Clinicopathological study of 50
cases of Dengue
Mane V1 , Mohite S 2
1Dr. Vaibhav Mane, MD, Associate Professor of Pathology, 2Dr. Sushant
Mohite M.B.B.S., Junior Resident Department of Pathology, Bharati
Vidyapeeth Deemed University, Medical College and Hospital, Sangli,
Maharashtra, India
Address for
correspondence: Dr. Vaibhav Mane, Email:
vaishnavilab@rediffmail.com
Abstract
Aim and objective:
The objective of this study was to correlate laboratory tests during
the evolution of dengue fever, comparing frequencies between the
different clinical forms in order to use test results to predict the
severity of the disease. Methods:
This is an observational, descriptive and retrospective study of 50
patients with clinical and serological diagnoses of dengue fever. The
tests analyzed were blood count, platelet count, and serum aspartate
aminotransferase (AST) and alanine aminotransferase (ALT)
concentrations. Results:
Thrombocytopenia and elevated transaminases were observed in patients
with classic dengue fever. The main laboratory abnormalities found in
dengue hemorrhagic fever were thrombocytopenia, hemoconcentration and
elevated transaminases, similar to severe dengue with the exception of
hemoconcentration. Most laboratory abnormalities started on the 3rd day
but were more evident on the 5th day with restoration of values by the
11th day; this was more prominent in under 15-year-olds and with the
more severe clinical forms. Conclusion:
These results are relevant in assessing the disease because they can be
used as markers for more severe forms and can help by enabling the
adaptation of the therapeutic conduct to the needs of individual
patients.
Keywords:
Dengue Hemorrhagic Fever, Dengue Shock Syndrome, Leucopenia,
Thrombocytopenia
Manuscript received:
4th Aug 2015, Reviewed: 11th
Aug 2015
Author Corrected:
19th Aug 2015, Accepted
for Publication: 28th Aug 2015
Introduction
Dengue is caused by one of the four serotypes of the dengue virus
(DEN-1, DEN-2, DEN-3 and DEN-4) also referred to as an arbovirus
(arthropod-borne viruses) that belongs to the genus Flavivirus of the
family Flaviviridae. It is a disease with a wide clinical spectrum and
a wide variety of presentations, ranging from asymptomatic to an
undifferentiated fever (viral syndrome) to the more severe forms such
as severe dengue (SD) or Dengue hemorrhagic fever (DHF).
Transmission to humans occurs by the bite of the female Aedes aegypti
mosquito infected by one of four serotypes of the virus.). The period
of transmission from humans to mosquitoes begins one day before the
start of fever up to the sixth day of illness corresponding to the
viremia phase. In humans, the incubation period ranges from 3 to 15
days (intrinsic incubation) with an average of 5 days.The diagnosis of
dengue fever is carried out based on clinical, epidemiological and
laboratory data.
Leucopenia is the most prominent hematological change, sometimes with
counts of less than 2 x 103/µL. However, there are reports of
mild leukocytosis at the onset of the disease, with neutrophilia.
Lymphocytosis is a common finding, with the presence of atypical
lymphocytes.
Of biochemical variables, the most frequent changes occur in liver
function tests such as in serum aspartate aminotransferase (AST), serum
alanine aminotransferase (ALT), Gamma-glutamyl transpeptidase and
alkaline phosphatase levels, and serum albumin concentrations.
In this context, the present study aimed to assess the biochemical and
hematological dynamics of patients with dengue fever in order to
increase the sensitivity of the screening by healthcare professionals
in the most serious cases and to try to identify laboratory markers
that may indicate this evolution.
Materials
and Methods
Fifty clinically suspected cases of dengue were studied
retrospectively.This case series was conducted in Bharati Medical
colloge Sangli And Vaishnavi pathology laboratory Sangli.
Inclusion criteria: All
patients presenting with fever of less than 2 weeks duration, body
rashes, flushing and bleeding manifestations were included.
Exclusion criteria: Patients
with fever of more than 2 weeks duration, haematological disorders and
malignancies, liver failure, peptic ulcer, chronic splenomegaly
syndrome, enteric fever and autoimmune disorders ,positive for malaria
were excluded.
This is an observational, descriptive and retrospective study of 50
patients with clinical and serological diagnoses of dengue fever. The
tests analyzed were blood count, platelet count, and serum aspartate
aminotransferase (AST) and alanine aminotransferase (ALT)
concentrations.
Fifty clinically suspected cases of dengue were studied. Case
definition criteria for dengue fever were high fever, fever with rash,
retro orbital pain, myalgia, arthralgia, and conjunctival congestion
[1]. The criteria for dengue hemorrhagic fever (DHA)[1] included a
triad of hemorrhagic manifestations, platelet count of less than 1.0
lakh/cumm and clinical signs of plasma leakage observed in the form of
pleural effusion or ascites.
Hematological examination included complete hemogram with Nihon Kohden
5 part differential cell counter and peripheral blood was evaluated.
Hemoconcentration was seen as raised hemoglobin or RBC count.
Leucopenia was defined as total WBC count less than 4000/cumm and
thrombocytopenia as less than 1.0 lakh/cumm. Liver function tests were
done on fully automated biochemistry analyzer.
Results
Out of 50 cases seropositive for dengue 27(54%) were positive for NS1,
19 (38 %)for IgM and 4(8%) for IgG. Serological test sensitivity was
96-98.9% & specificity was 96.2-100%. Out of 50 patients 20
were females and 30 were males.
The clinical, hematological and biochemical features observed are as in
Tables 1 to 7
Table 1 : Clinical
features in Dengue fever
|
Clinical Features
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
High Grade Fever
|
22 ( 81 % )
|
16 (83.2 % )
|
02 (50 % )
|
|
Fever With rash
|
13 (40.3 %)
|
10 ( 52 % )
|
00 ( 00 )
|
|
Myalgia
|
19( 70.3 % )
|
14 ( 72.8 % )
|
02 (50 % )
|
|
Arthalgia
|
10 (37 % )
|
04 ( 20.8 % )
|
01 (25 % )
|
|
Conjuctival congestion
|
11 ( 40.7 % )
|
08 (41.6 % )
|
01 ( 25 % )
|
|
Hepatomegaly
|
05 ( 18.5 % )
|
08 (41.6 % )
|
02 ( 50 % )
|
|
hepatospleenomegaly
|
02 ( 7.4 % )
|
02 (10.4 % )
|
01 ( 25 % )
|
|
Nausea
|
12 ( 44.4 % )
|
10 ( 50.2 % )
|
02 ( 50 % )
|
|
Vomiting
|
07 ( 25.9 % )
|
05 (26 % )
|
00 ( 00 % )
|
|
Headache
|
15 ( 55.5 % )
|
12 (62.4 % )
|
03 ( 75 % )
|
|
Swollen lymphnodes
|
10 (37 % )
|
07 (36.4 % )
|
01 ( 25 % )
|
|
Retroorbital pain
|
15 ( 55.5 % )
|
09 (46.8 % )
|
02 ( 50 % )
|
Table 2 : Haemoglobin in
Dengue fever : Dengue fever
|
Haemoglobin
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
9.0 -11.0
|
4 (14. 8 % )
|
05 (26 % )
|
00 ( 00 % )
|
|
11.0 -13.0
|
11 (40 .7 % )
|
07 (36.4 % )
|
02 ( 50 % )
|
|
13.0 -16.0
|
12 (44 .4 % )
|
07 36.4 % )
|
02 ( 50 % )
|
Table 3. : Total
leucocyte count in Dengue Fever
|
Total Leucocyte count
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
7000- 10000
|
02 ( 7.4 % )
|
02 (10.4 % )
|
00 ( 00 % )
|
|
4000 – 7000
|
07 (25.9 % )
|
06 (31.2 % )
|
02 ( 50 % )
|
|
Less than 4000
|
18 (66.6 % )
|
11 ( 57.2 % )
|
02 ( 50 % )
|
Table 4 : Platelet count
in Dengue Fever
|
Platelet count
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
More than 150000
|
01 ( 3.7 % )
|
02 (10.4 % )
|
01 (25 % )
|
|
150000 -100000
|
06 (22.2 % )
|
05 ( 26 % )
|
01 ( 25 % )
|
|
100000 -20000
|
20 ( 74 % )
|
12 ( 62.4 % )
|
02 ( 50 % )
|
Table 5 : SGOT levels in
Dengue fever
|
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
AST (SGOT ) Increased
|
22 ( 81.4 % )
|
11 (57.2 % )
|
03 ( 75 % )
|
|
AST ( SGOT )Normal
|
05 ( 18.6 % )
|
08 ( 41.6 % )
|
01 ( 25 % )
|
Table 6: SGPT Levels in
Dengue Fever
|
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
ALT ( SGPT ) increased
|
17 ( 62.9 % )
|
12( 63.4 % )
|
03 ( 75 % )
|
|
ALT ( SGPT )normal
|
10 (37.1 % )
|
07 (36.6 % )
|
01 ( 25 % )
|
Table 7 : Bilirubin
levels in dengue fever
|
|
NS1
N = 27
|
IgM
N = 19
|
IgG
N= 4
|
|
Bilirubin increased
|
02 ( 7.4 % )
|
03 (15.6 % )
|
00 ( 00 % )
|
|
Bilirubin normal
|
25 ( 92.5 % )
|
16 ( 83.2 % )
|
04 ( 100 % )
|
Hemoconcentration, Leucopenia, and Thrombocytopenia were chief
hematological features of seropositive dengue cases. Peripheral blood
smear showed activated lymphocytes.Aspartate aminotransferase and
alanine aminotransferase were mildly elevated in significant number of
cases. None had any bleeding manifestations
Discussion
Dengue fever is an infectious disease which is difficult to distinguish
from other viruses as there are no specific markers that can diagnose
the disease early. Because it is a disease that can evolve with serious
consequences and even be fatal, this study aimed at analyzing clinical
and epidemiological data and laboratory dynamics in order to try to
identify biomarkers that are predictive of severity.
Dengue is caused by a virus belonging to the flavi viridae family
(single stranded, positive, nonsegmented RNA virus). It has four
distinct serotypes DEN 1, DEN 2, DEN 3 and DEN 4 [1,2,4]. Infection
with one serotype confers immunity to only that serotype and hence a
person may be infected upto four times [1,2,4]. Humans are the main
reservoir of dengue virus [1,2 ,3]. Dengue presents as dengue fever,
dengue haemorrhagic fever (DHF) or dengue shock syndrome
(DSS).[1,2,34,5,].
It has been suggested that baseline microvascular permeability in
children is greater than that of adults and this could partly explain,
why DHF is more frequent in children [3,5,6,7,8 ]. In our study, none
of the children had DHF/DSS. This antibody dependant mechanism results
in an amplified cascade of cytokines and complement activation causing
endothelial dysfunction and consumption of coagulation factors leading
to plasma leakage and haemorrhagic manifestations. [2,3,8,9,10 ]The
severity of the disease depends on the strain and serotype of the
virus, age of the patient and degree of viremia.
The most common clinical feature of dengue in our study was high fever
of patients. The fever rash was typically macular or maculopapular,
often becoming confluent and sparing small islands of normal skin. The
rash was not associated with scaling or pruritus [1,2,11,12,13,].
Pervin et al [13] , reported occurrence of rash in 33% of patients.
Hepatomegaly was observed in more than 30% of our patients.
Hepatomegaly is more common in patients with secondary infection and
some of these may be associated with a increase in liver transaminases.
Myalgia was observed in 72% of patients. Pervin et al, reported myalgia
in 84.5% of patients. Hemoconcentration was seen in more than 50% of
patients [13].
Thrombocytopenia (platelets < 1,00,000/cmm) was seen in 80% of
patients. The platelet count in these patients ranged between
4,000-1,00,000/cmm. None had any bleeding manifestations. Platelet
count was evaluated by Nihon Kohden 5 part diferential cell counter as
well as on peripheral blood smear. The counter gives a false low
reading when large platelets are present. Such cases were obviated by
assessment of platelets on smear. Ratagiri et al [14], reported
thrombocytopenia in 82%, DHF in 60%, DSS in 22% and DF in 18% of
patients. Our study on the other hand reflected DF in 96%.
Leucopenia was observed in 26% of patients by Ratagiri et at [14].
Leucopenia was observed in more than 60% of patients in our study.
Development of antibodies potentially cross-reactive to plasminogen
(due to a similarity in 20 amino acid sequence of dengue E glycoprotein
and a family of clotting factors) could have a role in causing
haemorrhage in DHF [9,11,13]. The increased destruction or decreased
production of platelets could result in thrombocytopenia.
Virus-antibody complexes have been detected on the platelet surface of
DHF patients suggesting a role for immune-mediated destruction of
platelets [14]. The release of high levels of platelet-activating
factor by monocytes with heterologous secondary infection may explain
the haemorrhage, given that platelet-activating factor may induce
platelet consumption and augment adhesiveness of vascular endothelial
cells resulting in thrombocytopenia [12]. The presence of 1gM
antibodies in the sera DHF cases that cross-reacted with platelets has
been demonstrated [1,3,6,9]. These autoantibodies could be involved in
the pathogenesis of the disease. IgM and IgM antibodies assay by ELISA
is the commonest diagnostic test. The test based on an increase in the
IgG titre by a factor of four is difficult in routine clinical care
because a second blood sample is required at the convalescent stage.
Cross reactions with other flaviviruses interfere with serologic
testing, particularly the ELISA for IgG and this affects the
interpretation of test results in travellers
exposed to other flavivirus infections,including those
previously vaccinated against flavivirus infections, such as yellow
fever and Japanese encephalitis [7,13,14]. Rheumatoid factor may lead
to an IgM capture assay that is false positive for dengue and like many
other flavivirus infections (albeit lesser than with dengue IgG assays)
[8].
Primary infections are characterised by an increase in dengue-specific
NS1 antigen and IgM antibodies four to five days after the onset of
fever and by an increase in IgG antibodies only after seven to ten
days. IgM antibodies are detectable for three to six months, whereas
IgG antibodies remain detectable for life. In secondary infections, the
level of IgM antibodies is lower than in primary infections and the
antibodies are sometimes absent, whereas levels of 1gG antibodies rise
rapidly in secondary infections, even during the acute phase. Thus, the
presence of high titers of 1gG early in the course of the disease is a
criterion for secondary infection. The sensitivity of 1gM ranges from
90-97% as compared with the gold standard haemagglutination-inhibition
test. Some false positive reactions can be observed in less than 2% of
cases and a low or negative IgM reaction in secondary infections.
This study shows that DSS is an uncommon manifestation of dengue virus
infection.Dengue infection is generally self limiting. Patients with
bleeding manifestations usually have decreased platelet count and
leucocyte count. Hemoconcentration, leucopenia, thrombocytopenia,
raised AST, raised ALT and plasmacytoid lymphocytes in peripheral blood
smear shall give enough clue to test for Dengue serology so as to
reduce the morbidity and mortality due to this disease.
According to World Health Organization (WHO),[1,2,3] PCR is a powerful
method to be used for dengue diagnosis, but PCR is not widely available
and it still needs to be better standardized
Conclusion
Dengue fever evolves with laboratory alterations starting on the 3rd
day and becoming most evident on the 5th day with values restored to
normal by the 11th day. The disease was more severe in individuals aged
15 years and older with a more pronounced and persistent presence of
liver abnormalities (AST, ALT) and hemoconcentration. The study results
are relevant in the characterization of biological markers in the
evolution of the disease and can be used as markers for the most severe
forms thereby enabling early help with the adaption of therapeutic
conduct for specific patients
The results of this study have highlighted the importance of history,
clinical examination and the triad of thrombocytopenia, raised
hematocrit and elevated liver enzymes for the early diagnosis of DHF
without waiting for dengue serology for diagnosis which takes 2-3 days.
Therefore, it is recommended that the diagnosis of dengue fever should
be made early on the basis of basic investigations. Timely diagnosis
and early fluid and supportive therapy reduces the morbidity and
mortality from DHF
Funding:
Nil, Conflict of
interest: None initiated.
Permission
from IRB:
Yes
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How to cite this article?
Mane V, Mohite S. Clinicopathological study of 50 cases of Dengue. Int
J Med Res Rev 2015;3(8):794-799. doi:10.17511/ijmrr.2015.i8.149.