Dengue fever Flashcards
What causes dengue fever
Arboviral illness spread by culicine mosquitos - aedes aegypti and aedes albopictus esp
Where is dengue endemic to
South east asia and south america
What is severe dengue
Severe bleeding
Organ impairment
Plasma leakage
Where is denue endemic
South east asia
South and central america
Types of dengue
Without warning signs
With warning signs
Severe
Probable dengue criteria
Live in/travel to dengue endemic area
Fever +
-Nausea, vomit
-Rash
-Aches and pains
- + tourniquet test
-Leukopenia
-Any warning sign
Warning signs dengue criteria
Abdo pain or tenderness
Persistnet vomitting
Clinical fluid accumulation
Mucosal bleed
Lethargy, restlessness
Liver enlargement >2cm
Haematocrit increase w rapid decrease and rapid decrease in platelets
What bloods suggest dengue with warning signs
Rapid increase haematocrit, rapid decrease in platelets - extravasation of plasma
Crtieria for severe dengue
Severe plasma leakage - shock - DSS, fluid acc -> resp distress
Severe bleeding
Sev organ involvement
Liver AST or ALT >1000
CNS - impaired consciousness
Heart and other involvement
Phases of dengue
Febrile
Critical
Recovery
6 factors determining phase of dengue
Temperature
Oral intake
Urine output
WBC
platelet
HCT
Febrile phase features
4 days - high temp, normal bloods
Critical phase length
day 4-6
WCC and platelte drop
Haematocrit increase - concentrated
Recovery phase dengue featires
Reabsorption of fluid
Recovery of platelet, neutrophil and haematocrit count
WHy important to not overload fluid in recvoery phase
Reabsorption of plasma that was extravasated
What viral test use in febrile phase of dengue
PCR - high viraemia at this phase
When do IgG tests for dengue become positive
At end of febrile phase and start of critical phase
What is fluid loss from in febrile vs critical phases degnue
Febrile - poor oral intake
Insensible
Vomit and diraahoea
Critical - leaking nad bleeding + all of above
What diagnostic tests can use <5 days post fever onset
Viral RNA - RT- PCR
Virus antigen test - NS1
ELISA
Diagnositc tests>5 days post fever onset
IgM antibodies
What combination of diagnostic tests use in real life and why
RT-PCR + IgM
OR NS1 + IgM
Extend detection actue dengue to 10 days post fever onset
Principle of management of denfue
Correct dehydration in febrile nad critical phases
Prevent fluid overload in recovery phase
Initial presentation of dengue fever
Intermittent high pyrexias - break bone fever 3-7 dyas
Arhtralgia
Rash - blanching maculopapular erythematous rash (measles similar) may -> petechiae
Bleeding, gums, epistaxis, GI bleeds
Headache
Nausea & vomiting
Lymphadenopathy
Generalised myalgia
Backache
Ocular manifestations:
Retro-orbital pain
Conjunctival injection
Conjunctivitis
Symptoms of severe dengue
Pulmonary and facial oedema
Ascites
Pleural effusions
Meningism including photophobia
Worsening or more profuse haemorrhage
