Dengue is the fastest spreading vector-borne disease in the world endemic in 100 countries·
- Dengue virus has four serotypes (DENV1, DENV2, DENV3 and DENV4)
- First infection with one of the four serotypes usually is non-severe or asymptomatic, while second infection with one of other serotypes may cause severe dengue.
- Dengue has no treatment but the disease can be early managed.
- The five year average cases of dengue is 185,008; five year average deaths is 732; and five year average Case Fatality Rate is 0.39 (2012-2016 data).
Dengue virus is transmitted by day biting Aedes aegypti and Aedes albopictus mosquitoes.
DENGUE CASE CLASSIFICATION AND LEVEL OF SEVERITY
- Dengue illness is categorized according to level of severity as dengue without warning signs, dengue with warning signs and severe dengue.
- Dengue without warning warnings can be further classified according to signs and symptoms and laboratory tests as suspect dengue, probable dengue and confirmed dengue.
- dengue without warning signs
a.1 suspect dengue
– a previously well individual with acute febrile illness of 1-7 days duration plus two of the following: headache, body malaise, retro-orbital pain, myalgia, arthralgia, anorexia, nausea, vomiting, diarrhea, flushed skin, rash (petechial, Hermann’s sign)
a.2 probable dengue
– a suspect dengue case plus laboratory test: Dengue NS1 antigen test and atleast CBC (leukopenia with or without thrombocytopenia) or dengue IgM antibody test (optional)
a.3 confirmed dengue
– a suspect or probable dengue case with positive result of viral culture and/or Polymerase Chain Reaction (PCR) and/or Nucleic Acid Amplification Test- Loop Mediated Amplification Assay (NAAT-LAMP) and/ or Plaque Reduction Neutralization Test (PRNT)
b. dengue with warning signs
• a previously well person with acute febrile illness of 1-7 days plus any of the following: abdominial pain or tenderness, persistent vomiting, clinical signs of fluid accumulation (ascites), mucosal bleeding, lethargy or restlessness, liver enlargement, increase in haematocrit and/or decreasing platelet count
c. severe dengue
severe plasma leakage leading to
- shock (DSS)
- fluid accumulation with respiratory distress
- as evaluated by clinician
severe organ impairment
- Liver: AST or ALT ≥ 1000
- CNS: e.g. seizures, impaired consciousness
- Heart:and other organs (i.e. myocarditis, renal failure)
PHASES OF DENGUE INFECTION
- Febrile Phase
- Usually last 2-7 days
- Mild haemorrhagic manifestations like petechiae and mucosal membrane bleeding (e.g nose and gums) may be seen.
- Monitoring of warning signs is crucial to recognize its progression to critical phase.
- Critical Phase
- Phase when patient can either improve or deteriorate.
- Defervescence occurs between 3 to 7 days of illness. Defervescence is known as the period in which the body temperature (fever) drops to almost normal (between 37.5 to 38°C).
- Those who will improve after defervescence will be categorized as Dengue without Warning Signs, while those who will deteriorate will manifest warning signs and will be categorized as Dengue with Warning Signs or some may progress to Severe Dengue.
- When warning signs occurs, severe dengue may follow near the time of defervescence which usually happens between 24 to 48 hours.
- Recovery Phase
- Happens in the next 48 to 72 hours in which the body fluids go back to normal.
- Patients’ general well-being improves.
- Some patients may have classical rash of “isles of white in the sea of red”.
- The White Blood Cell (WBC) usually starts to rise soon after defervescence but the normalization of platelet counts typically happens later than that of WBC.
MANAGEMENT (based on patient type)
- Group A- patients who may be sent home
These are patients who are able to:
- Tolerate adequate volumes of oral fluids
- Pass urine every 6 hours
- Do not have any of the warning signs particularly when the fever subsides
- Have stable haematocrit
- Group B- patient who should be referred for in-hospital management
Patients shall be referred immediately to in-hospital management if they have the following conditions:
- Warning signs\
- Without warning signs but with co-existing conditions that may make dengue or its management more complicated ( such as pregnancy, infancy, old age, obesity, diabetes mellitus, hypertension, heart failure, renal failure, chronic haemolytic diseases such as sickle- cell disease and autoimmune diseases, etc.)
- Social circumstances such as living alone or living far from health facility or without a reliable means of transportation.
- The referring facility has no capability to manage dengue with warning signs and/or severe dengue.
- Group C- patient with severe dengue.requiring emergency treatment and urgent referral
These are patients with severe dengue who require emergency treatment and urgent referral because they are in the critical phase of the disease and have the following:
- Severe plasma leakage leading to dengue shock and/or fluid accumulation with respiratory distress;
- Severe haemorrhages;
- Severe organ impairment (hepatic damage, renal impairment, cardiomyopathy, encephalopathy or encephalitis)
Patients in Group C shall be immediately referred and admitted in the hospital within 24 hours.