Edema is the abnormal accumulation of fluid beyond the compensatory capacity in the interstitial compartment of tissues within the body. There are various mechanisms that have been proposed to drive edema formation including increased hydrostatic pressure, reduced oncotic pressure within vessels, increased blood vessel wall permeability, and obstruction of the lymphatic system. In clinical practice, it is important to evaluate the characteristics and distribution of edema including pitting edema or non-pitting edema, fast edema or slow edema, systemic edema or local edema and so on. The main pathophysiology of edema might change as various clinical issues change the driving forces of edema formation. Therefore, careful monitoring of clinical and laboratory status in each patient is required for the proper management of edema.
The intrarenal renin-angiotensin system has a crucial role in the pathophysiologic functions in not only hypertension but also chronic kidney disease. Previous studies have reported that enhanced intrarenal angiotensinogen levels have been demonstrated in various renal injuries, suggesting that angiotensinogen involves in the mechanism of kidney disease. Furthermore, recent reports showed that urinary excretion rates of angiotensinogen reflect a specific index of the intrarenal renin-angiotensin system status and kidney development in neonates. Also, angiotensin converting enzyme (ACE) 2, a homolog of ACE, associates with mesangial hypercellularity of pediatric IgA nephropathy. In addition, (pro) renin receptor has a key role in physiological function and the pathogenesis of crescent formation in rat glomerulonephritis model. The pleiotropic roles of activated intrarenal renin-angiotensin system in the progression of kidney disease are being investigated in ongoing studies.
Hypertension in children is usually detected incidentally during physical examinations. However, symptoms often found in pediatric general practice, i.e. fatigue and nausea can be caused by hypertension. Therefore, blood pressure should be taken during routine medical care as often as possible. Blood pressure measurement should be repeated using a manchette appropriate for the body size, and if hypertension is observed, measurements should be taken three times in a state of ease. It is important to note that different gender, age and stature groups have different standards for blood pressure. If the patient is two years old or younger and has severe hypertension, possibility of secondary hypertension should be considered. Since majority of secondary hypertension is caused by renal parenchymal hypertension, screening for renal disease should be performed first. In essential hypertension, non-pharmacological treatment should be initiated immediately to prevent progression to adult essential hypertension. In the case of secondary hypertension, the causative disease should be diagnosed and treated. In both essential and secondary hypertension, it is necessary to lower blood pressure to normal range, improve symptoms caused by hypertension and prevent target organ damage.
IgA nephropathy (IgAN) is more frequently found in chronic glomerulonephritis (CGN) in childhood. Recently, it is reported that the pathogenesis of IgAN may be associated with defective IgA1 forms circulating or in situ immune complexes. In the presence of the genetic backgrounds, the defective IgA1 immune complex produced by T cells and B cells activated by antigen stimulation is deposited in the glomerulus and these immune complexes induce inflammation through activation of complement, macrophages and mesangial cells, and glomerular damage progresses. The prognosis of IgA nephropathy varies from normalization of urinary findings to deterioration of proteinuria and deterioration of renal function. To control these inflammations, each useful treatment was chosen according to the severity of IgAN. For children with severe IgAN, the long-term prognosis improved by multi-drug combination therapy including steroid and immunosuppressive drugs or tonsillectomy steroid plus therapy. In the future, it is expected that a treatment method with less side effects will be established.
We conducted a retrospective study of the clinical feature of neonates with multicystic dysplastic kidney (MCDK). A total of 36 patients were analyzed, of whom 6 (16.7%) had vesicoureteral reflux (VUR). Among children with VUR, high-grade vesicoureteral reflux (grades 3 to 5) was observed in 5 (83%). Initially, all children with VUR were prescribed prophylactic antibiotics. Of the five children with high-grade VUR, VUR was resolved or downgraded to grade 1 in two. The remaining children showed no improvement, so endoscopic surgery (injection of Deflux at the ureteral orifice) was performed. All cases of reflux resolved after the first injection. No significant association was observed between anomaly of the contralateral kidney and overall VUR. Furthermore, the result remained the same even when considering the grade of VUR. In the present study, no prerequisite condition concerning the omission of VCUG (voiding cystourethrography) in neonates with MCDK was detected. In cases with only one normal kidney and a risk of developing reflux nephropathy, routine VCUG for neonates with MCDK is considered beneficial.
A 12-year-old girl with hematuria and proteinuria in school urinary screening was referred to us. Physical examination revealed no extrarenal lesions. Laboratory findings revealed impaired renal function and the elevation of serum MPOANCA (anti-neutrophil cytoplasmic antibody) level. Kidney biopsy showed necrotizing crescentic glomerulonephritis. From these findings, ANCA associated nephritis was made. Early remission was achieved with the combination treatment of methylprednisolone pulse therapy and rituximab. Long term remission without severe complications has been achieved with the maintenance treatment with the combination of prednisolone and azathioprine. Rituximab might be useful to achieve early remission in ANCA associated nephritis.
After infection with group A β-hemolytic streptococci, post-streptococcal acute glomerulonephritis (PSAGN), IgA vasculitis (IgAV), and Henoch-Schönlein purpura nephritis (HSPN) could develop. However, there have been few reports of cases complicated by three. We described an interesting case of IgAV after streptococcal infection, which was associated with acute nephritis syndrome and subsequent nephrotic syndrome. The histology was consistent with both PSAGN and HSPN, showing endocapillary proliferation, crescent formation, IgA and C3 deposition as well as subepithelial hump. In previous reports of concurrent post-streptococcal acute glomerulonephritis and HSPN, these complications developed almost simultaneously. However, in this case, these complications occurred in sequence, and a pathophysiology different from that previously reported was speculated. HSPN was successfully treated with steroid pulse and cocktail therapy and second biopsy after two years revealed also histological improvement.
There are few reports of acute kidney injury (AKI) in Bartterʼs syndrome (BS). Here we present a case of a 1-year-1-month-old female with type III BS who developed AKI. At 9 months of age, the patient was found to have hyponatremia,hypokalemia, metabolic alkalosis and failure to thrive which led us to suspect salt-losing tubular disorder. Thus, potassium supplements and angiotensin-converting enzyme inhibitor (ACE-I, enalapril) were administered orally. Since then, she had been hospitalized several times due to worsening electrolyte imbalance including hypokalemia following viral infections. At age of 1 year and 1 month, she developed AKI and severe hyperkalemia due to influenza infection and poor oral intake. A genetic test confirmed the classical type III BS, which is known as classic subtype in infants and characterized by milder clinical manifestations compared with other subtypes of BS in neonates. However, our case highlights that severe volume depletion due to poor oral intake caused by viral infections in combination with the use of ACE-I that leads to renal hypoperfusion may be a risk factor for AKI in infants with BS.
A 5-year-old boy with frequently relapsing nephrotic syndrome (FRNS) developed shingles caused by a varicella vaccine strain after rituximab (RTX) administration. He had no history of chickenpox and had received two doses of varicella vaccine at the age of 1 year. At the age of 3 years, he developed NS, which remitted following the administration of an oral corticosteroid. However, the disease relapsed three months after onset, and cyclosporine was added to his treatment. He exhibited frequent relapses thereafter, and the administration of RTX, along with methylprednisolone pulse therapy, was performed. Four months later, he developed shingles and was treated with an intravenous immunoglobulin preparation and acyclovir; subsequently, the shingles ameliorated without any serious problems. A virus identification test revealed that the shingles was caused by a varicella vaccine strain, which might be activated in children with NS who experience immunosuppression with RTX or other immunosuppressive drugs. Early diagnosis and treatment are considered important in such patients.
Congenital anomalies of the genitourinary organs, including congenital hydronephrosis, are the most common morphological anomalies diagnosed on fetal ultrasound, but many cases are difficult to distinguish from cystic kidney disease. This case was a 2-year-old boy. He had been diagnosed with hydronephrosis during the fetal period, but because of a family history of cystic kidney disease, he was referred to our department for a reevaluation. Close examination revealed a left ureter-ureteric transitional passage disorder and severe enlargement of the ureter. We diagnosed the patient with severe hydronephrosis. An MAG3 scintigram showed a partial renal function of <40% and poor urinary drainage, and the patient was treated with pyeloplasty at 1 year of age. One year after the surgery, the left ureter enlargement remained, but the renal function was within normal limits, including the urine and blood tests. In this case, the influence of the family history and undetermined diagnosis resulted in excessive anxiety about genetic disease. In cases where differentiation is difficult, a careful evaluation and diagnosis, including of the timing of the determination, is necessary.
The patient is a 16-year-old female with β-thalassemia major treated with hematopoietic stem cell transplantation, having received deferasirox (Def) therapy for 3 years for transfusional iron overload. At the age of 13 years, she was started on Def. After 5 months, she was found to have hypokalemia, hypophosphatemia, and hypouricemia and required phosphate supplementation. At 16 years, she developed gastroenteritis. Laboratory data showed hypokalemia, hypophosphatemia, hypouricemia, glycosuria, and low-molecular weight proteinuria. She was diagnosed as Fanconi syndrome related to Def and required potassium supplementation in addition to phosphate. In spite of reducing the dose of Def, Fanconi syndrome worsened 4 months later, which necessitated the discontinuation of Def. While hypophosphatemia, hypouricemia, glycosuria, and low-molecular weight proteinuria resolved after 1 month, urinary potassium loss persisted. She needed potassium supplementation for 1 year. In addition to hypokalemia, natriuresis and polyuria, recognized subsequently, also persisted. Enhanced NaCl intake along with an aldosterone blocker helped to reduce urinary potassium loss. It was considered that hypokalemia was attributable to decreased proximal reabsorption of sodium, increased distal delivery, and aldosterone-driven sodium-potassium exchange leading to urinary potassium loss.