the dengue virus is a single - stranded rna virus of the flaviviridae family causing dengue fever and dengue hemorrhagic fever .
dengue encephalopathy is usually secondary to multisystem derangement like shock , hepatitis , coagulopathy , and concurrent bacterial infection .
dengue encephalitis is a different entity , which occurs due to direct neuronal infiltration by the dengue virus .
we report a case of dengue shock syndrome with encephalitis , with peculiar mri findings .
a 17-year - old girl presented with a history of high - grade fever and rigors for three days .
she had two episodes of vomiting , generalized headache , and altered sensorium , lasting for 15 to 20 minutes , few hours prior to admission .
there was no significant past medical history . on admission she was febrile , with a temperature of 101f , pulse of 132 / minute , blood pressure of 90 / 40 mmhg ( map-60 mmhg ) and cold extremities . on pulse
she was pale , and skin rash , edema , icterus , and clubbing were absent .
first dose of third generation cephalosporin was given empirically in view of the possibility of bacterial infection .
investigations revealed hemoglobin ( hb ) of 14.5 g / dl , packed cell volume ( pcv ) of 45 , white blood cell count ( wbc ) of 7100 / cumm , with neutrophils 64% , lymphocytes 34% , and monocytes 2% .
the platelet count was 1.35 lacs / cumm and esr was 48 mm at the end of one hour .
u / l , sgpt-182u / l. serum albumin was 3.65 gm / dl , and inr was 2.0 .
blood urea nitrogen was 39 gm / dl with creatinine of 1.4 mg / dl .
there was evidence of metabolic acidosis with blood lactate 2.00 mmol / l on initial blood gas .
no hypoxia or hypercapnia was seen ; x- ray chest and 2 d echocardiography were normal .
ultrasonography ( usg ) showed evidence of bilateral minimal pleural effusion with mild ascites . the patient 's blood pressure and urine output improved after initial resuscitation with crystalloids .
a few hours later , this young girl had an episode of generalized tonic - clonic seizure with unresponsiveness .
she was intubated and ventilated in view of the poor level of consciousness after the seizure .
it showed [ figure 1 ] extensive parenchymal hyperintense lesions in the bilateral cerebellar cortex , vermis of the cerebellum , entire pons and midbrain , bilateral medial temporal lobes , and both thalami , on t2 and fluid attenuated inversion recovery ( flair ) images .
these lesions look hypointense on t1w images , hyperintense on flair images , and dark on the adc map .
small foci of hemorrhage in the thalamic lesions looking hypointense , were seen on the t2 gre images .
t 2 flair and t2-weighted images showing involvement of thalamus , pons , and cerebellum , with presence of hemorrhage on t2 and restricted diffusion on dwi cerebrospinal fluid ( csf ) analysis was done .
igg / igm antibodies for dengue were positive in the serum as also on the dna polymerase chain reaction ( pcr ) for dengue .
titers for hepatitis viruses were negative ( hav , hev , hbsag , hcv ) .
serum procalcitonin was 0.3 ng / ml ( negative less than 0.5 ng / ml ) .
her liver functions improved subsequently , and serum ammonia and electrolytes were within normal limits .
she remained comatose even after correction of shock , hepatitis , metabolic acidosis , and coagulopathy .
the mri brain findings were in favor of the possibility of direct extensive neuronal injury . although the mri brain findings were in favor of je , csf analysis was negative for je . therefore , the possibility of viral encephalitis due to dengue was strongly suspected . during the hospital course , she developed multiorgan dysfunction , shock , and acute respiratory distress syndrome ( ards ) .
empirical antibiotics and antimalarials were continued till reports of the causative agent were obtained , and then withdrawn .
table 2 shows her investigations over the next 10 days . in spite of all the treatment she continued to remain comatose , with hemodynamic compromise , and expired on the eleventh day after admission
dengue virus infections are among the most common cause for hospital admissions in western maharashtra .
it is estimated that 50 to 100 million infections and 25,000 fatalities occur worldwide every year . the world health organization ( who ) surveillance shows that the global incidence is rising .
numerous neurological manifestations like transverse myelitis , myositis , and gullian - barre syndrome have been reported .
dengue encephalopathy is a well - recognized and common entity , the incidence ranging from 0.5 to 6.2 % .
the possible mechanisms are liver failure ( hepatic encephalopathy ) , cerebral hypoperfusion ( shock ) , cerebral edema ( vascular leak ) , deranged electrolytes , and intracranial bleeding due to thrombocytopenia or coagulopathy , which is secondary to hepatic failure
. _ there are subsets of patients in whom the cause for neurological injury remains unclear even after excluding the above - mentioned indirect mechanisms .
dengue is thought to be a non - neurotropic virus . however , there are reports of the demonstration of dengue virus and igm antigen in the cerebrospinal fluid ( csf ) of patients with encephalopathy
. there are case reports by misra et al . , from india , and solomon et al . , from vietnam
, 11 patients were seen with confirmed dengue infection , but no csf study was reported .
solmon et al . , diagnosed dengue encephalitis in nine patients , but virus or antibody was found in the csf of only two cases .
kularatne et al . , had a similar study in which they showed the association of dengue with encephalitis .
on admission our patient had a history suggestive of encephalopathy with shock , coagulopathy , metabolic acidosis , and deranged liver functions .
the mri findings noted in our case are most characteristic of je and not commonly seen with dengue fever .
[ bilateral thalamic involvement with foci of hemorrhage , with involvement of temporal lobe and brain stem ] is very uncommon with dengue .
this case is presented to highlight the possible extensive involvement of the brain by dengue virus .
dengue is not classically a neurotropic virus , although there is recent evidence of direct neuronal injury .
dengue encephalitis must be thought of in differentials of encephalopathy , in patients with dengue . in such cases , neuroimaging and csf analysis
the virus or antibody can be isolated from the serum , but the csf samples may be negative .
the dengue encephalitis is thought to be benign , but can be fatal at times .
the role of an antiviral in such cases needs to be further defined because of the extensive parenchymal involvement and possible unfavorable outcome .
 we report a case of dengue fever with features of encephalitis . 
 the diagnosis of dengue was confirmed by the serum antibodies to dengue and the presence of a dengue antigen in the cerebrospinal fluid . 
 this patient had characteristic magnetic resonance imaging brain findings , mainly involving the bilateral thalami , with hemorrhage . 
 dengue is not primarily a neurotropic virus and encephalopathy is a common finding in dengue . 
 hence various other etiological possibilities were considered before concluding this as a case of dengue encephalitis . 
 this case explains the importance of considering the diagnosis of dengue encephalitis in appropriate situations . 
Introduction
Case Report
Discussion
Conclusions