis (AST/ALT ≥ 1000; reduce paracetamol max-dose to 60 mg/kg/d pediatric / 2 g/d adult; avoid additional hepatotoxic drugs), encephalitis (altered mental status, seizures, focal deficits — HSV encephalitis is major treatable mimic; empiric IV acyclovir 10 mg/kg q8h pending HSV PCR per Tunkel IDSA encephalitis 2008), myocarditis (cardiac dysfunction, arrhythmia, troponin elevation — echo + ECG + ICU + avoid fluid overload), AKI (Cr × 1.5-3 baseline; CRRT if RRT-requiring); ICU + supportive + organ-specific (WHO 2009 + 2024; Tunkel IDSA encephalitis 2008)(life-threatening)
AVOID aspirin / NSAIDs / IM injections / anticoagulants / corticosteroids in dengue critical phase — severe; bleeding risk (aspirin → Reye + bleeding; NSAIDs → bleeding + AKI; IM injections → hematoma in thrombocytopenia; anticoagulants → bleeding; corticosteroids no benefit, signal of harm); paracetamol ONLY for fever / pain (max 60 mg/kg/d pediatric or hepatitic; max 4 g/d adult, 2 g/d if hepatitis) per WHO 2009 + 2024 + AAP Red Book 2024 + FDA labels
Fluid overload in dengue recovery phase (days 7-10) — severe; third-space mobilization → pulmonary edema if over-resuscitated in critical phase; clinical features: dyspnea + crackles + CXR pulmonary congestion + falling Hct from haemodilution as third-space fluid returns to intravascular; reduce IV fluids + cautious furosemide IF clinical pulmonary edema (NOT prophylactic); reassess for myocarditis / cardiac dysfunction (echo + ECG + troponin); ICU monitoring if severe (WHO 2009 + 2024)

5. Follow-up

Post-acute: convalescent fatigue may last weeks; lifetime homologous-serotype immunity + ~ 2 yr cross-protection against heterologous serotypes; counsel on **secondary heterologous infection ADE risk** for future trips to endemic regions; lifetime serology baseline documented for future vaccine + risk-management decisions; vaccine decision (Dengvaxia seropositive-only per CDC ACIP 2021; Qdenga where approved); post-severe-dengue follow-up: hepatitis recovery (LFT trend), AKI recovery (creatinine + GFR trend), myocarditis recovery (echo + ECG), encephalitis recovery (neuro + neuropsychology + rehabilitation). Pregnancy: postpartum surveillance for neonatal dengue + PPH recovery + MFM follow-up. Travel-medicine counseling: vector avoidance + DEET-containing repellent + permethrin-treated clothing + standing-water elimination + pre-trip vaccination decision for future endemic-area travel. Public health reporting per local regulations (some jurisdictions require dengue reporting) (WHO 2009 + 2024; CDC Yellow Book 2024)

6. Sources

Guideline: WHO 2009 Dengue Guidelines: Diagnosis, Treatment, Prevention and Control + WHO 2024 update — canonical three-phase pathophysiology + warning signs + severe-dengue criteria + fluid algorithm + platelet-transfusion threshold + vaccine guidance + CDC Yellow Book 2024 Dengue chapter + PAHO 2022 Dengue Clinical Management Guidelines + AAP Red Book current edition (2024 + 2026 floor) Dengue chapter + CDC ACIP Dengvaxia 2021 (PMID 34978547; seropositive-only ≥ 9 yo) + EMA / Takeda Qdenga 2022 (TAK-003 tetravalent live attenuated; any serostatus 4-60 yo where approved; not yet FDA-approved) + Bhatt Nature 2013 (global burden) + Halstead Lancet 2007 (ADE) + Simmons NEJM 2012 (review) + Sridhar NEJM 2018 (Dengvaxia post-hoc subgroup) + Biswal NEJM 2019 (TIDES TAK-003) + Tricou Lancet Glob Health 2024 (TAK-003 long-term) + Lye Lancet 2017 (NO prophylactic platelet) + Wills NEJM 2005 (LR preferred first-line) + Paixao Lancet ID 2016 (pregnancy meta-analysis) + ACOG Practice Advisory Dengue in Pregnancy + Tunkel IDSA encephalitis 2008 (empiric IV acyclovir)