Has the time come to stop routine N-acetylcysteine treatment in young children in Denmark? A review of 300 suspected paracetamol overdoses in children aged 0-6 years

AIM

To evaluate the prevalence of potentially hepatoxic paracetamol ingestion and associated N-acetylcysteine treatment in young children suspected of paracetamol poisoning.

METHODS

A retrospective cohort study of children aged 0-6 years suspected of paracetamol poisoning with a related plasma-paracetamol measurement in the Capital Region of Denmark in the period 2010-2017. Data from the clinical laboratory system were linked to data from electronic patient records via the unique identification number given to all Danish residents.

RESULTS

Of 297 children included, suspected single paracetamol overdoses were present in 281 (95%). Sixty-nine per cent were treated with N-acetylcysteine, and the mean treatment period was 20.3 h (SD 20.8). A maximum of 6 (2%) of the children suspected of single overdose had plasma-paracetamol concentrations that exceeded the recommended treatment thresholds. No cases of severe hepatotoxicity were registered. Adverse events to N-acetylcysteine-treatment were registered in 3 (2%) children including one anaphylactoid reaction (0.5%).

CONCLUSION

This study shows that initiating N-acetylcysteine as a 'one size fit all' treatment regimen in all children aged 0-6 years with a suspected single paracetamol overdose leads to substantial overtreatment. The data support that it is feasible to initiate N-acetylcysteine within 10 h based on an early plasma-paracetamol test.

Focused HLA analysis in Caucasians with myositis identifies significant associations with autoantibody subgroups

Objectives

Idiopathic inflammatory myopathies (IIM) are a spectrum of rare autoimmune diseases characterised clinically by muscle weakness and heterogeneous systemic organ involvement. The strongest genetic risk is within the major histocompatibility complex (MHC). Since autoantibody presence defines specific clinical subgroups of IIM, we aimed to correlate serotype and genotype, to identify novel risk variants in the MHC region that co-occur with IIM autoantibodies.

Methods

We collected available autoantibody data in our cohort of 2582 Caucasian patients with IIM. High resolution human leucocyte antigen (HLA) alleles and corresponding amino acid sequences were imputed using SNP2HLA from existing genotyping data and tested for association with 12 autoantibody subgroups.

Results

We report associations with eight autoantibodies reaching our study-wide significance level of p<2.9×10^–5. Associations with the 8.1 ancestral haplotype were found with anti-Jo-1 (HLA-B*08:01, p=2.28×10^–53 and HLA-DRB1*03:01, p=3.25×10^–9), anti-PM/Scl (HLA-DQB1*02:01, p=1.47×10^–26) and anti-cN1A autoantibodies (HLA-DRB1*03:01, p=1.40×10^–11). Associations independent of this haplotype were found with anti-Mi-2 (HLA-DRB1*07:01, p=4.92×10^–13) and anti-HMGCR autoantibodies (HLA-DRB1*11, p=5.09×10^–6). Amino acid positions may be more strongly associated than classical HLA associations; for example with anti-Jo-1 autoantibodies and position 74 of HLA-DRB1 (p=3.47×10^–64) and position 9 of HLA-B (p=7.03×10^–11). We report novel genetic associations with HLA-DQB1 anti-TIF1 autoantibodies and identify haplotypes that may differ between adult-onset and juvenile-onset patients with these autoantibodies.

Conclusions

These findings provide new insights regarding the functional consequences of genetic polymorphisms within the MHC. As autoantibodies in IIM correlate with specific clinical features of disease, understanding genetic risk underlying development of autoantibody profiles has implications for future research.

Clinical features and outcome in a Danish cohort of juvenile dermatomyositis patients

OBJECTIVES

To assess disease characteristics and outcome in Danish juvenile dermatomyositis (JDM) patients (1977-2007).

METHODS

Medical record review of hospital records identified from the National Patient Register.

RESULTS

Fifty-seven JDM patients were identified. Follow-up time was 7 years (range 0.06-30). Female:male ratio was 2.5:1. Mean age at disease onset was 7 years (SD±3.7), range 1.5-16.0 years. Diagnostic delay was 0.7 years (SD±1.6), range 0.04-9 years. Mean disease duration was 3.7 years (SD±3.5), range 0.7-9 years. Thirty-nine patients (70%) were in full remission. Three patients (5%) were deceased. Disease/treatment-induced damage was present in 35 (61%) patients. Decreased pulmonary function occurred early in the disease course (median 10 months), osteoporosis and calcinosis occurred later (median 18 and 22 months). Four patients developed persistent damage within the first 6 months, four developed calcinosis within the first year. Shorter disease duration was associated with less damage (p=0.004). In a multivariate assessment analysis age >10 years at disease onset was associated with more damage (p<0.01), OR 10.96 (CI 1.6-73.6), and disease duration >4 years was associated with calcinosis (p=0.01) OR 23.2 (CI 2.6-206.2).

CONCLUSIONS

We present a nationwide retrospective study of Danish JDM patients from 1977-2007. Although 70% were in remission, 61% of the patients had clinical signs of damage. Only a few patients developed damage within the first year of the disease. Longer disease duration and higher age at disease onset was correlated with more disease damage.