European Journal of Cardiovascular Medicine

Scrub typhus is a rickettsial infection caused by mite-borne bacterium belonging to the family Rickettsiaceae Orientia T sutsugamushi .It is endemic in area of the world known as the "tsutsugamushi triangle" which extends from Japan to Australia, and to Pakistan and Afghanistan. The incidence of scrub typhus is increasing. It contributes to aboutfifty percent of the cases of acute undifferentiated febrile illness in various settings and is associated with high morbidity and mortality. Although the overall case fatality rate of patients admitted with scrub typhus infection is reported to be 9%, in those presenting with severe illness and requiring intensive care unit (ICU) admission, mortality may be as high as 24%.[1].

Scrub typhus involves the vascular endothelial cells, which induces many organ-system The main clinical features are high fever, rash, dysfunctions ,adenopathy, and eschar formation [2]. Few patients develop tremors, delirium, nervousness, or nuchal rigidity during the febrile stage [3]

The CNS is the most important site of infection in patients with rickettsial diseases [4,]. The characteristic pathological CNS finding in patients with scrub typhus include a diffuse or focal mononuclear cell exudate in the leptomeninges and the presence of typhus nodules (clusters of microglial cells) which are distributed throughout the brain substance [6]. In patients with severe central nervous system involvement patients may present with neurologic dysfunction, including neck stiffness, neurologic weakness, seizures, delirium, and coma. Meningismus or meningitis has been detected in nearly 5.7%-13.5% of patients [7]

Traditional neuroimaging may show non-specific findings in scrub typhus meningoencephalitis. Phukan et al. in their study revealed alteration of subcortical white-matter integrity in scrub typhus meningoencephalitis representing axonal degeneration and myelin breakdown [11]. Like TBM, CSF analysis in scrub typhus meningoencephalitis reveals lymphocytic pleocytosis which helps to differentiate from bacterial meningitis. CSF adenosine deaminase (ADA) of more than 10 U/L has a high sensitivity for tuberculous meningitis and may be used to differentiate the two diseases, though some studies have found CSF ADA in the same range in scrub typhus meningoencephalitis.[12]

Doxycycline for a minimum duration of five days or three afebrile days remains the standard treatment. Despite the early use of doxycycline in scrub typhus meningoencephalitis, mortality has been reported owing to its poor penetration of the blood-brain barrier, poor gastrointestinal absorption, antibiotic resistance, and immune-mediated damage [13]. Injectable doxycycline or azithromycin can be a good option in such situation [14].

AIM

Study of clnicopathological and biochemical profile in scrub encephalitis.

Hospital based observational study conducted at Medicine department of SMS hospital, Jaipur from January 2023 to June 2024 on 30 patients of Scrub Encephalitis.

Inclusion criteria

 ➼ Patient with AES proven to have scrub typhus with positive Scrub typhus detect IgM Elisa.

 ➼ Age>18year old patients

Exclusion criteria

➼ Patient in whom there was a definite proven cause such as pyogenic and tubercular meningitis, tumors, neurocysticercosis, fungal, epilepsy, or a definite metabolic/Structural cause.

➼All other causes of tropical illnesses causing encephalitis were excluded by appropriate investigation.

➼Patient not willing to give consent

Methodology

Study was done for a period from January 2023- June 2024 in SMS Medical College & Hospital Jaipur. Study includes a total of 30 patients of Scrub Encephalitis. Informed consent was taken from subjects and the study was approved by the institutional ethical and research committee.

Scrub typhus Detect IgM ELISA (by In BIOS International) test was done to ascertain positive cases of Scrub typhus. A thorough history of their presenting complaints and associated co-morbidities were taken using a structured proforma. Details of patient examination, focusing on neurological evaluation (including assessment of Glasgow coma scale [GCS]), and other systems were also collected. Data regarding laboratory investigations done to ascertain the cause of febrile illness (malaria, dengue, etc.), complete blood count, renal and hepatic function tests, and cerebrospinal fluid (CSF) analysis were collected.

Table-1 Demographic Parameters of patients

Table-2 Clinical Features of Patients

Table-3 CSF Profile of Patients

Table-4: MRI Brain profile of the Cases

In present study on MRI 4 cases show Acute Haemorrhagic Infarct,  2 cases have Diffuse Cerebral Oedema, 2 cases have Focal ring enhancing lesion, 6 cases have Hyperintense lesions on T2 imaging, 6 cases have Increased Signal intensity on T2 imaging,2 cases have Microhaemorrhages in Corpus Callosum, 2 cases have Microhaemorrhages in Corpus Callosum, 2 cases have Multiple areas of hyperintensity on T2 weighted images in periventricular and deep white matter

In present study the clinical features seen in Scrub Encephalitis cases includes fever, Headache, nausea and vomiting, altered sensorium, Seizures, Jaundice and pain abdomen.

In present study the prevalence of alter sensorium was 63.3% . In present study out of 30 patients 12 have seizures, neck rigidity was seen in 28 cases and Kernig sign was seen in 12 cases.

In present study out of 30 patients 12 have seizures, neck rigidity was seen in 28 cases and Kernig sign was seen in 12 cases. Altered sensorium was seen in 69% of our patients. This is higher than the findings from other studies of SE which noted around 56% of cases presenting with altered sensorium.[7] This could be attributed to referral bias as our center is a tertiary hospital providing service to several adjacent districts as well.   

Interestingly, headache which is usually a common feature in SE was noted in 24 patients (80%).

In present study mean duration of illness is 10.37+2.87 days. There was an association between the duration of fever and altered sensorium. It means that the longer the duration of fever, more the occurrence of altered sensorium.

AES due to viral etiology is known to be a close provisional diagnosis for patients with SE. However, in viral AES, the fever and the altered sensorium occur together at presentation. In SE, the altered sensorium occurs after a period of febrile illness. This temporal association of fever and altered sensorium can give a clue to the diagnosis of SE in patients who present with fever and altered sensorium.[15]

 It has been found that Scrub typhus involves the meninges more commonly, compared to other rickettsial infections. The overall CNS presentation in scrub typhus is ideally described as meningoencephalitis. However, studies have noted that patients without obvious signs of CNS involvement had reactive spinal fluid with mononuclear pleocytosis and their CSF tested positive for polymerase chain reaction for scrub typhus as well. This suggests that CNS invasion in scrub typhus is actually more common than what is suggested by associated CNS symptoms alone.[16]

In present study most common MRI brain finding seen were Increased Signal intensity in various parts of brain and acute infarct.

Scrub Encephalitis is an important diagnosis to be made in any patient with altered sensorium, as it is eminently treatable. Clinical clues such as eschar, and investigations showing altered liver function tests and thrombocytopenia, may point to this diagnosis as shown in our study. Prompt therapy can be lifesaving, and hence, this is an important diagnosis to be made in tropical countries.

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