BackgroundAnti-synthetase (AS) and dermato-pulmonary associated with anti-MDA-5 antibodies (aMDA-5) syndromes are near one of the other autoimmune inflammatory myopathies potentially responsible for severe acute interstitial lung disease. We undertook a 13-year retrospective multicenter study in 35 French ICUs in order to describe the clinical presentation and the outcome of patients admitted to the ICU for acute respiratory failure (ARF) revealing AS or aMDA-5 syndromes.ResultsFrom 2005 to 2017, 47 patients (23 males; median age 60 [1st–3rd quartiles 52–69] years, no comorbidity 85%) were admitted to the ICU for ARF revealing AS (n = 28, 60%) or aMDA-5 (n = 19, 40%) syndromes. Muscular, articular and cutaneous manifestations occurred in 11 patients (23%), 14 (30%) and 20 (43%) patients, respectively. Seventeen of them (36%) had no extra-pulmonary manifestations. C-reactive protein was increased (139 [40–208] mg/L), whereas procalcitonine was not (0.30 [0.12–0.56] ng/mL). Proportion of patients with creatine kinase ≥ 2N was 20% (n = 9/47). Forty-two patients (89%) had ARDS, which was severe in 86%, with a rate of 17% (n = 8/47) of extra-corporeal membrane oxygenation requirement. Proportion of patients who received corticosteroids, cyclophosphamide, rituximab, intravenous immunoglobulins and plasma exchange were 100%, 72%, 15%, 21% and 17%, respectively. ICU and hospital mortality rates were 45% (n = 21/47) and 51% (n = 24/47), respectively. Patients with aMDA-5 dermato-pulmonary syndrome had a higher hospital mortality than those with AS syndrome (n = 16/19, 84% vs. n = 8/28, 29%; p = 0.001).ConclusionsIntensivists should consider inflammatory myopathies as a cause of ARF of unknown origin. Extra-pulmonary manifestations are commonly lacking. Mortality is high, especially in aMDA-5 dermato-pulmonary syndrome.

Thrombotic thrombocytopenic purpura (TTP) has a devastating prognosis without adapted management. Sources of misdiagnosis need to be identified to avoid delayed treatment. We studied 84 patients with a final diagnosis of severe (<10%) acquired ADAMTS13 deficiency-associated TTP from our National database that included 423 patients, who had an initial misdiagnosis (20% of all TTP). Main diagnostic errors were attributed to autoimmune thrombocytopenia, associated (51%) or not (37%) with autoimmune hemolytic anemia. At admission, misdiagnosed patients were more frequently females (P = .034) with a history of autoimmune disorder (P = .017) and had organ involvement in 67% of cases; they had more frequently antinuclear antibodies (P = .035), a low/undetectable schistocyte count (P = .001), a less profound anemia (P = .008), and a positive direct antiglobulin test (DAT) (P = .008). In multivariate analysis, female gender (P = .022), hemoglobin level (P = .028), a positive DAT (P = .004), and a low schistocytes count on diagnosis (P < .001) were retained as risk factors of misdiagnosis. Platelet count recovery was significantly longer in the misdiagnosed group (P = .041) without consequence on mortality, exacerbation and relapse. However, patients in the misdiagnosed group had a less severe disease than those in the accurately diagnosed group, as evidenced by less organ involvement at TTP diagnosis (P = .006). TTP is frequently misdiagnosed with autoimmune cytopenias. A low schistocyte count and a positive DAT should not systematically rule out TTP, especially when associated with organ failure.