Leptospirosis mimicking acute cholecystitis among athletes participating in a triathlon

Acalculous Cholecystitis in COVID-19 Patients: A Narrative Review

Acute acalculous cholecystitis (AAC) represents cholecystitis without gallstones, occurring in approximately 5-10% of all cases of acute cholecystitis in adults. Several risk factors have been recognized, while infectious diseases can be a cause of cholecystitis in otherwise healthy people. Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has spread worldwide, leading to an unprecedented pandemic. The virus enters cells through the binding of the spike protein to angiotensin-converting enzyme 2 (ACE2) receptors expressed in many human tissues, including the epithelial cells of the gastrointestinal (GI) tract, and this explains the symptoms emanating from the digestive system. Acute cholecystitis has been reported in patients with COVID-19. The purpose of this review is to provide a detailed analysis of the current literature on the pathogenesis, diagnosis, management, and outcomes of AAC in patients with COVID-19.

Acute acalculous cholecystitis due to infectious causes

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder not associated with the presence of gallstones. It usually occurs in critically ill patients but it has also been implicated as a cause of cholecystitis in previously healthy individuals. In this subgroup of patients, infectious causes comprise the primary etiology. We, herein, discuss the pathophysiological mechanisms involved in AAC, focusing on the infectious causes. AAC associated with critical medical conditions is caused by bile stasis and gallbladder ischemia. Several mechanisms are reported to be involved in AAC in patients without underlying critical illness including direct invasion of the gallbladder epithelial cells, gallbladder vasculitis, obstruction of the biliary tree, and sequestration. We emphasize that multiple pathogenic mechanisms may concurrently contribute to the development of AAC in varying degrees. Awareness of the implicated pathogens is essential since it will allow a more focused examination of the histopathological specimens. In conclusion, additional research and a high degree of clinical suspicion are needed to clarify the complex spectrum of mechanisms that are involved in the pathogenesis of AAC.

Leptospira infection in people in the city of Durango, Mexico: a cross sectional study

Objective

To determine the seroprevalence of Leptospira immunoglobulin (Ig)G and IgM antibodies and its association with the characteristics of the study population from the northern Mexican city of Durango, Mexico.

Methods

Through a cross-sectional study design, inhabitants of Durango City, Mexico were surveyed between June 2018 and November 2018. Serum samples from the subjects were analysed for anti-Leptospira IgG and IgM antibodies using commercially available enzyme-linked immunosorbent assays. Sociodemographic, clinical, behavioural and housing characteristics were recorded. Data were analysed by bivariate and multivariate analyses.

Results

The study enrolled 413 people, of which 124 (30.0%) and 137 (33.2%) were positive for anti-Leptospira IgG antibodies and anti-Leptospira IgM antibodies, respectively. Multivariate analysis showed that Leptospira seropositivity was associated with professional occupation, alcohol consumption, ill clinical status, memory impairment and a history of surgery.

Conclusions

This is the first study to report the seroepidemiology of Leptospira infection in an urban general population in the north of Mexico. The seroprevalence of Leptospira infection found was higher than those previously reported in Mexican studies.

Study on causes of fever in primary healthcare center uncovers pathogens of public health concern in Madagascar

BACKGROUND

The increasing use of malaria diagnostic tests reveals a growing proportion of patients with fever but no malaria. Clinicians and health care workers in low-income countries have few tests to diagnose causes of fever other than malaria although several diseases share common symptoms. We propose here to assess etiologies of fever in Madagascar to ultimately improve management of febrile cases.

METHODOLOGY

Consenting febrile outpatients aged 6 months and older were recruited in 21 selected sentinel sites throughout Madagascar from April 2014 to September 2015. Standard clinical examinations were performed, and blood and upper respiratory specimens were taken for rapid diagnostic tests and molecular assays for 36 pathogens of interest for Madagascar in terms of public health, regardless of clinical status.

PRINCIPAL FINDINGS

A total of 682 febrile patients were enrolled. We detected at least one pathogen in 40.5% (276/682) of patients and 6.2% (42/682) with co-infections. Among all tested patients, 26.5% (181/682) had at least one viral infection, 17.0% (116/682) had malaria and 1.0% (7/682) presented a bacterial or a mycobacterial infection. None or very few of the highly prevalent infectious agents in Eastern Africa and Asia were detected in this study, such as zoonotic bacteria or arboviral infections.

CONCLUSIONS

These results raise questions about etiologies of fever in Malagasy communities. Nevertheless, we noted that viral infections and malaria still represent a significant proportion of causes of febrile illnesses. Interestingly our study allowed the detection of pathogens of public health interest such as Rift Valley Fever Virus but also the first case of laboratory-confirmed leptospirosis infection in Madagascar.

A Re-Emerging Ancient Disease: A Case Report

There have been repeated outbreaks of leptospirosis reported all over the world. Being one of the largest cities in the world, Hong Kong is no exception. We report a local case involved in an outbreak of the disease with a typical route of acquisition but rare complications. A brief account on the epidemiology of both Hong Kong and Southern China is given. Discussions on the pathophysiology of the disease and its complications are also presented.

Leptospirosis presenting as acute acalculous cholecystitis

Leptospirosis is the commonest zoonotic infection worldwide but is vastly underreported and extremely heterogeneous in its presentation. Acalculous cholecystitis is an under recognized presentation of acute leptospirosis. In the appropriate clinical context, with a clear exposure history, recognition of this association presents a unifying diagnosis and limits unnecessary surgical interventions.

Immunohistochemistry in the diagnosis of cutaneous bacterial infections

The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.

Atypical manifestations of leptospirosis

Leptospirosis is an illness with a wide spectrum of clinical manifestations and severe illness affects nearly all organ systems. Serious and potentially life-threatening clinical manifestations of acute leptospirosis are caused by both direct tissue invasion by spirochaetes and by the host immune responses. In its severe form, leptospirosis can cause multi-organ dysfunction and death in a matter of days. Therefore it is critical to suspect and recognize the disease early, in order to initiate timely treatment. While the classical presentation of the disease is easily recognized by experienced clinicians practising in endemic regions, rarer manifestations can be easily missed. In this systematic review, we summarize the atypical manifestations reported in literature in patients with confirmed leptospirosis. Awareness of these unusual manifestations would hopefully guide clinicians towards early diagnosis.

The impact of triathlon training and racing on athletes' general health

Although the sport of triathlon provides an opportunity to research the effect of multi-disciplinary exercise on health across the lifespan, much remains to be done. The literature has failed to consistently or adequately report subject age group, sex, ability level, and/or event-distance specialization. The demands of training and racing are relatively unquantified. Multiple definitions and reporting methods for injury and illness have been implemented. In general, risk factors for maladaptation have not been well-described. The data thus far collected indicate that the sport of triathlon is relatively safe for the well-prepared, well-supplied athlete. Most injuries 'causing cessation or reduction of training or seeking of medical aid' are not serious. However, as the extent to which they recur may be high and is undocumented, injury outcome is unclear. The sudden death rate for competition is 1.5 (0.9-2.5) [mostly swim-related] occurrences for every 100,000 participations. The sudden death rate is unknown for training, although stroke risk may be increased, in the long-term, in genetically susceptible athletes. During heavy training and up to 5 days post-competition, host protection against pathogens may also be compromised. The incidence of illness seems low, but its outcome is unclear. More prospective investigation of the immunological, oxidative stress-related and cardiovascular effects of triathlon training and competition is warranted. Training diaries may prove to be a promising method of monitoring negative adaptation and its potential risk factors. More longitudinal, medical-tent-based studies of the aetiology and treatment demands of race-related injury and illness are needed.

Acalculous cholecystitis: a rare presentation of leptospirosis progressing to Weil's disease

Leptospirosis is a zoonotic infection with higher incidence in tropics. Leptospirosis, is known for its variable manifestations, and is a clinical challenge for physicians in the tropics. Experienced clinicians, at times can mistake leptospirosis for non-medical conditions. A few reports of leptospirosis presenting as acalculous cholecystitis was found in review of literature. We intent to highlight acalculous cholecystitis as a rare but clinically significant presentation of leptospirosis.

Leptospirosis in a Dog with Uveitis and Presumed Cholecystitis

A 7 yr old castrated male Australian shepherd dog was examined for acute change in iris color, lethargy, and anorexia. Uveitis, acute renal failure, and presumed cholecystitis were diagnosed. Based on clinical findings, leptosporosis was suspected, and the dog was treated with antibiotics and supportive care. The dog made a complete recovery, and leptospirosis was confirmed on convalescent titers. Due to the zoonotic potential, leptospirosis should be considered in cases of uveitis, as well as possible cholecystitis.

Application of immunohistochemistry to infections

CONTEXT

Pathologists play an important role in the diagnosis or exclusion of infectious diseases. Traditionally, the diagnosis of infectious diseases rely on serologic assays and cultures. Serologic results may be difficult to interpret in the setting of immunosuppression, fresh tissue is not always available for culture, and culture of fastidious pathogens can be difficult and may take weeks or months to yield a result. Although some microorganisms or their cytopathic effects may be readily identifiable on routine and/or histochemical stains, often these changes are not specific or are sparse in the sample evaluated. In these cases, additional immunohistochemical stains are often needed to establish the diagnosis of infection.

OBJECTIVE

To review the current value and limitations of the use of immunohistochemistry in the diagnosis of infectious diseases in formalin-fixed tissue samples.

DATA SOURCES

Literature in Medline and the authors' own experience.

CONCLUSIONS

Immunohistochemistry has proven to be a useful tool in the diagnosis of infectious diseases in tissue samples. Immunohistochemistry is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, are noncultivable, or exhibit an atypical morphology. Finally, it is important to remember that there may be widespread occurrence of common antigens among bacteria and pathogenic fungi and both monoclonal and polyclonal antibodies must be tested for possible cross-reactivity with other organisms.

Histopathologic spectrum and immunohistochemical diagnosis of amebic meningoencephalitis

Traditionally, Naegleria fowleri infections are labeled primary amebic meningoencephalitis because of prominent meningeal neutrophilic inflammation. Acanthamoeba spp. and Balamuthia mandrillaris are labeled granulomatous amebic encephalitis because of parenchymal granulomatous inflammation. We compared histopathologic and immunohistochemical features of 18 cases with central nervous system free-living ameba infections. Immunohistochemical assays using polyclonal antibodies that reacted specifically against each genus identified 11 patients with Balamuthia infection, four with N. fowleri, and three with Acanthamoeba. Immunohistochemical assays highlighted the presence of trophozoites that were difficult to identify with hematoxylin and eosin stains in areas of necrosis or where macrophages were abundant. Immunohistochemical assays also demonstrated the presence of granular antigens inside macrophages and blood vessel walls. Amebic cysts were observed in three patients with Acanthamoeba infection and in three with Balamuthia. Patients with Acanthamoeba infection showed granulomatous inflammation. Patients with Naegleria infection had neutrophilic inflammation. Balamuthia infections showed a spectrum of inflammation that ranged from primarily neutrophils to granulomas. Meningitis was present in 88% of cases. Immunohistochemical assays were useful to demonstrate the presence of granular antigens and confirmed the genus of the ameba. The spectrum of inflammation in cases of Balamuthia meningoencephalitis is broader than previously described. The term amebic meningoencephalitis describes better the histopathologic findings than the currently used classification of primary amebic meningoencephalitis and granulomatous amebic encephalitis.

Suburban Leptospirosis: Atypical Lymphocytosis and - T Cell Response

Leptospirosis is a zoonotic disease associated with a changing global epidemiology. Recently, an increased incidence of canine leptospirosis in the northeastern United States and Canada has been associated with increasing rates of infection among reservoir hosts, such as skunks, raccoons, and squirrels, that are common in suburban settings. We describe a case of leptospirosis that provides new insight into the epidemiology, diagnosis, and pathogenesis of this disease acquired in the suburban setting. Atypical lymphocytosis corresponded to an expansion of gamma-delta T cells in peripheral blood.

Immunohistochemical and in situ hybridization studies of the liver and kidney in human leptospirosis

An in situ hybridization (ISH) assay for the detection of leptospiral DNA in tissues was described and its diagnostic and pathogenetic usefulness in combination with immunohistochemistry (IHC) was evaluated in formalin-fixed, paraffin-embedded liver and kidney samples from human fatal cases of leptospirosis. IHC assays with anti-E-cadherin antibodies assessed the liver-plate disarray frequently observed in leptospirosis. Immunohistochemistry detected leptospiral antigen (LAg) in macrophages, both in human liver and kidney. In guinea pigs, in addition to these findings, staining on cell membranes of hepatocytes and, occasionally, in apical membrane of kidney tubular cells was demonstrated. Positive ISH signal was observed chiefly in the nuclei of human hepatocytes and in the cytoplasm and nuclei of liver cells of experimentally infected guinea pigs. Loss of E-cadherin membrane expression is associated with liver-plate disarray. These findings were discussed in the contention that, in leptospirosis, cell membrane damage might be important for the pathogenesis of the disease. Finally, it was suggested that both IHC and/or ISH might be used for both diagnostic and research purposes.

Persistent Yersinia pestis antigens in ischemic tissues of a patient with septicemic plague

In November 2002, a couple from New Mexico traveled to New York where both had fever and unilateral inguinal adenopathy. The husband was in septic shock when he sought medical care and was admitted to an intensive care unit, where he developed ischemic necrosis of his feet which later required bilateral amputation. Yersinia pestis was grown from his blood. Immunohistochemical assays using anti-Y pestis antibodies demonstrated multiple bacteria and granular antigens in and around vessels of the ischemic amputation tissues obtained 20 days after initiation of antibiotics; however, no evidence of Y pestis was present in viable tissues. Immunohistochemical evidence of Y pestis inside vessels of gangrenous feet in this patient underscores the importance of adequate excision of necrotic or partially necrotic tissues because antibiotics cannot be effectively delivered to necrotic and poorly perfused tissues.

Medical considerations in triathlon competition: recommendations for triathlon organisers, competitors and coaches

Competitors in triathlons experience a range of environmental conditions and physiological demands in excess of that found in individual sport events of comparable duration. Consequently, there is a broad range of possible medical problems and complications that must be taken into account when preparing for such races. For most competitors, an Olympic-distance triathlon typically takes between 2-4 hours to complete. This race begins with a swimming segment of 1500 m. Given the wide variety of race venues found around the world, these swims occur in an assortment of water temperatures (from warm to cold) and conditions (from ocean surf to lake calm). Swimmers often exit the water in a state of moderate dehydration and hypothermia and then immediately start the 40 km cycling leg. Many do so in their swimming attire. A wide variety of road surfaces, technically challenging topography, variable environmental conditions and dramatically changing velocities can be encountered on the cycle course. The race concludes with a 10 km running leg. Since it is the final leg, it is often completed in higher ambient temperatures than those encountered at the start, with the athlete possibly running in a significant state of dehydration and fatigue. Other medical problems commonly encountered in triathlon include: muscle cramping, heat illness, postural hypotension, excessive exposure to ultraviolet radiation, musculoskeletal injuries and trauma, gastrointestinal problems as well as post-race bacterial infection, immunosuppression, sympathetic nervous system and psychological exhaustion, and haemolysis. The rate of occurrence of such events and the severity of their potentially negative outcomes is a function of the methods used by both the race organisers and the competitors to prevent or respond to the conditions imposed by the race. Triathletes also commonly compete in both shorter 'sprint distance' events (in the range of a 0.75 km swim, 20 km cycle and 5 km run) and longer events including both one-half and full Ironman distances (2.5 and 3.8 km swim, 80 and 180 km cycle, 20 and 42 km run, respectively), as well as ultra-distance events that exceed the Ironman distance. In the longer events, the previously mentioned medical considerations are further magnified and additional considerations such as hyponatraemia can also occur. Reducing risk associated with these concerns is accomplished by: taking into account weather and water temperature/conditions data prior to event scheduling; effective swim, cycle and run course organisation and management; environmental monitoring prior to and during the event; the implementation of a water safety plan; provision of appropriate fluid replacement throughout the course; implementation of helmet use and non-drafting regulations in the cycling leg; and competitor knowledge regarding fluid replacement, biomechanical technique, physical preparation, safe equipment and course familiarity. Despite these concerns, triathlon participation appears to relatively safe for persons of all ages, assuming that high-risk adults undertake health screening.

HLA-DQ6 and ingestion of contaminated water: possible gene-environment interaction in an outbreak of Leptospirosis

Leptospirosis is a zoonosis that can cause severe multisystem disease. While host gene-environment interactions likely modify infectious disease susceptibility, including for leptopsirosis, this has not been documented. In a 1998 leptospirosis outbreak investigation among triathletes in a lake swim, swallowing lake-water was a disease risk-factor. We used genomic DNA from 85 anonymized blood-sample remainders from that investigation to examine the association of laboratory-confirmed leptospirosis with gene polymorphisms (TNF-alpha alleles and serologically defined genotypes for HLA-DRB1 and HLA-DQB1). HLA-DQ6-positive triathletes had increased risk of laboratory-confirmed leptospirosis (OR=2.8, P=0.04) compared to DQ6-negatives. DQ6-positive triathletes swallowing lake-water had greatest risk (OR 8.46, P< or =0.001). This first report of a genetic risk-factor affecting susceptibility to leptospirosis is also the first documented gene-environment interaction (DQ6 and swallowed water) affecting infectious disease susceptibility. Based on these preliminary findings, we hypothesize a role for superantigens in leptospirosis and underscore the importance of outbreak investigations for understanding infectious disease gene-environment interactions.

Reemerging leptospirosis, California

Leptospirosis is a reemerging infectious disease in California. Leptospirosis is the most widespread zoonosis throughout the world, though it is infrequently diagnosed in the continental United States. From 1982 to 2001, most reported California cases occurred in previously healthy young adult white men after recreational exposures to contaminated freshwater. We report five recent cases of human leptospirosis acquired in California, including the first documented common-source outbreak of human leptospirosis acquired in this state, and describe the subsequent environmental investigation. Salient features in the California cases include high fever with uniform renal impairment and mild hepatitis. Because leptospirosis can progress rapidly if untreated, this reemerging infection deserves consideration in febrile patients with a history of recreational freshwater exposure, even in states with a low reported incidence of infection.

Outbreak of leptospirosis among triathlon participants and community residents in Springfield, Illinois, 1998

We investigated an outbreak of leptospirosis among athletes and community residents after a triathlon was held in Springfield, Illinois. A telephone survey was conducted to collect clinical information and data on possible risk factors, community surveillance was established, and animal specimens and lake water samples were collected to determine the source of the leptospiral contamination. A total of 834 of 876 triathletes were contacted; 98 (12%) reported being ill. Serum samples obtained from 474 athletes were tested; 52 of these samples (11%) tested positive for leptospirosis. Fourteen (6%) of 248 symptomatic community residents tested positive for leptospirosis. Heavy rains that preceded the triathlon are likely to have increased leptospiral contamination of Lake Springfield. Among athletes, ingestion of 1 or more swallows of lake water was a predominant risk factor for illness. This is the largest outbreak of leptospirosis that has been reported in the United States. Health care providers and occupational and recreational users of bodies of freshwater in the United States should be aware of the risk of contracting leptospirosis, particularly after heavy rains.