para>Dengue fever is reportable to the CDC.
EPIDEMIOLOGY
Incidence
The World Health Organization (WHO) estimates 50 to 100 million cases annually worldwide (1).
Prevalence
- Dengue is present in over 100 countries.
- The virus is common in urban and residential areas.
- There have been multiple dengue fever outbreaks in the continental U.S. over the past decade.
ETIOLOGY AND PATHOPHYSIOLOGY
- Dengue is transmitted by the bite from an infected female Aedes mosquito.
- Symptoms begin after a 3- to 7-day incubation.
- The virus spreads from the inoculation site to the bloodstream via the reticuloendothelial system.
- The disease has three phases: febrile, critical (plasma leak), and spontaneous recovery (convalescent phase)
- Dengue hemorrhagic fever (DHF) is a complication of dengue fever thought to be due to antibody-dependent response related to prior exposure to a different serotype with subsequent endothelial dysfunction and vascular instability.
RISK FACTORS
- Residing in or traveling to endemic areas
- Risk factors for the development of DHF include the following (2):
- Young age; female gender
- High body mass index
- Sequential infection by different DENV serotypes
GENERAL PREVENTION
- No vaccine or prophylaxis currently exists.
- Vector control is the most important preventive step.
- Vector control can be achieved through the use of chemical, biologic, and environmental means (e.g., removal of breeding sites-standing water).
- The Aedes mosquito is most active during the day and prefers to bite indoors. Patients should wear protective clothing and insect repellent to decrease bite exposures.
DIAGNOSIS
HISTORY
- Symptoms begin after a 3- to 7-day incubation period.
- Dengue fever presents with
- High fever (>38.5 °C-may be biphasic)
- Headache
- Cough, sore throat, and nasal congestion
- Relative bradycardia (typically seen in the febrile phase)
- Abdominal pain
- Vomiting
- Myalgia/arthralgia
- Lethargy
- Joint pain
- Rash
- DHF presents as a flulike illness, with high fever (104 °F) and at least two additional symptoms:
- Severe anemia or hemorrhage
- Retro-orbital pain
- Myalgias/arthralgias
- Nausea/vomiting
- Adenopathy
- Rash
- The risk of developing DHF occurs 3 to 7 days after the first symptoms of dengue fever.
PHYSICAL EXAM
- Dengue fever
- Vital signs-assess for hemodynamic stability.
- Cardiopulmonary exam
- Neurologic exam-assess meningeal signs and mental status in particular.
- Abdominal exam-hepatomegaly
- Rash
- Days 1 to 3: diffuse flushing on the face, neck, and chest
- Days 3 to 5: Maculopapular rash, which starts on the chest and trunk and spreads to extremities and face.
- Days 5 to 7: clusters of petechiae on the extremities with patches of normal skin
- Positive tourniquet test: Inflate a blood pressure cuff to the midpoint between the systolic and diastolic blood pressures and leave in place for 5 minutes. The test is positive if ≥10 petechiae per 2.5 cm2 are present.
- DHF
- Signs and symptoms of dengue fever, in addition to all of the following (associated with plasma leak syndrome):
- Hypotension (initially, systolic pressure may be normal). If the patient is hemodynamically unstable, they are classified as having dengue shock syndrome (DSS).
- Narrowing pulse pressure (pulse pressure ≤20 mm Hg)
- Pleural effusion, ascites
DIFFERENTIAL DIAGNOSIS
Influenza, malaria, typhoid, chikungunya, leptospirosis, viral hepatitis, rickettsial diseases, measles, rubella, bacterial sepsis, enterovirus infections, adenovirus infections, other arboviral infections
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
- CBC
- Leukopenia; thrombocytopenia
- Complete metabolic profile
- Liver function tests
- PT/PTT
- Blood type
- IgM anti-DENV serologies turn positive 4 to 5 days after symptoms begin
- Reverse-transcriptase-polymerase-chain-reaction assay or detection of the virus nonstructural protein 1 by enzyme-linked immunosorbent assay confirms the diagnosis.
- DHF associated with
- Hemoconcentration (defined as an increase in hematocrit ≥20% above average for age or decrease in hematocrit ≥20% from baseline after fluid replacement therapy)
- Hypoproteinemia
- Hyponatremia
Follow-Up Tests & Special Considerations
- Monitor for signs and symptoms of DHF and DSS as the initial fever decreases.
- Monitor heart rate, blood pressure, hemoconcentration, leukopenia, thrombocytopenia, fluids, and electrolyte balance.
TREATMENT
GENERAL MEASURES
- No prophylaxis or treatment is currently available.
- Supportive care with bed rest, hydration, pain, and fever control are mainstays of treatment.
MEDICATION
First Line
- Volume resuscitation and hemodynamic support
- Acetaminophen
- Do not use aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) because of the risk of gastric irritation, severe bleeding, worsening thrombocytopenia, and Reye syndrome (aspirin).
- Opiates for pain management
ISSUES FOR REFERRAL
Refer patient to an infectious disease specialist to rule out coinfections and for close monitoring. For patients requiring intensive hemodynamic support, consider consultation with a critical care specialist.
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
- Patients displaying signs and symptoms of DHF should be admitted and monitored for shock. Warning signs include:
- Refusal to eat or drink
- Lethargy and restlessness
- Persistent vomiting and abdominal pain
- Bleeding
- Worsening of general condition with defervesce
- Pregnancy, infancy, old age, obesity, diabetes mellitus, renal failure, and chronic hemolytic diseases increase the risk for severe dengue. Hospitalization is recommended for these patients (3).
- Serial laboratory testing and vital sign monitoring for appropriate fluid and electrolyte replacement
- Pain management
IV Fluids
Fluid resuscitation
- Useful guidelines for the resuscitation and management of patients with dengue infection are available from the CDC and WHO: http://www.cdc.gov/dengue/clinicalLab/clinical.html
- Monitor vital signs.
- Monitor inputs and outputs.
Discharge Criteria
Patients who are asymptomatic and afebrile and are able to eat and drink normally.
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
All patients should be referred to an infectious disease specialist. Dengue is reportable to the CDC:
Dengue Branch 1324 Calle Ca ±ada San Juan, Puerto Rico 00920-3860 800-CDC-INFO
PATIENT EDUCATION
- Dengue prevention should be part of a comprehensive travel visit prior to visiting endemic areas.
- Discuss signs and symptoms of dengue fever with patients so they can seek appropriate medical care while traveling.
- Patients with a history of dengue fever should be informed that they are at increased risk for DHF if they travel to a dengue endemic country.
PROGNOSIS
Death due to dengue fever and DHF is <1% with early detection and appropriate care.
COMPLICATIONS
There is a risk of developing DHF or DSS if infected with a second serotype of DENV.
REFERENCES
11 Guzman MG, Halstead SB, Artsob H, et al. Dengue: a continuing global threat. Nat Rev Microbiol. 2010;8(12)(Suppl):S7-S16.22 Simmons CP, Farrar JJ, Nguyen vV, et al. Dengue. N Engl J Med. 2012;366(15):1423-1432.33 World Health Organization. Dengue: guidelines for diagnosis, treatment, prevention and control. http://www.who.int/tdr/publications/documents/dengue-diagnosis.pdf
ADDITIONAL READING
- Centers for Disease Control and Prevention. CDC Web site. http://www.cdc.gov/dengue/
- Deen JL, Harris E, Wills B, et al. The WHO dengue classification and case definitions: time for a reassessment. Lancet. 2006;368(9530):170-173.
- Teixeira MG, Barreto ML. Diagnosis and management of dengue. BMJ. 2009;339:b4338.
- WHO Regional Office for Southeast Asia. Comprehensive Guidelines for Prevention and Control of Dengue and Dengue Haemorrhagic Fever. Revised and expanded version. New Delhi, India: SEARO Technical Publication Series; 2011.
CODES
ICD10
- A90 Dengue fever [classical dengue]
- A91 Dengue hemorrhagic fever
ICD9
- 061 Dengue
- 065.4 Mosquito-borne hemorrhagic fever
SNOMED
- Dengue (disorder)
- Dengue hemorrhagic fever (disorder)
CLINICAL PEARLS
- Mosquito control is the most effective approach to dengue prevention.
- Treatment requires active intravascular volume repletion to prevent or reverse hypovolemic shock
- Aspirin or NSAIDs should generally be avoided.
- Dengue-infected patients are either asymptomatic or present with one of three clinical syndromes: undifferentiated fever, dengue fever, or DHF/DSS.