Posterior reversible encephalopathy syndrome in scrub typhus fever

Rare neurological and neuropsychiatric manifestations of scrub typhus: a case series of 10 cases

INTRODUCTION

Scrub typhus is a potentially life-threatening but curable disease that can produce multi-organ failure. Neurological manifestations in scrub typhus have gained attention recently, where the entire neural axis except the myoneural junction can be involved. Although the pathogenesis of neurological involvement has not been established, immune-mediated mechanisms are suspected. This article reports the clinicopathological features of scrub typhus cases presenting several rare neurological and neuropsychiatric manifestations.

METHODS

Three hundred fifty-four serologically confirmed scrub typhus cases were admitted to the Department of General Medicine of Burdwan Medical College and Hospital (West Bengal, India) between May 2018 and May 2022. There were 50 patients who had predominantly neurological manifestations. Of these 50 cases, ten patients presented with extremely rare neurological manifestations.

RESULTS

We report 10 cases of scrub typhus (four men and six women) who presented with complex neurological pictures (posterior reversible encephalopathy syndrome, Opalski syndrome, parkinsonism, cerebellitis, isolated opsoclonus, acute transverse myelitis, myositis, polyradiculoneuropathy with cranial neuropathy, acute transient behavioral changes, and fibromyalgia). Immune-mediated mechanisms might have mediated the pathogenesis of most cases following scrub typhus infection.

CONCLUSION

From a clinicopathological point of view, each case was unique in its presentation and treatment response. In any acute onset neurological disorders associated with febrile illness in the tropics or subtropics, scrub typhus infection should be included in the differential diagnosis, despite the absence of eschar and unremarkable neuroimaging findings. This otherwise curable disease may result in multi-organ dysfunction syndrome and death if the diagnosis is delayed.

Neurological Manifestations of Scrub Typhus

PURPOSE OF REVIEW

The occurrence of cases of scrub typhus is on the rise in South Asian and Southeast Asian countries. The present review discusses neurological complications following scrub typhus to appraise clinicians practicing in endemic regions about considering this treatable disease in the differential diagnosis of acute febrile illnesses, especially when accompanied with clinical neurological features.

RECENT FINDINGS

While the association of aseptic meningitis, encephalitis, and meningoencephalitis with scrub typhus is well known, more recently described neurological syndromes associated with scrub typhus include acute disseminated encephalomyelitis, various cranial nerve palsies, cerebellitis, cerebrovascular diseases including cerebral venous sinus thrombosis, transverse myelitis, longitudinally extensive transverse myelitis, Guillain-Barré syndrome, opsoclonus-myoclonus syndrome, parkinsonism, and many more. Early diagnosis is key to successful treatment. While diagnostic confirmation is generally made by the detection of IgM antibody by either ELISA or indirect fluorescent antibody tests, conventional PCR using 56 kDa gene (cPCR) and loop-mediated isothermal amplification assay (LAMP assay), as well as a newly introduced metagenomic next-generation sequencing (mNGS), are currently available for detection of Orientia tsutsugamushi infection in clinically suspected cases. Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi. The cutaneous hallmark of the disease is the "eschar." Scrub typhus results in multisystem involvement. Neurological compromise is present in about 20% of scrub typhus patients and affects both the central nervous system and the peripheral nervous system. The postulated underlying mechanisms include direct invasion of the organism, a vasculitis-like process, or an immune-mediated injury. Diagnosis of scrub typhus is confirmed by detection of O. tsutsugamushi IgM antibody in serum. Awareness among clinicians regarding the varied presentations of this disease is very important in order to reduce morbidity and mortality. Co-infection with dengue and/or chickungunya viruses may occur in endemic regions. The history of an acute febrile illness preceding the neurological illness is crucial. A very careful search for the eschar is essential; however, the absence of the skin lesion cannot exclude the diagnosis of scrub typhus. Neurological manifestations mostly respond to doxycycline therapy.

Neurological facets of scrub typhus: A comprehensive narrative review

Scrub typhus is one of the most frequent causes of acute febrile illness in South and South-east Asian countries. Neurological features accompany 20% of scrub typhus infections, and may affect the central or peripheral nervous system, and sometime, may even occur in combination. Of late, its recognition among clinicians has increased with widening detection of its cutaneous hallmark, called eschar. Multiple mechanisms underlie neurological involvement, including direct invasion (meningitis, encephalitis), vasculitis (myositis) or immune-mediated mechanisms (opsoclonus, myoclonus, optic neuritis, Guillain–Barre syndrome). Despite an immunological basis for several neurological manifestations, response to doxycycline is remarkable, although immune therapy may be necessary for severe involvement. Scientific literature on scrub typhus neurology chiefly emanates from case reports, case series and small studies, and a comprehensive review is warranted to aid clinicians in recognising neurological involvement. This review aims at enriching this gap, and summarises clinical features, laboratory findings, and treatment options for various neurological facets of scrub typhus.