Acute Dengue Hemorrhagic Encephalitis in a Child: A Case Report.

Expanded dengue syndrome includes unusual or atypical manifestations of dengue fever by involving various organ systems. There have been increasing reports of dengue fever with unusual manifestations. Even though dengue virus is considered as a non-neurotropic virus, central nervous system complications have been reported. We are reporting a 4-year-old child who presented with acute dengue hemorrhagic encephalitis along with classical features of dengue infection and magnetic resonance imaging findings, suggestive of hemorrhage in the thalamus and cerebellum. Copyright:

INTRODUCTION

Dengue infection is caused by a virus, and there are four serotypes (dengue virus (DEN): DEN-1, DEN-2, DEN-3, and DEN-4). Reported dengue cases have increased from 2.4 million in 2010 to over 4.2 million in 2019.[1] Every year around 500,000 people with dengue haemorrhagic fever (DHF) require hospitalization. Approximately 90% of them are children aged less than five years, and case fatality of 2.5% in those who were affected.[2] However with significant improvement in case management, the case fatality rate has reduced to less than 1%.[1] Expanded dengue syndrome includes unusual or atypical manifestations of dengue fever by involving various organ systems. In recent years, there have been increasing reports of dengue fever (DF) and DHF with unusual manifestations.[2] These include neurological, hepatic, renal, and other isolated organ involvement. In dengue infection, central nervous system (CNS) complications have been reported in 0.5% and 6.2% of cases.[345] Dengue encephalitis, as a complication, has been reported in 33%–43% of dengue infection cases with neurological manifestations.[6] As such dengue hemorrhagic encephalitis is even more rare entity, and only few reports are available in children.[3] Therefore, we are reporting a 4-year-old child who presented with acute dengue hemorrhagic encephalitis and who recovered.

CASE REPORT

A 4-year-old girl presented with fever since 3 days and altered sensorium since morning. Events following admission are shown in Figure 1, magnetic resonance imaging (MRI) brain findings are shown in Figure 2, and investigations in Table 1.

Figure 1

Sequence of events after admission

Figure 2

Axial sections of MRI of brain of a patient with acute necrotizing hemorrhagic encephalitis. T1-weighted image (a and a1), T2-weighted image (b and b1), and fluid attenuated inversion recovery (FLAIR) image (c and c1) show symmetrical hyperintensities in bilateral thalami and cerebellar hemispheres. Axial sections of MRI brain diffusion sequence (d), apparent diffusion coefficient (ADC) map (e), and gradient sequence (f) at the level of bilateral thalami showing restricted diffusion (d) and corresponding low ADC value (e) in bilateral thalami suggestive of cytotoxic edema. Few foci of blooming are seen in bilateral thalami on gradient sequence (f) suggestive of haemorrhage. Red arrows showing symmetrical hyperintensities in bilateral thalami

Table 1

Investigations

Investigations	1st day	2nd day	3rd day	4th day	5th day	6th day	7th day	10th day
Hemoglobin (g/dL)	10.1	11.6	10.6	9.4	10.7	10.1	10.7	11.3
PCV (%)	30.9	34.2	31.5	29	32.3	31.1	29.5	34
TLC (cells/mm3)	8,110	22,470	21,050	11,580	13,900	9,180	10,190	10,760
Platelet count (cells/mm3)	2.38 lakh	1.54 lakh	97,000	54,000	39,000	56,000	1.45 lakhs
CRP (U/L)	28.6				79.1
Serum bilirubin (mg/dL)	0.08				0.34
SGOT (U/L)	149		731		489			58
SGPT (U/L)	59		568		429			97
PT/INR	20.3/1.5				12.6/0.84
APTT	38.5/1.17				33.8/1.02
Serum total protein (g/dL)	5.4
CKNAC (N = 20–180 U/L)		5341
Serum albumin (g/dL)	2.9				2.4
CSF
Cells/mm3	8 (7L, 1N)
Protein	76
Sugar	65 (CBG = 151)
Gram stain	Negative
Culture	Sterile

Initial urea (74mg/dL) and creatinine (1.0mg/dL) values were elevated but serial repeat values were normal. Serum dengue immunoglobulin M (IgM) antibodies by MAC-Capture ELISA was positive but CSF negative. Her malaria rapid card test, Weil–Felix, Widal, and leptospira IgM by ELISA was negative. Her blood culture and stool culture was sterile

CSF test panel by singleplex real-time PCR (QIAGEN PCR KIT) was negative, which includes: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, varicella zoster, Enterovirus, Mycobacterium tuberculosis, herpes simplex virus 1 and 2, Japanese encephalitis, Plasmodium falciparum, Cytomegalovirus, Mycoplasma pneumoniae, and rickettsial infections

Abdominal ultrasonography showed bilateral raised renal cortical echoes and maintained corticomedullary differentiation, ascites, and right pleural effusion. Chest X-ray was normal. MRI brain showed acute necrotizing hemorrhagic viral encephalitis, involving B/L thalamic and cerebellar hemisphere [Figure 2]

L = lymphocytes, N = neutrophils

DISCUSSION

Even though dengue virus is considered as a non-neurotropic virus, there is an increase in the number of reports of central nervous involvement.[57] In dengue infection, the permeability of the blood–brain barrier is reportedly increased, thereby dengue viruses may cross the blood–brain barrier and cause encephalitis.[7] Neurological manifestations are commonly associated with serotypes, DEN-2 and DEN-3.[3] The neurological complications of dengue fever can be broadly grouped into three categories: direct viral neurotropism (encephalitis, meningitis, and myelitis), systemic complications (encephalopathy and ischemic or hemorrhagic stroke), and postinfectious complications (acute disseminated encephalomyelitis [ADEM] and myelitis).[45] In acute meningoencephalitis syndrome surveillance (AMES), clinical case is defined as a person with sudden onset of fever and at least one of the following: change in mental status, new onset of seizures (excluding simple febrile seizures), neck stiffness, and other meningeal signs. If a person meets the clinical case definition defined by AMES surveillance plus a laboratory confirmed dengue infection (presence of dengue-specific immunoglobulin M [IgM] antibody in serum or cerebrospinal fluid [CSF] detected by dengue non-structural protein [NS1] or IgM-capture enzyme-linked immunosorbent assay [ELISA]), in the absence of coinfection with other etiologic agents, then the diagnosis of dengue encephalitis is made.[4] Accordingly, our child was diagnosed as AMES and dengue encephalitis. Her diagnosis also satisfies the criteria laid down by Soares and Marzia.[8] CSF test panel by singleplex real-time polymerase chain reaction (PCR) for various organisms was negative. Along with the aforementioned fact, our child also had all classical features of dengue infection such as rashes, conjunctival suffusion, shock, liver involvement, thrombocytopenia, and polyserositis. Her anti-dengue antibodies in CSF were negative. Low titers of anti-dengue antibodies in CSF make it an unreliable marker.[49] MRI brain features were suggestive of hemorrhagic encephalitis, and other encephalitis causes were excluded with appropriate investigations in the CSF and serum. Therefore, we diagnosed it as dengue hemorrhagic encephalitis.

Differential diagnosis of dengue encephalitis according to the MRI neuroimaging findings includes Japanese encephalitis, herpes simplex encephalitis, and ADEM.[5] In Japanese encephalitis, the typical anatomical sites include the bilateral basal ganglia–thalamus complex, and in herpes simplex encephalitis, the bilateral temporal/basifrontal lobes.[5] In herpes encephalitis, hemorrhagic foci are characteristic, whereas it is not seen in Japanese encephalitis.[5] However, hemorrhagic foci within the basal ganglia–thalamus complex have been rarely reported in cases of Japanese encephalitis.[5] Therefore, it is difficult to differentiate the etiology of encephalitis on the basis of MRI findings alone.[5] Good history, clinical examination, other investigations such as liver function test, sonography, and CSF analysis might provide clues to the specific etiology. On imaging, focal abnormalities are suggestive of encephalitis rather than encephalopathy.[7] Encephalopathy presents as diffuse involvement of brain without any specific findings on imaging.[7] However, chikungunya encephalitis shows T2-weighted hyperintense white matter lesions with restricted diffusion.[7] In ADEM, classically, there is involvement of the cerebral white matter and deep gray matter nuclei; although hemorrhagic foci have been reported, they are relatively uncommon.[5]

In a study of nine cases by Jugpal et al.,[5] MRI of all patients showed areas of altered signal intensity that appeared as hyperintensity on T2-weighted and fluid attenuated inversion recovery image (FLAIR) sequences, and the most commonly affected site was the basal ganglia–thalamus complex. Other affected sites included are the cerebellum, cerebral cortex, white matter, and brain stem.[5] All cases showed patchy areas of restricted diffusion, and gradient-recalled echo/susceptibility weighted imaging sequences showed focal areas of blooming suggesting hemorrhage.[5] Hemorrhages in encephalitis may be due to dengue-related endothelial dysfunction, thrombocytopenia, platelet dysfunction, and mild coagulopathy.[3]

In a study regarding acute encephalitis syndrome (AES) surveillance in India, of 10,107 patients with AES, an etiology could be established in 49.2% of patients. Among them, Japanese encephalitis virus (16%), scrub typhus (16%), and DEN (5.2%) were the top three agents. Authors concluded that there is underscore of the importance of dengue virus in the routine testing of AES cases.[10] In a study from Thailand, 18% of children with suspected encephalitis were found to have dengue infection.[4] Dengue encephalitis can present with headache, altered consciousness, and seizures. The mortality rate in dengue encephalitis varies from 5% to 22%.[4] In a study from Philippines, of 14 children, 50% fully recovered from neurologic changes, 21% showed partial recovery, and 21% had neurologic sequelae. Among them, one infant expired.[4] In fact, the actual burden of dengue encephalitis has been underreported according to the World Health Organization.[4]

CONCLUSION

In a tropical country such as India, clinician should know about expanded dengue syndrome as a manifestation of dengue fever. If any child who presents with AES, dengue as the etiology should be one of the differential diagnoses so that appropriate management can save life.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.