Proteinuria en la infancia: a propósito de un caso de enfermedad de Dent

Introducción: la proteinuria en la edad pediátrica es una entidad relativamente frecuente, la cual puede ser fisiológica o patológica. La segunda, por una alteración a nivel glomerular con pérdida de proteínas de gran tamaño o a nivel tubular, caracterizada por pérdida de proteínas de bajo peso molecular y alteraciones en la excreción de iones. Entre las enfermedades hereditarias que cursan con proteinuria tubular, se ha descrito la enfermedad de Dent, una patología ligada al cromosoma X. Esta enfermedad se manifiesta principalmente en varones, pero las mujeres pueden ser portadoras y tener manifestaciones clínicas leves de la enfermedad. La primera descripción de esta enfermedad fue hecha por Dent y Friedman en 1964. La mayoría de los casos recientemente reportados han sido en China y Alemania. Objetivo: realizar una revisión general de la enfermedad de Dent y del enfoque diagnóstico de la proteinuria en la infancia con base en nuestro caso, para así, sospechar de esta enfermedad. Descripción del caso: se presenta el caso de un paciente masculino sin antecedentes prenatales ni personales de importancia, quien presenta proteinuria persistente desde los primeros meses de vida y a quien, a los 7 años de edad, se le documenta la presencia de una variante ya conocida en el gen CLCN5, causante de la enfermedad de Dent tipo 1. Discusión: la proteinuria persistente patológica en la infancia debe ser estudiada debido a su posible relación con patologías que pueden afectar la función renal. Además de la diferenciación de la proteinuria persistente, de origen glomerular y tubular, la evaluación de alteraciones en la excreción de electrolitos, puede guiarnos hacia la realización de estudios genéticos y, por ende, al diagnóstico de patologías infrecuentes como la enfermedad de Dent. Conclusión: el enfoque diagnóstico de causas poco frecuentes de proteinuria tubular en la infancia, como la enfermedad de Dent, requiere de la valoración conjunta entre nefrología pediátrica y genética clínica.

Background: In pediatric patients, proteinuria is a relatively frequent entity that can be physiological or pathological. The second one, due to an alteration at the glomerular level with the loss of large proteins or at the tubular level, characterized mainly by the loss of low molecular weight proteins and changes in the excretion of ions. Among the hereditary diseases that present with tubular proteinuria, Dent disease is a disease linked to the X chromosome. Therefore, it manifests essentially in males, but women can be carriers and have minor clinical manifestations of the disease. Dent and Friedman made the first description of this disease in 1964. Recently, most of the cases have been reported in China and Germany. Objective: To perform a revision of Dent disease, as well as the diagnostic approach of childhood proteinuria based in our case in order to suspect this disease. Case description: This is the case of a masculine patient, without relevant prenatal and personal antecedents, the son of a father with polycystic renal disease, who presents persistent proteinuria from the first months of life, and who, at seven years old, the presence of a variant in the CLCN5 gene -causing of type 1 Dent disease- was documented. Discussion: The persistent pathological proteinuria in childhood must be studied due to its possible relation with pathologies that could affect renal function. Moreover, the differentiation among glomerular and tubular proteinuria can guide us to perform additional studies, including genetic tests to diagnose infrequent pathologies like Dent disease. Conclusion: The diagnostic approach to rare causes of tubular proteinuria in childhood, such as Dent's disease, requires joint assessment between pediatric nephrology and clinical genetics.

Kidney function in patients with primary distal renal tubular acidosis.

BACKGROUND: Recent reports indicate that chronic reduction of glomerular filtration rate (GFR) is common in patients with distal renal tubular acidosis (DRTA). Factors responsible for decreased GFR need clarification. METHODS: We reviewed records of 25 patients with genetically confirmed DRTA included in the RenalTube database. Patients < 18 years at diagnosis and having at least one annual follow-up were selected and classified in two groups according to GFR ≥ 90 (normal GFR) or < 90 mL/min/1.73 m2 (low GFR) after median follow-up of 8.8 years. RESULTS: Eighteen and seven patients had normal and low GFR (X ± SEM, 121.16 ± 28.87 and 71.80 ± 10.60 mL/min/1.73 m2, respectively, p < 0.01). At diagnosis, these 2 subgroups did not differ in sex, age, underlying mutated gene, GFR, height SDS, or percentage of ultrasound nephrocalcinosis. Serum creatinine (SCr) was different but likely due to median ages of presentation being 0.6 and 4.0 in normal and low GFR patients, respectively. On the last recorded visit, no differences between both groups were found in serum bicarbonate, serum potassium, or alkali dosage. Height SDS of patients with normal GFR was - 0.15 ± 0.47 whereas it was - 1.06 ± 0.60 in the low GFR group (p = 0.27). Interestingly, 23% of the whole group had low birth weight (LBW; < 2500 g), equating to 20% and 29% in the normal and low GFR patients, respectively (p = 0.65). CONCLUSIONS: Our findings confirm the risk of kidney function reduction in patients with DRTA of pediatric age onset, suggesting that low GFR is related with less favorable growth outcome and discloses the high frequency of LBW in primary DRTA, a hitherto unrecognized feature.

Acute renal failure in children. Multicenter prospective cohort study in medium-complexity intensive care units from the Colombian southeast.

BACKGROUND: Acute kidney injury is frequent in critically ill children; however, it varies in causality and epidemiology according to the level of patient care complexity. A multicenter prospective cohort study was conducted in four medium-complexity pediatric intensive care units from the Colombian southeast aimed to estimate the clinical prognosis of patients with diagnosis of acute kidney injury. METHODS: We included children >28 days and <18 years of age, who were admitted with diagnosis of acute kidney injury classified by Kidney Disease Improving Global Outcomes (KDIGO), during the period from January to December 2017. Severe acute kidney injury was defined as stage 2 and stage 3 classifications. Maximum KDIGO was evaluated during the hospital stay and follow up. Length of hospital stay, use of mechanical ventilation and vasoactive drugs, use of renal replacement therapy, and mortality were assessed until discharge. RESULTS: Prevalence at admission of acute kidney injury was 5.2% (95%CI 4.3% to 6.2%). It was found that 71% of the patients had their maximum KDIGO on day one; an increment in the maximum stage of acute kidney injury increased the pediatric intensive care unit stay. Patients with maximum KDIGO 3 were associated with greater use of mechanical ventilation (47%), compared with maximum KDIGO 2 (37%) and maximum KDIGO 1 (16%). Eight patients with maximum KDIGO 2 and 14 with maximum KDIGO 3 required renal replacement therapy. Mortality was at 11.8% (95%CI 6.4% to 19.4%). CONCLUSION: Acute kidney injury, established and classified according to KDIGO as severe and its maximum stage, was associated with worse clinical outcomes; early therapeutic efforts should focus on preventing the progression to severe stages.

Corticosteroids for septic arthritis in children.

BACKGROUND: Septic arthritis is an acute infection of the joints characterised by erosive disruption of the articular space. It is the most common non-degenerative articular disease in developing countries. The most vulnerable population for septic arthritis includes infants and preschoolers, especially boys. Septic arthritis disproportionately affects populations of low socioeconomic status. Systemic corticosteroids and antibiotic therapy may be beneficial for treatment of septic arthritis. Even if the joint infection is eradicated by antibiotic treatment, the inflammatory process may produce residual joint damage and sequelae. OBJECTIVES: To determine the benefits and harms of corticosteroids as adjunctive therapy in children with a diagnosis of septic arthritis. SEARCH METHODS: We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library, Latin American Caribbean Health Sciences Literature (LILACS), the World Health Organization (WHO) trials portal (www.who.int/ictrp/en/), ClinicalTrials.gov (www.ClinicalTrials.gov), and Google Scholar. We searched all databases from their inception to 17 April 2018, with no restrictions on language of publication. SELECTION CRITERIA: We included randomised controlled trials (RCTs) with patients from two months to 18 years of age with a diagnosis of septic arthritis who were receiving corticosteroids in addition to antibiotic therapy or as an adjuvant to other therapies such as surgical drainage, intra-articular puncture, arthroscopic irrigation, or debridement. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed eligibility, data extraction, and evaluation of risk of bias. We considered as major outcomes the presence of pain, activities of daily living, normal physical joint function, days of antibiotic treatment, length of hospital stay, and numbers of total and serious adverse events. We used standard methodological procedures expected by Cochrane. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created a 'Summary of findings' table. MAIN RESULTS: We included two RCTs involving a total of 149 children between three months and 18 years of age who were receiving antibiotics for septic arthritis. The most commonly affected joints were hips and knees. These studies were performed in Costa Rica and Israel. In both studies, dexamethasone administered intravenously (ranging from 0.15 to 0.2 mg/kg/dose every six to eight hours) during four days was the corticosteroid, and the comparator was placebo. Trials excluded patients with any degree of immunodeficiency or immunosuppression. The longest follow-up was one year. Trials did not report activities of daily living nor length of hospital stay. Both studies used adequate processes for randomisation, allocation concealment, and blinding, and review authors judged them to have low risk of selection and performance bias. Losses to follow-up were substantive in both studies, and we judged them to have high risk of attrition bias and of selective outcome reporting. We graded all outcomes as low quality due to concerns about study limitations and imprecision.The risk ratio (RR) for absence of pain at 12 months of follow-up was 1.33, favouring corticosteroids (95% confidence interval (CI) 1.03 to 1.72; P = 0.03; number needed to treat for an additional beneficial outcome (NNTB) = 13, 95% CI 6 to 139; absolute risk difference 24%, 95% CI 5% to 43%).The RR for normal function of the affected joint at 12 months of follow-up was 1.32, favouring corticosteroids (95% CI 1.12 to 1.57; P = 0.001; NNTB = 13, 95% CI 7 to 33; absolute risk difference 24%, 95% CI 11% to 37%).We found a reduction in the number of days of intravenous antibiotic treatment favouring corticosteroids (mean difference (MD) -2.77, 95% CI -4.16 to -1.39) based on two trials with 149 participants.Researchers did not report length of hospital stay. One trial (49 participants) reported that treatment with dexamethasone was associated with a shorter duration of IV antibiotic treatment, leading to a shorter hospital stay, and although duration of hospitalisation was a primary outcome of the study, study authors did not provide data on the duration of hospitalisation. We downgraded the quality by one level for concerns about study limitations (high risk of attrition bias and selective reporting), and by another level for imprecision.In one trial of 49 participants, researchers followed 29 children for 12 months, and parents reported that no children demonstrated adverse effects of the intervention. AUTHORS' CONCLUSIONS: Evidence for corticosteroids as adjunctive therapy in children with a diagnosis of septic arthritis is of low quality and is derived from the findings of two trials (N = 149). Corticosteroids may increase the proportion of patients without pain and the proportion of patients with normal function of the affected joint at 12 months, and may also reduce the number of days of antibiotic treatment. However, we cannot draw strong conclusions based upon these trial results. Additional randomised clinical trials in children with relevant outcomes are needed.