Monitoring the disease:
- Platelet count predicts the severity of disease, but is NOT predictive of bleeding.
- WCC normally normalizes followed by platelets.
- Norml Hct in man in Malaysia is ~45, in woman is ~40.
- Other important lab tests are coagulation profile (PT/PTT), LFT, renal profile, lactate and blood gases, CK
- Dengue IgM negative before day 5-7 cannot be used to exclude dengue infection.
- If dengue IgM is negative before day 7, repeat sample must be taken during recovery phase
- If dengue IgM is negative EVEN after day 7, need to take IgG.
Warning signs of dengue
- Diarrhea is now recognized as one of the warning signs.
Frequency of monitoring:
- Vital signs: 4-6 hourly; if critical 2-4 hourly
- Lab tests:FBC 4-12 hourly depending on clinical status, others at least daily
- Hct should be measured BEFORE and AFTER fluid resus
Common pitfalls in fluid management of dengue
Choice of fluid is crystalloid
- How to calculate IV fluid maintenance requirement?
– Non obese = 1.2-1.5 ml/kg/hour
– Obese = use ABW
ABW = IBW + 0.4(actual weight – IBW)
Role of colloid
- No role of HES –> increases incidence of renal failure and need for hemodialysis, contraindicated in liver and renal failure and with fluid overload state
- Albumin maybe okay
– Used in decompesated shock and if 2 rounds of crystalloids infusion does not improve condition
Dengue shock syndrome
- Pulse pressure < 20 and SBP < 90 are late signs, we want to prevent dengue to progress to decompesated shock.
- GXM early, ANTICIPATE BLOOD TRANSFUSION !
General idea of dengue shock resus
Metabolic acidosis in dengue
- Due to lactate acidosis due to tissue hypoperfusion
- Giving fluid will reverse acidosis, NaHCO3 is NOT recommended
- Persistent acidosis = CONSIDER BLEEDING !
- Lactate clearance >20% in 2 hours improve survival
- Due to met.acidosis, resp.alkalosis is predicted.
- IF resp.acidosis, consider PLEURAL EFFUSION or FLUID OVERLOAD !
- Hyponatremia is common and is a marker of disease severity.
When to consider occult bleeding?
- Transfuse whole blood 10-20 ml/kg or 10 ml/kg of PRBC
- Oxygen delivery at tissue level is deemed optimal only with fresh packed red cells or whole blood because of higher levels of 2, 3 diphosphoglycerate (2,3 DPG).
– However, recently published studies done in non-dengue critically ill patients and patients undergoing cardiac surgery have not shown any difference in patient outcomes when transfused fresh blood < 8 days old compared to blood stored longer (> 21 days).
Dengue in pregnancy?
- Diagnosis is hard because
– Hct is lower/near normal due to hemodilution.
– DBP is lower in 2nd trimester with wider PP.
– Due to presence of gravid uterus, detection of third space fluid accumulation is harder.
- Dengue in pregnancy is associated with bad maternal and fetal outcome
– Mother: more likely to develop DSS
– Fetal: abortion preterm birth, IUGR etc
– Complications are more likely if the infection happens in 1st and 3rd trimester.
- Vertical transmission is possible, BUT ONLY IN SYMPTOMATIC PATIENTS.
– Asymptomatic mother has lower level of viraemia so vertical transmission is less likely.
- Vaginal delivery is still the method of choice.
– If premature labour happens, it is advisable to use tocolytics to delay the delivery until acute infection resolves.
- During labour, IM INJECTION should be avoided (eg IM oxytocin for PPH)
- Routine platelet transfusion is NOT indicated.
- For the baby, serological test should be performed to confirm congenital infection. No long term fetal abns are noted with congenital dengue.
Marker of severity in dengue
Reference: CLINICAL PRACTICE GUIDELINES. MANAGEMENT OF DENGUE INFECTION IN ADULTS (THIRD EDITION). Published by: Malaysia Health Technology Assessment Section (MaHTAS)