ENDOCRINE MANIFESTATIONS OF PRIMARY HYPEROXALURIA

Spinal Cord Compression as the First Presentation of Primary Hyperoxaluria in a Patient With Kidney Failure: A Case Report and Literature Review

A 50-year-old woman with kidney failure complained of back pain and an inability to walk. The medical history included hypothyroidism, nephrolithiasis, and resistant anemia aligned with several transfusions. The examination showed hepatosplenomegaly, lower limb weakness, absence of reflexes, and lack of sensations with a sensory level T6. Laboratory results showed hypercalcemia with suppression of parathyroid hormone levels. Magnetic resonance imaging showed vertebral fractures and mass-like lesions that compressed the spine at T4, T9, L4, and L5. Vertebral and bone marrow biopsies showed calcium oxalate (CaOx) depositions. Here, we reported a rare case of primary hyperoxaluria (PH) in a patient with kidney failure who presented with spinal cord compression caused by vertebral fractures and mass-like lesions. We summarized a literature review of PH patients with spinal cord compression, which showed only 3 cases. The multiorgan CaOx infiltration in this patient also caused resistant anemia, hepatosplenomegaly, extensive bone lesions, hypoparathyroidism, hypothyroidism, and hypercalcemia. The overdiagnosis of renal osteodystrophy and the negative family history could delay the diagnosis of PH in patients with kidney failure. Thus, clinicians should always consider PH in the differential diagnosis of kidney failure patients with stone events given that the early diagnosis of PH could be lifesaving.

Percutaneous nephrolithotomy and laparoscopic surgery efficacy and renal function outcomes for large and complex renal calculi

Background

There is limited published evidence regarding the incidence of intraoperative and postoperative events and the effect of percutaneous nephrolithotomy (PCNL) in supine and prone positions and laparoscopic pyelolithotomy on kidney function in patients with large and complex calculi.

Materials and methods

We evaluated the surgical outcomes of 97 patients with large and complex kidney stones. The patients were divided into 3 groups: those who underwent PCNL in the prone position, PCNL in the supine position, and pyelolithotomy by laparoscopy and retroperitoneoscopy. General surgical outcomes, size of residual stones, stone-free rate, glomerular filtration rate (GFR), and split GFR obtained from Tc-99m renal dynamic scintigrams were analyzed.

Results

Percutaneous nephrolithotomy in the prone position was correlated with improved function of the affected kidney. In the supine PCNL group, none of the analyzed indicators demonstrated a significant difference. Dynamic nephroscintigrams revealed negative changes in terms of accumulation and secretion of the affected kidney. A slight decrease in creatinine clearance was noted. However, positive dynamics in split GFR and secretory index were seen in this group. The laparoscopic group showed positive results in all analyzed parameters. However, full assessment of the function of the affected kidney in this group was limited due to restricted use of laparoscopic pyelolithotomy for complex stones.

Conclusions

Percutaneous nephrolithotomy in the prone position resulted in the most favorable renal functional outcomes for patients with high-grade renal calculi, whereas a laparoscopic approach may be preferred for patients with stones of lower grades. The most significant factors that adversely affected renal function were intraoperative bleeding volume, kidney stone size and density, and body mass index.

Bone health in children with primary hyperoxaluria type 1 following liver and kidney transplantation

Background

Primary hyperoxaluria type 1 is characterized by hepatic oxalate overproduction, leading to nephrocalcinosis, kidney stones, kidney failure and systemic oxalosis, including oxalate osteopathy. Combined liver-kidney transplantation (CLKT) and kidney after liver transplantation (KALT) were established therapeutic options to stop the devastating consequences of oxalate bone disease.

Methods

We describe a retrospective cohort of 10 children with PH1who were referred to our hospital from different countries for combined transplantation. Demographic and clinical data were collected and symptoms of bone disease, conventional radiological examinations, plasma oxalate levels and other determinants of calcium-phosphate metabolism were compared pre and post transplantation.

Results

Ten patients (7 male, median age 5.8 years, median follow-up time 8.1 years) were included in this study. Seven patients were diagnosed with infantile oxalosis and 9 patients received an intensified dialysis regime prior to transplantation. In one patient the transplanted kidney never achieved primary function and the boy remained on HD. All other patients remained without graft failure and retained stable kidney and liver function. Prior to transplantation, seven patients suffered from severe skeletal pain and three children presented with 1-3 series of pathological fractures. Pathological fractures did no longer occur in children who underwent successful CLKT or KALT. Plasma oxalate levels dropped within 6 months following Tx. Determinants of calcium-phosphorus metabolism did not differ significantly in comparison to other HD children. Seven of ten children showed a restricted growth at the time of transplantation and presented a moderate catch-up-growth at the time of last follow-up.

Conclusions

Patients with PH1 suffer from severe consequences of a disturbed bone metabolism. However, bone health and growth can partially improve following CLKT/KALT.

Unusual cause of cerebral calcifications in an 8-year-old girl

Key Clinical Message

Genetic counseling and genetic screening for hyperoxaluria should be recommended for children with urinary lithiasis for early management to avoid progression to oxalosis especially if there is a family history of lithiasis.

Primary hyperoxaluria type 1 (PH1) is caused by a deficiency of the liver peroxisomal enzyme alanine-glyoxylate aminotransferase (AGT) resulting in overproduction of calcium oxalates. In its later stage, a systemic deposit of calcium oxalates is observed. We present the case of an 8-year-old girl with exceptional neurological involvement secondary to this disease.

Four novel variants identified in primary hyperoxaluria and genotypic and phenotypic analysis in 21 Chinese patients

Background: Primary hyperoxaluria (PH) is a rare genetic disorder characterized by excessive accumulation of oxalate in plasma and urine, resulting in various phenotypes due to allelic and clinical heterogeneity. This study aimed to analyze the genotype of 21 Chinese patients with primary hyperoxaluria (PH) and explore their correlations between genotype and phenotype. Methods: Combined with clinical phenotypic and genetic analysis, we identified 21 PH patients from highly suspected Chinese patients. The clinical, biochemical, and genetic data of the 21 patients were subsequently reviewed. Results: We reported 21 cases of PH in China, including 12 cases of PH1, 3 cases of PH2 and 6 cases of PH3, and identified 2 novel variants (c.632T > G and c.823_824del) in AGXT gene and 2 novel variants (c.258_272del and c.866-34_866-8del) in GRHPR gene, respectively. A possible PH3 hotspot variant c.769T > G was identified for the first time. In addition, patients with PH1 showed higher levels of creatinine and lower eGFR than those with PH2 and PH3. In PH1, patients with severe variants in both alleles had significantly higher creatinine and lower eGFR than other patients. Delayed diagnosis still existed in some late-onset patients. Of all cases, 6 had reached to end-stage kidney disease (ESKD) at diagnosis with systemic oxalosis. Five patients were on dialysis and three had undergone kidney or liver transplants. Notably, four patients showed a favorable therapeutic response to vitamin B6, and c.823_824dup and c.145A > C may be identified as potentially vitamin B6-sensitive genotypes. Conclusion: In brief, our study identified 4 novel variants and extended the variant spectrum of PH in the Chinese population. The clinical phenotype was characterized by large heterogeneity, which may be determined by genotype and a variety of other factors. We first reported two variants that may be sensitive to vitamin B6 therapy in Chinese population, providing valuable references for clinical treatment. In addition, early screening and prognosis of PH should be given more attention. We propose to establish a large-scale registration system for rare genetic diseases in China and call for more attention on rare kidney genetic diseases.

Association between urine cobalt and prevalence of kidney stones in Americans aged ≥ 20 years old

To determine whether urine cobalt (Co) is associated with the prevalence of kidney stones, we conducted a cross-sectional study of participants (≥ 20 years) involved in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. The urine Co level was divided into four groups: 0.02-0.22, 0.22-0.36, 0.36-0.58, and 0.58-37.40 μg/L. The independent correlation between urine Co and prevalence of kidney stones was determined by logistic regression analyses. A total of 10,744 participants aged over 20 years that were not pregnant were eligible. Among them, 1041 participants reported ever having developed kidney stones. Patients with kidney stones developed significantly higher urine Co than the non-stone participants. The kidney stone patients were more likely to have been smoking ≥ 100 cigarettes in life; have hypertension, diabetes, and cancer; and engage in heavy activity. Multivariate logistic regression indicated a significantly positive relationship between the urine Co level and occurrence of kidney stones (OR 1.059, 95% CI 1.018-1.102, P = 0.00430). Moreover, the outcome remained unchanged after some sophisticated factors were adjusted (OR 1.059, 95% CI 1.001-1.120, P = 0.04635), and kidney stones were significantly related to a higher level of Co (OR (95% CI) = 0.22-0.36 μg/L: 1.111 (0.869, 1.421); 0.36-0.58 μg/L: 1.392 (1.095, 1.770); 0.58-37.40 μg/L: 1.712 (1.351, 2.170), and P for trend < 0.00001). So, urine Co concentration is positively associated with the prevalence of kidney stones. However, more high-quality prospective studies are needed to elucidate the causal correlation between Co level and kidney stones.