Detection of hypophosphatasia in hospitalised adults in rheumatology and internal medicine departments: a multicentre study over 10 years.

INTRODUCTION: Hypophosphatasia (HPP) is a rare genetic disease caused by loss-of-function mutations in the ALPL gene encoding the tissue non-specific alkaline phosphatase (ALP). Mild HPP is usually misdiagnosed in adult age. While an elevated serum ALP value draws more attention than a low value, low serum ALP should be better recognised and may lead to HPP detection. METHODS: Patients were selected from the records of the biochemistry department of six University Hospitals in France. Patients were hospitalised in the departments of rheumatology and internal medicine between 2007 and 2017. RESULTS: 56 321 hospitalised patients had at least 2 serum ALP dosages and 664 of these patients had at least 2 low serum ALP≤35 UI/L. Among these 664 patients, 482 (72.6%) had fluctuating low values (mean age 62.9 years; 60% of women) and 182 patients (27.4%) had persistent low values below 35 IU/L (mean age 53.4 years; 67% of women). Among patients with persistent hypophosphatasaemia treated with bisphosphonates, 70.8% never had ALP measurement before treatment and 20.8% were treated despite an abnormal decrease of ALP. Genetic testing was performed in 18 patients and was positive in 11. Genetic diagnosis of HPP was at least 6.0% in persistent hypophosphatasaemia and at least 15.9% in patients with at least three symptoms suggestive of HPP. CONCLUSION: In this 10-year retrospective study, 0.32% of adult patients hospitalised in the rheumatology and internal medicine departments had persistently low serum ALP, and among them, 6% had genetically proven HPP. Reported hypophosphatasaemia represented only 3.6% of hospitalised patients.

Septic arthritis of the facet joint is also a severe vertebral infection: A multicenter retrospective study of 65 patients.

OBJECTIVE: Septic arthritis of the Facet Joints (SAFJ) is a rare condition. Little data has been published on the subject. We aimed to describe the clinical, biological and imagery presentations, as well as the course of this rare infection. METHODS: We included patients hospitalized between January 1st, 2016 and December 31th, 2019, in the Departments of Infectious Diseases or Rheumatology in 5 French centres in the CRIOGO network. We defined septic arthritis according to Newman's criteria and facet joint arthritis using imagery. RESULTS: Sixty-five patients were included, predominantly males (64.6%), with a mean age of 68.1 years. The mean time to diagnosis was 25.0 days. The principal symptoms at diagnosis were acute back pain (95.2%) and fever (76.9%). Neurological symptoms were present for 60.7% of the patients, including 16.4% motor deficit or cauda equina syndrome. SAFJ was located on the lumbosacral spine (73.4%) and was rarely multifocal (4.7%). Bacteriological identification was performed by blood cultures in 84.4% of the cases, and the pathogen was mainly Staphylococcus aureus (49.2%). Infective endocarditis was present for 26.9% of patients assessed by echocardiography. On MRI, soft tissue abscess or inflammation, epiduritis and epidural abscess were present in 87.1%, 66.7% and 33.9% of cases, and the pathogen was significantly more frequently Staphylococcus aureus. Mortality reached 9.2%, 18.5% and 23% at one, two, and three years respectively. CONCLUSION: SAFJ is a rare but severe disease. Microbiological diagnosis is primarily made on blood cultures, and S. Aureus was the main pathogen. Our results highlight the fact that SAFJ is associated with high morbidity and mortality, and with infective endocarditis.