1 - Paediatric Unit, Hospital São Bernardo, Arrábida Local Health Unit, Pediatric Unit, Setúbal, Portugal
2 - Paediatric Unit, Hospital Garcia de Orta, Almada-Seixal Local Health Unit, Pediatric Unit, Almada, Portugal
3 - Paediatric Nephrology Unit, Central Lisbon University Hospital Centre, Nephrology Unit, Lisbon, Portugal
4 - Nephrology Department, Central Lisbon University Hospital Centre, Lisbon, Portugal
5 - Paediatric Rheumatology Unit, Central Lisbon University Hospital Centre, Reumathology Unit, Lisbon, Portugal
- 56th Annual Meeting of the European Society for Paediatric Nephrology, 24-26/9/2024, Valência, Espanha, Poster
- Resumo publicado em: Pediatr Nephrol 2024;39(Suppl 1):S105-S106
Abstract:
Purpose: Blau syndrome, a rare autosomal dominant autoinflammatory disorder mediated by NFkB, usually presents with a classical triad of granulomatous polyarthritis, dermatitis, and uveitis. Visceral organ involvement is rare. We present a case of a female adolescent with Blau syndrome complicated by chronic kidney disease (CKD). We aim to highlight the diagnostic and therapeutic challenges in this case.
Case description: A 15-year-old female was referred to our hospital at the age of 13 from her homeland, Cape Verde, with a history of recurrent early-onset episodes of polyarthritis, which would last 3 to 6 days and were associated with camptodactyly, erythematous-desquamative papular exanthema, and uveitis. Additionally, she had developed CKD (stage 4), secondary hypertension, left ventricular hypertrophy, and dyslipidemia. As the hypothesis of an autoinflammatory syndrome was considered, treatment with steroids was continued, and methotrexate was added. A renal biopsy showed 19 globally sclerotic glomeruli, interstitial fibrosis with mononuclear cells infiltrate and tubular atrophy involving 90% of the cortex. Immunofluorescence and Congo red stain for amyloid were negative. Genetic testing showed a c.1001G>A (p.Arg334Gln) heterozygous mutation in NOD2 gene (R334Q), confirming the diagnosis of Blau Syndrome. With methotrexate, systemic complaints improved, but renal function deteriorated rapidly despite dose adjustments to eGFR and drug level monitoring, prompting a switch to adalimumab to mitigate nephrotoxicity. Renal function recovered to baseline over the following months. One year later, adalimumab was changed to infliximab due to hypercalcemia. Anti-TNF therapy doses and frequency of administrations were guided by clinical response, recommended adjustments to eGFR, and drug levels. Increasing doses or frequency were associated with improved systemic control of the disease and renal function deterioration. At present, the patient is being treated with infliximab every six weeks, alongside pharmacological therapy for CKD. Systemic complaints and ocular disease are relatively well controlled despite persisting refractory knee arthritis, and eGFR has remained stable at 20 mL/min/1.73 m2. The patient is being prepared for renal transplantation.
Conclusions: Blau syndrome represents a clinical and diagnostic challenge due to its rarity and heterogeneous presentation. Characterized by the classical triad of polyarthritis, dermatitis, and uveitis, this autoinflammatory disease can affect multiple organ systems, including the kidneys. Definitive diagnosis of Blau syndrome often relies on genetic testing for NOD2 gene pathogenic mutations. Finding the best therapeutic regimen to balance disease control without accelerating the decline in renal function due to nephrotoxicity is challenging.
Keywords: Blau syndrome, chronic kidney disease