Osteoporosis, bone mineral density and CKD-MBD (II): Therapeutic implications. / Osteoporosis, densidad mineral ósea y complejo CKD-MBD (II): implicaciones terapéuticas.

Osteoporosis (OP) and chronic kidney disease (CKD) both independently affect bone health. A significant number of patients with CKD have decreased bone mineral density (BMD), are at high risk of fragility fractures and have an increased morbidity and mortality risk. With an ageing population, these observations are not only dependent on "renal osteodystrophy" but also on the associated OP. As BMD predicts incident fractures in CKD patients (partI), we now aim to analyse the potential therapeutic consequences. Post-hoc analyses of randomised studies have shown that the efficacy of drugs such as alendronate, risedronate, raloxifene, teriparatide and denosumab is similar to that of the general population in patients with a mild/moderate decline in their glomerular filtration rate (especially CKD-3). These studies have some flaws however, as they included mostly "healthy" women with no known diagnosis of CKD and generally with normal lab test results. Nevertheless, there are also some positive preliminary data in more advanced stages (CKD-4), even though in CKD-5D they are more limited. Therefore, at least in the absence of significant mineral metabolism disorders (i.e. severe hyperparathyroidism), the potential benefit of these drugs should be considered in patients with a high or very high fracture risk. It is an important change that the new guidelines do not make it a requirement to first perform a bone biopsy and that the risk/benefit ratio of these drugs may be justified. However, we must also be aware that most studies are not consistent and the level of evidence is low. Consequently, any pharmacological intervention (risk/benefit) should be prudent and individualised.

Rituximab for Steroid-Dependent or Frequently Relapsing Idiopathic Nephrotic Syndrome in Adults: A Retrospective, Multicenter Study in Spain.

BACKGROUND: Patients with difficult-to-treat idiopathic nephrotic syndrome (INS), steroid-dependent nephrotic syndrome (SDNS), or frequently relapsing nephrotic syndrome (FRNS) require long-term immunosuppressive therapy. Rituximab offers an alternative treatment for patients with disease that has not responded to multiple therapies. OBJECTIVE: Our objective was to determine the efficacy and safety of rituximab in adult patients with difficult-to-treat (SDNS or FRNS) INS. METHODS: We performed a retrospective multicenter study that included 50 adults with difficult-to-treat INS in six Spanish centers. All patients were treated with steroids in combination with another immunosuppressant: 28 patients received rituximab as the additional treatment (rituximab group), and the other 22 patients not treated with rituximab served as the control group. RESULTS: Of the patients treated with rituximab, 23 (82%) experienced complete remission, 20 (71%) had no relapses after receiving rituximab, and 13 (46%) did not receive any immunosuppressant. Of those in the control group, 14 (63%) experienced complete remission, including eight without immunosuppressants (29%). The rituximab group experienced highly significant reductions in total number of relapses per year (p < 0.001), proteinuria (p = 0.03), steroid doses (p = 0.002), and tacrolimus doses (p = 0.001). Mean follow-up after rituximab was 31 ± 26 months (range 8-86). The need for steroids and other immunosuppressants to achieve sustained remission was lower in the rituximab group than in the control group. CONCLUSIONS: Rituximab treatment was safe and well tolerated. It effectively reduced the incidence of relapses and need for maintenance immunosuppressive therapy in adults with difficult-to-treat INS.

Renal angiomyolipoma bleeding in a patient with TSC2/PKD1 contiguous gene syndrome after 17 years of renal replacement therapy. / Sangrado de angiomiolipoma renal en paciente con síndrome de genes contiguos (TSC2/PKD1) tras 17 años de tratamiento renal sustitutivo.

We report the case of a 32-year-old male diagnosed with TSC2/PKD1 contiguous gene syndrome, presenting with tuberous sclerosis (TS) and autosomal dominant polycystic kidney disease simultaneously. He progressed to end-stage renal disease and received a kidney transplant at the age of 12. The native kidneys presented angiomyolipomas (AML), which are common benign tumours in patients with TS. Seventeen years after transplantation, he presented with abdominal pain, anaemia and a retroperitoneal haematoma, the latter caused by renal AML bleeding. Selective embolisation was performed. Our patient could have benefited from the administration of mTOR inhibitors at transplant. This therapy is immunosuppressive and reduces the size of benign tumours in TS as well as the risk of rupture and bleeding. This patient did not receive mTOR inhibitors at the time of the transplant because the relationship between mTOR inhibitors and TS was unknown at that time. This case confirms the persistent risk of renal AML bleeding for both transplanted patients and patients on dialysis. As a result, we would recommend routine check-ups of native kidneys and nephrectomy assessment.