Scrub typhus with cerebral venous sinus thrombosis: a rare presentation

Association of scrub typhus with the risk of venous thromboembolism and long-term mortality: a population-based cohort study

BACKGROUND

The existing literature lacks studies examining the epidemiological link between scrub typhus and deep vein thrombosis (DVT) or pulmonary embolism (PE), and the long-term outcomes. The objective of this study is to explore the potential association between scrub typhus and the subsequent risk of venous thromboembolism, and long-term mortality.

METHOD

This nationwide cohort study identified 10,121 patients who were newly diagnosed with scrub typhus. Patients with a prior DVT or PE diagnosis before the scrub typhus infection were excluded. A comparison cohort of 101,210 patients was established from the general population using a propensity score matching technique. The cumulative survival HRs for the two cohorts were calculated by the Cox proportional hazards model.

RESULT

After adjusting for sex, age, and comorbidities, the scrub typhus group had an adjusted HR (95% CI) of 1.02 (0.80-1.30) for DVT, 1.11 (0.63-1.93) for PE, and 1.16 (1.08-1.25) for mortality compared to the control group. The post hoc subgroup analysis revealed that individuals younger than 55 years with a prior scrub typhus infection had a significantly higher risk of DVT (HR: 1.59; 95% CI: 1.12-2.25) and long-term mortality (HR: 1.75; 95% CI, 1.54-1.99).

CONCLUSION

The scrub typhus patients showed a 16% higher risk of long-term mortality. For those in scrub typhus cohort below 55 years of age, the risk of developing DVT was 1.59 times higher, and the risk of mortality was 1.75 times higher. Age acted as an effect modifier influencing the relationship between scrub typhus and risk of new-onset DVT and death.

The burden, risk factors and unique etiologies of stroke in South-East Asia Region (SEAR)

The World Health Organization (WHO) South East Asia Region (SEAR) comprises 11 countries, which are one of the most culturally, topographically, and socially diverse areas worldwide, undergoing an epidemiological transition towards non-communicable diseases, including stroke and other cardiovascular diseases (CVDs). This region accounts for over 40% of the global stroke mortality. Few well-designed population-based epidemiological studies on stroke are available from SEAR countries, with considerable variations among them. Ischemic stroke, a common stroke subtype, has higher frequencies of intracerebral hemorrhage in many countries. Along with an aging population, the increased prevalence of risk factors such as hypertension, diabetes mellitus, tobacco and alcohol consumption, lack of physical activity, high ambient pollution, heat, and humidity contribute to the high burden of stroke in this region. SEAR's many unique and uncommon stroke etiologies include cerebral venous thrombosis, tuberculosis, dengue, scrub typhus, falciparum malaria, snake bite, scorpion sting, etc. Current data on stroke burden and risk factors is lacking, compelling an urgent need for high-quality hospital-level and population-level data in all SEAR countries. Strategies towards a consolidated approach for implementing improved stroke prevention measures, stroke surveillance, and established stroke systems of care are the path to bridging the gaps in stroke care.

Multifaceted realities of scrub typhus: a case series from southern India

Scrub typhus is an acute febrile illness caused by Orientia tsutsugamushi, a Gram-negative bacillus, commonly occurring in the Asia-Pacific region. It is transmitted to humans by the bite of an infected Leptotrombidium mite and the bacterium causes endothelial dysfunction resulting in widespread vasculitis and the possible development of thrombocytopenia, meningitis, acute respiratory distress syndrome, and infrequently, myocarditis. Early diagnosis and prompt treatment are crucial in managing scrub typhus. Here, we present four cases of scrub typhus with a comprehensive literature review. This study highlights the significance of considering scrub typhus as a possible diagnosis in patients of all ages from endemic regions who exhibit symptoms such as fever, thrombocytopenia, or transaminitis, even in the absence of typical clinical features. Two cases exhibited the characteristic lesion of eschar at the site of mite feeding. One case involved a middle-aged woman who was diagnosed with typhus-induced myocarditis with left ventricular dysfunction. Another case involved a 23-day-old neonate with poor feeding and seizures, who was diagnosed with late-onset sepsis with meningitis. Scrub typhus was confirmed in all cases using a positive qualitative IgM ELISA. However, it is preferred to use paired (ELISA before and after antibiotic therapy) or quantitative titers for confirmation. Healthcare providers must consider the patient's exposure history and clinical presentation to diagnose and treat scrub typhus promptly.

Cerebral Venous Sinus Thrombosis Following Scrub Typhus Infection: A Case Report and a Review of the Literature

Neurological manifestations of scrub typhus, a re-emerging infectious disease of tropic/subtropics caused by Orientia tsutsugamushi infection, have been ever-evolving. Several central nervous system infections have been acknowledged for the development of cerebral venous sinus thrombosis (CVT). Nevertheless, CVT has been a rarely described addendum to the ever-evolving "neuro-scrub" spectrum. Proposed pathogenesis for the development of CVT is disseminated endotheliitis resulting in the triad of venous stasis (due to raised intracranial pressure), cerebral vasculopathy (endothelial damage), and capillary perivasculitis (endothelial damage and resultant hypercoagulable state generated by inflammatory mediators). We herein report a case of a previously healthy young female from the Indian subcontinent who was diagnosed with CVT, following scrub typhus. She responded well to conventional therapy with antibiotics and anticoagulants. CVT is amid the few completely reversible neurological catastrophes if diagnosed and treated early. Again, scrub typhus infection is treated with commonly available and extremely "affordable" antibiotics therapy. Hence, the authors propose that all cases of acute febrile illness with neurological manifestations from scrub-typhus endemic zones (like several parts of India) should be tested for the presence of Orientia tsutsugamushi infection and treated accordingly.

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.