Unusual Magnetic Resonance Imaging Features of Scrub Typhus Encephalitis

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi. The diagnosis of scrub typhus relies on the patient's history of exposure, clinical manifestations, and results of serological tests. Our patient had a history of altered sensorium, inability to walk, and macular rashes predominantly distributed over the chest and bilateral upper limbs. Post serological testing, the patient was referred to the radiology department for MRI brain. Radiologically, MRI being a superior modality helps in the evaluation of lesions in depth, helping to simplify the diagnosis of meningitis, scrub typhus encephalitis, and other related conditions. Various findings have been described in scrub typhus encephalitis in MR brain imaging, and our case shows an unusual finding in brain imaging.

Performance evaluation of a rapid molecular diagnostic, MultiCode based, sample-to-answer assay for the simultaneous detection of Influenza A, B and respiratory syncytial viruses

BACKGROUND

Clinical signs and symptoms of different airway pathogens are generally indistinguishable, making laboratory tests essential for clinical decisions regarding isolation and antiviral therapy. Immunochromatographic tests (ICT) and direct immunofluorescence assays (DFA) have lower sensitivities and specificities than molecular assays, but have the advantage of quick turnaround times and ease-of-use.

OBJECTIVE

To evaluate the performance of a rapid molecular assay, ARIES FluA/B & RSV, using laboratory developed RT-PCR assays (LDA), ICT (BinaxNOW) and DFA.

METHODS

Analytical and clinical performance were evaluated in a retrospective study arm (stored respiratory samples obtained between 2006-2015) and a prospective study arm (unselected fresh clinical samples obtained between December 2015 and March 2016 tested in parallel with LDAs).

RESULTS

Genotype inclusivity and analytical specificity was 100%. However, ARIES was 0.5 log, 1-2logs and 2.5logs less sensitive for fluA, RSV and fluB respectively, compared to LDA. In total, 447 clinical samples were included, of which 15.4% tested positive for fluA, 9.2% for fluB and 26.0% for RSV, in both LDA and ARIES. ARIES clinical sensitivity compared to LDA was 98.6% (fluA), 93.3% (fluB) and 95.1% (RSV). Clinical specificity was 100% for all targets. ARIES detected 10.6% (4 fluA, 8 fluB, 11 RSV) and 26.9% (7 fluA, 3 fluB, 22 RSV) more samples compared to DFA and ICT, all confirmed by LDA.

CONCLUSION

Although analytically ARIES is less sensitive than LDA, the clinical performance of the assay in our tertiary care setting was comparable, and significantly better than that of the established rapid assays.