Complement-Mediated Thrombotic Microangiopathy with 10 Years of Stable Renal Function After a Year-Long Treatment with Eculizumab with Coincidental Polycystic Kidney Disease.

BACKGROUND Complement-mediated thrombotic microangiopathy (cTMA), is a genetic disease that results when an unchecked alternative complement pathway is triggered by an external factor, resulting in endothelial cell injury with microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure, though other organ systems may be involved. CASE REPORT A 5-year-old girl presented with non-bloody diarrhea, hemolysis, renal failure, and thrombocytopenia. She was negative for Shiga toxin. She was diagnosed with cTMA, and this diagnosis was confirmed later by a mutation in the complement factor H (CFH) gene. The patient was started on eculizumab 8 weeks after onset of symptoms. A month later, she was able to stop hemodialysis. Eculizumab was given for a year, and then, because of clinical remission, was stopped. At the time of stopping hemodialysis, serum creatinine was 2.07 mg/dL; at the end of eculizumab therapy, it was 1.23 mg/dL. Now, 10 years later, it is 1.10 mg/dL. Glomerular filtration rate by Schwartz equation was 52 mL/min/1.73 m² after eculizumab and 60 mL/min/1.73 m² currently. The cTMA lab parameters normalized after 2 doses of eculizumab and have remained normal for 10 years. Two years ago, on routine ultrasound, renal cysts were noted. Recent genetic testing re-confirmed the CFH mutation and additionally showed a polycystic kidney disease (PKD1) mutation. Notably, there is no family history of either. Currently, the patient has mild proteinuria. CONCLUSIONS Instead of lifelong eculizumab treatment, we successfully managed the patient's condition with a year of eculizumab and intensive followup on sixty occasions over a decade. This approach can work if there are no relapses. Genetic tests revealed mutations for cTMA and autosomal dominant polycystic kidney disease (ADPKD)/PKD1 in the same patient. These have not been reported before, to the best of our knowledge.

A Rare Complication of Peritoneal Dialysis (PD) Catheter: Perforation of Sigmoid Colon by Migrating Tip of Peritoneal Dialysis Catheter.

BACKGROUND Peritoneal dialysis (PD) has benefits over hemodialysis (HD), including the ability of daily performance at home without interfering with important activities such as school attendance in children. However, there are risks and complications associated with it. This is the third pediatric case report of a dormant PD catheter tip perforating the colon and protruding through the anus, but without peritonitis, as would be highly expected. CASE REPORT A 12-year-old male with ESRD secondary to obstructive uropathy received a pre-emptive deceased donor kidney transplant that failed within a few days due to thrombosis secondary to factor V Leiden deficiency. Transplant nephrectomy was performed and several months later he was started on PD. Subsequently, due to multiple episodes of catheter drain failure, the modality was switched to HD with a plan to remove the PD catheter later. Two months after discontinuing PD, he presented to the Emergency Department with the catheter tip protruding through the anus and he was asymptomatic. Abdominal X-ray (AXR) and CT scans were performed. The PD catheter was removed and the colon was repaired by proctosigmoidoscopy and laparotomy. Five years later, he continues to be on HD by preference, with arteriovenous fistula (AVF), without any complications of perforation. CONCLUSIONS There are 2 cases previously reported in children with colonic perforation by the tip of a PD catheter without signs and symptoms of peritonitis, but those patients were on immunosuppression after kidney transplant. Our patient is unique because he was not on immunosuppression.

Persisting Hypocalcemia After Surgical Parathyroidectomy: The Differential Effectiveness of Calcium Citrate Versus Calcium Carbonate With Acid Suppression.

The effectiveness of oral calcium (Ca) may be contingent on a patient׳s factors beyond compliance, such as proton-pump inhibitor use and the choice of calcium supplements. A 32-year-old Hispanic male with end-stage renal disease on peritoneal dialysis underwent successful surgical parathyroidectomy (intact parathyroid hormone level: 2,328pg/mL; postsurgical: 287-69pg/mL [normal: 8.5-72.5]). His postoperative course was complicated by severe and recurrent hypocalcemia as outpatient and he needed repeated admissions for intravenous Ca gluconate. Initially, severe hypocalcemia (corrected Ca: 4.8-5.6mg/dL; nadir ionized Ca: 0.57-0.69mmol/L) was attributed solely to medical noncompliance with oral Ca carbonate (3750mg, 3×/day between meals) and calcitriol (2-4mcg/day). Recognizing coexisting treatment with proton-pump inhibitor, oral Ca supplement was changed to calcium citrate (2,850mg, 3×/day) with prompt resolution of hypocalcemia (corrected Ca: 8.1-8.3mg/dL). This current case and the included literature review emphasize the disproportionate effectiveness of Ca citrate in subjects with achlorhydria.

Clinical Utility of Potassium-Sparing Diuretics to Maintain Normal Serum Potassium in Peritoneal Dialysis Patients.

♦ BACKGROUND: Hypokalemia is a vexing problem in end-stage renal disease patients on peritoneal dialysis (PD), and oral potassium supplements (OPS) have limited palatability. Potassium-sparing diuretics (KSD) (spironolactone, amiloride) may be effective in these patients. ♦ METHODS: We performed a cross-sectional review of 75 current or past (vintage > 6 months) PD patients with regard to serum potassium (K+), OPS, and KSD utilization. We reviewed charts for multiple clinical and laboratory variables, including dialysis adequacy, residual renal function, nutritional status and co-existing medical therapy. ♦ RESULTS: The cohort was middle-aged with a mean age of 49.2 years (standard deviation [SD] = 14.7) and overweight with a body mass index of 29.5 (6.7) kg/m2. Of all the participants, 57.3% were female, 73.3% African-American, and 48% diabetic with an overall PD vintage of 28.2 (24.3) months at the time of enrollment. Weekly Kt/V was 2.12 (0.43), creatinine clearance was 73.5 (33.6) L/week/1.73 m2 with total daily exchange volume of 10.8 (2.7) L. Residual urine output (RUO) measured at 440 (494) mL (anuric 30.6%). Three-month averaged serum K+ measured at 4 (0.5) mmol/L with 36% of the participants receiving K+ supplements (median: 20 [0;20] mmol/day) and 41.3% KSD (spironolactone dose: 25 - 200 mg/day; amiloride dose: 5 - 10 mg/day). Serum K+ correlated positively with weekly Kt/V (r = 0.239; p = 0.039), PD vintage (r = 0.272; p = 0.018) but not with PD modality, daily exchange volume, RUO, or KSD use. However, KSD use was associated with decreased use of OPS (r = -0.646; p < 0.0001). ♦ CONCLUSIONS: Potassium-sparing diuretics were effective in this cohort of PD patients and decreased the need for OPS utilization.

Successful Peritoneal Dialysis in Large-Weight Subjects: Clinical Features and Comparisons with Normal-Weight Subjects.

Peritoneal dialysis (PD) obviates the need for temporary vascular access in end-stage renal disease; however, extremely heavy weight has been viewed as a relative contraindication to PD.We performed a cross-sectional review of multiple clinical and laboratory variables for 75 current or past PD patients (vintage > 6 months), comparing dialysis adequacy parameters for those with a large body weight (>100 kg, LWS group) and with a normal body weight (<75 kg, NWS group).In the LWS group (n = 17), mean weight was 117.2 ± 15.7 kg, and mean body mass index (BMI) was 37.2 ± 6.3 kg/m2; in the NWS group (n = 33), mean weight was 63.2 ± 9.2 kg, and mean BMI was 25.3 ± 4.5 kg/m2. Despite the marked differences in weight and BMI between the groups (both p < 0.0001), achieved Kt/V was adequate, although marginally less, in large subjects (1.96 ± 0.29 for the LWS group vs. 2.22 ± 0.47 for the NWS group, p = 0.022), and weekly global creatinine clearance was significantly better in the LWS group (92.5 ± 43.5 L/1.73 m2 vs. 62.2 ± 27.5 L/1.73 m2, p = 0.016). The total daily exchange volume was approximately 30% higher in the LWS group (12.8 ± 2.5 L vs. 9.9 ± 2.2 L, p < 0.0001). Residual creatinine clearance (p = 0.224) and residual urine output (p = 0.125) were similar and did not seem to influence the results. Compared with their LWS counterparts, members of the NWS group were more likely to have higher iron saturation (p = 0.053) and serum ferritin (p = 0.004), but lower achieved hemoglobin (p = 0.055).Successful PD is feasible in larger-weight individuals; however, given the retrospective nature of the present study, prospective trials are needed to confirm that observation.

Serum galactose-deficient IgA1 level is not associated with proteinuria in children with IgA nephropathy.

Introduction. Percentage of galactose-deficient IgA1 (Gd-IgA1) relative to total IgA in serum was recently reported to correlate with proteinuria at time of sampling and during follow-up for pediatric and adult patients with IgA nephropathy. We sought to determine whether this association exists in another cohort of pediatric patients with IgA nephropathy. Methods. Subjects were younger than 18 years at entry. Blood samples were collected on one or more occasions for determination of serum total IgA and Gd-IgA1. Gd-IgA1 was expressed as serum level and percent of total IgA. Urinary protein/creatinine ratio was calculated for random specimens. Spearman's correlation coefficients assessed the relationship between study variables. Results. The cohort had 29 Caucasians and 11 African-Americans with a male : female ratio of 1.9 : 1. Mean age at diagnosis was 11.7 ± 3.7 years. No statistically significant correlation was identified between serum total IgA, Gd-IgA1, or percent Gd-IgA1 versus urinary protein/creatinine ratio determined contemporaneously with biopsy or between average serum Gd-IgA1 or average percent Gd-IgA1 and time-average urinary protein/creatinine ratio. Conclusion. The magnitude of proteinuria in this cohort of pediatric patients with IgA nephropathy was influenced by factors other than Gd-IgA1 level, consistent with the proposed multi-hit pathogenetic pathways for this renal disease.