Overview

The Epidemiology and Disease Control Division (EDCD) has released a new Short Guideline on Dengue Case Management to provide clear information on case definitions, diagnosis, and a step-by-step guide for the treatment and monitoring of patients.

Dengue is one of the re-emerging arboviral diseases transmitted mainly by Aedes mosquitoes. The hallmark features of severe dengue include plasma leakage, bleeding, and severe organ impairment which can lead to severe complications and death.

Case definition of probable dengue

Patients having acute febrile illness with at least 2 of the following symptoms and signs:

• Headache, Retro-orbital pain
• Myalgia, Arthralgia
• Rash/Exanthema
• Hemorrhagic manifestations as indicated by positive tourniquet test, cutaneous bleeding and mucosal bleeding
• Leukopenia as indicated by white blood cells count ≤4,000 cells/mm3
• Hematocrit 5-10% increased from baseline
• Platelets count ≤100,000/mm3

Note: Patients who presented with acute fever, positive tourniquet test and leukopenia had positive predictive value of 70-83% for dengue diagnosis.

Diagnosis of plasma leakage

If patients with diagnosis of dengue or probable dengue develop at least 1 of the following:

• Hemoconcentration ≥20%
• Pleural effusion and/or ascites and/or thickening of gallbladder wall
• Serum albumin ≤3.5 g/dl in normal weight or ≤4.0 g/dl in obesity.

Clinical symptoms and signs of severe dengue 

If patients with diagnosis of dengue or probable dengue develop at least one of the following symptoms and signs of severe dengue:

• Severe plasma leakage evidenced by high or progressively rising hematocrit leading to shock or fluid accumulation (pleural effusion or ascites) with respiratory distress.
• Circulatory failure indicates as rapid and weak pulse, cold clammy skin particularly cold extremities, and pulse pressure _≤20 mmHg
• Hypotension with tissue hypoperfusion indicate as dizziness, fainting, syncope, decrease urine output, restlessness, altered sensorium, and capillary refill time >2 seconds

Warning signs for development of severe disease in dengue

• No clinical improvement and/or weakness when fever subside
• Abdominal pain or vomiting >3 times/day (persistent vomiting)
• Mucosal bleeding
• Altered sensorium, drowsiness, irritable, restlessness
• Refuse to eat or drink, crying infants
• Dizziness, fainting, syncope, cold clammy skin or sweating
• Decrease urine volume in 4-6 hours.

Tourniquet test

• Take the patient’s BP and record it, example 120/80 mm Hg
• Inflate the BP cuff to a point midway between the systolic and diastolic pressure (120+80) /2= 100 mm Hg
• Wait for 5 minutes
• The test is considered positive when 10 or more petechiae per sq. inch are observed.
• The test may be negative or only mildly positive in obese patients and during the phase of profound shock. It usually becomes positive, sometimes strongly positive after recovery from shock.

Indications for Admission

If patients with diagnosis of dengue or probable dengue have at least 1 of the following:

• No clinical improvement and/or weakness when fever subside
• Abdominal pain, persistent vomiting and/or poor appetite with moderate to severe dehydration
• Significant bleeding as indicated by blood loss >6–8 ml/kg (children) or > 300 ml (adults), and hematocrit decrease >10 % or below baseline after Dextran-40 infusion
• Decreased urine volume in 4-6 hours
• White blood cells count ≤4,000 cells/mm3 in high risk groups (infants, elderly, pregnant women, prolonged shock, abnormal bleeding, underlying diseases and neurological manifestations)
• Platelets count ≤100,000/mm3 with weakness and/or poor appetite 
• Rising hematocrit ≥10%.

Indications for transferring dengue patients to referral hospitals/Require emergency treatment 

• Prolonged shock 
• Clinical symptoms and signs of severe dengue 
• Clinical symptoms and signs of fluid overload
• Significant bleeding 
• High risk groups (Infant, Elderly, Pregnant, Obese patients, bleeding, Underlying disease)
• Organ(s) involvement such as AST/ALT >500 U/l, altered sensorium, cardiac arrhythmia, etc.
• Beyond potential of hospital to patient care such as health care staffing shortages, unavailable laboratory investigations, shortages of intravenous fluid or blood products etc. 

Indications for starting intravenous fluid

• Patients with persistent vomiting
• Patients with signs of moderate to severe dehydration
• Patients having plasma leakage in the critical phase with hematocrit rising ≥10%* or refuse to eat or drink 
• Patients with dengue shock syndrome.

Note: *Patients with bleeding may not have hematocrit rising.

Disease phase in dengue

There are 3 phases of disease in dengue.

1. Febrile phase: 2–7 days with mean duration of 4 days (Encourage for oral intake as much as possible and avoid i/v fluids
2. Critical/Leakage phase: 24–48 hours after febrile phase
   a) A practical indicator for determining critical phase is platelets count ≤100,000/mm3.
3. Reabsorption/Recovery phase: 3–5 days after critical phase
   a) Clinical symptoms and signs of recovery: A–Appetite, B–Bradycardia, C–Convalescence rash or itching, D–Diuresis
   b) Be aware of fluid overload as reabsorption of extravasated plasma occurs in 36 hours after starting shock or 60 hours after platelets count ≤100,000/mm3 

Clinical and laboratory parameters for monitoring critical phase of dengue

Parameters for monitoring critical phase of dengue are as follows:

• Clinical: consciousness, appetite, bleeding, abdominal pain, vomiting
• Vital signs:
  a. Temperature: every 4–6 hours
  b. BP, PR, PV, RR, capillary refill time, cold clammy skin/cold extremities: every 1–3 hours in non-shock patients.
  c. BP, PR, PV, RR, SpO2, capillary refill time, cold clammy skin/cold extremities: every 15 minutes − 1 hour in shock patients or until stable

• Hematocrit: every 6 -12 hours or more frequent in cases of suspected bleeding and after blood transfusion
• Urine output: every 6–8 hours in non-shock patients and every 1–4 hours in shock patients (keep urine output 0.5–1 ml/kg/h except infants, obese patients and pregnant women keep urine output 0.5 ml/kg/h).

Management of common complications in dengue 

Practical investigations (ABCSF) in the following cases:

• Dengue patients with prolonged shock 
• Complicated cases: organs impairment (liver, kidney etc.), bleeding, fluid overload
• Dengue shock syndrome patients with no clinical improvement after receiving adequate fluid resuscitation.

Related readings

• Dengue Vaccine
• Dengue Control Strategy
• Dengue in Nepal
• Prevention & Control of Dengue Fever