Distar Renal Tubular Acidosis (dRTA): Epidemiological, diagnostics, clinical follow-up and therapeutical issues. Nephrologists cohort survey outcome.

BACKGROUND AND OBJECTIVES: dRTA is a genetic or acquired rare disease, characterized by an unability to excrete hydrogens (H+) into urine, hypobicarbonatemia, hyperchloremia, and frequently hypercalciuria and hypokalaemia. Genetic forms are usually diagnosed during the first months of life and its treatment is based on providing alkali supplements in order to prevent long term clinical consequences, particularly chronic kidney disease (described in some cohorts up to 82% of dRTA patients) and the associated bone disease. A 10 queries multi choice closed response survey was designed to know more about epidemiological, diagnostics, clinical management and therapeutical issues of this disease among Spanish nephrologists. METHODS AND MATERIALS: This survey was delivered to the attendees to a scientific meeting on dRTA at the Spanish Nephrology Society congress in 2019. Surveys were collected at the end of this dRTA event. Results were analyzed by using a parametric statistical test, obtaining the percentage of each response for the 10 questions. RESULTS: Among the survey responders, 44.4% and 37.7% did not visit any dRTA patient during the 1st and 3rd last year respectively. When having a suspicious diagnose, confirming genetic diagnostic test is only performed on the 13.3% of cases and pedigree studies only on 11.1%. Only a 26.6% confirms that metabolic control is excellent, good or very good. 69% of the responders believe that treatment compliance is not bad, bad or very bad. CONCLUSIONS: This survey enhances the fact that dRTA is not a well known entity, satisfaction with metabolic control is poor and compliance is low. All these factors can lead to a higher severity of renal and bone diseases associated to dRTA.

Importance of Assessing Compliance with Conservative Treatment of Primary Hyperoxaluria Type 1: A Case Report of a Patient with I244T/c.969-3C>G Mutation.

INTRODUCTION: Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inherited disorder that progresses to end-stage renal disease. Patients experience excessive urinary oxalate excretion, which causes nephrocalcinosis and recurrent urolithiasis. When the glomerular filtration rate declines, calcium oxalate accumulates in extrarenal tissues, causing end-organ damage. More than 190 responsible mutations have been documented, with some genotype-phenotype differences reported. Regardless of the genetic basis, prompt diagnosis and treatment are decisive for the long-term outcome. If the condition advances to chronic kidney disease stage 4 or 5, a combined liver-kidney transplant should be considered. CASE PRESENTATION: We describe a 5-month-old asymptomatic female patient with bilateral diffuse nephrocalcinosis and nephrolithiasis. Laboratory and genetic findings confirmed PH1. She was promptly administered conservative treatment consisting of high fluid intake, calcium oxalate crystallization inhibitors, and pyridoxine. Nephrocalcinosis and urolithiasis disappeared after 2 years of treatment. As far as we know, this is a unique case of a patient with an I244T/null mutation diagnosed after the neonatal period and with normal renal function, who remained asymptomatic during an 18-year follow-up. This case is also unique because of the long-term therapeutic success. DISCUSSION: Physicians need a high level of suspicion to diagnose this rare disease. It has been previously demonstrated that early conservative treatment improves long-term outcomes, averting preemptive transplant during childhood. This case report emphasizes the importance of encouraging compliance with this approach, reinforces the need for good physician-patient communication, and raises awareness of the problems that might arise during conservative PH1 treatment.

Anti-GBM and anti-MPO antibodies coexist in a case of pulmonary renal syndrome.

The case of a 12-year-old boy with pulmonary renal syndrome is described. Antimyeloperoxidase (anti-MPO) and antiglomerular basement membrane (anti-GBM) antibodies were positive. The clinical course and immunosuppressive therapy are discussed. Pulmonary renal syndrome is a rare event in childhood and coexistence of the two types of antibodies is exceptional.