Flemish network on rare connective tissue diseases (CTD): patient pathways in systemic sclerosis. First steps taken.

Despite the low prevalence of each rare disease, the total burden is high. Patients with rare diseases encounter numerous barriers, including delayed diagnosis and limited access to high-quality treatments. In order to tackle these challenges, the European Commission launched the European Reference Networks (ERNs), cross-border networks of healthcare providers and patients representatives. In parallel, the aims and structure of these ERNs were translated at the federal and regional levels, resulting in the creation of the Flemish Network of Rare Diseases. In line with the mission of the ERNs and to ensure equal access to care, we describe as first patient pathways for systemic sclerosis (SSc), as a pilot model for other rare connective and musculoskeletal diseases. Consensus was reached on following key messages: 1. Patients with SSc should have multidisciplinary clinical and investigational evaluations in a tertiary reference expert centre at baseline, and subsequently every three to 5 years. Intermediately, a yearly clinical evaluation should be provided in the reference centre, whilst SSc technical evaluations are permissionably executed in a centre that follows SSc-specific clinical practice guidelines. In between, monitoring can take place in secondary care units, under the condition that qualitative examinations and care including interactive multidisciplinary consultations can be provided. 2. Patients with early diffuse cutaneous SSc, (progressive) interstitial lung disease and/or pulmonary arterial hypertension should undergo regular evaluations in specialised tertiary care reference institutions. 3. Monitoring of patients with progressive interstitial lung disease and/or pulmonary (arterial) hypertension will be done in agreement with experts of ERN LUNG.

[Life-threatening flare of an underlying «paraneoplastic¼ dermatomyositis in a patient with lung adenocarcinoma treated with anti-PD-1 pembrolizuma]. / Poussée sévère d'une dermatomyosite pré-existante chez une patiente avec un adénocarcinome pulmonaire traité par pembrolizumab, un anti-PD-1.

Dermatomyositis is an autoimmune disease mainly characterized by muscle and skin involvement. Its association with cancer is known but the term «paraneoplastic¼ remains debated. We report here the case of a 71-year-old woman with a new diagnosis of dermatomyositis with, at the same time, the discovery of a lung adenocarcinoma. Lung cancer was treated with pembrolizumab, an immune checkpoint inhibitor directed against the "Programmed cell Death protein 1" (PD-1) receptor. Three weeks later, the patient presented a severe flare of dermatomyositis. Administration of intravenous corticosteroids and infliximab were ineffective. Intravenous immunoglobulins were then administered, followed by subcutaneous methotrexate, with a progressive positive evolution. Flares of pre-existing autoimmune diseases are observed under immune check point inhibitors, even when the evolution of the cancer is favourable. These immune-related adverse events are often «mild to moderate¼ and severe immune related side effects are not more frequent when the patient has a pre-existing autoimmune disease. Treatment can be maintained in the majority of cases. However, as demonstrated in this clinical case, although immune checkpoint inhibitors are not contraindicated in autoimmune diseases, the presence of myositis requires special attention given the potential severity of flares.

: La dermatomyosite est une maladie auto-immune principalement caractérisée par une atteinte musculaire et cutanée. Son association avec le cancer est connue, mais le terme «paranéoplasique¼ reste débattu. Nous rapportons ici le cas d'une patiente de 71 ans avec un nouveau diagnostic de dermatomyosite et, au même moment, la découverte d'un adénocarcinome pulmonaire. La néoplasie pulmonaire a été traitée par pembrolizumab, un inhibiteur des points de contrôle immunitaire dirigé contre le récepteur «Programmed cell Death protein 1¼ (PD-1). Trois semaines plus tard, la patiente présentera une poussée sévère de dermatomyosite, ne répondant pas à la corticothérapie intraveineuse ni à l'infliximab. Des immunoglobulines intraveineuses sont alors administrées, suivies de méthotrexate sous-cutané, avec une évolution progressivement positive. On observe des poussées de maladies auto-immunes préexistantes sous inhibiteurs de points de contrôle immunitaire, même quand l'évolution néoplasique est favorable. Ces effets secondaires immuno-induits sont souvent «légers à modérés¼ et on n'observe pas plus de manifestations indésirables «sévères¼ lorsque le patient présente une maladie auto-immune pré-existante. Le traitement peut être maintenu dans la majorité des cas. Toutefois, comme démontré dans ce cas clinique, bien que les inhibiteurs de points de contrôle immunitaire ne soient pas contre-indiqués en cas de maladie auto-immune, la présence d'une myosite nécessite une attention particulière vu la gravité potentielle des poussées.

Acetate metabolism and bicarbonate generation during hemodialysis: 10 years of observation.

The capacity of chronically hemodialyzed patients to metabolize acetate during conventional hemodialysis was evaluated using a retrospective study in 219 patients dialyzed for up to ten years under similar dialysis conditions. For each patient, and using all available data, a regression line relating the changes of plasma total CO2 during dialysis as a function of the pre-dialysis value was calculated. The intercept of this function indicates the plasma concentration where the losses of bicarbonate in the dialysate is matched by the generation of bicarbonate arising from the metabolism of acetate. This value therefore represents an individual index of the capacity of each patient to metabolize acetate. A value for this index smaller than 18.0 mM was considered abnormal. It was shown that around 10% of chronically hemodialyzed patients are clearly unable to metabolize acetate optimally. This defect is not related to the duration of dialysis, body weight or quality of hemodialysis treatments but is strongly related to sex, 19 of the 22 "acetate intolerant" patients being women. In a prospective study, all the 60 patients of the same population undergoing active dialysis were studied, and this index identified 12 abnormal (11 women, 1 man) patients and 48 normal patients. Plasma acetate measured at the end their dialysis treatments were significantly higher in abnormal than in normal patients. It is concluded: that this index is useful to identify the patients unable to metabolize acetate optimally; that only around 10% of hemodialyzed patients present a severe problem when dialyzed against acetate and should be dialyzed against bicarbonate; that dialysis against acetate does not fully correct the metabolic acidosis even in "normal" patients.

The acid-base status does not influence the rate of acetate metabolism in hemodialyzed patients.

The present study was undertaken to evaluate whether the acid-base status influences the rate of acetate metabolism in patients chronically hemodialyzed against acetate. Ten patients (5 "intolerant" and 5 "tolerant" to acetate) received in a randomized order and for three consecutive dialyses each of the six following infusions in the venous line of the dialyzer: NaHCO3 (22, 44 or 88 mEq/h), NaCl (22 or 44 mEq/h) or Dextrose 5% in water (30 mmol/h). Plasma acetate was measured at the end of the dialysis. Bicarbonate infusions increased significantly blood pH and plasma bicarbonate but did not change the plasma acetate concentration at the end of dialysis. We conclude that the rate of acetate metabolism is not modified by changes in the acid-base status within the range usually observed in hemodialyzed patients. A significant hypoxemia per dialysis was noted only in AT patients with lower plasma acetate and rapid acetate metabolism. We conclude that acetate metabolism (and not plasma acetate concentration) plays a significant role in dialysis-induced hypoxemia.

Urinary tract candidiasis: report of a case with bilateral ureteral obstruction.

A brief review of the literature on urinary tract candidiasis is presented. The presence of Candida albicans in the urine is rather uncommon and most patients have candiduria without any apparent disease. Among the others, three different clinical types of infection are recognized: (1) pyelonephritis, (2) lower urinary tract infection and (3) ureteral obstruction. Of this last type only seven cases were found in the literature; four of the patients died. We add one case in which the patient did very well after the obstruction of the ureters was relieved by means of ureteral catheters and a large urinary output was maintained for several days.