Dengue is on the rise – let’s get protected!
Friday, 27 June 2014 08:01
What is dengue?
Dengue is a viral infection transmitted by the bite of an infected mosquito. There are
four closely related but antigenically different serotypes of the virus that can cause dengue
(DEN1, DEN 2, DEN 3, DEN 4).Dengue has a wide spectrum of infection outcome
(asymptomatic to symptomatic). Symptomatic illness can vary from undifferentiated fever
(viral syndrome), dengue fever (DF), dengue haemorrhagic fever (DHF) and dengue with
unusual manifestations. DF and DHF comprise the bulk of symptomatic illness while unusual
dengue is a rare entity (usually <1%).
Types of Dengue
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Dengue Fever (DF) – marked by an onset of sudden high fever, severe headache, pain
behind the eyes, and pain in muscles and joints. Some may also have a rash and varying
degree of bleeding from various parts of the body (including nose, mouth and gums or skin
bruising).
Dengue Haemorrhagic Fever (DHF) – is a more severe form, seen only in a small proportion
of those infected. DHF is a stereotypic illness characterized by 3 phases; febrile phase with
high continuous fever usually lasting for less than 7 days; critical phase (plasma leaking)
lasting 1-2 days usually apparent when fever comes down, leading to shock if not detected
and treated early; convalescence phase lasting 2-5 days with improvement of appetite,
bradycardia (slow heart rate), convalescent rash (white patches in red background), often
accompanied by generalized itching (more intense in palms and soles), and diuresis
(increase urine output).
Symptoms and signs (features of disease)
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Disease varies in severity
Incubation period is 2-7 days.
All haemorrhagic fever syndromes begin with abrupt onset of fever (39.5–
41ºC) and muscle pain.
Fever is often biphasic (rise and down) with two peaks.
Fever is associated with frontal or back of the eyes pain (frontal or retroorbital headache) lasting 1–7 days, accompanied by generalised red
coloured rash which disappear when press over it (macular, blanching
rash).
Initial rash usually fades after 1–2 days.
Symptoms regress for a day or two then rash reappears in (maculopapular,
morbilliform pattern), sparing palms and soles of feet. Fever recurs but
not as high. There may be desquamation.
Dengue fever cases experience severe bony and muscle pain in legs, joints
and lower back which may last for weeks (hence breakbone fever).
Nausea, vomiting, skin rashes, taste disturbance and anorexia are common.
Abdominal pain may occur and if severe suggests Dengue haemorrhagic
fever pattern.
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When to see a doctor?
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Patients should seek medical advice in the presence of following features particularly
when fever settles:
Severe vomiting
Abdominal pain
Increase thrust
Drowsiness and excessive sleepiness
Refusing to eat or drink
Abnormal bleeding manifestations – eg: heavy menstrual bleeding or menstruation starting
earlier than usual
If the following features are present seek medical attention immediately:
Cold clammy skin and extremities
Restless and irritability
Skin mottling
Decreased/no urine output
Behaviour changes – confusion or using foul language
Early detection of Dengue illness
Early identification and management of Dengue illness can minimize morbidity and
mortality. In the present hyper-endemic setting in Sri Lanka, Dengue illness (Dengue Fever DF /Dengue Haemorrhagic Fever - DHF) is considered in the differential diagnosis of patients
presenting with acute onset of fever with headache, retro-orbital pain, myalgia, arthralgia,
rash (diffuse, erythematous, macular), haemorrhagic manifestation (petechiae, positive
tourniquet test), Leukopenia (<5000/mm3), Platelet count ≤150,000/mm3 and rising
Haematocrit of 5-10%.
Sometimes Dengue patients may present with atypical manifestations like respiratory
symptoms such as cough, rhinitis or Injected pharynx and gastro-intestinal symptoms such
as constipation, colicky abdominal pain, diarrhoea or vomiting without the classical clinical
presentation described above.
If a patient with high fever is seen with flushed face/extremities (diffuse blanching erythema
in adults) and a positive tourniquet test (even with a normal platelet count) with leukopenia
(WBC <5000 /mm3) without any focus of infection, it is very likely that the patient is having
Dengue illness.
In any patient who presents with shock (particularly afebrile at presentation with cold
extremities and tachycardia with low volume pulse and hypotension) consider Dengue
Shock as a likely diagnosis.
Detection of NS1 antigen from blood is novel laboratory diagnostic test for dengue during
early febrile phase. However, NS1 only implies that the person is having dengue illness and
it does not help in differentiating DF from DHF. Therefore, NS1 test may be useful in
situations where early clinical diagnosis is doubtful.
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Investigations
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Value of Full Blood Count (FBC/CBC)
OPD level:
FBC is mandatory on all fever patients – from day 3 onwards
Special patient categories – FBC on day 1 or first day of visit/contact (Pregnancy, Infancy,
elderly, those with co-morbidities, etc.)
FBC daily from day 3 if platelet (plt) count ≥150,000/ mm3
FBC twice daily when plt count ≤150,000/ mm3 (admission to hospital based on clinical
judgment, warning signs and social reasons)
Admit all patients with platelet count ≤100,000/ mm3
Inward level
For any patient admitted to hospital on or before day 3 of illness same criteria of performing
FBC as in OPD level is applicable unless and otherwise more frequent counts are requested
by the clinician.
Important Advice for Ambulatory Care Patients (OPD level):
First contact doctors should ensure adequate oral fluid intake.
In adults around 2500 ml for 24 hours (if the body weight is less than 50kg fluids given as
50ml/kg for 24hours or 2ml/kg/hr) is recommended during Febrile Phase (before admission
to hospital).
In children calculation of maintenance fluid is as follows:
M (Maintenance)=100ml/kg for first 10 kg
+50ml/kg for next 10 kg
+20ml/kg for balance weight
Patients/parents should be asked to return immediately for review if any of the following
occur on/beyond day three:
Clinical deterioration with settling of fever
Inability to tolerate oral fluid
Severe abdominal pain
Cold and clammy extremities
Lethargy or irritability/restlessness
Bleeding tendency including inter-menstrual bleeding or menorrhagia
Not passing urine for more than 6 hours
Differentiation of DHF from DF:
It is important to differentiate DHF from DF early because it is the patients with DHF who
develop plasma leakage and resultant complications usually after the third day of fever. DHF
may become evident as the fever settles. Tachycardia (increase heart rate) without fever (or
disproportionate tachycardia with fever) and narrowing of pulse pressure (eg: difference
between systolic and diastolic narrows from 40mmHg to 30 mmHg) is an early indication of
leaking which warrants referral to the hospital. A progressively rising Haematocrit suggests
that the patient may have entered the leaking phase. However, an ultra sound scan focused
on chest and abdomen to detect selective and progressive fluid accumulation is a more
objective evidence of plasma leakage in DHF.
Admission to a hospital:
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The first contact doctor will decide to admit a patient to a hospital based on the clinical
judgment. It is essential to admit the following patients:
-Platelet count below<100,000/mm3
-With the following warning signs on or beyond day 3 of fever/illness:
Abdominal pain or tenderness
Persistent vomiting
Mucosal bleeding (eg: bleeding from mouth, nose etc.)
Lethargy, restlessness
Liver enlargement >2cm
Rising HCT with rapid decrease in platelet count in FBC
Clinical signs of plasma leakage: pleural effusion, ascites (late sign)
Other patients who may need admission even without above criteria are:
Pregnant mothers - admission on second day of fever and close follow up with daily FBC is
very important.
Elderly patients/infants
Obese patients
Patients with co-morbid conditions like diabetes, chronic renal failure, ischemic heart
disease, haemoglobinopathies such as thalassaemia and other major medical problems
Patients with adverse social circumstances -e.g. living alone, living far from health facility
without reliable means of transport.
Clinical and haemo-dynamical stability with no fever for 48 hours indicates
recovery from Dengue illness.
Latest Disease Trends
Approximately 60.57% of dengue cases were reported from the Western province. The
highest numbers of dengue cases were reported during the twenty second week of 2014.
This situation warrants regular removal of possible mosquito breeding sites from the
environment. It is also important to seek medical attention in the event of fever by day
three of the illness.
January
3605
February
1986
March
1607
April
1623
May
3501
TOTAL
12322
Dengue fever pattern seems to be increasing for last decade with some fluctuations but
from 2010 it is on the rise causing increased number of casualties.
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Dengue Deaths are reducing in numbers from 2010 onwards
Case Fatality Ratio (CFR)? 2009 -346
2010 – 246
2011 – 185
2012 – 181
2013 - 89
Current dengue situation
Reporting of dengue cases has been increased in last month and sudden rise of dengue
incidence have been noted in certain areas of the country but compare to the last year
incidence, reported cases are lower than last year by this time (14479).
During the last 6 months of the year 2014, 13556 suspected dengue cases have been
reported to the Epidemiology Unit from all over the island.
What you have to do?
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If Fever is present, always suspect as having dengue
1. Give a good/adequate rest
Never allow to do hard work or to be tired by any means
2. Give adequate liquids to drink
Milk, Fruit juice , Orange juice, Jeewani ,conjee, soup are suitable
Do not give only water all the time
Allow the patient to take usual solid foods if possible
Never give red/brown coloured foods/drinks or beverages
3. Keep an eye on the number of times of passing urine
If the number of times of passing urine less than usual take the patient to a hospital
4. If a child has fever,
Wet the body with normal water
Give Paracetamol recommended dose (for the age/weight) and 6hrly
Never give other drugs to reduce fever
Eg: Diclofinac/ Ibuprofen/Mefenamic Acid – Tablets / Syrups
5. If the fever continues for more than 2 days,
Take the patient to a hospital on the 3rd day and do a blood test (FBC)
6. Take the patient immediately to a hospital, if you notice these symptoms,
Inability to tolerate oral fluids (Repeated vomiting)
Refuse to eat /drink
Feeling extreme thirsty
Reduced number of times of passing urine/not passing urine more than 6 hrs
Abdominal pain
Drowsiness
Behavioral changes
Vomiting reddish or blackish stained vomits
Bleeding manifestation – Gum bleeding, red color urine
Dizziness /Giddiness( vertigo)
Pale looking
Cold limbs (arms and legs)
Find out and eliminate Dengue mosquito breeding places
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Discarded non-biodegradable items
Discarded biodegradable items
Places where rain water can be accumulated
Uncovered water storage tanks, containers
Ornamental & fancy items where water can be collected
Special home appliances
Water containing small containers inside and outside of the house
Plants/ parts of plants, tree holes
Others such as;
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Unused “Cisterns”
Cemented shallow wells
Unused boats
Water leaking cement floor
Water dispenser’s tray
Fence poles
At the construction sites
Inside the grinding stones
Tube Wells
Earth pipe hole
Water meter
How to prevent?
Integrated vector management
Prevention and control of dengue virus transmission depends entirely on control of the
mosquito vectors or interruption of human – vector contact.
Environmental Management
Environmental management is a key element of IVM. Environmental management can
include environmental modification, environmental manipulation, and strategies
that reduce contacts between vectors and humans.
In the case of mosquitoes, the larvae are easier to control than adults because they are
confined to water bodies. Therefore, removing whatever practicable, water collection called
“source reduction” should be a primary consideration in mosquito control.
Environmental manipulation
Strategies involve recurrent activities such as measures that have a temporary effect on
vector habitat and need to be repeated Eg. Covering of water storage containers or tanks
with tight lids, screens or net covers
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