[Necrotizing fasciitis and cellulitis of the upper limb resulting from centipede bite: two case reports]

Effectiveness of antibiotic prophylaxis in patients with centipede stings: a randomized controlled trial

OBJECTIVE

Centipede stings are a common problem in tropical countries. Current treatment guidelines do not include recommendations for antibiotic prophylaxis to prevent the associated bacterial infection since no previous study has assessed the effectiveness of antibiotic treatment in patients bitten by centipedes. Thus, this study aimed to compare the effectiveness of antibiotic prophylaxis over placebo for the skin infections that occur after a centipede sting.

METHODS

In this randomized, double-blind, multi-center clinical trial conducted in the emergency departments in four hospitals, patients with any history of a centipede sting were prospectively enrolled and divided randomly into two groups. One group received dicloxacillin and the other a placebo. The primary outcome was the incidence of wound infection 3 to 5 days after the centipede sting.

RESULTS

From December 2014 to October 2015, a total of 83 patients were enrolled in the study and were randomized into antibiotic (n=43) and placebo (n=40) groups. Two patients in the antibiotic group developed wound infections, while none showed wound infection in the placebo group (5% vs. 0%). The wound infection rate did not differ significantly between the two groups (P=0.496).

CONCLUSION

Antibiotic prophylaxis may be unnecessary in cases of centipede stings. Proper wound care is an adequate and appropriate treatment for patients with centipede stings. However, the patient should be re-evaluated for detection of secondary bacterial infection.

Patients with centipede bites presenting to a university hospital in Bangkok: a 10-year retrospective study

INTRODUCTION

Centipede envenomation occurs commonly in tropical and subtropical countries. In most cases, centipede envenomation causes benign clinical manifestations. Serious complications are reported occasionally. Clinical studies regarding centipede envenomation are limited to case reports and case series. This study aimed to determine the prevalence and clinical characteristics of centipede bites in Bangkok, Thailand.

METHODS

This was a retrospective medical record review study. We included patients who were clearly envenomated by a centipede presenting to the emergency department of a tertiary university hospital in Bangkok from January 1, 2006, to December 31, 2015. Data were collected on demographics, details of the exposure, signs, symptoms, treatment, and complications of envenomation.

RESULTS

A total of 245 cases were included. The prevalence of centipede bite was 0.0367%. The majority were female (56.7%). The median age was 34.6 years (range: 1 month to 90 years). The number of envenomations was highest from October through December. Feet (38.3%) and hands (19.1%) were the parts of the body most often envenomated. Local effects were common with 99.5% of patients having localized pain and 87% having local swelling at the bite site. In terms of systemic effects, urticarial rash (5.7%) and fever (4.1%) were most frequently observed. Twelve cases (5%) had clinical pictures compatible with anaphylaxis. For pain management, all patients who had pain received analgesic drugs, while 29.7% were injected with local anesthesia. Antibiotics, antihistamines, and steroids were prescribed in 53.9%, 20.4%, and 10.2% of cases, respectively. No deaths occurred in this study.

CONCLUSIONS

Even though the location of our hospital is in a metropolitan city in Thailand, there were centipede bites every month, especially during the last three months of each year. Nearly all patients had local effects. In contrast, serious complications such as anaphylaxis and systemic infection only occurred occasionally.

Deep neck cellulitis: a challenging diagnosis

A 38-year-old woman with Crohn's disease, under immunosuppressive therapy, was referred to the emergency department for severe progressive neck pain and fever, with 1 week of evolution. She was unable to perform neck mobilisation due to the intense pain aroused. She referred dysphagia. Oral cavity, oropharynx, hypopharynx and larynx showed no alterations. She had an increased C reactive protein. Central nervous system infections were excluded by lumbar puncture. CT was normal. Only MRI showed T2 hyperintensity of the retropharyngeal and prevertebral soft tissues of the neck without signs of abscess. The patient was treated with broad spectrum antibiotics. Complications of deep neck infection include abscess formation, venous thrombosis and mediastinitis. In this case, no complications occurred. A high degree of clinical suspicion is essential as deep neck infections need to be promptly diagnosed and treated given their rapidly progressive character, especially in immunocompromised patients.

A systematic review of necrotising fasciitis in children from its first description in 1930 to 2018

BACKGROUND

Necrotising fasciitis is a rapidly progressing soft-tissue infection with a low incidence that carries a relevant risk of morbidity and mortality. Although necrotising fasciitis is often fatal in adults, its case fatality rate seems to be lower in children. A highly variable clinical presentation makes the diagnosis challenging, which often results in misdiagnosis and time-delay to therapy.

METHODS

We conducted a protocol-based systematic review to identify specific features of necrotising fasciitis in children aged one month to 17 years. We searched 'PubMed', 'Web of Science' and 'SCOPUS' for relevant literature. Primary outcomes were incidence and case fatality rates in population-based studies, and skin symptoms on presentation. We also assessed signs of systemic illness, causative organisms, predisposing factors, and reconstructive procedures as secondary outcomes.

RESULTS

We included five studies reporting incidence and case fatality rates, two case-control studies, and 298 cases from 195 reports. Incidence rates varied between 0.022 and 0.843 per 100,000 children per year with a case-fatality rate ranging from 0% to 14.3%. The most frequent skin symptoms were erythema (58.7%; 175/298) and swelling (48%; 143/298), whereas all other symptoms occurred in less than 50% of cases. The majority of cases had fever (76.7%; 188/245), but other signs of systemic illness were present in less than half of the cohort. Group-A streptococci accounted for 44.8% (132/298) followed by Gram-negative rods in 29.8% (88/295), while polymicrobial infections occurred in 17.3% (51/295). Extremities were affected in 45.6% (136/298), of which 73.5% (100/136) occurred in the lower extremities. Skin grafts were necessary in 51.6% (84/162) of the pooled cases, while flaps were seldom used (10.5%; 17/162). The vast majority of included reports originate from developed countries.

CONCLUSIONS

Clinical suspicion remains the key to diagnose necrotising fasciitis. A combination of swelling, pain, erythema, and a systemic inflammatory response syndrome might indicate necrotising fasciitis. Incidence and case-fatality rates in children are much smaller than in adults, although there seems to be a relevant risk of morbidity indicated by the high percentage of skin grafts. Systematic multi-institutional research efforts are necessary to improve early diagnosis on necrotising fasciits.

Proteotranscriptomic Analysis and Discovery of the Profile and Diversity of Toxin-like Proteins in Centipede

Centipedes are one of the oldest venomous animals and use their venoms as weapons to attack prey or protect themselves. Their venoms contain various components with different biomedical and pharmacological properties. However, little attention has been paid to the profiles and diversity of their toxin-like proteins/peptides. In this study, we used a proteotranscriptomic approach to uncover the diversity of centipede toxin-like proteins in Scolopendra subspinipes mutilans Nine hundred twenty-three and 6,736 peptides, which were separately isolated from venom and torso tissues, respectively, were identified by ESI-MS/MS and deduced from their transcriptomes. Finally, 1369 unique proteins were identified in the proteome, including 100 proteins that exhibited overlapping expression in venom and torso tissues. Of these proteins, at least 40 proteins were identified as venom toxin-like proteins. Meanwhile, transcriptome mining identified ∼10-fold more toxin-like proteins and enabled the characterization of the precursor architecture of mature toxin-like peptides. Importantly, combined with proteomic and transcriptomic analyses, 25 toxin-like proteins/peptides (neurotoxins accounted for 50%) were expressed outside the venom gland and involved in gene recruitment processes. These findings highlight the extensive diversity of centipede toxin-like proteins and provide a new foundation for the medical-pharmaceutical use of centipede toxin-like proteins. Moreover, we are the first group to report the gene recruitment activity of venom toxin-like proteins in centipede, similar to snakes.

Clinical consequences of centipede bite: Is it neurotoxic?

The primary purpose of this article was to review the current literature regarding the clinical consequences of centipede envenomation in humans, in order to determine whether the bite of these arthropods is neurotoxic to humans or not. A thorough search of the literature regarding the clinical consequences of centipede bites in humans was applied, with great respect to neurological symptoms potentially caused by such bites. Centipede bite commonly causes only local reactions, which usually resolve within a few days without sequelae. The patients in the majority of centipede envenomations describe a painful but benign syndrome. However, mild constitutional symptoms are relatively frequent. Remarkably, centipedes can rarely cause severe systematic reactions such as anaphylaxis or even hypotension and myocardial ischemia. Factors such as patient age, comorbidity, anatomic site of envenomation, and size/species of centipede should be considered when evaluating a centipede envenomation victim. According to the current literature, the centipede bite does not seem to be neurotoxic to humans. However, it commonly causes symptoms mediated by the nervous system. These include local and generalized symptoms, with the first dominated by sensory disturbances and the second by non-specific symptoms such as headache, anxiety and presyncope. Based on our results, the answer to our study’s question is negative. The centipede bite is not neurotoxic to humans. However, it commonly causes symptoms mediated by the nervous system, which include primarily local pain and sensory disturbances, as well as generalized non-specific symptoms such as headache, anxiety and vagotonia.

Centipede venom: recent discoveries and current state of knowledge

Centipedes are among the oldest extant venomous predators on the planet. Armed with a pair of modified, venom-bearing limbs, they are an important group of predatory arthropods and are infamous for their ability to deliver painful stings. Despite this, very little is known about centipede venom and its composition. Advances in analytical tools, however, have recently provided the first detailed insights into the composition and evolution of centipede venoms. This has revealed that centipede venom proteins are highly diverse, with 61 phylogenetically distinct venom protein and peptide families. A number of these have been convergently recruited into the venoms of other animals, providing valuable information on potential underlying causes of the occasionally serious complications arising from human centipede envenomations. However, the majority of venom protein and peptide families bear no resemblance to any characterised protein or peptide family, highlighting the novelty of centipede venoms. This review highlights recent discoveries and summarises the current state of knowledge on the fascinating venom system of centipedes.

Knee Osteochondritis Dissecans Treated by the AO Hook Fixation System: A Four Year Follow-Up of an Alternative Technique

Surgical fixation is recommended for stable osteochondritis dissecans (OCD) lesions that have failed nonoperative management and for all unstable lesions. In this study we set out to describe and evaluate an alternative method of surgical fixation for such lesions. Five knees with unstable OCD lesions in four male adolescent patients with open physes were treated with the AO Hook Fixation System. The outcome was evaluated both clinically and with three separate outcome systems (IKDC 2000, KOOS, Lysholm) at one and a mean four year follow-up. We demonstrated excellent clinical results in all patients. At four years, all scoring systems demonstrated statistically significant improvement when compared to the preoperative status. Our study suggests that the AO Hook Fixation System is an alternative method of surgical intervention with comparable medium term results with other existing modes of fixation and the added biomechanical advantage of the absence of distracting forces during hardware removal.

Bite injuries to the hand - review of the literature

Patients presenting to the emergency department with bite injuries to the hand sustain them through a number of causes including domesticated as well as stray animal bites, and human bites commonly sustained as a result of violence. The nature of the injuries sustained can be very deceptive. A small tooth mark on the exterior can be a fulminant infection in the tissues deeper down. Tendon injuries, fractures of the metacarpals and phalanges and management of the wound are critical issues faced by a surgeon in dealing with such patients. Similarly the less common bite injuries to the hand, often with disastrous and sometimes fatal complications, do also present to the emergency department. A high incidence of suspicion is needed in dealing with these injuries effectively. In our article we discuss the common as well as uncommon causes of bite injuries to the hand and their management. In addition to reviewing the literature to ascertain the management of such injuries, we also discuss interesting and rare case reports.

Variation in venom yield and protein concentration of the centipedes Scolopendra polymorpha and Scolopendra subspinipes

Venom generally comprises a complex mixture of compounds representing a non-trivial metabolic expense. Accordingly, natural selection should fine-tune the amount of venom carried within an animal's venom gland(s). The venom supply of scolopendromorph centipedes likely influences their venom use and has implications for the severity of human envenomations, yet we understand very little about their venom yields and the factors influencing them. We investigated how size, specifically body length, influenced volume yield and protein concentration of electrically extracted venom in Scolopendra polymorpha and Scolopendra subspinipes. We also examined additional potential influences on yield in S. polymorpha, including relative forcipule size, relative mass, geographic origin (Arizona vs. California), sex, time in captivity, and milking history. Volume yield was linearly related to body length, and S. subspinipes yielded a larger length-specific volume than S. polymorpha. Body length and protein concentration were uncorrelated. When considering multiple influences on volume yield in S. polymorpha, the most important factor was body length, but yield was also positively associated with relative forcipule length and relative body mass. S. polymorpha from California yielded a greater volume of venom with a higher protein concentration than conspecifics from Arizona, all else being equal. Previously milked animals yielded less venom with a lower protein concentration. For both species, approximately two-thirds of extractable venom was expressed in the first two pulses, with remaining pulses yielding declining amounts, but venom protein concentration did not vary across pulses. Further study is necessary to ascertain the ecological significance of the factors influencing venom yield and how availability may influence venom use.

Necrotizing soft tissue infections

Necrotising soft tissue infection (NSTI) presents unique challenges in diagnosis and management. The key to a successful outcome is a high index of suspicion in appropriate clinical settings. Type II NSTI tends to occur on an extremity in younger, healthier patients with a history of known trauma, and to be monomicrobial. Type I NSTI tends to occur on the trunk of older, less healthy patients without an obvious history of trauma, and tends to be polymicrobial. Other, rarer types exist as well. The pathophysiology of both types involves superantigen acticivty, as well as a number of microbial byproducts which collectively decrease the viscosity of pus, facilitating its spread along deep tissue planes and ultimately causing diffuse deep thrombosis and aggressive systemic sepsis. The most important physical finding is tenderness to palpation beyond the area of redness, and the lack of crepitus should not be seen as a reassuring sign. Suspected cases should undergo early surgical exploration for diagnosis, which may be performed at bedside through a small incision. Most imaging techniques are not sufficiently specific to warrant a delay in surgical exploration. The Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) shows promise as a tool for excluding suspected cases. Successful outcomes in cases of NSTI require early and aggressive serial debridement and a multidisciplinary critical care approach.

On the venom system of centipedes (Chilopoda), a neglected group of venomous animals

Centipedes are among the oldest extant terrestrial arthropods and are an ecologically important group of soil and leaf litter predators. Despite their abundance and frequent, often painful, encounters with humans, little is known about the venom and venom apparatus of centipedes, although it is apparent that these are both quite different from other venomous lineages. The venom gland can be regarded as an invaginated cuticle and epidermis, consisting of numerous epithelial secretory units each with its own unique valve-like excretory system. The venom contains several different enzymes, but is strikingly different to most other arthropods in that metalloproteases appear to be important. Myotoxic, cardiotoxic, and neurotoxic activities have been described, most of which have been attributed to high molecular weight proteins. Neurotoxic activities are also unusual in that G-protein coupled receptors often seem to be involved, either directly as targets of neurotoxins or indirectly by activating endogenous agonists. These relatively slow responses may be complemented by the rapid effects caused by histamines present in the venom and from endogenous release of histamines induced by venom cytotoxins. The differences probably reflect the ancient and independent evolutionary history of the centipede venom system, although they may also be somewhat exaggerated by the paucity of information available on this largely neglected group.