Dengue fever

Written by Dr.Md.Redwanul Huq (Masum)
Sunday, 15 January 2012 16:12

Definition:

Dengue fever, also known as breakbone fever, is a virus-based disease which is caused by one of four dengue viruses ( DEN 1, 2, 3 and 4), spread by mosquitoes, most commonly the mosquito Aedes aegypti, which is found in tropic and subtropic regions.

Classification of dengue fever:

  •  The 1997 WHO classification (which is still widely used)-

Classification of dengue fever

DHF is also divided into four grades according to the severity of Dengue infection-

  • DHF grade I
  • DHF grade II
  • DHF grade III
  • DHF grade IV

DHF grade III and IV are also called as Dengue Shock Syndrome (DSS).

  •  The 2009 WHO classification-
  1. Uncomplicated Dengue fever
  2. Severe Dengue fever

Symptoms, Signs & Laboratory Findings of Dengue Fever (DF) & Dengue Haemorrhagic Fever (DHF):

DF / DHF

Grades

Symptoms & Signs

*Laboratory Findings

DF

 Fever (of 2 – 7 days duration) with two or more of the following symptoms:
Headache , retro – orbital pain , myalgia /arthralgia, rash .		 Leukopenia, Thrombocytopenia may occasionally be present but No evidence of plasma loss(which is manifested by one or more of the following:
• A > 20 % rise in haematocrit (Hct) following treatment with fluids as compared to the baseline.
• Signs of plasma leakage( Pleural effusion,Ascites or Hypoprotienaemia).

DHF

 I Above symptoms plus Haemorrhagic manifestations like petechiae and positive tourniquet test( i.e. 20 or more petechiae per 1 square inch ) and signs of plasma leakage( Pleural effusion , Ascites or Hypoprotienaemia). Thrombocytopenia, Total Platelet Count(TPC) is
< 100×10^3/µl, Hct rise 20% or more.

DHF

 II Above symptoms & signs plus spontaneous bleeding, e.g.epistaxis, gum bleeding, bleeding from injection sites, haematemesis, melaena etc. Thrombocytopenia, Total Platelet Count(TPC) is
< 100×10^3/µl, Hct rise 20% or more.

DHF

 III Above symptoms & signs plus circulatory failure (rapid & weak pulse , narrow pulse pressure (20 mm Hg or less) ,hypotension  for age , cold & clammy skin & restlessness) . Thrombocytopenia, Total Platelet Count(TPC) is
< 100×10^3/µl, Hct rise 20% or more.

DHF

 IV Profound shock with undetectable blood pressure & pulse . Thrombocytopenia, Total Platelet Count(TPC) is
< 100×10^3/µl, Hct rise 20% or more.

DHF grade III & IV are also called as Dengue Shock Syndrome (DSS).

* Anti Dengue IgM (appear approximately 5 days after onset of symptoms, rise for next 1-3 weeks and detectable for up to 6 months) or IgG (detectable at approximately 14 days after onset of symptoms of dengue fever and are maintained for life) – Positive.

Treatment for Dengue Fever :

Febrile Phase Management
Duration 2 – 7 days
  • Bed rest
  • Keep the body temperature below 39° C
  • Paracetamol – yes
  • Aspirin –No
  • Ibuprofen or any other NSAID–should not be used in treatment for Dengue fever
  • Oral Rehydration Therapy (ORT)
  • Folow-up the patient for any change in TPC / Hct.

 
Afebrile Phase(Critical phase ) Management
Duration 2 – 3 days
  • Bed rest
  • Check TPC / Hct
  • Oral fluids & electrolyte therapy
Convalescence Phase Management
Duration 7 –10 days after critical stage
  • Normal diet
  • No special advice
  • No restrictions

Treatment of Dengue Haemorrhagic Fever (DHF) Grade I & II:

Treatment of Dangue Haemorrhagic Fever (DHF) Grade I & II

Volume Replacement Flow Chart for Patients With DHF Grade I  & II:

Volume Replacement Flow Chart for Patients With DHF Grade I & II

  • * Improvement-Haematocrit falls, Pulse rate & Blood Pressure stable, Urine output rises.
  • ** No improvement-Haematocrit or Pulse rate rises,Pulse Pressure <20 mm Hg, Urine output falls.
  • *** Unstable vital signs- Urine output falls, Signs of Shock.
Convalescence Phase Management
Duration 2-3days after critical stage
  • Normal diet
  • No need of medication.

Treatment of Dengue Haemorrhagic Fever (DHF) Grade III & IV:

 Treatment of Dengue Haemorrhagic Fever (DHF) Grade III & IV

Volume Replacement Flow Chart for Patients With DHF Grade III  & IV:

Volume Replacement Flow Chart for Patients With DHF Grade III & IV

 • Give Platelet rich plasma transfusion when TPC is < 5×10^3 – 10×10^3/µl.

Convalescence Phase Management
Duration 2-3days after recovery from critical/shock stage of DHF
  • Rest for few days
  • Normal diet
  • No need of medication.

Complications of Dengue Fever (DF):

  •  Febrile convulsions
  • Severe dehydration

Complications of Dengue Haemorrhagic Fever (DHF):

  •  Encephalopathy
  • Liver damage
  • Residual brain damage
  • Seizures
  • Shock

Prevention of Dengue Fever (DF) & Dengue Haemorrhagic Fever (DHF):

  • Clothing,
  • Use of mosquito repellent (Diethyltoluamide),
  • Use of mosquito net,
  • Traveling during periods of minimal mosquito activity,
  • Directing mosquito abatement programs.

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