Acquired methemoglobinemia after hydroxocobalamin administration in a patient with burns and inhalation injury.

CONTEXT: Hydroxocobalamin is an effective cyanide antidote. While erythema, hypertension, and chromaturia are recognized side effects, methemoglobinemia has not been reported. Methemoglobin levels are most accurately measured by co-oximetry. We describe an extensively burned patient who developed methemoglobinemia within an hour of hydroxocobalamin administration. CASE DETAILS: A 47-year old man without genetic deficiencies or abnormal hemoglobin variants presented with 61% body surface area thermal burns and grade 1 inhalation injury sustained during a tugboat engine explosion. On admission, lactate was 9.24 mmol/L, methemoglobin 1%, and carboxyhemoglobin 0.2% by blood gas analysis with co-oximetry. Despite large-volume resuscitation, lactate remained elevated (7-8 mmol/L). Intravenous hydroxocobalamin (5 g) was administered at postburn hour 19 for possible cyanide toxicity. Immediately thereafter, he became hypertensive with reflex bradycardia. Lactate decreased to 5.51 mmol/L, methemoglobin rose to 4.10%, and oxygen saturation by pulse oximetry decreased to 74-80% (despite arterial oxygen saturation of 95% by cooximetry). Methemoglobin concentration peaked at 13.40% at postburn hour 33. Methylene blue was not administered. CONCLUSIONS: Methemoglobinemia in our patient was temporally associated with hydroxocobalamin administration.

Thermal injury patterns associated with electronic cigarettes.

E-cigarettes are typically lithium-ion battery-operated devices that simulate smoking by heating a nicotine-solution into a vapor that the user inhales. E-cigarette use is becoming rapidly popular as an alternative to traditional cigarette smoking. This report describes an emerging problem associated with e-cigarettes, consisting of 10 thermally injured patients seen at a single burn center over a 2-year period from 2014 to 2016. Our cohort was comprised mainly of young adults who sustained mixed partial and full thickness burns as a result of e-cigarette-related explosions. In many documented scenarios, a malfunctioning or over-heated battery is the cause. Our data support the need for increased awareness among healthcare providers and the general public of the potential harms of e-cigarette use, modification, storage, and charging.

Pathophysiologic Mechanisms and Current Treatments for Cutaneous Sequelae of Burn Wounds.

Burn injuries are a pervasive clinical problem. Extensive thermal trauma can be life-threatening or result in long-lasting complications, generating a significant impact on quality of life for patients as well as a cost burden to the healthcare system. The importance of addressing global or systemic issues such as resuscitation and management of inhalation injuries is not disputed but is beyond the scope of this review, which focuses on cutaneous pathophysiologic mechanisms for current treatments, both in the acute and long-term settings. Pathophysiological mechanisms of burn progression and wound healing are mediated by highly complex cascades of cellular and biochemical events, which become dysregulated in slow-healing wounds such as burns. Burns can result in fibroproliferative scarring, skin contractures, or chronic wounds that take weeks or months to heal. Burn injuries are highly individualized owing to wound-specific differences such as burn depth and surface area, in addition to patient-specific factors including genetics, immune competency, and age. Other extrinsic complications such as microbial infection can complicate wound healing, resulting in prolonged inflammation and delayed re-epithelialization. Although mortality is decreasing with advancements in burn care, morbidity from postburn deformities continues to be a challenge. Optimizing specialized acute care and late burn outcome intervention on a patient-by-patient basis is critical for successful management of burn wounds and the associated pathological scar outcome. Understanding the fundamentals of integument physiology and the cellular processes involved in wound healing is essential for designing effective treatment strategies for burn wound care as well as development of future therapies. Published 2018. Compr Physiol 8:371-405, 2018.

Long-term outcome of a consecutive series of subscapularis tendon tears repaired arthroscopically.

PURPOSE: The purpose of this study was to evaluate the long-term outcome of arthroscopic repair of subscapularis tendon tears. METHODS: A retrospective review was performed of subscapularis tendon tears treated with an arthroscopic technique from 1999 to 2003. Revision repairs and open repairs were excluded. The minimum follow-up was 7 years. Postoperative functional outcome was determined by University of California, Los Angeles and American Shoulder and Elbow Surgeons scores. RESULTS: Seventy-nine patients with a mean age of 60.8 years at the time of surgery were available for follow-up at a mean of 104.7 months. Mean University of California, Los Angeles scores improved from 16.5 preoperatively to 30.1 postoperatively (P < .001), and mean American Shoulder and Elbow Surgeons scores improved from 40.8 preoperatively to 88.5 postoperatively (P < .001). Results were rated as good or excellent in 83.3% of cases, 92.4% of patients returned to normal activities, and 92.4% of patients were satisfied. CONCLUSIONS: Arthroscopic rotator cuff repair that includes repair of the subscapularis tendon can lead to good or excellent results in most cases. This study shows that improvement in functional outcome after arthroscopic repair of a subscapularis tendon tear is maintained long-term. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Functional outcome after arthroscopic repair of massive rotator cuff tears in individuals with pseudoparalysis.

PURPOSE: The purpose of this study was to evaluate the functional results after arthroscopic rotator cuff repair (ARCR) for patients with preoperative pseudoparalysis. METHODS: This retrospective review examined massive rotator cuff tears treated with an ARCR over a 10-year period. Pseudoparalysis was defined as active forward flexion (FF) less than or equal to 90° with full passive FF. Primary ARCRs (group I) and revision ARCRs (group II) were included. Postoperative reversal of pseudoparalysis, functional outcome, and complications were self-assessed at a minimum of 2 years postoperatively. RESULTS: In group I 39 patients with a mean age of 62 years at the time of surgery were available for follow-up at a mean of 75 months. Active FF improved from 49° preoperatively to 155° postoperatively (P < .001), and pseudoparalysis was reversed in 90% of patients. In group II 14 patients with a mean age of 63 years at the time of surgery were available for follow-up at a mean of 72 months. Active FF improved from 43° to 109° (P < .001), and pseudoparalysis was reversed in 43% of patients. The mean American Shoulder and Elbow Surgeons score improved in both group I (P < .001) and group II (P = .033). Recovery of FF greater than 90° in group I was associated with a shorter interval before repair (P = .021) and a complete repair (P = .026). CONCLUSIONS: ARCR of massive rotator cuff tears with advanced mobilization techniques can lead to reversal of preoperative pseudoparalysis in 90% of patients who have not had previous surgery. In these patients functional improvement can be obtained with a low rate of complications. However, in the setting of a revision ARCR and pseudoparalysis, only 43% of patients regained FF above 90°. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Long-term outcome of arthroscopic massive rotator cuff repair: the importance of double-row fixation.

PURPOSE: The purpose of this study was to (1) evaluate the long-term functional outcome of arthroscopic rotator cuff repair of massive rotator cuff tears (RCTs) and (2) compare double-row (DR) and single-row (SR) repairs. METHODS: This was a retrospective review of massive RCTs treated with an arthroscopic rotator cuff repair over an 8-year period. Minimum 5-year follow-up was available for 126 repairs at a mean of 99 months. Among 107 complete repairs, there were 62 SR and 45 DR repairs. Functional outcome was determined by University of California, Los Angeles (UCLA) and American Shoulder and Elbow Surgeons scores. A multivariate analysis was performed to examine the role of a DR repair. RESULTS: For all repairs combined, improvements were observed in forward flexion (132° v 168°), pain (6.3 v 1.3), UCLA score (15.7 v 30.7), and American Shoulder and Elbow Surgeons score (41.7 v 85.7) (P < .001). A good or excellent outcome, obtained in 78% of cases, was associated with a complete repair (P = .035) and a DR repair (P = .008). When we excluded partial repairs, postoperative UCLA gain was greater after a DR repair (P = .007). Patients reported their shoulder as feeling closer to normal after a DR repair compared with an SR repair (93.5% v 84.4%, P = .006). A DR repair was 4.9 times more likely to lead to a good or excellent outcome (P = .021). CONCLUSIONS: When a DR repair of a massive RCT is possible, on the basis of the ability to mobilize the tendons, a better long-term functional outcome can be expected compared with an SR repair. Given the known high risk of recurrence after repair of massive RCTs and the knowledge that functional outcome is related to recurrence, a DR repair of massive RCTs should be performed when there is sufficient tendon mobility.

Epigenetic memory at malaria virulence genes.

During its red blood cell stage, the malaria parasite Plasmodium falciparum can switch its variant surface proteins (P. falciparum erythrocyte membrane protein 1) to evade the host immune response. The var gene family encodes P. falciparum erythrocyte membrane protein 1, different versions of which have unique binding specificities to various human endothelial surface molecules. Individual parasites each contain approximately 60 var genes at various locations within their chromosomes; however, parasite isolates contain different complements of var genes, thus, the gene family is enormous with a virtually unlimited number of members. A single var gene is expressed by each parasite in a mutually exclusive manner. We report that control of var gene transcription and antigenic variation is associated with a chromatin memory that includes methylation of histone H3 at lysine K9 as an epigenetic mark. We also discuss how gene transcription memory may affect the mechanism of pathogenesis and immune evasion.