Brown recluse spider (Loxosceles reclusa) envenomation leading to acute hemolytic anemia in six adolescents

Conservative Reconstruction of the Lower Limb with a Bilayer Porous Collagen Matrix after a Spider Bite

ABSTRACT

Brown recluse spider bites may cause symptoms ranging from local cutaneous reactions to systemic visceral loxoscelism. Most bites are self-limiting, but some can lead to necrotic ulcerations with severe complications and soft tissue defects. Necrotizing ulcers are uncommon and have various clinical presentations, so no standard treatment exists. A 68-year-old man required medical attention after getting a spider bite while traveling in Tanzania. After returning to Italy, the patient presented with a posterior lower limb black papule, local edema, and fever. The lesion quickly ulcerated with an eschar. Medical history and symptoms suggested a brown recluse spider bite. Ulcer management was conservative, with careful surgical debridement and a two-step reconstruction using a split-thickness skin graft and a bilayer porous collagen matrix. Treatment resulted in functional recovery and acceptable aesthetics.

Phylogenetics and species delimitation of the recluse spider, Loxosceles rufescens (Araneae: Sicariidae) populations invading Bangkok, Thailand

The Mediterranean recluse spider, Loxosceles rufescens, has been discovered for the first time inhabiting human dwellings in Bangkok, Thailand. Expeditions across 39 localities revealed five establishments with L. rufescens populations. The highest density was recorded in a storage house on Yaowarat Road, located in the heart of Bangkok's Chinatown, where 315 individuals were found, including adults, juveniles, and spiderlings. This medically significant spider's presence in such a densely populated urban area raises concerns about potential envenomation risks. Thirteen specimens of L. rufescens were extracted for DNA and sequenced for molecular phylogenetic analyses. COI and ITS2 markers were used to investigate relationships within L. rufescens and across available Loxosceles species sequences. Results indicate COI is superior for resolving species-level genetic clusters compared to ITS2. Surprisingly, L. rufescens individuals from the same house were found in significantly distant COI lineages, suggesting mtDNA may not be suitable for studying intra-specific phylogeography in this case. Species delimitation methods ABGD and ASAP demonstrated promising results for both COI and ITS2, while bPTP and GMYC tended to overestimate species numbers. ITS2 exhibited high sequence similarity in L. rufescens, suggesting potential utility as a barcoding marker for identification of this globally distributed species. Genetic distance analyses revealed a potential barcoding gap (K2P) of 8-9 % for COI and <2 % for ITS2 in Loxosceles. This study contributes valuable sequence data for the medically important genus Loxosceles and highlights the need for integrative approaches in understanding its evolution and spread. The findings have important implications for pest management strategies and public health in urban environments.

Systemic loxoscelism leading to autoimmune haemolytic anaemia in a healthy young adult

The brown recluse spider (Loxosceles reclusa) is endemic to the southcentral Midwest and the Southern United States. A bite from a brown recluse spider may result in symptoms that range from local skin necrosis to systemic complications such as acute haemolytic anaemia, disseminated intravascular coagulopathy, rhabdomyolysis and death. Although rare, systemic loxoscelism is a clinical diagnosis of exclusion that should be considered in a patient with acute autoimmune haemolytic anaemia. We describe a case of a young man with autoimmune haemolytic anaemia secondary to systemic loxoscelism successfully treated with intravenous immunoglobulin and steroids.

Clinical Evolution After Administering Antivenom in Patients With Loxoscelism

Spiders are the most numerous arthropods of the arachnid class. More than 45 thousand species of spiders have been identified, and only a few are dangerous to humans. Among them, the "violin spider" or "brown spider" of the genus Loxosceles (family Sicariidae) has a worldwide distribution, and its bite can cause loxoscelism. Initial treatment of a Loxosceles spider bite includes application of local cold, rest, elevation of the extremity if possible, and systemic pharmacotherapy with antihistamines, corticosteroids, antibiotics, polymorphonuclear inhibitors, and analgesics or nonsteroidal anti-inflammatory drugs. During cutaneous or systemic loxoscelism, administration of Loxosceles antivenom (immunoglobulin (Ig)G F(ab')2 fragments) may be indicated to prevent progression to severe systemic phases. In this manuscript, we present three cases of patients with loxoscelism treated with the fabotherapeutic Reclusmyn®, developed and manufactured in Mexico. Two patients had a satisfactory outcome without severe skin or systemic damage. Only one patient with loxoscelism, despite early initiation of antivenom, had extensive skin lesions that healed satisfactorily, leaving only a non-disabling scar. Due to the global presence of this clinical problem, further studies are needed to establish local and general guidelines for the treatment and prevention of loxoscelism. This will allow health professionals to provide more efficient and higher quality medical care and feel supported in their decisions.

Massive dermal ulcerative lesions due to brown recluse spider bite: a rare case report and review of literature

A brown recluse spider (BRS) bite is challenging to confirm, but may be clinically diagnosed by considering the location, the season of the year, and the clinical manifestations. Here, the case of a 26-year-old male who presented after an insect bite with a skin lesion, bruising, severe swelling, and diffuse blisters on the right lower extremity after three days, is described. Following clinical examination, patient history assessment, and consideration of other relevant factors, the patient received a differential diagnosis of necrotizing fasciitis caused by BRS bite. Although spider bite poisoning is rare, proper diagnosis and management are important because, in some cases, the outcomes may be devastating.

Massive dermal ulcerative lesions because of brown recluse spider bite: a rare case report and review of literature

A brown recluse spider (BRS) bite is challenging to confirm, but can be clinically diagnosed by considering the location, the season of the year and the clinical manifestations. We described a 26-year-old male who presented after a BRS bite with a skin lesion, bruising, severe swelling and diffuse blisters on the right lower extremity after 3 days. This case should be considered in the differential diagnosis of necrotizing fasciitis. Although spider bite poisoning is rare, proper diagnosis and management are important because, in some cases, it can have devastating outcomes.

Systemic Loxoscelism, Less Frequent but More Deadly: The Involvement of Phospholipases D in the Pathophysiology of Envenomation

Bites of Loxosceles spiders can lead to a set of clinical manifestations called loxoscelism, and are considered a public health problem in many regions. The signs and symptoms of loxoscelism are divided into cutaneous and systemic forms. The former is more frequent and includes signs of envenoming at the bite site or neighboring regions. Systemic loxoscelism, although much less frequent, is associated with complications, and can even lead to death. It may include intravascular hemolysis, acute renal failure, and thrombocytopenia. Loxosceles venoms are enriched with phospholipases D (PLDs), which are a family of isoforms found at intra-species and inter-species levels. Under experimental conditions, these enzymes reproduce the main clinical signs of loxoscelism, including an exacerbated inflammatory response at the bite site and dermonecrosis, as well as thrombocytopenia, intravascular hemolysis, and acute renal failure. The role of PLDs in cutaneous loxoscelism was described over forty years ago, when studies identified and purified toxins featured as sphingomyelinase D. More recently, the production of recombinant PLDs and discoveries about their structure and mechanism has enabled a deeper characterization of these enzymes. In this review, we describe these biochemical and functional features of Loxosceles PLDs that determine their involvement in systemic loxoscelism.

A 14-Year-Old Boy With Neck Pain, Fevers, and Diffuse Erythematous Rash

A previously healthy 14-year-old boy developed right-sided neck pain, tachycardia, a diffuse erythematous rash, and subjective fevers over 2 days. He sought medical attention in a local urgent care clinic, where he had a negative Sars-CoV-2 antigen test and was referred to the local emergency department (ED) for persistent tachycardia and further workup. After fluid resuscitation, his tachycardia was not improved, so he was admitted to the Pediatric Hospital Medicine Service. Physical examination showed large areas of erythema and erythroderma of multiple body sites, perioral sparing, increased erythema in flexor skin folds, posterior soft palate petechiae, and a white strawberry tongue. There was a small, tender lesion with surrounding erythema without discharge on his right neck thought to be a possible entry point for infection. Laboratory results showed thrombocytopenia, normal white blood cell count, normal hemoglobin concentration, absolute lymphopenia, and an elevated C-reactive protein (CRP) to 130 mg/L. He was started on intravenous fluids and antibiotics for a presumed infectious cause of the rash and laboratory findings. The next morning, an expanded diagnostic workup was undertaken including electrocardiogram, echocardiogram, ferritin, triglycerides, liver enzymes, lactate dehydrogenase (LDH), brain natriuretic peptide, coagulation studies, and fibrinogen. With treatment and supportive care, his tachycardia and energy improved, so he was discharged with oral antibiotics and follow-up with the Infectious Disease Clinic in 2 days. When seen in follow-up, he was immediately admitted to the hospital for worsening fatigue, tachycardia, and new findings that prompted multiple consultations, and transfer to pediatric critical care services.

Systemic loxoscelism induced warm autoimmune hemolytic anemia: clinical series and review

OBJECTIVES

Describe the development of warm autoimmune hemolytic anemia warm (AIHA) secondary to a brown recluse spider (Loxosceles reclusa) bite is known as systemic loxoscelism; and review epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

METHODS

Cases series of two cases of warm AIHA due to systemic loxoscelism and a review of the current literature: epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

RESULTS

Presented here are two cases of warm AIHA due to systemic loxoscelism. Each patient was generally healthy appearing and presented with symptomatic anemia in the setting of brown recluse spider bites. Both patients were eventually found to have warm AIHA. Upon recognition of the diagnosis, the patients were started on corticosteroids and aggressive intravenous fluid hydration. In addition, they received transfusions of packed red blood cells. Their clinical courses improved, and they recovered to eventually be discharged home.

CONCLUSION

Envenomation by a brown recluse spider, Loxosceles reclusa, can result in systemic loxoscelism which can cause warm AIHA. The diagnosis of warm AIHA is confirmed by the direct antiglobulin/Coomb's test. Warm AIHA can be a life-threatening disease process. Hemodynamic support with intravenous fluids and RBC transfusion is the initial step in the management of these patients. Corticosteroids are the mainstay of current management. Second line treatments include rituximab. Rarely patients require splenectomy for refractory disease. Corticosteroids should be tapered over a three-month period.

Laboratory Predictors of Hemolytic Anemia in Patients With Systemic Loxoscelism

OBJECTIVES

To develop a sensitive and specific protocol for detecting preclinical hemolysis in patients with brown recluse spider (BRS) bites by comparing a large cohort of individuals with brown recluse spider (BRS) bites with and without hemolytic anemia.

METHODS

A cross-sectional, retrospective analysis of clinical features and laboratory values, including urinalysis (UA) and peripheral blood results, and timing of positive laboratory values prior to a significant drop in hematocrit was performed to evaluate effective predictors of clinically significant hemolysis.

RESULTS

In total, 275 patients with BRS bites were identified (64 with hemolytic anemia). Sensitivity and specificity of UA positive for blood (with and without microscopic hematuria) for detecting hemolysis were 72% and 75%, respectively. The combination of elevated serum total bilirubin (TB) and lactate dehydrogenase (LDH) had greater sensitivity (94%) and specificity (91%) for detecting patients developing hemolysis. When TB and LDH were evaluated prior to a significant decrease in hematocrit, they were positive in 82% of cases, while UA was positive for blood prior to a hematocrit decrease in 38% of cases.

CONCLUSIONS

Serum TB and LDH levels are more effective at detecting preclinical hemolysis than UA and should be serially analyzed to triage patients with BRS bites before life-threatening hemolysis occurs.

Atypical systemic and dermatologic loxoscelism in a non-endemic region of the USA

INTRODUCTION

Loxosceles reclusa (LR), commonly known as the brown recluse spider, is endemic to the south central United States. We present a case of LR envenomation in a healthy adult male outside the usual geographic range, with atypical dermatologic and delayed, prolonged systemic loxoscelism (LX). This case demonstrates the importance of expanding the depth of knowledge of LR envenomations.

CASE REPORT

A previously healthy 27 year-old male presented to an emergency department (ED) in central Virginia two hours after a LR envenomation to his left proximal arm. He was treated with diphenhydramine and discharged on oral methylprednisolone for a 5-day taper. On post-bite Days 1 and 2, the patient developed subjective fevers, chills, arthralgias, and myalgias, followed by a blanching, pruritic, morbilliform rash throughout his trunk and lower extremities. Post-bite Day 3, the patient presented to the ED again because of marked erythema of face and the right lateral thigh, and posterior and anterior trunk. Vital signs and laboratory analysis were generally unremarkable. The patient was observed overnight, and discharged with a prescription for prednisone 60 mg per day. On post-bite Day 7, the patient noted a petechial rash on the palms and soles and returned to the ED with a fever of 102.6 °F, a heart rate of 130 beats per minutes, and systolic blood pressure ranging 80-90 mmHg. After considering this may be an atypical presentation of LX, corticosteroids were increased to methylprednisolone 1 mg/kg IV every 6 h. The patient's condition slowly improved and he was discharged on post-bite Day 10. On post-bite Day 24, he had nearly complete resolution of skin findings.

CONCLUSIONS

LR envenomation can cause a variety of dermatological and systemic manifestations of toxicity. It is critical for toxicologists to be aware of the variety of presentations and findings to appropriately assess and treat LX.

Clinical aspects, diagnosis and management of Loxosceles spider envenomation: literature and case review

The genus Loxosceles comprises 140 species widely distributed around the world. These spiders are nocturnal, sedentary and remarkably nonaggressive, although they cause accidents in humans with wide degrees of severity, generating signs and symptoms that define the clinical condition known as loxoscelism. Its local signs and symptoms were first reported in 1872, and over the years, a large medical literature has been accumulated; unfortunately, it is not always trustworthy. Assessing the reliability of such information, we reviewed 120 case reports of loxoscelism published in 84 articles over the past 20 years. This search allowed us to gather information on the clinical aspects, diagnosis and treatment of loxoscelism, showing that the severity of these accidents has multiple degrees and that it is influenced by many factors. Thus, coupled with epidemiological and species occurrence information, this study can be a useful tool for the clinical practice of loxoscelism. It may support and provide a multidisciplinary view that should be taken into consideration when establishing the therapeutic approach in cases of Loxosceles envenomation.

Cutaneous-hemolytic loxoscelism following brown recluse spider envenomation: new understandings

Background: Brown recluse spider (BRS) (Loxosceles reclusa) envenomation can cause local dermonecrotic lesions, constitutional symptoms, and potentially fatal hemolysis (i.e., cutaneous-hemolytic loxoscelism). As the incidence of hemolysis is low and the spider habitat is limited, little is known regarding the clinical course of cutaneous-hemolytic loxoscelism.Methods: We performed a retrospective observational study of patients following BRS envenomation over an eight-year period. Demographics, clinical course, laboratories, and interventions were assessed. Wilcoxon rank-sum tests and Pearson chi-square tests were used in the univariate analyses. Logistic regression assessed the independent contribution of symptoms in a multivariate analysis.Results: Of the 97 patients, 40.2% (n = 39) developed hemolysis; the majority (66.7%) were 18 years old or younger. Univariate analysis revealed that constitutional symptoms were associated with hemolysis, but multivariate analysis showed only myalgia (aOR: 7.1; 95% CI: 2.2-22.7; p < .001) and malaise (aOR: 12.76; 95% CI: 1.4-119.9; p = .026) were independently associated with hemolysis. The median time to hemolysis onset was 1.0 days (IQR: 1.0-2.5) and all occurred within a week of envenomation. Hemolysis durations were longer in patients DAT positive for IGG antibodies (7.5 vs. 4.0 days; p = .042). Most (76.9%) of hemolyzing patients received blood. In patients with cutaneous-hemolytic loxoscelism, hematuria occurred in 32.4%, rhabdomyolysis occurred in 60.9%, and elevated transaminases with normal hepatic synthetic function occurred in 29.4% but all of these patients developed rhabdomyolysis. Hemolysis was both intravascular and extravascular. Complications (hyperkalemia, INR ≥2.0, metabolic acidosis requiring bicarbonate, hypotension requiring vasopressors, and hypoxia requiring intubation) occurred only in patients with profound hemolytic anemia (hemoglobin <4 g/dL); one patient died.Conclusions: Constitutional symptoms occur in both cutaneous and cutaneous-hemolytic loxoscelism, although they occur more frequently in patients who develop hemolysis. Children may be at a higher risk of hemolysis after envenomation. Renal involvement (as evidenced by hematuria) and rhabdomyolysis may occur more frequently than has been previously reported. Hemolysis was both intravascular and extravascular.

Brown Recluse Spider Bites in Patients With Neutropenia: A Single-institution Experience

Brown recluse spider bites can cause local and systemic signs, including rash, dermonecrosis, edema, hemolysis, and acute kidney failure. These are mostly attributed to sphingomyelinase D, the main toxin. To evaluate the severity of the disease in pediatric patients with and without neutropenia, we retrospectively reviewed records of patients treated at St. Jude Children's Research Hospital between 1970 and 2015 and identified 19 patients who met the inclusion criteria. Variables of interest included the type of underlying illness, presence of neutropenia, number of days of hospitalization, disease signs and outcome of the bite, and treatments administered. We used descriptive statistics to summarize the manifestations and severity of spider bites in patients with and without neutropenia. Six patients experienced pain from the bite, 11 had erythema, 7 developed edema, and 5 had fever. The response to spider bites in neutropenic patients was no milder than that in non-neutropenic individuals. Six patients developed systemic complications. Compared with non-neutropenic patients, neutropenic patients had antibiotics prescribed more often and experienced longer hospital stays. Spider bites do not seem to have a different clinical course in neutropenic patients. Therefore, a conservative approach may be best for these patients, with close monitoring and local wound care.

Probable cutaneous loxoscelism with mild systemic symptoms: A case report from Spain

We present a case from Valencia, Spain, of a 25-year-old woman who presented with a painful erythematous skin lesion, initially diagnosed as cellulitis. The lesion was unresponsive to antibiotic treatments and progressed into a hemorrhagic blister with necrotic ulcer formation. Posterior collection of a spider from the patient's home and expert identification of the spider as Loxosceles rufescens was achieved, establishing the diagnosis of probable cutaneous loxoscelism. Symptomatic treatment, general wound care and ultimately surgery, resulted in complete recovery with minor residual scarring. This case illustrates some of the difficulties encountered in the diagnosis and treatment of loxoscelism and adds to the increasing reports of loxoscelism in the Mediterranean Basin.

Defining the complex phenotype of severe systemic loxoscelism using a large electronic health record cohort

Objective

Systemic loxoscelism is a rare illness resulting from the bite of the recluse spider and, in its most severe form, can lead to widespread hemolysis, coagulopathy, and death. We aim to describe the clinical features and outcomes of the largest known cohort of individuals with moderate to severe loxoscelism.

Methods

We performed a retrospective, cross sectional study from January 1, 1995, to December 31, 2015, at a tertiary-care academic medical center, to determine individuals with clinical records consistent with moderate to severe loxoscelism. Age-, sex-, and race-matched controls were compared. Demographics, clinical characteristics, laboratory measures, and outcomes of individuals with loxoscelism are described. Case and control groups were compared with descriptive statistics and phenome-wide association study (PheWAS).

Results

During the time period, 57 individuals were identified as having moderate to severe loxoscelism. Of these, only 33% had an antecedent spider bite documented. Median age of individuals diagnosed with moderate to severe loxoscelism was 14 years old (IQR 9.0–24.0 years). PheWAS confirmed associations of systemic loxoscelism with 29 other phenotypes, e.g., rash, hemolytic anemia, and sepsis. Hemoglobin level dropped an average of 3.1 g/dL over an average of 2.0 days (IQR 2.0–6.0). Lactate dehydrogenase and total bilirubin levels were on average over two times their upper limit of normal values. Eighteen individuals of 32 tested had a positive direct antiglobulin (Coombs’) test. Mortality was 3.5% (2/57 individuals).

Conclusion

Systemic loxoscelism is a rare but devastating process with only a minority of patients recalling the toxic exposure; hemolysis reaches a peak at 2 days after admission, with some cases taking more than a week before recovery. In endemic areas, suspicion for systemic loxoscelism should be high in individuals, especially children and younger adults, presenting with a cutaneous ulcer and hemolysis or coagulopathy, even in the absence of a bite exposure history.

Rare case of dermonecrosis caused by a recluse spider bite in Europe

Spider poisoning is rare in Europe, with very few reported cases in the literature. Recluse spider (genus Loxosceles) bites may lead to cutaneous and systemic manifestations known as loxoscelism. We report the second known case of spider bite poisoning in Malta caused by Loxosceles rufescens (Mediterranean recluse spider). A young adult female presented with localised erythema and pain on her left thigh after a witnessed spider bite. Over a few days, the area developed features of dermonecrosis together with systemic symptoms, including fever, fatigue and a generalised erythematous eruption. She was managed by a multidisciplinary team and the systemic symptoms resolved within 6 days, while the skin lesion healed with scarring within 2 months. A recluse spider bite should be considered in patients with dermonecrosis. Although spider bite poisoning is uncommon in Europe, it is important to diagnose and manage it appropriately since it could lead to potentially serious sequelae.

Low Health System Performance, Indigenous Status and Antivenom Underdosage Correlate with Spider Envenoming Severity in the Remote Brazilian Amazon

Background

A better knowledge of the burden and risk factors associated with severity due to spider bites would lead to improved management with a reduction of sequelae usually seen for this neglected health problem, and would ensure proper use of antivenoms in remote localities in the Brazilian Amazon. The aim of this study was to analyze the profile of spider bites reported in the state of Amazonas in the Western Brazilian Amazon, and to investigate potential risk factors associated with severity of envenomation.

Methodology/Principal Findings

We used a case-control study in order to identify factors associated with spider bite severity in the Western Brazilian Amazon from 2007 to 2014. Patients evolving to any severity criteria were considered cases and those with non-severe bites were included in the control group. All variables were retrieved from the official Brazilian reporting systems. Socioeconomical and environmental components were also included in a multivariable analysis in order to identify ecological determinants of incidence and severity. A total of 1,181 spider bites were recorded, resulting in an incidence of 4 cases per 100,000 person/year. Most of the spider bites occurred in males (65.8%). Bites mostly occurred in rural areas (59.5%). The most affected age group was between 16 and 45 years old (50.9%). A proportion of 39.7% of the bites were related to work activities. Antivenom was prescribed to 39% of the patients. Envenomings recorded from urban areas [Odds ratio (OR) = 0.40 (95%CI = 0.30–0.71; p<0.001)] and living in a municipality with a mean health system performance index (MHSPI >median [OR = 0.64 (95%CI = 0.39–0.75; p<0.001)] were independently associated with decreased risk of severity. Work related accidents [OR = 2.09 (95%CI = 1.49–2.94; p<0.001)], Indigenous status [OR = 2.15 (95%CI = 1.19–3.86; p = 0.011)] and living in a municipality located >300 km away from the state capital Manaus [OR = 1.90 (95%CI = 1.28–2.40; p<0.001)] were independently associated with a risk of severity. Living in a municipality located >300 km away from the state capital Manaus [OR = 1.53 (95%CI = 1.15–2.02; p = 0.003)] and living in a municipality with a MHSPI <median [OR = 1.91 (95%CI = 1.28–2.47; p = 0.002)] increased the odds of antivenom underdosage.

Conclusions

Spider bites is prevalent across the study region with a higher incidence in the rainy season in rural areas. Spider bites can be painful and lead to local manifestations but rarely result in life-threatening envenoming. Major local complications were dermonecrosis and secondary infection in cases diagnosed as Loxosceles bites. Based on the correlations shown here, envenomings occurring in remote rural areas, Indigenous status and living in a municipality located >300 km away from the state capital Manaus could be contributing factors to higher severity of spider envenomings in this area, as well as to antivenom underdosage.

The Clinical Pictures of Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia is characterized by shortened red blood cell survival and a positive Coombs test. The responsible autoantibodies may be either warm reactive or cold reactive. The rate of hemolysis and the severity of the anemia may vary from mild to severe and life-threatening. Diagnosis is made in the laboratory by the findings of anemia, reticulocytosis, a positive Coombs test, and specific serologic tests. The prognosis is generally good but renal failure and death sometimes occur, especially in cases mediated by drugs.

Successful use of plasma exchange for profound hemolysis in a child with loxoscelism

We describe a 6-year-old boy who presented with massive hemolysis, shock, disseminated intravascular coagulopathy, and acute renal failure after loxosceles envenomation. In this patient, plasma exchange therapy (PEX) successfully cleared the plasma from an initial hemolytic index of 2000 (equivalent to 2 g/dL hemoglobin, where optimetric laboratory evaluation is impossible) to an index of <50 (no detectable hemolysis). This allowed the PICU team to correct his coagulopathy, assess his degree of organ dysfunction, and provide routine laboratory assessments during continuous venovenous hemodiafiltration. After 9 single volume PEX sessions, his hemolysis and coagulopathy had resolved and his plasma had cleared sufficiently to permit routine laboratory assessments without difficulty. Multiorgan system support with an aggressive transfusion strategy, mechanical ventilation, inotropes, and continuous venovenous hemodiafiltration resulted in complete recovery. We conclude that in the presence of overwhelming hemolysis, plasma can become so icteric that optimetric laboratory evaluation is impossible. In this setting, PEX can be used to clear the plasma, restoring the ability to perform routine laboratory assessments.

Acute kidney injury and dermonecrosis after Loxosceles reclusa envenomation

Spiders of the Loxosceles species can cause dermonecrosis and acute kidney injury (AKI). Hemolysis, rhabdomyolysis and direct toxin-mediated renal damage have been postulated. There are very few reports of Loxoscelism from India. We report a case of AKI, hemolysis and a "gravitational" pattern of ulceration following the bite of the brown recluse spider (Loxosceles spp).

Immune-mediated mechanism for thrombocytopenia after Loxosceles spider bite

Loxoscelism, characterized by high fever, vomiting, malaise, a dermonecrotic lesion, and thrombocytopenia, was diagnosed in a 3-year-old female. Clinical laboratory and dermatological signs are described. Blood test showed a transient hypercoagulable state and the presence of IgG antibodies against platelets, suggesting an immune-mediated mechanism for platelet destruction, in addition to the direct toxic effect of the spider venom. The finding of platelet antibodies after a Loxosceles spider bite has not been previously reported.

Viscerocutaneous Loxoscelism in an Adult with Acute Generalized Exanthematous Pustulosis

This case describes an unusual presentation of a woman with viscerocutaneous (VCT) loxoscelism and exanthematous pustulosis. Due to a complex presentation resembling sepsis and errant information, she was unnecessarily treated with multiple antibiotics and intravenous immunoglobulin (IVIG) which may have complicated her course. Given recent reports of quick progression and death from a similar presentation, it is imperative that clinicians be familiar with signs, symptoms and complications of VCT loxoscelism, which can include hemolysis and acute exanthematous pustulosis.

Brown Recluse spider bite mediated hemolysis: clinical features, a possible role for complement inhibitor therapy, and reduced RBC surface glycophorin A as a potential biomarker of venom exposure

Background

The venom of Loxoscelesreclusa (Brown Recluse spider) can cause a severe, life-threatening hemolysis in humans for which no therapy is currently available in the USA beyond supportive measures. Because this hemolysis is uncommon, relatively little is known about its clinical manifestation, diagnosis, or management. Here, we aimed to clarify the clinical details of envenomation, to determine the efficacy of the complement inhibitor eculizumab to prevent the hemolysis invitro, and to investigate markers of exposure to Brown Recluse venom.

Study Design and Methods

We performed a 10-year chart review of cases of Brown Recluse spider bite-mediated hemolysis at our institution. We also designed an invitro assay to test the efficacy of eculizumab to inhibit hemolysis of venom exposed red blood cells. Finally, we compared levels of CD55, CD59 and glycophorin A on venom exposed versus venom-naïve cells.

Results

Most victims of severe Brown Recluse spider mediated hemolysis at our institution are children and follow an unpredictable clinical course. Brown Recluse spider bite mediated hemolysis is reduced by 79.2% (SD=18.8%) by eculizumab invitro. Erythrocyte glycophorin A, but not CD55 or CD59, is reduced after red blood cells are incubated with venom invitro.

Conclusion

Taken together, our laboratory data and clinical observations indicate that L. reclusa venom exposure results in non-specific antibody and complement fixation on red blood cells, resulting in complement mediated hemolysis that is curtailed by the complement inhibitor eculizumab invitro. Glycophorin A measurement by flow cytometry may help to identify victims of L. reclusa envenomation.

Spider bite

Spiders are a source of intrigue and fear, and several myths exist about their medical effects. Many people believe that bites from various spider species cause necrotic ulceration, despite evidence that most suspected cases of necrotic arachnidism are caused by something other than a spider bite. Latrodectism and loxoscelism are the most important clinical syndromes resulting from spider bite. Latrodectism results from bites by widow spiders (Latrodectus spp) and causes local, regional, or generalised pain associated with non-specific symptoms and autonomic effects. Loxoscelism is caused by Loxosceles spp, and the cutaneous form manifests as pain and erythema that can develop into a necrotic ulcer. Systemic loxoscelism is characterised by intravascular haemolysis and renal failure on occasion. Other important spiders include the Australian funnel-web spider (Atrax spp and Hadronyche spp) and the armed spider (Phoneutria spp) from Brazil. Antivenoms are an important treatment for spider envenomation but have been less successful than have those for snake envenomation, with concerns about their effectiveness for both latrodectism and loxoscelism.

The relationship between calcium and the metabolism of plasma membrane phospholipids in hemolysis induced by brown spider venom phospholipase-D toxin

Brown spider venom phospholipase-D belongs to a family of toxins characterized as potent bioactive agents. These toxins have been involved in numerous aspects of cell pathophysiology including inflammatory response, platelet aggregation, endothelial cell hyperactivation, renal disorders, and hemolysis. The molecular mechanism by which these toxins cause hemolysis is under investigation; literature data have suggested that enzyme catalysis is necessary for the biological activities triggered by the toxin. However, the way by which phospholipase-D activity is directly related with human hemolysis has not been determined. To evaluate how brown spider venom phospholipase-D activity causes hemolysis, we examined the impact of recombinant phospholipase-D on human red blood cells. Using six different purified recombinant phospholipase-D molecules obtained from a cDNA venom gland library, we demonstrated that there is a correlation of hemolytic effect and phospholipase-D activity. Studying recombinant phospholipase-D, a potent hemolytic and phospholipase-D recombinant toxin (LiRecDT1), we determined that the toxin degrades synthetic sphingomyelin (SM), lysophosphatidylcholine (LPC), and lyso-platelet-activating factor. Additionally, we determined that the toxin degrades phospholipids in a detergent extract of human erythrocytes, as well as phospholipids from ghosts of human red blood cells. The products of the degradation of synthetic SM and LPC following recombinant phospholipase-D treatments caused hemolysis of human erythrocytes. This hemolysis, dependent on products of metabolism of phospholipids, is also dependent on calcium ion concentration because the percentage of hemolysis increased with an increase in the dose of calcium in the medium. Recombinant phospholipase-D treatment of human erythrocytes stimulated an influx of calcium into the cells that was detected by a calcium-sensitive fluorescent probe (Fluo-4). This calcium influx was shown to be channel-mediated rather than leak-promoted because the influx was inhibited by L-type calcium channel inhibitors but not by a T-type calcium channel blocker, sodium channel inhibitor or a specific inhibitor of calcium activated potassium channels. Finally, this inhibition of hemolysis following recombinant phospholipase-D treatment occurred in a concentration-dependent manner in the presence of L-type calcium channel blockers such as nifedipine and verapamil. The data provided herein, suggest that the brown spider venom phospholipase-D-induced hemolysis of human erythrocytes is dependent on the metabolism of membrane phospholipids, such as SM and LPC, generating bioactive products that stimulate a calcium influx into red blood cells mediated by the L-type channel.

Clinical picture and laboratorial evaluation in human loxoscelism

Loxosceles spiders are found globally, especially in South and North America. In Brazil, approximately 10,000 cases of Loxosceles spp. spider bites are reported annually. Herein we analyzed 81 patients diagnosed as either cutaneous or cutaneous-hemolytic loxoscelism, in a geographical area where most accidents are caused by Loxosceles gaucho, and we report their clinical and laboratory data obtained during week 1 and 2 after the bite. Massive hemolysis was noticed in only 2 cases, but high serum bilirubin and LDH levels, suggestive of hemolysis, were noticed in 25 cases on admission. Anemia was not frequent (14.7%), and reticulocytosis was particularly noticed during week 2 (in 56% of patients). High D-dimer levels were suggestive of endothelial cell activation and intravascular thrombin generation, but thrombocytopenia was noticed in only 17.6% of patients in week 1. Acute kidney injury (AKI) only occurred in patients with massive hemolysis. The definitive diagnosis of overt disseminated intravascular coagulation (DIC) could not be established on admission. Fever was associated with the presence of hemolysis (p = 0.03). Altogether, these findings provide evidence that mild hemolysis is frequent in loxoscelism and suggest that AKI is uncommon, exclusively occurring in patients with massive hemolysis.

Loxosceles gaucho venom-induced acute kidney injury--in vivo and in vitro studies

BACKGROUND

Accidents caused by Loxosceles spider may cause severe systemic reactions, including acute kidney injury (AKI). There are few experimental studies assessing Loxosceles venom effects on kidney function in vivo.

METHODOLOGY/PRINCIPAL FINDINGS

In order to test Loxosceles gaucho venom (LV) nephrotoxicity and to assess some of the possible mechanisms of renal injury, rats were studied up to 60 minutes after LV 0.24 mg/kg or saline IV injection (control). LV caused a sharp and significant drop in glomerular filtration rate, renal blood flow and urinary output and increased renal vascular resistance, without changing blood pressure. Venom infusion increased significantly serum creatine kinase and aspartate aminotransferase. In the LV group renal histology analysis found acute epithelial tubular cells degenerative changes, presence of cell debris and detached epithelial cells in tubular lumen without glomerular or vascular changes. Immunohistochemistry disclosed renal deposition of myoglobin and hemoglobin. LV did not cause injury to a suspension of fresh proximal tubules isolated from rats.

CONCLUSIONS/SIGNIFICANCE

Loxosceles gaucho venom injection caused early AKI, which occurred without blood pressure variation. Changes in glomerular function occurred likely due to renal vasoconstriction and rhabdomyolysis. Direct nephrotoxicity could not be demonstrated in vitro. The development of a consistent model of Loxosceles venom-induced AKI and a better understanding of the mechanisms involved in the renal injury may allow more efficient ways to prevent or attenuate the systemic injury after Loxosceles bite.

Complications and outcomes of brown recluse spider bites in children

Brown recluse spider bites may cause severe local and systemic morbidity, but data regarding morbidity in children are limited. This study reviewed inpatient medical records (n = 26; 10 years) with a discharge diagnosis of "spider bite" from a tertiary pediatric hospital. The majority (85%) of children had an inflammatory response accompanying necrosis, usually with signs of secondary cellulitis (77%). Hemolytic anemia (50%), rhabdomyolysis (27%), and acute renal failure (12%) were the most prevalent systemic effects. Hemolytic anemia was bimodal in distribution relative to the time-of-onset of the bite (early, 2.2 ± 0.4; late, 6.9 ± 1.5 days postbite, respectively; P = .004). Although no fatalities occurred in the population, 65% of children had major morbidity, including wound complications requiring surgical care and acute orbital compartment syndrome. The findings emphasize the importance of anticipatory patient/family education for outpatients and careful monitoring for systemic morbidity in inpatients. Timely and appropriate supportive care should yield favorable outcomes in most cases.