Dengue

Question 1

Dengue

Answer 1

acute febrile illness - 2-7 days duration

Aedes aegypti and Aedes albopticus

Question 2

Pathogenesis of Dengue

Answer 2

Macrophage/monocyte infection

Question 3

Dengue Hemorrhagic Fever (DHF) and/or Dengue Shock Syndrome (DHS)

Answer 3

more severe infection

2nd infection w/ a serotype different from that involved in the primary infection —> DHF and/or DHS

Question 4

Classic symptoms of Dengue

Answer 4

break bone fever

sudden onset of fever, headache, retroorbital pain and back pain w/ severe myalgia

Question 5

Other signs and symptoms of dengue fever

Answer 5

anorexia
N/V
cutaneous hypersensitivity
maculopapular rash on the trunk —> extremities and face

Question 6

Incubation period of Dengue

Answer 6

2-7 days

Question 7

Dengue without warning signs

Answer 7

PROBABLE DENGUE
-lives and travels to dengue endemic area
-fever + 2 of the ff:
   N/V
   rash
   aches and pains
   tourniquet test

-lab tests: leukopenia +/- dengue NS1 antigen test or dengue IgM antibody test

LAB CONFIRMED DENGUE

• viral culture isolation
• PCR

Question 8

Dengue with Warning Signs

Answer 8

CLINICAL WARNING SIGNS
-lives in/travels to dengue endemic area
-fever for 2-7 days plus any of the ff:
    abdominal pain or tenderness
    persistent vomiting
    clinical fluid accumulation
    mucosal bleed
    lethargy, restlessness
    liver enlargement > 2 cm

LAB WARNING SIGNS

inc in hematocrit
rapid dec in platelet count

Question 9

Severe Dengue

Answer 9

manifestations of dengue w/ or w/o warning signs plus any of the ff:

SEVERE PLASMA LEAKAGE leading to:

• shock (DSS)
• fluid accumulation w/ respiratory distress

SEVERE BLEEDING

SEVERE ORGAN INVOLVEMENT

• liver: AST or ALT > 1000
• CNS: impaired consciousness, seizures
• cardiac: impaired function (myocarditis)
• renal: impaired function (azotemia)

Question 10

Febrile Phase

Answer 10

sudden onset of high fever, arches, rashes

earliest abnormality in the CBC - decreasing WBC count

significant viremia

Question 11

To watch out for during febrile phase

Answer 11

dehydration

neurologic disturbance

Question 12

Critical Phase (day 3-7 of illness)

Answer 12

defervescence (drop in temp to 37.5-38. or less)
patients may either improve or deteriorate

warning signs - occur d.t. inflammation and capillary fragility which marks the beginning of the critical phase

progressive leukopenia and rapid decrease in platelet count

antibodies start to develop

Question 13

To watch out for in critical phase

Answer 13

shock from plasma leakage
severe hemorrhage
organ dysfunction

Question 14

Recovery phase (next 2-3 days)

Answer 14

gradual reabsorption of extravasated fluid via lymphatics

improvement in well being and hemodynamic status (diuresis ensues)

hct stabilizes or may be lower d.t. dilutional effect of reabsorbed fluid

WBC count starts to rise after defervescence but recovery of platelet count is later than that of WBC

Question 15

To watch out for in recovery phase

Answer 15

hypovolemia

Question 16

rising hct + unstable patient

Answer 16

active plasma leakage

need for further IVF

Question 17

decreasing hct + unstable patient

Answer 17

hemorrhage

blood transfusion

Question 18

rising hct + stable patient

Answer 18

monitor closely and expect that hct will fall w/n 24 hrs as plasma leakage stops

Question 19

decreasing hct + stable patient

Answer 19

hemodilution (reabsorption of extravasated fluid)

decrease (or stop) IVF to avoid pulmonary edema

Question 20

IgM antibody

Answer 20

detected after day 5 illness (for acute/recent infection)

Question 21

IgG antibody

Answer 21

detects past dengue infection

Question 22

Discharge criteria for Dengue

Answer 22

ALL MUST BE PRESENT

no fever for 48 hrs
improved status (well being, appetite, hemodynamics, UO)
increasing trend of platelet count
stable hematocrit w/o IVF

Question 23

Compensated Shock

Answer 23

clear and lucid patient
prolonged capillary refill time (CRT)
cool extremities
weak and thready pulses
tachycardia
tachypnea
normal SBP and rising DBP
narrow pulse pressure

Question 24

Hypotensive Shock

Answer 24

with changes in mental status
very prolonged CRT
mottled skin
cold and clammy extremities
feeble or absent pulses 
tachycardia or (bradycardia - late stage)
tachypnea, Kussmaul breathing - deep, rapid and labored breathing
hypotensive or unrecordable BP
narrow pulse pressure (<20 mmhg)