Podcast
Questions and Answers
What is indicated by a positive tourniquet test?
What is indicated by a positive tourniquet test?
How can specificity be increased in the diagnosis of thrombocytopenia?
How can specificity be increased in the diagnosis of thrombocytopenia?
During which phase of dengue might a temperature drop indicate that the patient is in a critical phase?
During which phase of dengue might a temperature drop indicate that the patient is in a critical phase?
What is the most important question to initially ask a patient to assess for dengue risk?
What is the most important question to initially ask a patient to assess for dengue risk?
Signup and view all the answers
Which of the following is a hemorrhagic manifestation associated with dengue?
Which of the following is a hemorrhagic manifestation associated with dengue?
Signup and view all the answers
Which of the following is true regarding the relationship between shock and the tourniquet test?
Which of the following is true regarding the relationship between shock and the tourniquet test?
Signup and view all the answers
What is the causative agent of dengue fever?
What is the causative agent of dengue fever?
Signup and view all the answers
How long can a mosquito transmit the dengue virus after becoming infected?
How long can a mosquito transmit the dengue virus after becoming infected?
Signup and view all the answers
What is the typical incubation period for dengue after a mosquito bite?
What is the typical incubation period for dengue after a mosquito bite?
Signup and view all the answers
Dengue fever has how many identified serotypes?
Dengue fever has how many identified serotypes?
Signup and view all the answers
Which statement about the dengue virus serotypes is true?
Which statement about the dengue virus serotypes is true?
Signup and view all the answers
In which season do dengue cases typically peak in the Philippines?
In which season do dengue cases typically peak in the Philippines?
Signup and view all the answers
What mechanism does the mosquito use to prevent blood from clotting while feeding?
What mechanism does the mosquito use to prevent blood from clotting while feeding?
Signup and view all the answers
What is the estimated number of dengue cases globally as of March 2024?
What is the estimated number of dengue cases globally as of March 2024?
Signup and view all the answers
What is the role of genetic variation within dengue virus serotypes?
What is the role of genetic variation within dengue virus serotypes?
Signup and view all the answers
What does the presence of more than 10 petechiae typically indicate?
What does the presence of more than 10 petechiae typically indicate?
Signup and view all the answers
What is a sign of severe dengue related to plasma leakage?
What is a sign of severe dengue related to plasma leakage?
Signup and view all the answers
What can result from a cytokine storm in severe dengue?
What can result from a cytokine storm in severe dengue?
Signup and view all the answers
What is a potential neurological symptom of severe dengue?
What is a potential neurological symptom of severe dengue?
Signup and view all the answers
What does the IgM antibody indicate in primary dengue infection?
What does the IgM antibody indicate in primary dengue infection?
Signup and view all the answers
What describes the immunity conferred by primary dengue infection?
What describes the immunity conferred by primary dengue infection?
Signup and view all the answers
What is a symptom indicative of severe gastrointestinal involvement in dengue?
What is a symptom indicative of severe gastrointestinal involvement in dengue?
Signup and view all the answers
What does the term 'hemorrhagic syndrome' refer to in severe dengue?
What does the term 'hemorrhagic syndrome' refer to in severe dengue?
Signup and view all the answers
Which of the following indicates potential circulatory compromise in severe dengue?
Which of the following indicates potential circulatory compromise in severe dengue?
Signup and view all the answers
What organ impairment may occur in severe cases of dengue?
What organ impairment may occur in severe cases of dengue?
Signup and view all the answers
What phenomenon occurs when antibodies from a primary infection do not neutralize a second serotype?
What phenomenon occurs when antibodies from a primary infection do not neutralize a second serotype?
Signup and view all the answers
What is one characteristic symptom of the condition described?
What is one characteristic symptom of the condition described?
Signup and view all the answers
During which phase does Herman's rash become prominent?
During which phase does Herman's rash become prominent?
Signup and view all the answers
What is the incubation period for the described condition?
What is the incubation period for the described condition?
Signup and view all the answers
What does a positive Tourniquet test indicate?
What does a positive Tourniquet test indicate?
Signup and view all the answers
Which symptom is associated with retroorbital pain?
Which symptom is associated with retroorbital pain?
Signup and view all the answers
What happens during the antibody-dependent enhancement phenomenon?
What happens during the antibody-dependent enhancement phenomenon?
Signup and view all the answers
What is a significant feature of the rash described?
What is a significant feature of the rash described?
Signup and view all the answers
What is the average calculated from a recorded blood pressure of 120/80?
What is the average calculated from a recorded blood pressure of 120/80?
Signup and view all the answers
What might happen if a person experiences a second exposure to the same serotype?
What might happen if a person experiences a second exposure to the same serotype?
Signup and view all the answers
What laboratory tests are recommended for diagnosing liver involvement in dengue?
What laboratory tests are recommended for diagnosing liver involvement in dengue?
Signup and view all the answers
Which symptom is NOT considered a warning sign in dengue fever?
Which symptom is NOT considered a warning sign in dengue fever?
Signup and view all the answers
What indicates the need for strict observation in a dengue patient?
What indicates the need for strict observation in a dengue patient?
Signup and view all the answers
What is a common laboratory finding associated with severe dengue?
What is a common laboratory finding associated with severe dengue?
Signup and view all the answers
Which condition is classified as severe dengue?
Which condition is classified as severe dengue?
Signup and view all the answers
What is the purpose of the tourniquet test in dengue assessment?
What is the purpose of the tourniquet test in dengue assessment?
Signup and view all the answers
Which symptom is associated with severe organ involvement in dengue?
Which symptom is associated with severe organ involvement in dengue?
Signup and view all the answers
In the classification of dengue, which condition requires laboratory confirmation?
In the classification of dengue, which condition requires laboratory confirmation?
Signup and view all the answers
Which of the following symptoms is NOT listed as commonly associated with dengue fever?
Which of the following symptoms is NOT listed as commonly associated with dengue fever?
Signup and view all the answers
What constitutes a probable dengue diagnosis?
What constitutes a probable dengue diagnosis?
Signup and view all the answers
Study Notes
Dengue Fever
- Dengue is caused by a virus belonging to the Flaviviridae family, with four distinct serotypes (DENV-1, DENV-2, DENV-3, and DENV-4). A fifth variant, DENV-5, was discovered in 2013.
- All serotypes grant lifelong immunity to the specific serotype and short-term cross-immunity to other serotypes. However, some genetic variants within serotypes can be more virulent, leading to varying disease severity.
- The dengue virus is spread through the bite of an infected Aedes mosquito, primarily Aedes aegypti and Aedes albopictus.
- The virus undergoes a period of extrinsic incubation within the mosquito, lasting 8-10 days. Once infected, the mosquito remains infectious for life.
- Dengue is most common during the rainy seasons, with a peak incidence observed in July and August.
- In the Philippines, there were over 208,000 dengue cases reported in September 2024, with 7 deaths.
- Global estimates indicate over 200 million dengue cases and 500 dengue-related deaths annually.
Dengue Virus Transmission and Pathogenesis:
- The mosquito's saliva contains anticoagulants, preventing blood clotting and facilitating efficient blood feeding.
- The incubation period for dengue in a human is typically 4-7 days after the bite of an infected mosquito.
- The Antibody-Dependent Enhancement (ADE) phenomenon is a key factor in severe dengue, characterized by pre-existing antibodies from a previous infection failing to neutralize the virus. This results in an increased viral load, potentially leading to dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS).
- ADE occurs when antibodies from a previous infection bind to a different serotype but fail to neutralize it. This complex can attach to Fc receptors on monocytes, leading to more efficient viral entry into monocytes and macrophages.
Dengue Signs and Symptoms:
-
Classic Dengue:
- Fever, often biphasic in nature, lasting 2-7 days.
- Severe headache.
- Retro-orbital pain (pain behind the eyes).
- Nausea and vomiting.
- Maculopapular or macular rash, often appearing during the convalescent phase and often described as "white islands in a sea of red."
- Positive Tourniquet test, indicating capillary fragility and potential for bleeding (≥10 petechiae per 2.5 cm²).
-
Severe Dengue: Presence of warning signs is crucial for diagnosis and treatment.
- Plasma Leakage: Increased hematocrit, pleural effusions, ascites, circulatory compromise, and shock.
- Bleeding: Epistaxis, gingival bleeding, bleeding from injection sites.
- Organ Involvement: Liver impairment (elevated AST/ALT >/= 1000), acute renal failure, encephalopathy, CNS impairment, and cardiomyopathy.
Dengue Classification and Diagnosis:
-
WHO Dengue Case Classification:
- Probable Dengue: Fever plus two of the following: nausea/vomiting, rash, aches/pains, positive tourniquet test, leukopenia, or any warning signs.
- Warning Signs: Abdominal pain/tenderness, persistent vomiting, fluid accumulation, mucosal bleeding, lethargy/restlessness, liver enlargement >2 cm, rapid decrease in platelet count with increasing hematocrit.
- Severe Dengue: Severe plasma leakage, bleeding, organ involvement.
- Specimen Collection: Blood samples are essential for laboratory confirmation, detecting dengue virus RNA, and monitoring platelet and hematocrit levels.
Key Diagnostic Tools:
-
Tourniquet Test (Capillary Fragility Test):
- Evaluates hemorrhagic tendencies.
- A positive result indicates thrombocytopenia and increased capillary fragility.
- More likely to be positive during the defervescence phase.
Dengue Hemorrhagic Fever:
- Also known as "Dengue Viral Illness with Warning Signs."
- Characterized by biphasic fever, hemorrhagic manifestations, and warning signs mentioned above.
Management and Prevention:
-
Management:
- Supportive care, fluid replacement, and close monitoring.
- Early recognition and management of warning signs are essential for preventing complications.
-
Prevention:
- Mosquito control measures: eliminating mosquito breeding grounds, wearing protective clothing, using mosquito repellents.
- Vaccination: Several dengue vaccines are available, offering protection against various serotypes.
Epidemiology:
- Dengue is a major public health problem, particularly in tropical and subtropical regions.
- Global incidence, morbidity, and mortality are increasing.
- Outbreaks occur seasonally, especially during monsoon or rainy seasons.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the key aspects of dengue fever, including its causes, transmission, and global statistics. Learn about the dengue virus serotypes and their implications for immunity. It also highlights the impact of seasonal changes on dengue incidence and provides insight into its spread through mosquito vectors.
