Scrub typhus increases the risk of developing acute coronary syndrome: a nationwide cohort study

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.

Association Between Endophthalmitis and the Incidence of Acute Coronary Syndrome in Patients With Ankylosing Spondylitis: A Nationwide, Population-Based Cohort Study

Purpose

Ankylosing spondylitis (AS) is a risk factor for acute coronary syndrome (ACS). However, the influence of infectious insults, such as endophthalmitis, on the risk of ACS among AS patients has not been studied yet. In this study, we aimed to investigate the relationship between endophthalmitis in patients with AS and the incidence of ACS.

Methods

This retrospective cohort study extracted medical records from the Taiwan Longitudinal Health Insurance Database (LHID) from January 1, 2000, to December 31, 2015. The primary outcome was the incidence of ACS. Univariate and multivariate Cox regression analyses with and without Fine and Gray’s competing risk model and Kaplan–Meier survival curve were used for the analyses. Spearman’s rank correlation coefficient was performed for sensitivity analysis.

Results

We identified 530 AS patients with endophthalmitis and 2,120 AS patients without endophthalmitis for comparison. The incidence rate of endophthalmitis in our study population was 2.66%. The overall incidence rate of ACS was 1,595.96 per 100,000 person-years in AS patients with endophthalmitis and 953.96 per 100,000 person-years in AS patients without endophthalmitis (adjusted HR = 1.787; 95% CI: 1.594–2.104, p < 0.001). In comparison to those without comorbidities, higher adjusted HRs were found in AS patients with endophthalmitis and comorbidities such as diabetes mellitus, hyperlipidemia, hypertension, cerebrovascular accident, congestive heart failure, chronic obstructive pulmonary disease, asthma, and coronary artery disease. Besides, the age ≥ 60 years revealed a high risk for ACS in AS patients with endophthalmitis.

Conclusion

Endophthalmitis was found to be an independent risk factor for ACS in patients with AS. Further clinical studies are required to elucidate the underlying mechanisms and status of systemic inflammation during endophthalmitis.

Scrub typhus manifesting as electrocardiographic disturbance: A case report and review of literature

Scrub typhus (ST) has wide organ system involvement, but cardiac involvement is paramount in this spectrum due to early hemodynamic compromise. Various forms of cardiac involvement have been described in the literature, but we are describing rare electrocardiographic changes in the ST infection. A young male presented in our emergency department with complaints of restlessness and vomiting of 2 days’ duration. The patient was having stable vitals on presentation, but his electrocardiogram (ECG) demonstrated second-degree atrioventricular block type 1 (also known Mobitz 1) and Osborn wave in the precordial leads. Further, he was having thrombocytopenia and eventually diagnosed with ST. For this, appropriate antibiotic treatment was given, which led to considerable symptomatic improvement and reversal of the ECG changes.

Buerger’s Disease May be a Chronic Rickettsial Infection with Superimposed Thrombosis: Literature Review and Efficacy of Doxycycline in Three Patients

Buerger’s disease (BD) is a chronic inflammatory vasculitis of unknown etiology. The infectious etiology of BD was proposed by Buerger in 1914. Furthermore, there are scattered reports insisting that BD may be related to rickettsial infection, first asserted by Goodman since 1916, followed by Giroud and other French investigators from the 1940s through the 1960s, Nicolau in the 1960s, Bartolo (1980s), and Fazeli (2010s). However, their causal relationship has hardly been accepted because rickettsial infections are known to be acute febrile, vector-borne illnesses, whereas BD is a chronic afebrile illness. In this article we review the relevant literature on the chronic nature of Rickettsia and Orientia infections and on the rickettsial etiology of BD. Excellent initial responses to doxycycline in three patients with BD are briefly described. Based on these findings, we hypothesize that BD patients acquired a rickettsial infection far before the onset of BD. Over years, the infected area expands to become a segment of the infected vessel. Subsequently, thrombus develops on the luminal surface of the infected endothelial cells, which produces the vascular obstructive manifestations of BD. Collectively, it is postulated that BD is a chronic infection with a member of the family Rickettsiaceae with superimposed thrombosis.

A rare case of scrub typhus vasculitis presenting as acute coronary syndrome diagnosed by skin manifestations

A 48-year-old diabetic man presented with complaints of acute onset chest heaviness with palpitations, anxiety and headache. He had raised troponin-T level and electrocardiogram showed ST elevation myocardial infarction. There was a prior history of fever of 4 days duration with associated abdominal pain. He later developed skin rash and neurological symptoms following admission to the hospital. Dermatological examination revealed purpura and a livedo-like rash. Investigations revealed deranged liver and renal function tests and positive serological tests for scrub typhus. Coronary angiography revealed no evidence of atherosclerosis or any other pathology. He was therefore diagnosed as a case of scrub typhus-induced vasculitis with coronary manifestations and was managed with oral doxycycline. Scrub typhus presenting like an acute coronary syndrome has been reported very rarely previously. In addition, patient had gastrointestinal, central nervous system and hematological involvement which added to the rarity of the case.

Risk of cerebro- and cardiovascular disease in patients with scrub typhus

We analyzed the National Health Insurance Service-National Sample Cohort (NHIS-NSC) data to evaluate whether scrub typhus infection is associated with increased risk of subsequent cardio- and cerebrovascular disease. Compared with the control group, the scrub typhus group showed a greater incidence rate of cardiovascular disease (14.5 vs. 9.0 cases per 1000 person-years). In contrast, the scrub typhus group showed no difference in incidence rate of cerebrovascular disease (12.0 vs. 13.3 cases per 1000 person-years). Based on the NHIS-NSC data, patients with scrub typhus are at greater risk of developing cardiovascular disease long term compared with that of the general population.

New-onset atrial fibrillation predicting for complicating cardiac adverse outcome in scrub typhus infection

BACKGROUND

Scrub typhus is a well-known infectious disorder of the Asia-Pacific region. However, adverse cardiac outcomes are an under-recognized complication of scrub typhus infection, and new-onset AF has been reported to be a prognostic factor in other, more common infectious diseases. The present study investigated whether new-onset atrial fibrillation (AF) is significantly associated with 3-month mortality and adverse cardiac complications in scrub typhus infection.

METHODS

We examined data from the National Health Information Database (NHID) which covers nearly the entire population of South Korea, from 2006 to 2016. In total, 233 473 patients diagnosed with scrub typhus infection were selected as study participants. New-onset AF, acute heart failure (AHF), ischemic heart disease (IHD), and 3-month mortality were analyzed using a generalized estimating equation model with a Poisson distribution.

RESULTS

Of these, 2402 patients (1%) were diagnosed with new-onset AF (87.2% were over 60 years of age, 43.3% were male). Those with new-onset AF were more likely to have underlying cardiovascular disease compared to those without new-onset AF. After being adjusted for demographic factors and comorbidities, those with new-onset AF had a higher incidence risk of concurrent AHF (4.1-fold) and IHD (1.9-fold) compared with those without new-onset AF. In particular, the 3-month mortality was also significantly associated with new-onset AF (1.3-fold), concurrent AHF (2.4-fold), and IHD (13.7-fold).

CONCLUSIONS

New-onset AF was significantly associated with 3-month mortality and concurrent AHF and IHD. Therefore, new-onset AF could be a poor prognostic factor for 3-month mortality and cardiac complications in scrub typhus infection.

Increased risk of ankylosing spondylitis after Mycoplasma pneumonia: A Nationwide population-based study

This study aimed to investigate the relationship between Mycoplasma pneumonia (MP) infection and new development of ankylosing spondylitis (AS).Using data from the Taiwan National Health Insurance Research Database, we included a total of 116,084 patients with newly diagnosed MP between 2000 and 2012. The control cohort consisted of patients who did not have MP, matched 1:4 by age, sex, and index year. The follow-up period was defined as the time from the initial diagnosis of MP to the date of diagnosis of AS, censoring, or 31 December 2013. Cox proportional hazards regression analysis was used to analyze the risk of autoimmune diseases by sex, age, and comorbidities, with hazard ratios (HRs) and 95% confidence intervals (CIs).The eligible study participants included 116,084 patients in the MP group and 464,336 patients in the comparison group. The incidence rates of AS in the MP group and comparison groups were 1.49 and 0.74 per 1,000,000-person years, respectively. The adjusted HR of AS for the MP group was 2.45 (95% CI = 1.02-5.90) compared to the control group after adjustment for age, sex, and all covariates.MP remained an independent risk factor for developing AS in terms of sex, age, and comorbidities.

Association of Scrub Typhus With the Risk of Autoimmune Diseases: A Population-Based Cohort Study

Infection plays a major role in the development of autoimmune diseases. In this study, we investigated the relationship between scrub typhus and systemic autoimmune diseases. We enrolled 6,928 hospitalized patients with scrub typhus between 2000 and 2012 from the Taiwan National Health Insurance Research Database, and we compared them with 27,712 selected inpatients who had never been diagnosed with scrub typhus (1:4 ratio, matched by age, sex, and index year) in relation to the risk of developing autoimmune diseases. Cox proportional hazards regression analysis was used to analyze the risk of autoimmune diseases by sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The adjusted hazard ratio for autoimmune diseases for the scrub typhus group was 2.4 (95% confidence interval: 1.66, 3.48, P < 0.0001) compared with the control group. Subgroup analysis showed that women aged <40 years had a significant higher risk of autoimmune diseases. The risk was significantly higher within 3 years after scrub typhus infection. In conclusion, a higher risk of autoimmune diseases was found among the scrub typhus group, especially for female patients, those aged <40 years, and within the first 3 years after getting scrub typhus.

Scrub typhus and depression: a nationwide cohort analysis

BACKGROUND

Studies on the relationship between depression and scrub typhus are limited. We conducted a retrospective cohort study to investigate whether scrub typhus is a risk factor for depression.

METHODS

Using Taiwan's National Health Insurance Research Database, this study investigated the incidence of depression, and its risk factors, in patients diagnosed with scrub typhus between 2000 and 2010. Scrub typhus patients who did not have a history of depression before the index date were enrolled. For each patient with scrub typhus, four controls without a history of scrub typhus and depression were randomly selected and frequency matched by sex, age, year of the index date, and comorbidities. The follow-up period was from the time of initial scrub typhus diagnosis to the date of diagnosis of depression, censoring, or December 31, 2010. Cox proportional hazards regression models were used to analyze the risk of depression according to sex, age, and comorbidities.

RESULTS

The study comprised a 5238-patient scrub typhus group and a 20,952-patient non-scrub typhus group with similar sex and age distributions. During the follow-up period, the cumulative incidence of depression was higher in the scrub typhus than the non-scrub typhus group (log-rank test P < 0.001). In the scrub typhus group, 45 patients developed depression, yielding an incidence rate of 1.67 per 1000 person-years, and in the non-scrub typhus group, 117 patients developed depression, yielding an incidence rate of 1.08 per 1000 person-years. This yielded a crude hazard ratio (HR) of 1.55 (95% confidence interval [CI] 1.41-1.70) and adjusted HR (aHR) of 1.56 (95% CI 1.42-1.71). Compared with the non-scrub typhus group, the risk of depression in the scrub typhus group was higher in patients of both sexes (men: aHR = 1.46, 95% CI 1.29-1.64; women: aHR = 1.68, 95% CI 1.45-1.96), in patients aged younger than 65 (≤ 49 years: aHR = 1.95, 50-64 years: aHR = 1.73), and in patients without comorbidities (aHR = 2.06, 95% CI 1.85-2.29).

CONCLUSIONS

The risk of depression was 1.56-fold higher in patients with scrub typhus than in the general population.

Clinical manifestations of scrub typhus

The mite-borne rickettsial zoonosis scrub typhus is widely prevalent in parts of Southeast and Far East Asia, and northern Australia. The disease is an acute febrile illness, associated with rash and often an eschar, which responds dramatically to treatment with antibiotics. In some cases it results in a serious illness leading to multiple organ involvement and death. The disease manifestations are thought to result from a systemic vasculitis, caused by both direct effects of the organisms as well as an exaggerated immune response, although little is understood about its pathogenesis. A wide spectrum of clinical manifestations, affecting nearly every organ system, have been described with scrub typhus. Some of these manifestations are serious and life threatening. In this systematic review, we summarise the typical and atypical manifestations of scrub typhus reported in the literature. Awareness of these unusual manifestations will hopefully guide clinicians towards diagnosing the condition early, and initiating early appropriate antibiotics and other supportive measures.

Estimating the burden of scrub typhus: A systematic review

BACKGROUND

Scrub typhus is a vector-borne zoonotic disease that can be life-threatening. There are no licensed vaccines, or vector control efforts in place. Despite increasing awareness in endemic regions, the public health burden and global distribution of scrub typhus remains poorly known.

METHODS

We systematically reviewed all literature from public health records, fever studies and reports available on the Ovid MEDLINE, Embase Classic + Embase and EconLit databases, to estimate the burden of scrub typhus since the year 2000.

FINDINGS

In prospective fever studies from Asia, scrub typhus is a leading cause of treatable non-malarial febrile illness. Sero-epidemiological data also suggest that Orientia tsutsugamushi infection is common across Asia, with seroprevalence ranging from 9.3%-27.9% (median 22.2% IQR 18.6-25.7). A substantial apparent rise in minimum disease incidence (median 4.6/100,000/10 years, highest in China with 11.2/100,000/10 years) was reported through passive national surveillance systems in South Korea, Japan, China, and Thailand. Case fatality risks from areas of reduced drug-susceptibility are reported at 12.2% and 13.6% for South India and northern Thailand, respectively. Mortality reports vary widely around a median mortality of 6.0% for untreated and 1.4% for treated scrub typhus. Limited evidence suggests high mortality in complicated scrub typhus with CNS involvement (13.6% mortality), multi-organ dysfunction (24.1%) and high pregnancy miscarriage rates with poor neonatal outcomes.

INTERPRETATION

Scrub typhus appears to be a truly neglected tropical disease mainly affecting rural populations, but increasingly also metropolitan areas. Rising minimum incidence rates have been reported over the past 8-10 years from countries with an established surveillance system. A wider distribution of scrub typhus beyond Asia is likely, based on reports from South America and Africa. Unfortunately, the quality and quantity of the available data on scrub typhus epidemiology is currently too limited for any economical, mathematical modeling or mapping approaches.

Incidence and risk of acute coronary syndrome in patients with acute pancreatitis: A nationwide cohort study

BACKGROUND

Studies on the relationship between acute pancreatitis (AP) and acute coronary syndrome (ACS) are scant. We conducted a nationwide cohort study to investigate the incidence and risk of ACS in patients with AP.

METHODS

We enrolled patients newly diagnosed with AP between 2000 and 2010 from the Taiwan National Health Insurance Research Database and randomly selected a control cohort without a history of AP after frequency-matching for age, sex, and index year at a ratio of 4:1 for each patient with AP. The follow-up period was from the index date of new AP diagnosis to the diagnosis of ACS, censoring, or the end of 2011.

RESULTS

We assessed 87 068 patients in the AP cohort and 348 272 participants in the control cohort for 508 991 and 2 301 317 person-years, respectively. The AP cohort exhibited a higher overall incidence of ACS than the control cohort (5.44 vs 3.03 per 1000 person-y). After adjustment for sex, age, and comorbidities, the AP cohort exhibited a 1.24-fold higher adjusted hazard ratio (aHR) of ACS (95% confidence interval = 1.19-1.30) than did the control cohort. When stratified by age, the patients with AP aged ≤39 years presented a 2.37-fold higher aHR of ACS than did their corresponding controls (95% CI = 1.88-2.99). Approximate one third of ACS developed within 1 month of AP occurrence.

CONCLUSIONS

This nationwide cohort study indicated that patients with AP are at an increased risk of ACS compared with those without AP.

Fatal water intoxication and cardiac arrest in runners during marathons: prevention and treatment based on validated clinical paradigms

Cerebral edema due to exercise-associated hyponatremia and cardiac arrest due to atherosclerotic heart disease cause rare marathon-related fatalities in young female and middle-aged male runners, respectively. Studies in asymptomatic middle-aged male physician-runners during races identified inflammation due to skeletal muscle injury after glycogen depletion as the shared underlying cause. Nonosmotic secretion of arginine vasopressin as a neuroendocrine stress response to rhabdomyolysis mediates hyponatremia as a variant of the syndrome of inappropriate antidiuretic hormone secretion. Fatal hyponatremic encephalopathy in young female runners was curtailed using emergent infusion of intravenous hypertonic (3%) saline to reverse cerebral edema on the basis of this paradigm. This treatment was arrived at through a consensus process within the medical community. An increasing frequency of cardiac arrest and sudden death has been identified in middle-aged male runners in 2 studies since the year 2000. Same-aged asymptomatic male physician-runners showed post-race elevations in interleukin-6 and C-reactive protein, biomarkers that predict acute cardiac events in healthy persons. Hypercoagulability with in vivo platelet activation and release of cardiac troponin and N-terminal pro-brain natriuretic peptide were also observed post-race in these same subjects. High short-term risk for atherothrombosis during races as shown by stratification of biomarkers in asymptomatic men may render nonobstructive coronary atherosclerotic plaques vulnerable to rupture. Pre-race aspirin use in this high-risk subgroup is prudent according to conclusive evidence for preventing first acute myocardial infarctions in same-aged healthy male physicians. On the basis of validated clinical paradigms, taking a low-dose aspirin before a marathon and drinking to thirst during the race may avert preventable deaths in susceptible runners.

Prerace aspirin to protect susceptible runners from cardiac arrest during marathons: is opportunity knocking?

While endurance exercise such as marathon training is cardioprotective, an increasing frequency of race-related cardiac arrests and sudden death has been observed in middle-aged men since the year 2000. An evidence-based strategy for prevention is considered based on identifying atherothrombosis as the underlying cause in this susceptible subgroup. Review of all articles on PubMed related to acute cardiac events during marathons. Male gender and the marathon compared with the half-marathon were identified as significant risk factors for race-related cardiac arrests, which events increased 2.3-fold in the latter half of a 10-year prospective registry beginning in the year 2000. There were 50 cardiac arrests in runners who were 86% male with a mean age of 42 years. The main cause of sudden death was atherosclerotic heart disease in those over the age of 40 including myocardial infarction in 12 of 13 (93%) cases over the age of 45 as assessed retrospectively. Inflammatory biomarkers predicting acute cardiac events and hypercoagulability with in vivo platelet activation were demonstrated in same-aged asymptomatic middle-aged men during marathons. Excess cardiac morbidity and mortality in middle-aged men during marathons is mediated by atherothrombosis which may render non-obstructive coronary atherosclerotic plaques vulnerable to rupture. Prerace low-dose aspirin usage is prudent to protect susceptible runners from a high, if transient, risk for cardiac arrest during races as evidence-based to prevent first myocardial infarctions in same-aged healthy men.