Safety of Direct Drug Provocation for the Evaluation of Penicillin Allergy in Low-Risk Adults

BACKGROUND

About 10% of patients have a penicillin allergy label, but less than 5% of them are actually allergic. Unnecessary penicillin avoidance is associated with serious medical consequences. Given the growing number of these labels, it is imperative that our diagnostic strategy for penicillin allergy be as efficient as possible. The validity of traditionally used skin tests (STs) has been questioned, whereas drug provocation testing (DPT), the criterion standard, without previous ST appears very safe in most cases.

OBJECTIVE

To evaluate the safety of direct DPT without consideration for ST results and the validity of ST in the diagnosis of penicillin allergy.

METHODS

In this prospective cohort study without a control group, we recruited patients consulting an allergist for penicillin allergy. Patients underwent ST followed by DPT regardless of ST results. Patients with anaphylaxis to penicillin within the past 5 years or a severe delayed reaction were excluded, as were those with significant cardiorespiratory comorbidity.

RESULTS

None of the 1002 recruited patients had a serious reaction to DPT. Ten (1.0%) had a mild immediate reaction, of whom only 1 (0.1%) was considered likely IgE-mediated. The positive and negative predictive values of ST for an immediate reaction were 3.6% and 99.1%, respectively.

CONCLUSIONS

In a low-risk adult population reporting penicillin allergy, ST has very poor positive predictive value. Direct DPT without ST is safe and appears to be an ideal diagnostic strategy to remove penicillin allergy labels that could be implemented in first-line practice.

A82 PREVALENCE AND NON-INVASIVE SCREENING FOR CYSTIC FIBROSIS RELATED LIVER DISEASE IN A COHORT FOLLOWED AT A CYSTIC FIBROSIS REFERENCE CENTER

Background

The reported prevalence of cystic fibrosis (CF) related liver disease (CFLD) varies widely based on diagnostic criteria but reaches up to 40% in some cohorts. Furthermore, its clinical impact is significant as hepatic involvement is the 3^rd leading cause of mortality in CF patients and is associated with a lower life expectancy. Due to the heterogeneous clinical presentation of CFLD, clear diagnostic criteria and non-invasive assessment methods are lacking.

Purpose

This study aimed to measure the prevalence of CFLD in a cohort of patients followed at a tertiary CF center.

Method

The files of all patients followed at the CF clinic of the Centre hospitalier de l’Université de Montréal in 2021 were retrospectively reviewed. Imaging reports, histopathology, laboratory values and transient elastography results were assessed. The NIH criteria were used to define CFLD through either presence of one major criteria (abnormal imaging) or two minor criteria (persistently abnormal lab values, hepatosplenomegaly, or transient elastography ≥ 7 kPa).

Result(s)

358 patients were included in our study, 56% male with a median age of 36 years. While mean liver tests were within normal limits (ALT 24 U/L, AST 26 U/L, ALP 96 U/L, GGT 29 U/L), 182 patients (51%) had at least one episode of abnormal liver function tests (LFTs), and 85 patients (24%) had persistently abnormal LFTs. CFLD was present in 42 patients (12%), with 39 patients presenting major criteria and 3 patients presenting minor criteria. In addition, 67 patients (19%) had solely hepatic steatosis. Furthermore, clinically significant portal hypertension and esophageal varices were detected in 50% of patients with CFLD who underwent upper endoscopy (n=20). Median transient elastography value was 5.4 kPa (interquartile range 4.25 kPa) in the 51 patients with exam results, and 32% had values ≥ 7 kPa. Fibroscan values correlated well with the presence of major criteria, with an area under the curve (AUROC) of 0.80 (0.68-0.92, p=0.0007), while non-invasive serological markers did not perform as well (Fib4: AUROC 0.70 (0.59-0.81) and APRI: AUROC 0.69 (0.59-0.80)).

Conclusion(s)

The overall prevalence of CFLD, including hepatic steatosis, was 31% in this cohort. Prompt recognition is important in clinical care in order to prevent hepatic complications from cirrhosis and portal hypertension. The use of Fibroscan seems promising for detecting CFLD.

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Disclosure of Interest

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A271 ETIOLOGICAL CHARACTERIZATION OF DRUG-INDUCED ACUTE PANCREATITIS

Background

Drugs are considered a relatively rare and understudied cause of acute pancreatitis (AP). The lack of convincing and conclusive data on drug-induced AP (DIAP) complicates the diagnosis as well as the identification of the causative drug.

Aims

We hypothesized that documenting the causes of DIAP in the Saguenay-Lac-Saint-Jean (SLSJ) will add new evidence to the current literature and will provide a comprehensive picture of this health condition in the region. The aim of this study is to document causes of DIAP cases that occurred in the SLSJ population.

Methods

We have conducted a retrospective and descriptive population-based study of DIAP cases that occurred between 2006 and 2014 in the six hospitals deserving the SLSJ entire population. Cases were selected from the Quebec Ministry of Health hospitalizations registry (MED-ECHO) administrative public database. Medical chart review was performed in attempt to characterize DIAP hospitalizations and to identify the imputable drugs.

Results

During the studied period, 75 cases (30.7% male, 69.3% female) were included totalling 90 hospitalizations for DIAP. Among them, 51 causative drugs were identified and were distributed in 17 different drug classes. Recurrent DIAP were documented in 13 cases and among them, 6 cases have experimented positive rechallenge. Six drugs (5-fluorouracil, atorvastatin, bortezomib, nilotinib, rosuvastatin and triamcinolone) were associated with the highest degree of evidence. The most common causative drugs of DIAP hospitalization were azathioprine (n = 7), followed by atorvastatin (n =6), hydrochlorothiazide (n = 5), rosuvastatin (n = 4) and codeine (n = 4).

Conclusions

This study has added new evidences about potentially pancreatitis-associated drugs in literature. This is the first study to report definite 5-fluorouracil and triamcinolone-induced AP. An updated version of the evidence-based literature review is needed to support the clinicians in the identification of the causative drugs.

Funding Agencies

None

Myocardial Perfusion Scans and Mortality in Asymptomatic Patients Awaiting Renal Transplantation

Cardiac risk assessment for asymptomatic patients awaiting renal transplantation is controversial. Patients awaiting renal transplantation in Southern Saskatchewan from 2005 to 2015 were retrospectively reviewed. Patients underwent cardiac risk stratification with stress myocardial perfusion scan. Baseline clinical characteristics, nuclear scan results, all-cause mortality, and cardiovascular events were analyzed. Abnormal scans were defined as studies with reversible defects, wall motion abnormalities, lung uptake, or transient ischemic dilation. Descriptive statistics and survival analysis were calculated. Charts from 285 consecutive patients with 608 nuclear scans were analyzed. Mean age was 55.2 ± 11.7 years and 34.7% were female. Forty-three (15.1%) patients were transplanted and 99 (40.9%) patients died while awaiting renal transplantation. One hundred fifty-three patients (63.2%) had at least one abnormal scan. The mean follow-up period was 5.47 ± 3.11 years. An abnormal scan was not associated with decreased survival and/or coronary events (hazard ratio: 0.94, P = .77; 95% confidence intervals: 0.62 to 1.43). Patients awaiting renal transplantation in Saskatchewan with abnormal myocardial perfusion scans were not at greater risk of death or coronary events.

Ralstonia mannitolilytica in cystic fibrosis: A new predictor of worse outcomes

Background

Patients with Cystic Fibrosis are subject to repeated respiratory tract infections, with recent increasing isolation of unusual pathogens. Ralstonia species have lately been isolated at our institution, an organism historically frequently misidentified as Burkholderia or Pseudomonas. The prevalence of Ralstonia spp. in cystic fibrosis populations has yet to be determined, along with its clinical implications.

Case presentations

Seven patients out of the 301 followed at our cystic fibrosis clinic have had Ralstonia strains identified in their respiratory tract. Most strains identified were multi-drug resistant. After aquisition of Ralstonia spp., the patients' clinical course was characterized by more frequent and more severe respiratory infections along with prolonged hospitalizations, greater decline of lung function, and greater mortality. The mortality rate in this group of patients was 86%. No other factor that could explain such a dramatic evolution was identified upon review of patient data. Some of the strains involved were recognized as clones on Pulse Field Electrophoresis Gel, raising the question of person-to-person transmission.

Conclusion

New pathogens are identified with the evolution of the microbiota in cystic fibrosis respiratory tracts. In our cohort of patients, acquisition of Ralstonia spp. was associated with dramatic outcomes in terms of disease acceleration and raised mortality rates. It is of critical importance to continue to better define the prevalence and clinical impact of Ralstonia in cystic fibrosis populations.

Decreased somatic hypermutation induces an impaired peripheral B cell tolerance checkpoint

Patients with mutations in AICDA, which encodes activation-induced cytidine deaminase (AID), display an impaired peripheral B cell tolerance. AID mediates class-switch recombination (CSR) and somatic hypermutation (SHM) in B cells, but the mechanism by which AID prevents the accumulation of autoreactive B cells in blood is unclear. Here, we analyzed B cell tolerance in AID-deficient patients, patients with autosomal dominant AID mutations (AD-AID), asymptomatic AICDA heterozygotes (AID+/-), and patients with uracil N-glycosylase (UNG) deficiency, which impairs CSR but not SHM. The low frequency of autoreactive mature naive B cells in UNG-deficient patients resembled that of healthy subjects, revealing that impaired CSR does not interfere with the peripheral B cell tolerance checkpoint. In contrast, we observed decreased frequencies of SHM in memory B cells from AD-AID patients and AID+/- subjects, who were unable to prevent the accumulation of autoreactive mature naive B cells. In addition, the individuals with AICDA mutations, but not UNG-deficient patients, displayed Tregs with defective suppressive capacity that correlated with increases in circulating T follicular helper cells and enhanced cytokine production. We conclude that SHM, but not CSR, regulates peripheral B cell tolerance through the production of mutated antibodies that clear antigens and prevent sustained interleukin secretions that interfere with Treg function.

Activation-Induced Cytidine Deaminase Expression in Human B Cell Precursors Is Essential for Central B Cell Tolerance

Activation-induced cytidine deaminase (AID), the enzyme-mediating class-switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes, is essential for the removal of developing autoreactive B cells. How AID mediates central B cell tolerance remains unknown. We report that AID enzymes were produced in a discrete population of immature B cells that expressed recombination-activating gene 2 (RAG2), suggesting that they undergo secondary recombination to edit autoreactive antibodies. However, most AID+ immature B cells lacked anti-apoptotic MCL-1 and were deleted by apoptosis. AID inhibition using lentiviral-encoded short hairpin (sh)RNA in B cells developing in humanized mice resulted in a failure to remove autoreactive clones. Hence, B cell intrinsic AID expression mediates central B cell tolerance potentially through its RAG-coupled genotoxic activity in self-reactive immature B cells.

[Monitoring of vancomycin in pediatrics]

OBJECTIVES

The authors wanted to determine if the current local practice (initial prescription and monitoring) in pediatrics allowed reaching vancomycin therapeutic concentrations.

PATIENTS AND METHODS

Thirty patients that had received vancomycin for at least five days with at least one evaluation of serum concentration, at the Sainte-Justine university hospital center, were retrospectively studied. Vancomycin trough and peak levels were analyzed.

RESULTS

The values of vancomycin serum concentration were within therapeutic ranges (local standards of 5 to 10mg/L for trough level and 20 to 40 mg/L for peak level) in 60% and 33% of cases at the fifth day of treatment for trough and peak levels, respectively.

CONCLUSION

The current practice does not allow reaching vancomycin serum concentrations in the target range. Using a wider range for the trough values could be considered.

Dichotomy between postprandial glucose and lipid profiles in adults with cystic fibrosis: a pilot study

BACKGROUND

Cystic fibrosis (CF) patients present a high incidence of glucose tolerance abnormalities. Altered insulin secretion combined with recommended high-fat intake could be associated with dysregulation of glucose and lipid metabolism. We examined postprandial glucose and lipid profiles during an oral glucose tolerance test (OGTT) and following a standardized high-fat test meal (TM).

METHODS

Sixteen CF patients with normal glucose tolerance (NGT) or CF-related diabetes (CFRD) and 16 controls underwent a 4 h OGTT and a TM. We then measured plasma glucose, insulin, free fatty acid (FFA) and triglyceride (TG) concentrations.

RESULTS

CF patients presented higher glucose excursion compared to controls after the OGTT and TM. However, in CF patients, this excursion was significantly reduced in both amplitude and length after the TM. The TM provoked a comparable increase in TG levels in both groups whereas they remained stable during the OGTT. FFAs were suppressed similarly in both groups after both challenges.

CONCLUSION

CF is associated with abnormal glucose excursion in the presence of relatively normal lipid excursion. The rapid normalization of glucose values after a mixed meal should be further explored and, if confirmed, might have significant implications for CFRD diagnostic.

Étude pilote sur la mise en place des soins pharmaceutiques dans le service de pédiatrie générale d'un hôpital français. Collaboration et comparaison franco-québécoise

STATE OF THE PROBLEM AND OBJECTIVES: French pharmacists are quasi absent from hospital wards. Our objective was to describe the implantation of pharmaceutical care in a patient unit of a French paediatric hospital.

MATERIAL AND METHODS

Following an internship in pharmaceutical care at the Sainte-Justine hospital (SJ) in Montreal, a French pharmacist returned to France to implement the pharmaceutical model in a paediatric unit at Robert Debré hospital (RD) in Paris. We first collected pharmaceutical interventions carried out during a 5-month period. In a second phase, we compared pharmaceutical interventions provided by the team composed of the same French pharmacist and a pharmacist from Québec in both settings during 14 days respectively.

RESULTS

In the first phase, 556 interventions were done (8.2+/-2,0 per day) with a significant increase observed during the first 2 months. In the second phase, 216 interventions were done at RD and 174 at SJ. The interventions were mainly related to drug information, modification of treatment and seamless care with the pharmacy of the hospital or a community pharmacy. The interventions targeted junior (30.5 to 55.4%), senior physicians (16.2 to 38.5%) and pharmacy (11.5 to 16.2%) in the different phases and sites. A high level of physician acceptance was observed, with respectively 86.0 and 93.1% at RD and SJ.

DISCUSSION

French pharmacists can apply the pharmaceutical care model following a specific training. Further studies are required to evaluate the feasibility and the impact of pharmaceutical care in France.

[The use of head CT scan in adult trauma victims: an algorithm]

INTRODUCTION

The purpose of this study was to identify, through recursive partitioning, clinically relevant criteria which predict the need for acute neurosurgical intervention in a group of patients with mild head injury.

MATERIALS AND METHODS

A retrospective cohort of all adult patients, from April 2000 to March 2001, who sustained a blunt trauma and underwent head CT scan, was reviewed. The following inclusion criteria for mild head injury were used: initial Glasgow Coma Scale (GCS) ranging from 13 to 15; no loss of consciousness lasting more than one hour; no obvious skull fracture; a cranial CT scan performed. We collected demographic and trauma related data, interventions and outcome. Univariate and multivariate analyses were undertaken. In parallel, recursive partitioning was carried out using all variables to elaborate a decision algorithm.

RESULTS

There were 405 patients in the sample. CT identified lesions in 12% of patients. Twelve patients (3%) required acute neurosurgical intervention. The recursive partitioning analysis identified three significant sequential nodes: deterioration of the GCS; an initial GCS of 13 vs 14 or 15; and the presence of associated injuries or comorbid conditions.

CONCLUSIONS

A simple three step rule predicts the need for acute neurosurgical intervention based on clinical findings: a deteriorating GCS; an initial GCS of 13; and the presence of associated injuries or comorbid conditions.

Diabetes: a major co-morbidity of cystic fibrosis

Cystic fibrosis-related diabetes (CFRD) is a frequent complication of cystic fibrosis, its prevalence increases with age of patient and is close to 30% at the age of 30 years. As life expectancy greatly increases, the number of cystic fibrosis patients developing diabetes will increase too. CFRD shares some features with type 1 and type 2 diabetes, initial phase is characterised by postprandial hyperglycaemia followed by a progression toward insulin deficiency. Insulin deficiency is an essential factor in the development of diabetes with an additional contribution of insulin resistance. Systematic screening with an oral glucose tolerance test is recommended from the age of 14 years because clinical signs of CFRD are often confused with signs of pulmonary infection and CFRD occurrence is associated with weight and pulmonary function deterioration. In observational studies CFRD diagnosis is associated with a significant increase in mortality, while treatment allow correction of weight and lung deterioration suggesting that CFRD has a significant impact on CF evolution. Microvascular complications are recognised, although paucity of data does not permit a clear description of their natural history. Annual screening for microvascular complication is recommended. There is no evidence by now that CF patients develop macrovascular complications. The only recommended pharmacological treatment is insulin therapy.

Recurrent acute epiglottitis in adults: defective antibody response

BACKGROUND

Recurrent acute epiglottitis is uncommon in adults. In the medical literature, very little is known about the immune status of this population.

OBJECTIVE

To evaluate the immune system of a group of four adult patients with recurrent acute epiglottitis, in what represents the largest series ever reported.

METHODS

The clinical course of these episodes was carefully evaluated and a basic immune deficiency work-up was carried out for each patient.

RESULTS

All four patients displayed clinical and laboratory evidence of impaired humoral immunity. One patient was splenectomized. Another patient had a below normal immunoglobulin G level. At the time of their first evaluation, none of our patients had specific antibodies against Haemophilus influenzae and one had a subnormal Streptococcus pneumoniae immunoglobulin G level for a majority of serotypes. After specific vaccination, two patients had persistent abnormalities in their response to one or more polysaccharides or conjugate-polysaccharide antigens. In the other two, the transient abnormalities were corrected by immunization.

CONCLUSIONS

When recurrent acute epiglottitis occurs in adults, it is important to investigate the immune system because a quantitative or a specific antibody deficiency could be found. It also follows that these patients will be successfully treated either by immunization or antibody replacement.

Analysis of SWAP-70 as a candidate gene for non-X-linked hyper IgM syndrome and common variable immunodeficiency

SWAP-70 is a recently identified protein that functions as the only B cell-specific component of an isotype switch recombination complex called SWAP. The SWAP complex has specificity for the switch regions upstream of the constant region immunoglobulin genes and it facilitates the transfer of DNA between switch regions. These features suggested that mutations in the gene encoding SWAP-70 might result in humoral immunodeficiency. To test this hypothesis we determined the genomic structure of this gene and used single-stranded conformational polymorphism (SSCP) analysis to screen DNA from 38 patients with either non-X-linked hyper IgM syndrome or common variable immunodeficiency. The results demonstrated that SWAP-70 consists of 12 exons spread over 89 kb at chromosome 11p15.2. SSCP analysis of the patient population revealed five polymorphic variants in the gene, one of which (Q505E) is an amino acid substitution in the putative nuclear export signal of SWAP-70. However, none of the alterations appeared to be associated with disease in the patients screened.

Mutations in activation-induced cytidine deaminase in patients with hyper IgM syndrome

Recent studies have shown that mutations in a newly described RNA editing enzyme, activation-induced cytidine deaminase (AID), can cause an autosomal recessive form of hyper IgM syndrome. To determine the relative frequency of mutations in AID, we evaluated a group of 27 patients with hyper IgM syndrome who did not have defects in CD40 ligand and 23 patients with common variable immunodeficiency. Three different mutations in AID were identified in 18 patients with hyper IgM syndrome, including 14 French Canadians, 2 Lumbee Indians, and a brother and sister from Okinawa. No mutations were found in the remaining 32 patients. In the group of patients with hyper IgM syndrome, the patients with mutations in AID were older at the age of diagnosis, were more likely to have positive isohemagglutinins, and were less likely to have anemia, neutropenia, or thrombocytopenia. Lymphoid hyperplasia was seen in patients with hyper IgM syndrome and normal AID as well as the patients with hyper IgM syndrome and defects in AID.

The incidence and pathogenesis of cardiopulmonary deterioration after abrupt withdrawal of inhaled nitric oxide

We studied the effect of abrupt discontinuation of inhaled nitric oxide (iNO) in patients receiving this drug for treatment of acute hypoxemic respiratory failure (AHRF), in order to determine the need for continued therapy, the incidence and nature of adverse events, and the risk factors predicting these adverse events. Thirty-one patients who showed an initial increase in Pa(O(2)) of > 20 mm Hg in response to iNO underwent a discontinuation trial at 10 to 30 h after beginning iNO. Indwelling arterial and pulmonary artery catheters facilitated monitoring of hemodynamic and gas-exchange parameters. For the group, discontinuation of iNO caused a significant decrease in Pa(O2 ), arterial and mixed venous oxygen saturation, and ratio of Pa(O(2)) to fraction of inspired oxygen (FI(O(2))). Three patterns of response were observed. Eight of 31 (25.8%) patients had minimal changes in oxygenation or hemodynamics, suggesting no need for ongoing therapy. Fifteen of 31 (48%) patients had worsened gas exchange as a predominant response. Eight of 31 patients exhibited hemodynamic collapse, defined as > 20% fall in cardiac output and/or mean arterial blood pressure. In this last subgroup, the pattern of cardiovascular changes suggested that this response arose from an acute increase in right ventricular afterload, and was not a consequence of gas-exchange abnormalities. In all cases, reinstitution of iNO promptly reversed worsened hemodynamics and gas exchange. Independent factors associated with an increased risk of cardiovascular collapse included multisystem organ failure, older age, and initial blood pressure increase in response to iNO; a smaller change in the ratio of Pa(O(2)) to FI(O(2)) with initiation of iNO therapy also tended to correlate with this phenomenon. We conclude that careful and monitored discontinuation of iNO in patients with AHRF will identify substantial fractions of patients who are either receiving no benefit from this therapy or who require iNO to maintain an adequate circulation and are therefore at risk for adverse outcome with transport or inadvertent discontinuation of iNO. Future trials of iNO should recognize this complication of such therapy and include assessments for it.