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Query: UMLS:C0451641 (urolithiasis)
 3,973 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Secondary hyperoxaluria is due either to increased intestinal oxalate absorption or to excessive dietary oxalate intake. Certain intestinal diseases like short bowel syndrome, chronic inflammatory bowel disease or cystic fibrosis and other malabsorption syndromes are known to increase the risk of secondary hyperoxaluria. Although the urinary oxalate excretion is usually lower than in primary hyperoxaluria, it may still lead to significant morbidity by recurrent urolithiasis or progressive nephrocalcinosis. A clear distinction between primary and secondary hyperoxalurias is important. As correct classification may be difficult, appropriate diagnostic tools are needed to delineate the metabolic background as a basis for optimal treatment. We developed an individual approach for the evaluation of patients with suspected secondary hyperoxaluria. First, 24 h urines are examined repeatedly for lithogenic (e.g. calcium, oxalate, uric acid) and stone-inhibitory (e.g. citrate, magnesium) substances, and the patients are asked to fill in a dietary survey form. Urinary saturation is calculated using the computer based program EQUIL2, and the BONN-Risk-index is determined. The measurement of plasma oxalate and of urinary glycolate helps to distinguish between primary and secondary hyperoxalurias. If secondary hyperoxaluria is suspected, the stool is examined for Oxalobacter formigenes, an intestinal oxalate degrading bacterium, as lack or absence may lead to increased intestinal oxalate absorption. The last diagnostic step is to study the intestinal oxalate absorption using [13C2]oxalate. Depending on the results, various therapeutic options are available: 1) a diet low in oxalate, but normal or high in calcium, 2) a high fluid intake (>1.5 L/m2/d), 3) medications to increase the urinary solubility, 4) specific therapeutic measures in patients with malabsorption syndromes, depending on the underlying pathology, and 5) intestinal recolonization of Oxalobacter formigenes or the treatment with other oxalate degrading bacteria.
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PMID:Diagnostic and therapeutic approaches in patients with secondary hyperoxaluria. 1295 11

Acute oxalate nephropathy can occur due to primary hyperoxaluria and secondary hyperoxaluria. The primary hyperoxalurias are a group of autosomal recessive disorders of endogenous oxalate overproduction. Secondary hyperoxaluria may occur as a result of excess dietary intake, poisoning with oxalate precursors (ethylene glycol), or enteric hyperoxaluria. The differential diagnosis of enteric hyperoxaluria includes inflammatory bowel disease, short bowel syndrome, bariatric surgery (with jejunoileal bypass or Roux-en-Y gastric bypass), celiac disease, partial colectomy, and chronic pancreatitis. The common etiology in all these processes is fat malabsorption, steatorrhea, saponification of calcium, and absorption of free oxalate. Hyperoxaluria causes increased urinary oxalate excretion, urolithiasis (promoted by hypovolemia, decreased urinary pH caused by metabolic acidosis, and decreased citrate and magnesium concentrations in urine), tubulointerstitial oxalate deposits, and tubulointerstitial nephritis. We report a rare case of acute oxalate nephropathy due to pancreatic atrophy and exocrine insufficiency caused by newly diagnosed pancreatic cancer.
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PMID:Acute oxalate nephropathy due to pancreatic atrophy in newly diagnosed pancreatic carcinoma. 2661 99

Calcium oxalate (CaOx) crystal deposition within the tubules is often a perplexing finding on renal biopsy of both native and transplanted kidneys. Understanding the underlying causes may help diagnosis and future management. The most frequent cause of CaOx crystal deposition within the kidney is hyperoxaluria. When this is seen in native kidney biopsy, primary hyperoxaluria must be considered and investigated further with biochemical and genetic tests. Secondary hyperoxaluria, for example due to enteric hyperoxaluria following bariatric surgery, ingested ethylene glycol or vitamin C overdose may also cause CaOx deposition in native kidneys. CaOx deposition is a frequent finding in renal transplant biopsy, often as a consequence of acute tubular necrosis and is associated with poorer long-term graft outcomes. CaOx crystal deposition in the renal transplant may also be secondary to any of the causes associated with this phenotype in the native kidney. The pathophysiology underlying CaOx deposition is complex but this histological phenotype may indicate serious underlying pathology and should always warrant further investigation.
Urolithiasis 2020 Oct
PMID:Calcium oxalate crystal deposition in the kidney: identification, causes and consequences. 3271 90