Ji Young Oh

Syndrome of inappropriate antidiuretic hormone secretion and cerebral/renal salt wasting syndrome: similarities and differences

Hyponatremia (sodium levels of <135 mEq/L) is one of the most common electrolyte imbalances in clinical practice, especially in patients with neurologic diseases. Hyponatremia can cause cerebral edema and brain herniation; therefore, prompt diagnosis and proper treatment is important in preventing morbidity and mortality. Among various causes of hyponatremia, diagnosing syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral/renal salt wasting syndrome (C/RSW) is difficult due to many similarities. SIADH is caused by excess of renal water reabsorption through inappropriate antidiuretic hormone secretion, and fluid restriction is the treatment of choice. On the other hand, C/RSW is caused by natriuresis, which is followed by volume depletion and negative sodium balance and replacement of water and sodium is the mainstay of treatment. Determinating volume status in hyponatremic patients is the key point in differential between SIADH and C/RSW. However, in most situations, differential diagnosis of these two diseases is difficult because they overlap in many clinical and laboratory aspects, especially to assess differences in volume status of these patients. Although distinction between the SIADH and C/RSW is difficult, improvement of hypouricemia and an increased fractional excretion of uric acid after the correction of hyponatremia in SIADH, not in C/RSW, may be one of the helpful points in discriminating the two diseases. In this review, we compare these two diseases regarding the pathophysiologic mechanisms, diagnosis, and therapeutic point of view.

Mean platelet volume in young children with urinary tract infection

Mean platelet volume (MPV) has not yet been well-established in urinary tract infection (UTI). The purpose of this study was to evaluate the role of MPV as an acute phase reactant in children with UTI. Data from 118 young children (<2 years) with UTI between 2012 and 2013 were grouped as acute pyelonephritis (APN) and lower UTI according to the dimercaptosuccinic acid (DMSA) scan abnormalities. MPV, platelet distribution width (PDW) platelet count, and other infection markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], and C-reactive protein [CRP]) were measured. WBC (P = 0.001), ESR (P = 0.005), CRP (P < 0.001) and MPV levels (P = 0.011) were significantly higher in the APN group than those in the lower UTI group. MPV positively correlated with PDW, CRP and negatively with platelet count. Multiple logistic regression analyses showed that CRP and MPV were independent predictive factors for APN patients. However, the area under the Receiver Operating Characteristic (ROC) curve analysis for MPV was lower than CRP. Our results suggest that MPV can be an inflammatory marker in UTI, but the predictive value of MPV was not superior to CRP in the diagnosis of APN.

Noninfectious Complications of Peritoneal Dialysis in Korean Children: A 26-Year Single-Center Study

Purpose The aim of this study was to investigate noninfectious complications of peritoneal dialysis (PD), including mechanical and metabolic complications, at a single center in Korea. Materials and Methods We analyzed data from 60 PD patients aged ≤18 years (40 boys and 20 girls) during the period between 1986 and 2012. The collected data included gender, age, causes of PD, incidence of noninfectious complications, and treatment for the complications. Results The mean duration of PD therapy was 28.7±42.1 months (range 1-240 months). The most common cause of end-stage renal disease was glomerular disease (43.3%). There were no statistically significant differences between patients with and without mechanical complications regarding gender, age at the start of PD, and total duration of PD. Outflow failure was the most common catheter-related complication (14.3%), followed by leakage (10.0%) and hernia (8.6%). Metabolic complications, such as hyperglycemia and hypokalemia, were observed in three of 16 patients. The frequency of noninfectious complications of PD in our study was comparable with those in previous pediatric studies. PD was switched to hemodialysis (HD) in only three patients. Conclusion Our results indicate that noninfectious complications of PD are common, though they hardly lead to catheter removal or HD in pediatric patients on PD.

Successful treatment of tubulointerstitial nephritis and uveitis with steroid and azathioprine in a 12-year-old boy

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease, often underdiagnosed or misdiagnosed in children. We describe the case of a 12-year-old boy who presented to Severance Hospital with a 1-month history of bilateral conjunctival injection. He was first evaluated by an Ophthalmologist in another hospital and diagnosed with panuveitis. Laboratory tests indicated renal failure, and a renal biopsy confirmed the diagnosis of acute tubulointerstitial nephritis. An extensive exclusion of all possible causes allowed a diagnosis of TINU syndrome. The patient was treated with a systemic corticosteroid (initially prednisolone, 2 mg/kg and later deflazacort 1 mg/kg) and topical steroid drops for 1 month. Azathioprine was later added to the treatment regimen and the systemic steroid was slowly tapered. The final outcome of renal-ocular disease was favorable in the patient. However, long-term follow-up is necessary to properly manage frequent relapses and incomplete renal recovery. TINU should be considered as a differential diagnosis in children with uveitis or acute renal failure.

Outcomes of Hemodialysis in Children: A 35-Year Experience at Severance Hospital

Purpose The aim of this study was to analyze the results of children treated with hemodialysis (HD) at Severance Hospital over 35 years in terms of incidence, etiologies, characteristics, complications, and clinical outcomes. Materials and Methods We analyzed 46 children admitted to Severance Hospital who had undergone HD between January 1979 and December 2013. Results The main etiologies of the 23 end-stage renal disease (ESRD) patients who had received HD were chronic glomerulonephritis (7 patients, 30.4%) and congenital anomalies of the kidney and urinary tract (7 patients, 30.4%), whereas the etiology of the 23 acute kidney injury (AKI) patients was hemolytic uremic syndrome (6 patients, 26.1%). Compared with ESRD patients, hemocatheter placement in the femoral vein was preferred over the subclavian or internal jugular vein in the AKI patients (p=0.012). The most common complication was catheter related complication (10 patients, 21.7%). The site of hemocatheter insertion was not related to the frequency of oozing. Placing the hemocatheter in the femoral vein resulted in significantly more events of catheter obstruction than insertion in the internal jugular vein or the subclavian vein (p=0.001). Disequilibrium syndrome occurred more frequently in older patients (p=0.004), as well as patients with a greater body weight (p=0.008) and a higher systolic and diastolic blood pressure before HD (systolic: p=0.021; diastolic: p=0.040). Conclusion Based on the 35 years of experience in our center, HD can be sufficiently and safely carried out even in children without significant complications.

Could increased IgA induced by BAFF be the cause of IgA nephropathy development in Behcet's disease? Comment on: Behcet's disease and IgA nephropathy (Rheumatol Int. 2012 Jul; 32(7):2227-9).

We read with interest the article by Altay et al. [1]. They reported two cases with Behcet’s disease (BD) who developed IgA nephropathy later and described that BD is not known to cause augmented IgA production, and they cannot exclude simple coincidence of the two diseases [1]. However, we would like to suggest some possible pathomechanisms regarding the associations between the two diseases. Scully et al. [2] previously reported that IgA concentrations, but not IgG, IgM, IgD or IgE, were significantly raised in BD compared with controls, and the serum IgA levels were also highly elevated in Altay et al.’s [1] two cases. Also, Fortune et al. [3] suggested that mucosal ulceration of the oral and genital tissues in BD is associated with changes in the IgA class of immune responses. They showed that the proportion of cytophilic IgA1 was significantly increased in circulating CD8 and CD4 cells (P \ 0.01), and 30–40 % of the cytophilic IgA1 on T cells may have been of the polymeric secretory type and IgA isotype of B cells was also significantly increased (P \ 0.001) [3]. Polymeric IgA1 has been known to be an important molecule in the pathogenesis of IgA nephropathy [4]. Recently, there have been some reports showing that B cell activation factor belonging to the TNF family (BAFF) might induce an increase in serum IgA, causing glomerulonephritis in mice [5, 6]. McCarthy et al. showed that BAFF overexpression resulted in increased IgA levels within the intestinal lamina propria and deposition of IgA immune complexes in the renal glomerular mesangium [5] and also demonstrated that BAFF-overexpressing transgenic mice had mesangial deposits of IgA along with high circulating levels of polymeric IgA that is aberrantly glycosylated [6]. Aberrant glycosylation of polymeric IgA is known to be an important pathogenesis of IgA nephropathy [4]. In humans, Hamzaoui et al. [7] reported that serum BAFF levels were elevated in patients with active BD compared to the healthy controls, and disease remission was accompanied by decreased BAFF levels. Xin et al. [8] showed that serum BAFF levels were also elevated in patients with IgA nephropathy and were associated with clinical and pathological features of the disease. Therefore, there is a possibility that increased BAFF levels in BD might result in an increase in serum IgA, causing IgA nephropathy, although BAFF levels were not measured in Altay et al.’s cases, rather than simple coincidence of the two diseases. Further studies should be performed to elucidate how BAFF is involved in aberrant glycosylation of polymeric IgA.

Diagnostic Value of Renal Doppler Ultrasonography for Detecting Nutcracker Syndrome in Children With Recurrent Gross Hematuria

To the Editor, We read with great interest the recent contribution by Jodorkovsky et al. They reported a 10-year-old boy with recurrent gross hematuria who underwent a cystoscopy and a renal biopsy to evaluate its glomerular and extraglomerular causes, and nutcracker syndrome (NS) was diagnosed later by magnetic resonance angiography. They emphasized an increased awareness of the NS to avoid unnecessary invasive procedures. Agreeing to their conclusions, we would like to add a few notions to the comments. First, childhood NS is underestimated and underrecognized, which means that NS is really not a rare cause of hematuria in children. One of us (JIS) previously reported that 72 cases (33.3%) of 216 children with isolated hematuria and 9 cases (22.5%) of 40 children with gross hematuria were diagnosed with NS when Doppler sonographic criteria (aortomesenteric peak velocity [PV2]/hilar PV [PV1] in left renal vein [LRV] > 4.1) were applied. NS was the most common cause of isolated hematuria in children without urinary tract infection or proteinuria. Second, although renal venography combined with measurement of the pressure gradient between the inferior vena cava and LRV has been introduced to be the most accurate tool to diagnose NS, it is an invasive and time-consuming procedure. In the case of Jodorkovsky et al, NS was diagnosed by magnetic resonance angiography, which is too expensive. However, Doppler sonographic findings were comparable to venographic findings, and the sensitivity and specificity of the PV2/ PV1 ratios were higher than those of the ratio of LRV diameters (sensitivity 80% vs 69%; specificity 94% vs 89%) in adults with NS. According to the criterion for the PV ratio (>4.7), the sensitivity, specificity, and accuracy were also 100%, 90%, and 93%, respectively, in children with NS. Finally, regarding the treatment of NS, childhood NS can conservatively be managed because of the possibility of spontaneous resolution by physical development. Renal biopsy may be delayed in children with asymptomatic microscopic hematuria until hematuria persists in spite of the improvement of Doppler findings. In conclusion, we speculate that NS is one of the leading causes of isolated hematuria during childhood and suggest that renal Doppler ultrasonography be considered as the first screening tool for detecting NS to prevent children with NS from undergoing unnecessary invasive procedures such as cystoscopy and renal biopsy.