2. INTRODUCTION
• Dengue fever is an acute febrile illness characterised by fever ,
myalgia , arthralgia and rash .
• Severe dengue infection is characterised by abnormalitiesin
hemostasis and by leakage of plasma from the capillaries which may
lead to dengue shock syndrome.
3. ETIOLOGY
VIRUS :
• Dengue fever is caused by any of the 4 dengue serotypes ,
arboviruses of the family Flaviviridae .
• Four well defined dengue viruses are identified , DENV -1, DENV -
2,DENV -3 and DENV – 4 .
• The envelop protein bears epitopes that are unique to the serotypes .
• Antibodies to these antibodies neutralize by interfering with entry of
virus into the cells .
• There are other epitopes that are shared between dengue viruses
and other flaviviruses .
4. ETIOLOGY
VECTOR :
• Female Aedes mosquito .
• Also known as tiger mosquito .
• Day biter , mainly feeds on human beings in domestic and peri
domestic situations .
• Bites repeatedly .
• Typically container habitat species .
• Mosquito breeds in any type of man made containers or storage
containers having even a small quantity of water .
• Eggs of Aedes aegypti can live without water for more than one year .
5. ETIOLOGY
TRANSMISSION
• Dengue viruses are transmitted to humans through bites of infected
Aedses mosquito .
• Mosquitoes acquire the virus while feeding on blood of an infected
person .
• After incubation period of 3-7days , an infected mosquito is capable ,
during probing and blood feeding of transmitting the virus to
susceptible individuals for the rest of its life .
• The virus circulates in the blood of the infected humans for 2-7 days ,
at approximately the same time of the fever .
7. CLINICAL MANIFESTATIONS
FEBRILE PHASE
• High grade fever lasting for 2-7 days .
• Accomapanied by facial flushing , skin erythema , bodyache , myalgia
,arthralgia , headache , nausea and vomiting ,sore throat , injected
pharynx and conjunctiva .
• Petechiae , epistaxis and gum bleeding may be seen .
• The earliest change in the full blood count is a progressive decrease
in the WBC count and platelet count .
8. CLINICAL MANIFESTATIONS
CRITICAL PHASE
• Usually appears during defervescence , 3-7days from onset of fever
• Progressive leucopenia , thrombocytopenia usually preceeds
plasma leakage. Rising HCT is another early sign .
• It may present as
1. Dengue Shock Syndrome (DSS) :
Increased capillary permeability leads to plasma leakage
Loss of plasma volume- volume depletion , features of shock ,
raised hematocrit .
Accumulation of fluid in serous cavities – ascites , pleural effusion .
2. Dengue Hemmorhagic Fever (DHF) : Due to thrombocytopenia
May present as –
Superficial bleed ( purpura ,echymosis, epistaxis and gum bleeding)
Deep bleed (GI bleed , GU bleed , ICH , Intra abdominal bleeding )
3. Multiorgan dysfunction : Hepatitis, encephalitis , myocarditis etc .
9. CLINICAL MANIFESTATIONS
RECOVERY PHASE
• After 24-48 hours of critical phase ,a gradual resorption of
extravascular compartment fluid takes place in next 48-72 hrs .
• The general well being improves, apetite returns, hemodynamic
status improves.
• Some may exhibit pruritus , rash of ‘islets of white in the sea of red’
• Blood parameters : PCV stabilizes or may be low due to hemodilution
, WBC count rise after defervescence , recovery of thrombocytopenia
may take longer.
10. WARNING AND DANGER SIGNS OF DENGUE
• Bleeding: epistaxis, scanty haemoptysis, haematemesis, gum bleeding,
black coloured stools, excessive menstrual bleeding, dark-coloured urine or
haematuria.
• Lethargy and/or restlessness, sudden behavioural changes.
• Convulsions.
• Difficulty in breathing or palpitation or breathlessness.
• Persistent vomiting >3 times a day.
• Severe abdominal pain
• Enlarged and/or tender liver > 2 cm.
• Clinical fluid accumulation.
• Postural hypotension-dizziness.
• Pale, cold clammy hands and feet.
• Not able to drink and no urine output for 4-6 h/ urine output less than 0.5
ml/kg/h.
• Rising HCT (>45%)together with rapid fall in platelet count.
• Metabolic acidosis.
• Derangement of liver/ kidney function tests.
• Pleural effusion/ ascites/ gall bladder oedema on imaging.
17. MANAGEMENT OF DENGUE FEVER
i. Management of dengue fever is symptomatic and supportive
ii. Bed rest is advisable during the acute phase.
iii. Use cold/tepid sponging to keep temperature below 38.5° C.
iv. Antipyretics may be used to lower the body temperature. Aspirin/NSAIDs like
ibuprofen, etc should be avoided since it may cause gastritis, vomiting,
acidosis,platelet dysfunction and severe bleeding. Do not even use combination
of paracetamol with above mentioned drugs .
v. Encourage oral intake to replace fluid loss from fever and vomiting. Small
amounts of oral fluids should be given frequently for those with nausea and
anorexia. The choice of fluids should be based on the local culture: coconut water,
rice water or barley water. Oral rehydration solution or soup and fruit juices may be
given to prevent electrolyte imbalance and are preferable to plain water . Sufficient
oral fluid intake should result in a urinary frequency of at least 4 to 6 times per day.
A record of oral fluid and urine output could be maintained and reviewed daily .
vi.Patients should be monitored for 24 to 48 hours after they become afebrile for
development of complications .
[Note: In children the dose of paracetamol is calculated as per 10-15 mg/Kg body
weight per dose. Paracetamol dose can be repeated at intervals of 6 hrs
depending upon fever and body ache.]
25. DETAILS ABOUT INTRAVENOUS FLUID THERAPY
1. What type of IV Fluids therapy should we use ?
• Use isotonic solutions ( NS , RL )
• NS is the preferred fluid of choice.
• RL may not be suitable for resuscitation of patients with severe
hyponatremia as it has lower sodium level ( 131 mmol/l ) . However , it is a
suitable solution after 0.9 % NS has been given and the serum chloride level
has exceeded the normal range .
• RL should be preferably be avoided in liver failure and in patients taking
metformin where lactate metabolism may be impaired .
• Colloids are preferred if BP has to be restored early .
2. When are colloids given ?
• Hypotensive shock .
• If Hct does not decrease after crystalloid administration in shock state .
3. Which IV fluids are not used ?
• Hypotonic fluids , eg 0.45 % NS
• Dextrose solutions should be limited to avoid hyperglycemia .
• Albumin solutions .
27. MANAGEMENT OF SEVERE BLEEDING
• In case of severe bleeding , patient should be admitted in the hospital
• Investigate to look for the cause and the site of bleeding .
• Immediate attempt should be made to stop the bleeding .
• If the patient has thrombocytopenia with active bleeding , it should
be treated with BT and if required platelet transfusion .
• In case of massive hemorrhage blood should be tested to rule out
coagulopathy by PT and APTT .
• Patients of severe bleeding may have liver dysfunction , LFTs should
also be performed .
30. MANAGEMENT OF FLUID OVERLOAD
A patient of dengue may have fluid overload due to
• excessive or rapidly transfused IV fluids , hypotonic fluids , and
inappropriate use of FFP or platelets .
• Continuation of IV fluids even during the phase of plasma
reabsorption and recovery .
Management :
1. Oxygen therapy .
2. Discontinuation or reduction of IV fluids .
3. Furosemide 0.1-0.5 mg/kg/dose once or twice daily , maintain
serum potassium .
4. Look for occult hemorrhage and transfuse packed cells .
33. DISCHARGE CRITERIA
• No fever for atleast 24-48 hrs with clinical improvement .
• Normal blood pressure .
• No respiratory distress from pleural effusion and ascites .
• Improvement in clinical status ( general well being , return of apetite ,
adequate urine output , no respiratory distress ).
• Persistent platelet count > 50,000 / cumm .
