DENGUE FEVER Amila Weerasinghe MBBS Undergraduate 2010/2011 Batch (21 st ) Faculty of Medical Sciences University of Sri Jayewardenepura Sri Lanka 19/01/2015
DENGUE
FEVER
Amila Weerasinghe
MBBS Undergraduate2010/2011 Batch (21st )Faculty of Medical SciencesUniversity of Sri JayewardenepuraSri Lanka
19/01/2015
1. What is ‘’Dengue’’ ?
2. Epidemiology
3. Vector
4. Virus
5. Pathogenesis of the disease
6. Classification
7. The natural course of the illness
8. Diagnosis and Management at OPD level
and by primary care physician.
9. In-ward Management of DF/DHF
10. Management of complicated patients
Contents
A vector borne disease.
The most rapidly spreading mosquito-borne viral disease in the world.
A notificable disease in Sri Lanka
World situation
last 50 years, 30 fold rise
2.5 billion or 40% of the world, live in
dengue endemic countries.
WHO (2009).Dengue: guidelines for diagnosis, treatment, prevention and control -- New edition
Sri Lankan situation
First serologically confirmed case - 1962
First documented dengue outbreak -1965- 1966
First epidemic of DHF/ Dengue Shock Syndrome - 1989 – 1990.
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
Cases
Year 2014, 46584 suspected dengue cases
55.26% of dengue cases from the Western province.
http://www.epid.gov.lkhttp://www.dengue.health.gov.lk
A biological vector – Mosquitoes In Sri Lanka Aedes albopictus and Aedes aegypti
Aedes aegypti is the main species.
Genus – Flavi virus
Family – Flaviviridae
Virus – Dengue virus (DEN)
Serotypes – 4 serotypes
DEN 1 to 4
Secondary dengue infection
# Viral infection, except
which resulted the primary infection.
# NOT necessarily the ‘’second’’ dengue
infection.
2 – 7 days of illness + high grade feverHeadacheRetro – orbital painMyalgiaArthralgiaRash & haemorrhagic manifestations
positive tourniquet test
petechiae
Criteria
High fever/ recent history of acute fever
A (+)ve tourniquet test
Thrombocytopaenia <100,000 cells/mm3
Objective evidence of leaky capilaries•≥20% Elevated haematocrit•Pleural or other effusion - eg, ascites.•Low protein.
Dengue haemorrhagic fever is a
dynamic disease
1. Febrile phase
2. Critical phase
3. Convalescent phase
Management as out patients
Oral fluid (maintainance)
Eg:-oral rehydration fluid,king coconut juice, fruit juices….etc
Except plain water and red and brown drinks
Rest & tepid sponging
Paracetamol 10-15mg/kg/dose (max 60mg/kg/day)
Anti-emetics and H2 RB.
NO NSAIDs or any STEROID
Review with FBC , 1st after 3 days of onset
Advice to return immediately for
review…… if……
When to admit the patient ?
Clinical judgment
All patients with plt 100,000/mm3
All patients with warning signs
Following patients with probable dx of DF
should admit.
Infants
Obese
Major co-morbidities
Adverse social circumstances
Platelet count
Initially normal drops < 100,000/mm3
in 50% DF & 100% DHF
Tender hepatomegaly DHF > DF
Erythematous/ maculo-papular rash DHF < DF
Adequate fluid intake
Total fluid requirement degree of dehydration(oral + IV)
Maintenance volume
Infants <6 months – 5% dextrose in N/2
Others – normal saline
Adequate physical rest
Paracetamol 10-15mg/kg/dose
(max 60mg/kg/day)
NO all NAIDSs & STEROIDS
Monitoring - ( Annexure iii) in the dengue
guideline
Seen only in DHF
late febrile phase;
3rd day to 7th day of illness up.
Rapid drop in temperature
Lasts for 24 – 48 hours
DHF is a very dynamic disease.
Identifying
the beginning & the end of the critical phase
is a KEY FACTOR
in guiding fluid therapy in DHF.
Leak starts slowly, increases gradually,
peak around 24 hours, slows down and
ceases around 48 hours.
0
5
10
15
20
25
30
0 20 40 60
.
Until the very last stage of shock; patient can
appear conscious & very alert
If Pulse Rate & Blood pressure NOT measured,
early shock could be missed.
Platelets <100,000/mm3
Be Alert
Patient may be in either of the,
DF(50% of patients)
DHF febrile phase
DHF critical phase (early or late)
2. Objective evidence detected radiologically
Pleural effusion USS chest
Chest X-ray RightLateral decubitus
Ascites : USS abdomen
3. Biochemical parameters
Serum albumin < 3.5g/dl or dropped by 0.5g/dl
Serum cholesterol <100mg/dl or dropped by 20mg/dl
( NON fasting )
Calculation of the fluid quota (oral+IV)
Max fluid intake during ENTIRE critical phase [Irrespective of its length]
Maintenance + 5% deficit
Maintenance = 100ml/kg for 1st 10kg
+ 50ml/kg for next 10kg
+ 20ml/kg for the balance weight
5% deficit = 50ml/kg x body weight (kg)
Ideal body weight
Weight for height [ BEST ]Weight for age
BUT
Actual body weight is taken for the calculations,
if the actual weight < ideal weight
Growth chart –50th centile
IV fluids
N/2 +5% dextrose < 6 months infants
N saline + 5% dextrose > 6 months; who is not taking orally for prolonged
[ 50ml of 50% dextrose + 450ml N saline ]
A patient without shock
IV normal saline/ Hartmann’s solution –largest possible size for the age. + oral fluids
Initially; oral +IV = 1.5ml/kg/hr
Who can drink well = 0.5ml/kg/hr
Pulse, BP, Pulse pressure, CRFT,HCT &
UOP
UOP calculation
Hourly UOP ; Best guide for the rate of infusion
0.5-1.0ml/kg/hr sufficient
IF
UOP >1.0 – too high infusion rates
UOP <0.5 – inadequate fluids
Signs
• Cold extremities
• CRFT > 2 sec
• Unexplained tachycardia
• Increased DBP
• Narrowing pulse pressure 20mm/Hg
Mx of shock (if pulse & BP not picked up.)
After 2 crystalloid boluses;
Already having a fluid overload
The full fluid quota given.
Dextran 40 – up to 3 doses within 24 hrs(10ml/kg/hr)
6% Starch – up to 5 doses within 24 hrs(10ml/kg/hr)
Lasts for 2-5 days
Reabsorption of the extravasated fluid.
ComplicationsFluid overloadHypocalaemiaNosocomial infections
No fever 24hrs, without antipyretics
At least 2 days after recovery from shock
Generally good & Increasing apetite
Normal HCT for age..
[baseline around 38-40% when not known]
No distress from pleural effusion or ascitis
Rising platelet count & >50,000/mm3
No other complication
Prolonged shock
>4 hrs organ failure
Liver failure 50% prognosis
Liver + Renal 10% prognosis
3 organs(+ respiratory) very bad
Fluid overload
Features :-
Early- puffy eye lids, distended abdomen
(ascites), tachypnoea, mild dyspnoea
Late – Respiratory distress, SOB, &
wheezing
Acidosis
More prone to DIC & massive bleeding.
pH < 7.35 (Arterial normal 7.35-7.45)
HCO3- < 15 mmol/l (Arterial normal 22-24)
Emperically
NaHCO3 1ml/kg slow bolus (max 50ml)
Diluted in equal volume of Normal Saline
Use Packed Red Cells
5ml/kg once
5ml/kg of PRC HCT by 5 points
(eg:- 30 to 35)
If HCT > 45%, blood given only after
reducing HCT by a colloid.
Hypocalcaemia
Mostly with ‘’convulsions’’Measure serum Ca2+ levels
Give calcium if complicated
1ml/kg of 10% Ca Gluconate,(max 10ml)Slow IV bolus over 15-20 minsDiluted in equal volume of NSRepeat 6 hourly
Hypoglycaemia
Prevented by NS with 5% Dextrose
•Dextrose saline (0.9% NaCl with 5%
Dextrose)
•Add 50ml 50% Dextrose to 450ml of
0.9% NaCl
Immediate goalplasma glucose at least 70mg/dl
10% dextrose, 2ml/kg by IV push
Continue IV dextrose rate at 8mg/kg/min
Hyponatraemia
Mainly due to Hyponatraemic fluids
N/2 NaCl, N/5 NaCl, Water
3% NaCl is 3-5ml/kg
Slow IV
Through a larger vein; mostly a central vein
Encephalopathy
Mainly - Hepatic encephalopathy
Maintain cerebral perfusion pressure(CPP)
Maintain - Mean arterial pressure (MAP)
Reduce – Intra Cranial pressure (ICP)
CPP = MAP - ICP
Airway oxygenation with O2 therapy
Fluid management
Maintain MAP
Reduce ICP
Maintain blood sugar level >70 mg/dl
Maintain K+ & Na+ levels normal3% NaCl if Na+ < 120meq/l
Vit K IV 3mg <1yr 5mg 1-5yrs, 10mg >5yrs
IV Phenobarbitone - cerebral metabolismControls seizures
Gut cleaning NG tubeAntibiotics – MetranidazoleLactulose
Platelet transfusionRecombinant factor vii InotropsSteroids & IV immunoglobulinsFresh frozen plasma (FFP)Frusemide
Consider each patient as a dengue patient,
as its presentation is changed.
Avoid all NSAIDs & steroids.
Correct diagnosis during early febrile phase
improves the prognosis.
Identifying the beginning & the end of the critical phase is a key factor in guiding fluid therapy in DHF.
Correct fluid management during the critical phase is the most important.
Pulse pressure, HR, HCT & UOP
Be concern about the possible complications.