Lucy Lamb

Bromine, bear-claw scratch fasciotomies, and the Eagle effect: management of group A streptococcal necrotising fasciitis and its association with trauma

Necrotising fasciitis is a rare, but potentially fatal, soft-tissue infection. Historical depictions of the disease have been described since classical times and were mainly recorded in wartime reports of battle injuries. Although several different species of bacteria can cause necrotising fasciitis, perhaps the most widely known is group A streptococcus (GAS). Infection control, early surgical debridement, and antibiotic therapy are now the central tenets of the clinical management of necrotising fasciitis; these treatment approaches all originate from those used in wars in the past 150 years. We review reports from the 19th century, early 20th century, and mid-20th century onwards to show how the management of necrotising fasciitis has progressed in parallel with prevailing scientific thought and medical practice. Historically, necrotising fasciitis has often, but not exclusively, been associated with penetrating trauma. However, along with a worldwide increase in invasive GAS disease, recent reports have cited cases of necrotising fasciitis following non-combat-related injuries or in the absence of antecedent events. We also investigate the specific association between GAS necrotising fasciitis and trauma. In the 21st century, molecular biology has improved our understanding of GAS pathogenesis, but has not yet affected attributable mortality.

Skin and soft tissue infections in the military.

Skin and soft tissue infections (SSTI) are common in military populations regularly living and training in close contact with each other. The majority of such infections are simple and can be easily treated with antibiotics and appropriate infection control practices. Some, however, can progress to become complex and even life threatening, such as Panton-Valentine Leukocidin (PVL)-associated staphylococcus aureus pneumonia, or Streptococcus pyogenes necrotising fasciitis, which carry a mortality rate of up to 65% and 30%, respectively. This review focuses on the most important SSTIs and those more commonly affecting military personnel with advice on how they are best managed.

Formulating and improving care while mitigating risk in a military Ebola virus disease treatment unit.

This paper describes the development of the UK militarys Ebola Virus Disease Treatment Unit (EVD TU) that was deployed to Sierra Leone as part of the UK response to the West African Ebola virus disease (EVD) epidemic in 2014 and 2015. It highlights specific challenges faced within this unique Field Hospital environment. The military EVD TU was initially established to provide confidence to international healthcare workers coming to Sierra Leone to assist in the international response to the EVD epidemic and formed a key part of the action plan by the UKs Department for International Development. It was designed and staffed to provide a high level of care to those admitted with suspected or confirmed EVD and was prepared to admit the first patient within 6 weeks of the original activation order by the Ministry of Defence. This article outlines the main hazards perceived at the outset of the operation and the methods used to mitigate the risk to the healthcare workers at the EVD TU. The article examines the mechanisms that enabled the hospital to respond positively to challenges that emerged during the deployment, while simultaneously reducing the risk to the healthcare workers involved in care delivery.

Ebola virus disease managed with blood product replacement and point of care tests in Sierra Leone

Learning Point for Clinicians 1. Blood product transfusion and point-of-care tests can be safely and successfully used in Ebola virus disease (EVD) in resource-constrained settings. 2. Significant coagulopathy and haemorrhage in EVD is not always a pre-terminal event and patients can survive with advanced supportive care. A 28-year-old nurse presented to the Kerry Town Ebola Virus Disease Treatment Unit (EVDTU) in Sierra Leone on Day 5 of his illness with a positive Ebola Virus reverse transcriptase polymerase chain reaction (RT-PCR) test result, made on Day 3 at his employing hospital. His presenting symptoms included malaise, headache, sore throat, nausea and diarrhoea. Initial examination findings demonstrated a fever of 39°C and mild epigastric tenderness but was otherwise unremarkable. A rapid malaria test was negative. Although the EVDTU has a …

Snakebites in Africa and Europe: a military perspective and update for contemporary operations

Snakebite envenoming is rare among military patients, with few cases reported in recent years. Increasingly, however, military operations are taking place in remote parts of Africa, which are inhabited by numerous species of venomous snake, and in Europe, where dangerous species exist but are less common. Bites from a venomous snake may prove fatal, and therefore military medics must be adequately prepared to manage them. This paper reviews the most medically significant species of venomous snake present in Africa and Europe, before suggesting an evidence-based approach to snakebite prevention and management, including possible changes to the UK’s Clinical Guidelines for Operations.

Asymptomatic group A Streptococcal throat carriage in Royal Marines recruits and Young Officers

AIMS A prospective observational study was conducted in Royal Marines (RM) recruits to investigate throat carriage of group A Streptococcus (GAS) and incidence of soft tissue infections. METHODS 1012 RM recruits were followed through a 32-week training programme, with throat swabs being obtained in weeks 1, 6, 15, and 32. Alongside a separate cohort of 46 RM Young Officers (YO) undergoing training were sampled in parallel. RESULTS Carriage of group A Streptococcus was detected in only 5/1012 (0.49%) recruits at the beginning of training and remained low throughout training. There was no association between GAS carriage and development of soft tissue infection. There was no carriage of GAS in the smaller YO cohort at the start of training, (0/46). At week 6, a surge in GAS carriage was detected in 8/46 (17%) YO, that could be ascribed to a cluster of GAS genotype emm83. CONCLUSIONS Asymptomatic GAS carriage is very infrequent among young adults in England and this should be borne in mind when considering the relevance of a positive throat swab result in symptomatic patients or outbreaks. Despite low prevalence, there is however potential for GAS to rapidly and transiently disseminate among adults during outbreaks.

The effect of trauma on invasive group A streptococcal disease

BACKGROUND Necrotising fasciitis due to invasive group A streptococcus (iGAS) is frequently associated with type emm1 isolates, with an attendant mortality of 40%. Some cases occur in previously healthy individuals with a history of upper respiratory tract infection, soft tissue contusion, and no obvious portal of entry. Using a new model of mild contusion injury, we set out to determine the effect of contusion on iGAS bacterial burden, phenotype, and host cytokine response. METHODS A new model of mild contusion was developed using a weight drop device and characterised in two strains of mice, CD1 and FVB/n. The effect of contusion on emm1 iGAS infection was assessed in three murine models of infection: lower respiratory tract (intranasal challenge of 1 × 10(7) colony forming units [CFU] per mouse), intravenous (1 × 10(7)· per mouse via the lateral tail vein), and muscle (1 × 10(8) CFU per mouse intramuscularly) at three timepoints after injury (24, 48, and 72 h). Bacterial burden, host cytokine response, and histological changes were analysed. Further molecular work was performed to assess the change in bacterial morphology observed after contusion injury in the muscle model. Mann-Whitney U test was used to compare differences in bacterial burden and cytokine responses between trauma and control groups. FINDINGS Application of a force of 15·7 mJ resulted in histological changes in muscle consistent with mild trauma with no evidence of overlying skin injury, no bony injury, and minimum cytokine response. Contusion to soft tissue had no effect on bacterial burden or cytokine response in a mouse model of systemic infection (after intravenous inoculation) at three timepoints. Despite bacteraemia, specific seeding of the contused tissue did not occur in this model. By contrast, blunt contusion affected progression of a subsequent local GAS muscle infection and increased dissemination to blood in the lower respiratory tract infection model. Specifically, contusion increased emm1 GAS dissemination locally to draining lymph nodes (controls median 183 CFU per node [IQR 8-5800] vs trauma group 20 000 [1875-601 250]). Dissemination to lymph node was linked to a phenotypic change in bacterial capsule morphology. This phenotypic change was stable despite passage, consistent with a genetic change, and was associated with an increase in bacterial hyaluronan production (mucoid colonies 200 μg per CFU and no detectable capsule production in the non-mucoid colonies). INTERPRETATION We found that non-penetrating trauma was associated with an enhanced susceptibility to invasive GAS disease. This model of mild contusion did not provide a focus for initiation or seeding of bacteraemic infection but instead provided an environment that determined the phenotype of the bacteria and enhanced local dissemination after iGAS infection at the same site. The environmental and genetic cues underlying dissemination are the subject of continuing research. FUNDING Royal Army Medical Corps, Surgeon Generals Research Strategy Group, Ministry of Defence.

Impact of contusion injury on intramuscular emm1 group a streptococcus infection and lymphatic spread

ABSTRACT Invasive group A Streptococcus (iGAS) is frequently associated with emm1 isolates, with an attendant mortality of around 20%. Cases occasionally arise in previously healthy individuals with a history of upper respiratory tract infection, soft tissue contusion, and no obvious portal of entry. Using a new murine model of contusion, we determined the impact of contusion on iGAS bacterial burden and phenotype. Calibrated mild blunt contusion did not provide a focus for initiation or seeding of GAS that was detectable following systemic GAS bacteremia, but instead enhanced GAS migration to the local draining lymph node following GAS inoculation at the same time and site of contusion. Increased migration to lymph node was associated with emergence of mucoid bacteria, although was not specific to mucoid bacteria. In one study, mucoid colonies demonstrated a significant increase in capsular hyaluronan that was not linked to a covRS or rocA mutation, but to a deletion in the promoter of the capsule synthesis locus, hasABC, resulting in a strain with increased fitness for lymph node migration. In summary, in the mild contusion model used, we could not detect seeding of muscle by GAS. Contusion promoted bacterial transit to the local lymph node. The consequences of contusion-associated bacterial lymphatic migration may vary depending on the pathogen and virulence traits selected.

Systemic cytokine storm in severe eosinophilic dermatitis

### Learning point for clinicians Severe eosinophilic dermatitis with systemic symptoms is rare. We report, for the first time, that the systemic clinical symptoms and high CRP (123 mg/l) were due to an IL-6 and IL-8 cytokine storm. Systemic disease control was only achieved with high dose oral prednisolone, topical triamcinolone to affected skin and dapsone. A 27-year-old woman presented with a 12-day history of worsening fever and rash. Erythematous, indurated and pruritic lesions had been developing on her inner thighs. They went on to spread to her arms and back. She was previously fit and well with no relevant past medical or family history. During her first week in hospital, she became intermittently confused and disorientated and was also intermittently febrile between 38.3°C and 40°C. Her skin lesions became ‘woody hard’ subcutaneous swelling and were associated with dark mottling of the overlying skin. During her second week in …