Transcript Document
Dengue Fever Manual
Department of Medicine Lahore General Hospital/PGMI Lahore 1
Dengue Fever
Dengue virus Most prevalent vector borne viral illness in the world Main mosquito vector is
Aedes Aegypti and Albopictus
Year round transmission
Incidence
50-100 million dengue fever infections per year globally 500,000 cases of severe dengue, dengue hemorrhagic fever or dengue shock syndrome 100-200 cases annually in U.S. Average case fatality 5%
Distribution
Endemic in more than 100 tropical and subtropical countries Pandemic began in Southeast Asia after WW II with subsequent global spread Several epidemics since 1980s Distribution is comparable to malaria
Virology
Flavivirus family Small enveloped viruses containing single stranded positive RNA Four distinct viral serotypes (Den-1, Den 2, Den-3, Den-4)
Pathophysiology
Transmitted by the bite of Aedes mosquito (Aedes aegypti and albopictus) Incubation 3-14 days Acute illness and viremia 3-7 days Recovery or progression to leakage phase
Clinical Presentation
Spectrum of illness • non-specific febrile illness • classic dengue • dengue hemorrhagic fever • dengue shock syndrome • other (CNS dysfunction, liver failure, myocarditis)
The course of dengue illness
3 Phases A. Febrile Phase B. Critical Phase C. Recovery Phase 8
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Febrile Phase
Critical Phase Recovery Phase
Dehydration; high fever may cause neurological disturbances and febrile seizures in young children
Shock from plasma leakage; severe haemorrhage; organ impairment Hypervolaemia (only if intravenous fluid therapy has been excessive and/or has extended into this period) 10
Differential Diagnosis of Dengue Fever
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D/D of Dengue Fever
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D/D of Dengue Fever
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Approach to a Patient with Dengue Fever
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Approach to a patient with Dengue Fever
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Treatment Recommendations
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Step I—Overall assessment
History
The history should include: – date of onset of fever/illness; – quantity of oral intake; – assessment for warning signs ; – diarrhea; – change in mental state/seizure/dizziness; – urine output (frequency, volume and time of last voiding); – other important relevant histories, such as family or neighborhood dengue, co-existing conditions (e.g. infancy, pregnancy, obesity, diabetes mellitus, hypertension), 17
Step I—Overall assessment
Physical examination
The physical examination should include: – assessment of mental state; – assessment of hydration status; – assessment of hemodynamic status – checking for tachypnoea/acidotic breathing/pleural effusion; – checking for abdominal pain, tenderness/hepatomegaly/ascites; – examination for rash and bleeding manifestations; – tourniquet test (repeat if previously negative or if there is no bleeding manifestation).
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Step I—Overall assessment
Investigations: 1. CBC , PLATELET COUNT, HCT 2. ELECTROLYTES, CREATININE, BICARBONATE, BSR 3. LFT’S 4. URINE C/E 5. BLOOD GROUP
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Step II—Diagnosis, assessment of disease phase and severity
• On the basis of evaluations of the history, physical examination and/or full blood count and haematocrit, confirm.
The diagnosis as dengue.
assess the phase (febrile, critical or recovery) Presence of warning signs The hydration and hemodynamic status o Needs for admission and/or referral to emergency department.
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Step II—Diagnosis, assessment of disease phase and severity
Hospital Admission Criteria 1.
Warning signs
Any of the warning signs if present.
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Step II—Diagnosis, assessment of disease phase and severity Hospital Admission Criteria
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Monitoring of Dengue Fever Patients
• • • • • • Feeling of well being Fever Pulse pressure, Blood pressure and Heart rate Vomiting/loose stool and oral intake Urine output Blood counts specially HCT 23
Management decisions
Depending on the clinical manifestations and other circumstances,
Patients may be sent home (Group A)
Referred for in-hospital management or (Group B)
Require emergency treatment and urgent referral (Group C).
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Home care for dengue
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(
OPD care - Group A)
Home care card for dengue Adequate bed rest Adequate fluid intake (>5 glasses for average-sized adults or accordingly in children) Milk, fruit juice (caution with diabetes patient) and isotonic electrolyte solution (ORS) and barley/rice water.
- Plain water alone may cause electrolyte imbalance.
Take paracetamol (not more than 8tabs (4 Gm) per day for adults and accordingly in children) Tepid sponging with water or cold water shower Look for mosquito breeding places in and around the home and eliminate them 25
Home care for dengue
What should be avoided?
• Do not take acetylsalicylic acid (aspirin), mefenemic acid (ponstan), ibuprofen or other non-steroidal anti-inflammatory agents (NSAIDs), or steroids. • Antibiotics are not required and they are best avoided.
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Home care for dengue
Approach the hospital staff early if Bleeding Red spots or patches on the skin Bleeding from nose or gums Vomiting blood Black-colored stools Heavy menstruation/vaginal bleeding Frequent vomiting Severe abdominal pain Drowsiness, mental confusion or seizures Pale, cold or clammy hands and feet Difficulty in breathing 27
In hospital management for dengue (Group B)
Compensated shock (systolic pressure) maintained but has signs of reduced perfusion) Fluid resuscitation with isotonic crystalloid 5-10 ml/kg/hr over 1 hour Improvement YES NO Check HCT IV crystalloid 5-7 ml/kg/hr for 1-2 hours, then: reduce to 3-5 ml/kg/hr for 2-4 hours; reduce to 2-3 ml/kg/hr for 2-4 hours.
If patient continues to improve, fluid can be further reduced.
Monitor HCT 6-8 hourly.
If the patient is not stable, act according to HCT levels: if HCT increases, consider bolus fluid administration or increase fluid administration; if HCT decreases, consider transfusion with fresh whole transfusion.
Stop at 48 hours.
YES HCT or high Administer 2nd bolus of fluid 10-20 ml/kg/hr for 1 hour Improvement NO HCT Consider significant occult/overt bleed Initiate transfusion with fresh whole blood If patient improves, reduce to 7-10 ml/kg/hr for 1-2 hours Then reduce further 28
In Hospital Management of Dengue Fever (Group C – Emergency care)
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YES
Hypotensive shock I/V fluid 20ml / kg isotonic crystalloid or colloid over 15 min
Improvement NO Crystalloid/colloid 10 ml/kg/hr for 1 hour, then continue with: IV crystalloid 5-7 ml/kg/hr for 1- 2 hours; reduce to 3-5 ml/kg/hr for 2-4 hours; reduce to 2-3 ml/kg/hr for 2-4 hours.
If patient continues to improve, fluid can be further reduced.
Monitor HCT 6-hourly.
If the patient is not stable, act according to HCT levels: if HCT increases, consider bolus fluid administration or increase fluid administration; if HCT decreases, consider transfusion with fresh whole transfusion.
Stop at 48 hours.
Review 1st HCT HCT or high HCT Administer 2nd bolus fluid (colloid) 10-20 ml/kg over ½ to 1 hour Consider significant occult/overt bleed Initiate transfusion with fresh whole blood Improvement YES NO Repeat 2nd HCT HCT or high YES Administer 3rd bolus fluid (colloid) 10-20 ml/kg over 1 hour Improvement NO Repeat 3rd HCT HCT 30
Complications of Dengue Fever
• • • • • • • • • Haemorrhagic complications Fluid overload – Ascites, Pleural effusion, Pulmonary aedema Metabolic acidosis and electrolyte imbalance Severe shock Acute Respiratory Distress Syndrome Hyperglycaemia and hypoglycaemia Nosocomial infections Mycocarditis Hepatitis 31
Vaccination
No current dengue vaccine Estimated availability in 5-10 years Vaccine development is problematic as the vaccine must provide immunity to all 4 serotypes Lack of dengue animal model Live attenuated tetravalent vaccines under phase 2 trials New approaches include infectious clone DNA and naked DNA vaccines
Hospital Discharge Criteria
Clinical No fever for 48 hours.
Improvement in clinical status (general well-being, appetite, haemodynamic status, urine output, no respiratory distress).
Laboratory Increasing trend of platelet count.
Stable haematocrit without intravenous fluids.
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Do and don’t of Dengue Fever
Good Practice
Administration of Paracetomal for high fever and myalgia.
Clinical assessment of the haemodynamic status before and after each fluid bolus Give intravenous fluids for repeated vomiting or a high rapidly rising haematocrit Use the isotonic intravenous fluids for severe dengue Avoid intramuscular injections Tight Glycemic control
Bad Practice
Sending patients with non-severe dengue home with no follow-up and inadequate instructions Administration of acetylsalicylic acid (aspirin) or ibuprofen No clinical assessment of patient with respect to fluid therapy Administration of intravenous fluids to any patient with non-severe dengue Giving intramuscular injections to dengue patients Not monitoring blood glucose 34
Prevention
Personal: clothing to reduce exposed skin insect repellent especially in early morning, late afternoon. Bed netting is of little utility. Environmental: reduced vector breeding sites solid waste management public education
Prevention
Biological: Target larval stage of Aedes in large water storage containers Larvivorous fish (Gambusia), endotoxin producing bacteria (Bacillus), copepod crustaceans (mesocyclops) Chemical: Insecticide treatment of water containers Space spraying (thermal fogs)
Public Health
Major and escalating global public health problem Global demographic changes: urbanization and population growth with substandard housing, water, and waster management systems Deteriorating public health infrastructure with limited resources resulting in “crisis management” not prevention Increased travel Lack of effective mosquito control