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Infectious Disease – Dengue
DENGUE
ESSENTIALS DESCRIPTION
A virus called dengue is spread by mosquitoes and causes a serious sickness that resembles the flu. With a 1–5% patient mortality rate, the virus can occasionally cause potentially fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS).
The study of epidemiology
The prevalence
• Two-fifths of the world's population, or over 2.5 billion people, are susceptible to infection
The rainy season increases transmission. An estimated 50–100 million infections, including 500,000 DHF cases and 22,000 fatalities, occur globally each year
The frequency
• The virus can be found in tropical regions and
It is endemic in around 100 nations in Asia, the Pacific, the Americas, Africa, and the Caribbean. It is found in subtropical zones, primarily in urban and suburban settings.
RISK ELEMENTS
Visiting or residing in dengue-endemic areas
Genetics
There are no hereditary elements at play.
GENERAL PREVENTION: Steer clear of mosquito bites and stay away from dengue endemic regions.
Wear long sleeves, ideally with permethrin insecticide impregnated. Apply mosquito repellent with at least 30% N,N-diethyl-3-methylbenzamide (DEET) on exposed skin and clothing.
– Because Aedes mosquitoes bite during the day, bed nets are not very effective.
• Vector control: Get rid of mosquitoes indoors by using insecticides; remove standing water from pools to get rid of mosquito breeding grounds.
Apply larvicidal compounds to sources of stagnant water, such as Abate.
Predatory copepods are introduced into stagnant water sources to control biological vectors.
Pathophysiology
• The incubation period for dengue after inoculation is 3–14 days, although it is often 4–7 days
• The virus replicates in dendritic cells; it then infects reticuloendothelial cells, including dendritic cells, hepatocytes, and endothelial cells; it releases immune mediators that influence cellular and humoral responses; the resulting acute febrile illness lasts 5–7 days; the patient recovers fully in 7–10 days; prior exposure to another dengue serotype predisposes the patient to DHF and DSS; and DHF and DSS typically appear between the third and seventh day of illness at the end of the febrile period. Capillary fragility, thrombocytopenia, and disseminated intravascular coagulation (DIC) cause hemorrhages ranging from minor petechiae to potentially fatal gastrointestinal (GI) bleeding; liver damage causes abnormal liver function tests; and increased capillary permeability causes plasma leakage, which leads to hemoconcentration and potential pleural effusions and ascites.
& coagulopathies • Hepatitis caused by Dengue can be lethal
ETIOLOGY The dengue virus belongs to the family Flaviviridae (ssRNA); it has four antigenically unique serotypes (types 1–4); the sole hosts of infection are humans and nonhuman primates; and Aedes mosquitoes, primarily Aedes aegypti and Aedes albopictus, are the vectors of transmission. Considerations for Children
There is evidence of mother-to-child transmission under COMMONLY ASSOCIATED CONDITIONS
History of Diagnosis
• Signs: fever, chills, headache, and myalgias Rash, bone pain following fever onset, nausea, vomiting, cutaneous hyperesthesia, altered taste perception, appetite loss, abdominal discomfort, and hemorrhagic symptoms such as bruising, epistaxis, gingival bleeding, gastrointestinal bleeding, and menorrhagia
• History of travel
PHYSICAL EXAMINATION • Fever • Shock symptoms, such as prolonged capillary refill, tachycardia, and hypotension • Rash: generalized blanching macular rash
Morbilliform maculopapular rash, which spares the palms and soles, is the second type of rash.
– Symptoms of bleeding include petechiae, purpura, epistaxis, gum bleeding, and gastrointestinal bleeding. In 97% of instances, conjunctival injection and pharyngeal injection are used.
Hepatomegaly, generalized lymphadenopathy, bleeding mucosae, and mental state assessment for changes in mental state brought on by encephalopathy—which is a result of cerebral edema and intracranial hemorrhages--
Tests for Diagnosis and Interpretation
Initial laboratory tests
IgG and IgM antibody serology (ELISA); complete blood count; leucopenia, frequently accompanied by lymphopenia; elevated hematocrit; thrombocytopenia; liver function tests; elevated transaminases; low albumin; and chemistry panel
Acidosis, elevated blood urea nitrogen (BUN), and hyponatremia
Low fibrinogen and high fibrin breakdown products in DIC; elevated prothrombin time (PT); elevated activated partial thromboplastin time (APTT); and coagulation screen
Currently unavailable in the clinical context are polymerase chain reaction (PCR) techniques; arterial blood gas in critically unwell patients
Follow-up and Particular Points to Remember
• When there is a significant bleeding, blood must be cross-matched. Blood and other bodily fluid cultures should be carried out as needed to rule out other potential causes of sickness.
Imagining
• Pleural effusion may be seen on a chest radiograph; ultrasound may be used to assess ascites, pericardial effusions, and pleural effusions as needed; CT scan of the head for individuals with altered mental states or low consciousness
Pathological Results
As mentioned in the first lab tests
DIFFERENTIAL DIAGNOSIS: Hepatitis, meningitis, leptospirosis, rickettsial disease, typhoid, malaria, yellow fever, bacterial sepsis, other viral infections (such as influenza, chikungunya, Rift Valley fever, and West Nile), bacterial sepsis, and pre-eclampsia during pregnancy
MEDICATION FOR TREATMENT
There is no particular treatment for DSS, DHF, or dengue fever.
ADDITIONAL MEDICATION
General Measures: • Adequate analgesics and antipyretics should be used; • Avoid aspirin because of the hemorrhagic character of the sickness; • Symptomatic and supportive therapy
Referral issues include: • Cardiologist for patients with pericardial effusions; • Critical care specialist for individuals with DHF or DSS; • Infectious disease specialist
Considering the patient
First Stabilization
Resuscitate using the advanced life support (ALS) protocol; administer oxygen empirically; use a large-bore intravenous catheter; administer intravenous colloids to maintain systolic blood pressure greater than 90 mm Hg; administer therapy for DIC if necessary; use an arterial line for continuous blood pressure monitoring and serial blood gas measurements if necessary; use a urethral catheter to measure urine output if necessary; reverse electrolyte abnormalities and acidosis; and cross-match blood in the event of a major bleeding incident secondary to DHF.
Requirements for Admission
Patients with hemodynamic instability; those with DHF or DSS; those who are hypotensive or in DIC should be admitted to intensive care units (ICUs); otherwise, they should be admitted to a general medicine ward.
IV fluids; fluids used in colloids for resuscitation, such as Gelofusine,
• Ringer's lactate maintenance fluids, such as dextran, hetastarch, and human albumin solution
For patients who are really sick, keep a tight fluid input-output log. Patients who are not awake may require frequent neuro-observations.
The patient must be hemodynamically stable and have preferably fully recovered from their sickness in order to be discharged.
Continuing Care Follow-Up Suggestions
• No particular advice for follow-up
Patients should be informed that they are more likely to develop DHF or DSS if they catch dengue of a different serotype. Cases should be reported to the Department of Public Health.
DIET: No particular diet is required. Promote the consumption of oral fluids.
Refer to the General Prevention Section on Patient Education.
PROGNOSIS: The majority of individuals with dengue fever recover completely, and the prognosis is excellent.
• Individuals who make it through the crucial phases of DSS and DHF
Neurological symptoms, brain damage from prolonged ischemia in shock or intracranial bleeding, encephalitis/encephalopathy, seizures, neuropathies, Guillain-Barré syndrome, transverse myelitis, myocarditis, and liver failure are among the conditions that typically resolve without any long-term effects.
DENGUE
ESSENTIALS DESCRIPTION
A virus called dengue is spread by mosquitoes and causes a serious sickness that resembles the flu. With a 1–5% patient mortality rate, the virus can occasionally cause potentially fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS).
The study of epidemiology
The prevalence
• Two-fifths of the world's population, or over 2.5 billion people, are susceptible to infection
The rainy season increases transmission. An estimated 50–100 million infections, including 500,000 DHF cases and 22,000 fatalities, occur globally each year
The frequency
• The virus can be found in tropical regions and
It is endemic in around 100 nations in Asia, the Pacific, the Americas, Africa, and the Caribbean. It is found in subtropical zones, primarily in urban and suburban settings.
RISK ELEMENTS
Visiting or residing in dengue-endemic areas
Genetics
There are no hereditary elements at play.
GENERAL PREVENTION: Steer clear of mosquito bites and stay away from dengue endemic regions.
Wear long sleeves, ideally with permethrin insecticide impregnated. Apply mosquito repellent with at least 30% N,N-diethyl-3-methylbenzamide (DEET) on exposed skin and clothing.
– Because Aedes mosquitoes bite during the day, bed nets are not very effective.
• Vector control: Get rid of mosquitoes indoors by using insecticides; remove standing water from pools to get rid of mosquito breeding grounds.
Apply larvicidal compounds to sources of stagnant water, such as Abate.
Predatory copepods are introduced into stagnant water sources to control biological vectors.
Pathophysiology
• The incubation period for dengue after inoculation is 3–14 days, although it is often 4–7 days
• The virus replicates in dendritic cells; it then infects reticuloendothelial cells, including dendritic cells, hepatocytes, and endothelial cells; it releases immune mediators that influence cellular and humoral responses; the resulting acute febrile illness lasts 5–7 days; the patient recovers fully in 7–10 days; prior exposure to another dengue serotype predisposes the patient to DHF and DSS; and DHF and DSS typically appear between the third and seventh day of illness at the end of the febrile period. Capillary fragility, thrombocytopenia, and disseminated intravascular coagulation (DIC) cause hemorrhages ranging from minor petechiae to potentially fatal gastrointestinal (GI) bleeding; liver damage causes abnormal liver function tests; and increased capillary permeability causes plasma leakage, which leads to hemoconcentration and potential pleural effusions and ascites.
& coagulopathies • Hepatitis caused by Dengue can be lethal
ETIOLOGY The dengue virus belongs to the family Flaviviridae (ssRNA); it has four antigenically unique serotypes (types 1–4); the sole hosts of infection are humans and nonhuman primates; and Aedes mosquitoes, primarily Aedes aegypti and Aedes albopictus, are the vectors of transmission. Considerations for Children
There is evidence of mother-to-child transmission under COMMONLY ASSOCIATED CONDITIONS
History of Diagnosis
• Signs: fever, chills, headache, and myalgias Rash, bone pain following fever onset, nausea, vomiting, cutaneous hyperesthesia, altered taste perception, appetite loss, abdominal discomfort, and hemorrhagic symptoms such as bruising, epistaxis, gingival bleeding, gastrointestinal bleeding, and menorrhagia
• History of travel
PHYSICAL EXAMINATION • Fever • Shock symptoms, such as prolonged capillary refill, tachycardia, and hypotension • Rash: generalized blanching macular rash
Morbilliform maculopapular rash, which spares the palms and soles, is the second type of rash.
– Symptoms of bleeding include petechiae, purpura, epistaxis, gum bleeding, and gastrointestinal bleeding. In 97% of instances, conjunctival injection and pharyngeal injection are used.
Hepatomegaly, generalized lymphadenopathy, bleeding mucosae, and mental state assessment for changes in mental state brought on by encephalopathy—which is a result of cerebral edema and intracranial hemorrhages--
Tests for Diagnosis and Interpretation
Initial laboratory tests
IgG and IgM antibody serology (ELISA); complete blood count; leucopenia, frequently accompanied by lymphopenia; elevated hematocrit; thrombocytopenia; liver function tests; elevated transaminases; low albumin; and chemistry panel
Acidosis, elevated blood urea nitrogen (BUN), and hyponatremia
Low fibrinogen and high fibrin breakdown products in DIC; elevated prothrombin time (PT); elevated activated partial thromboplastin time (APTT); and coagulation screen
Currently unavailable in the clinical context are polymerase chain reaction (PCR) techniques; arterial blood gas in critically unwell patients
Follow-up and Particular Points to Remember
• When there is a significant bleeding, blood must be cross-matched. Blood and other bodily fluid cultures should be carried out as needed to rule out other potential causes of sickness.
Imagining
• Pleural effusion may be seen on a chest radiograph; ultrasound may be used to assess ascites, pericardial effusions, and pleural effusions as needed; CT scan of the head for individuals with altered mental states or low consciousness
Pathological Results
As mentioned in the first lab tests
DIFFERENTIAL DIAGNOSIS: Hepatitis, meningitis, leptospirosis, rickettsial disease, typhoid, malaria, yellow fever, bacterial sepsis, other viral infections (such as influenza, chikungunya, Rift Valley fever, and West Nile), bacterial sepsis, and pre-eclampsia during pregnancy
MEDICATION FOR TREATMENT
There is no particular treatment for DSS, DHF, or dengue fever.
ADDITIONAL MEDICATION
General Measures: • Adequate analgesics and antipyretics should be used; • Avoid aspirin because of the hemorrhagic character of the sickness; • Symptomatic and supportive therapy
Referral issues include: • Cardiologist for patients with pericardial effusions; • Critical care specialist for individuals with DHF or DSS; • Infectious disease specialist
Considering the patient
First Stabilization
Resuscitate using the advanced life support (ALS) protocol; administer oxygen empirically; use a large-bore intravenous catheter; administer intravenous colloids to maintain systolic blood pressure greater than 90 mm Hg; administer therapy for DIC if necessary; use an arterial line for continuous blood pressure monitoring and serial blood gas measurements if necessary; use a urethral catheter to measure urine output if necessary; reverse electrolyte abnormalities and acidosis; and cross-match blood in the event of a major bleeding incident secondary to DHF.
Requirements for Admission
Patients with hemodynamic instability; those with DHF or DSS; those who are hypotensive or in DIC should be admitted to intensive care units (ICUs); otherwise, they should be admitted to a general medicine ward.
IV fluids; fluids used in colloids for resuscitation, such as Gelofusine,
• Ringer's lactate maintenance fluids, such as dextran, hetastarch, and human albumin solution
For patients who are really sick, keep a tight fluid input-output log. Patients who are not awake may require frequent neuro-observations.
The patient must be hemodynamically stable and have preferably fully recovered from their sickness in order to be discharged.
Continuing Care Follow-Up Suggestions
• No particular advice for follow-up
Patients should be informed that they are more likely to develop DHF or DSS if they catch dengue of a different serotype. Cases should be reported to the Department of Public Health.
DIET: No particular diet is required. Promote the consumption of oral fluids.
Refer to the General Prevention Section on Patient Education.
PROGNOSIS: The majority of individuals with dengue fever recover completely, and the prognosis is excellent.
• Individuals who make it through the crucial phases of DSS and DHF
Neurological symptoms, brain damage from prolonged ischemia in shock or intracranial bleeding, encephalitis/encephalopathy, seizures, neuropathies, Guillain-Barré syndrome, transverse myelitis, myocarditis, and liver failure are among the conditions that typically resolve without any long-term effects.
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