Updates in our understanding of local anaesthetic systemic toxicity: a narrative review

Despite advances in clinical practice, local anaesthetic systemic toxicity continues to occur with the therapeutic use of local anaesthesia. Patterns of presentation have evolved over recent years due in part to the increasing use of ultrasound which has been demonstrated to reduce risk. Onset of toxicity is increasingly delayed, a greater proportion of clinical reports are secondary to fascial plane blocks, and cases are increasing where non-anaesthetist providers are involved. The evolving clinical context presents a challenge for diagnosis and requires education of all physicians, nurses and allied health professionals about these changing patterns and risks. This review discusses: mechanisms; prevention; diagnosis; and treatment of local anaesthetic systemic toxicity. The local anaesthetic and dose used, site of injection and block conduct and technique are all important determinants of local anaesthetic systemic toxicity, as are various patient factors. Risk mitigation is discussed including the care of at-risk groups, such as: those at the extremes of age; patients with cardiac, hepatic and specific metabolic diseases; and those who are pregnant. Advances in the changing clinical landscape with novel applications and settings for the use of local anaesthesia are also described. Finally, we signpost future directions to potentially improve the management of local anaesthetic systemic toxicity. The utility of local anaesthetics remains unquestionable in clinical practice, and thus maximising the safe and appropriate use of these drugs should translate to improvements in patient care.

Human papillomavirus genotype distribution in head and neck cancer: Informing developing strategies for cancer prevention, diagnosis, treatment and surveillance

Current clinical practice algorithms for HPV testing make no effort to discern the impact of genotypes for patients with head and neck squamous cell carcinoma (HNSC). Data was collected for all patients with HNSCs that had undergone HPV testing at an academic hospital as part of clinical care (2012-2019). Screening was performed using real-time PCR targeting L1 of low and high-risk HPV types, followed by genotyping of positive cases. Genotype status was correlated with age, site and histologic parameters. Of the 964 patients tested, 68% had HPV-positive cancers. Most arose from the oropharynx (OP) (89%) and sinonasal tract (5%). The most frequent genotype was 16 (84.4%) followed by 35 (5.6%), 33 (4.1%), 18 (2.7%), 45 (1.1%), 69 (0.8%) and others (1.3%). There was an association between genotype (16 vs non-16) and tumor origin (OP vs non-OP) (p < 0.0001). HPV18 was associated with transformation to an aggressive small cell phenotype, but HPV16 was not (22% vs 0%, p < 0.0001). Patients with HPV-non-16 OP carcinomas were older than patients with HPV16 OP carcinomas, but the difference was not significant. HPV genotypes are variable and unevenly distributed across anatomic sites of the head and neck. The association of HPV18 with small cell transformation suggests that variants can track with certain phenotypes in ways that may account for differences in clinical behavior. This study challenges the prevailing assumption of HPV equivalency across all high-risk genotypes in ways that may inform preventive, diagnostic, therapeutic and surveillance strategies.

Evaluation of a routine screening program with tuberculin skin testing on rates of detection of latent tuberculosis infection and prevention of active tuberculosis in patients with multiple myeloma at a Canadian cancer centre

Background

Chemotherapy-induced T cell dysfunction, resulting from treatment of multiple myeloma (mm), enhances the risk for reactivation of latent tuberculous infection (ltbi). However, routine screening for ltbi has its limitations. The objective of the present study was to assess the number of patients treated for ltbi both before and after the introduction of a consistent tuberculin skin test (tst) screening program for patients with mm at our cancer centre.

Methods

This retrospective observational study analyzed adult patients with mm treated with autologous hematopoietic stem-cell transplantation from 1 January 2013 to 31 December 2014, for whom tst was consistently performed at our cancer facility. Baseline demographic characteristics of patients who received tst testing and ltbi therapy were compared with those of a pre-intervention cohort of patients (1 January 2008 to 31 December 2009) who were not tested.

Results

During the post-intervention period, 170 patients with mm had a tst. In 14 patients (8.2%) results were positive, and 11 of the 14 received ltbi therapy. Of another 12 patients with radiographic imaging changes consistent with prior granulomatous disease and negative tst results, 2 were treated. No cases of tuberculosis (tb) reactivation were noted in individuals who completed ltbi therapy. One case of active tb was diagnosed in a patient with a negative tst. In contrast, in the pre-intervention matched cohort of 170 patients, no tsts were performed, and no cases of active tb were documented.

Conclusions

Patients with mm could benefit from a consistent tst testing policy coupled with subsequent ltbi therapy. However, universal testing might not be required. A targeted program combining evaluation of host risk factors, imaging findings, and screening tests might optimize ltbi diagnosis and management, and thus be effective in preventing the development of active tb in at-risk patients with mm.

The Prevalence, Anatomic Distribution and Significance of HPV Genotypes in Head and Neck Squamous Papillomas as Detected by Real-Time PCR and Sanger Sequencing

Squamous papillomas (SPs) of the head and neck are generally regarded as a human papillomavirus (HPV)-driven process, but reported rates of HPV detection vary dramatically. Moreover, they are generally considered a benign condition, but the detection of high risk HPV types is commonly reported. This latter finding is particularly disturbing to clinicians and their patients given the alarming rise of HPV-associated head and neck cancer. The capriciousness of HPV detection reflects in large part differences in methodologies. The purpose of this study was to review an institutional experience using a state of the art detection method to determine the presence, type and anatomic distribution of HPV in head and neck SPs. The surgical pathology files of the Mount Sinai Hospital were reviewed for all SPs that had undergone HPV testing between 2012 and 2018. HPV screening was performed on tissue blocks with real-time PCR using primers designed to target the L1 region of low and high-risk HPV types. Genotyping was performed on HPV positive cases. HPV detection was repeated for cases that were originally reported to be positive for high risk HPV. 134 cases had undergone HPV analysis. Of the 131 with sufficient cellular material, 2 were excluded because the HPV testing yielded inconclusive results. The remaining 129 cases were the basis of this study. Thirty-eight cases (29%) were HPV positive and 91 (71%) were negative. The most common genotype was HPV 6 (n = 27, 71%), followed by HPV 11 (n = 10, 26%). One case (1%) was HPV positive but the genotype could not be determined. Of the HPV negative cases, 3 were originally reported as HPV 16 positive but found to be HPV negative on re-review and repeat testing. SPs arising in the larynx were more likely to harbor HPV than those arising in the oral cavity and oropharynx (64% vs. 10%, p < 0.00001). Similarly, recurrent respiratory papillomatosis (RRP) were much more likely to be HPV positive than solitary SPs (71% vs. 10%, p < 0.00001). Almost a third of head and neck SPs harbor HPV, but incidence is highly dependent on anatomic site. Those arising in the larynx are more prone to be HPV-driven than those arising in the oral cavity and oropharynx, particularly when occurring in the setting of RRP. High risk HPV could not be confirmed in any of the cases. Routine HPV testing as a strategy to unmask potentially malignant lesions harboring high risk HPV is not likely to be useful.

Reversible renal allograft dysfunction and proteinuria from nutcracker-like syndrome: a case report

A 27-year-old Hispanic man with hypertension and renal failure was on hemodialysis for 4 years prior to receiving a living donor renal transplant from his 19-year-old sister. His serum creatinine decreased to 1.7 mg/dL at 3 weeks posttransplant with a urine protein creatinine ratio (UP) of 0.1 (g/g). Over the next 2 months, he experienced repeated episodes of allograft dysfunction with elevation of creatinine and proteinuria levels, associated with a lymphocele. Doppler studies of the allograft revealed renal vein compression. His symptoms responded to aspiration of the fluid collection, resolving completely with surgical drainage. We believe that the episodes of allograft dysfunction and proteinuria were related to recurrent lymphocele, causing a nutcracker-like syndrome.