The symptoms of dengue fever are similar to acute
fevers of viral origin. These are sudden onset of fever, headache,
bodyache, joint pains, and retro - orbital pain. Other common
symptoms are anorexia, altered taste sensation, constipation, colicky
pain,
abdominal tenderness, dragging pains in the inguinal region,
sore throat and general depression. Patient may or may not have
rash.
Some of the patients may also show signs of bleeding from the
gum, nose, etc.
Dengue Haemorrhagic Fever : DHF
DHF is a severe form of dengue
fever. Typically, it begins abruptly with high fever accompaniednby
headache, anorexia, vomitting and abdominal pain. During the
first few days, the illness resembles classical Dengue Fever (DF),
but
a maculopapular rash is less common.
A haemorrhagic diathesis is commonly demonstrated by scattered
fine petechiae on the extremities, face and trunk and in the axilae.
A positive tourniquet test and a tendency to bruise at venipuncture
site are always present. Bleeding from nose, gums and gastrointestinal
tract are less common. Haematuria is extremely rare.
The liver is usually enlarged, soft and tender. Approximately
50 % of patients have generalized lymphadenopathy.
The critical stage is reached after 2-7 days, when the fever subsides.
Accompanying or shortly after a rapid drop in body temperature,
varying degree of circulatory disturbances occur. The patient is
usually restless and has cold extremities. Sometimes, there may
be sweating.
In less severe cases, the changes in vital signs are minimum and
transient. The patient recovers spontaneously or recovers after
a brief period of therapy.
DHF is clinically confirmed by the positive tourniquet test (a
blood pressure cuff is used to impede venous flow. A test is considered
positive if there are > 20 petechiae / square inch)
Thrombocytopenia and haemoconcentration are constant findings
in DHF. Haemoconcentration - indicating plasma leakage is always
present.
In more severe cases, shock ensues and the patient may die within
12 -24 hours. Prolonged shock is often complicated by metabolic
acidosis and severe bleeding, which indicate a poor prognosis.
If the patient is appropriately treated before the irreversible
shock has developed, rapid recovery is the rule.
A major cause of deaths due to DHF is leakage of plasma in the
pleural and abdominal cavities leading to hypovolaemic shock. Determination
of haematocrit and platelet is essential for diagnosis and case
management. The time course relationship between the fall in the
platelet count and a rise in haematocrit level appears to be unique
to DHF. These changes occur before the subsidence of fever and
before the onset of shock and are correlated with the disease severity.
Encephalitic signs associated with intracranial haemorrhage, metabolic
and electrolyte disturbances, and hepatic failure (a form of Reye's
syndrome) may occur. They are uncommon but carry a grave prognosis.
C) Dengue Shock syndrome (DSS)
All the above criteria, plus evidence of circulatory failure menifested
by rapid and weak pulse, and narrow pulse pressure (< 20 mm
Hg) or hypo-tension for age cold, clammy skin and altered mental
status.
CHIKUNGUNYA FEVER
CASE DEFINITION OF CHIKUNGUNYA FEVER
SUSPECT CASE OF CHK
Acute onset
High fever of less than 7 days duration
Severe headache
Myalgia
Severe Arthralgia
With or without rash
PROBABLE CASE
Suspect case of CHK
High vector density
Presence of confirmed case of CHK in the area
CONFIRMED CASE
Isolation of virus from blood in early phase
Serological test for IgM antibody after 5th day of illness
Demonstration of 4 fold or greater rise in IgG antibodies in paired
sera
