Orlistat-induced oxalate nephropathy: an under-recognised cause of chronic kidney disease.

Two patients developed kidney failure due to oxalate deposition in the kidney while taking orlistat. Cessation of orlistat was followed by partial recovery of kidney function. The mechanism by which orlistat causes hyperoxaluria and the management of orlistat-induced oxalate nephropathy is reviewed. We suggest that all patients taking orlistat are at risk of this condition, which may develop insidiously and is easily overlooked. Monitoring of kidney function of patients taking orlistat is warranted.

CRYSTALLINE RETINOPATHY FROM HYPEROXALURIA: LONG-TERM FOLLOW-UP.

PURPOSE: To report long-term follow-up in a patient with retinal oxalosis from primary hyperoxaluria. METHODS: Retrospective chart review was performed for this patient. PATIENTS: A 6-year-old girl that presented to our clinic before and after combined kidney/liver transplant. RESULTS: Optical coherence tomography and fundus findings consistent with oxalate crystal deposition. CONCLUSION: Progressive macular changes, including atrophy and fibrosis can occur in crystalline retinopathy, secondary to hyperoxaluria, after combined hepatorenal transplant.

A rare case of primary hyperoxaluria type 1 co-existing with autosomal-dominant polycystic kidney disease in a newborn.

We describe the first reported case to our knowledge of an infant presenting with the extremely rare association of primary hyperoxaluria type 1 (PH-1) and autosomal-dominant polycystic kidney disease (ADPKD). This diagnosis was suspected on the basis of the renal US findings and confirmed by complementary examinations. It led to severe oxalosis with very rapid onset of end-stage renal failure (ESRF) and required combined liver-kidney transplantation at the age of 18 months. The boy died 13 days after transplantation.

Long term results of liver-kidney transplantation in children with primary hyperoxaluria.

From 1990 to 2000, we performed eight liver-kidney transplants in eight children, aged 1-16 years, with end-stage renal failure (ESRF) due to primary hyperoxaluria (PH1). The duration of dialysis before transplantation ranged from 2 to 42 months (mean 14 months) and was <1 year in four patients. Only the first patient underwent postoperative hemodialysis; in the other five, we chose to induce maximal diuresis from the first hours with intravenous and intragastric hyperhydration (> or =3 l/m2 per day). High water intake with nocturnal tube hydration was maintained for 6 months to 5 years, as long as oxaluria exceeded 0.5 mmol/day. A quadruple sequential immunosuppressive regimen was used. Two patients died during liver graft surgery. The other six patients are alive and well, with a mean follow-up of 7.4 years (range 5-11 years). Patient and graft survival is 75% at 5 years. At latest follow-up, liver tests were normal in all six patients; creatinine clearance ranged from 55 to 95 ml/min per 1.73 m2 (mean=74). Oxaluria was lower than 0.4 mmol/day in all patients (mean=0.22). The six patients underwent 15 renal biopsies, 1-11 years after transplantation. Chronic transplant nephropathy was present in four patients and mild cyclosporin nephrotoxicity in another. No oxalate crystals were seen and repeat ultrasonography has been consistently normal in all patients. The three patients with bone oxalosis showed progressive complete healing of bone lesions. All six children or adolescents now live a normal life. From this series, we conclude that early combined liver-kidney transplantation is the treatment of choice for children with ESRF due to primary hyperoxaluria.

A case of hyperoxaluria. Radiological aspects.

PURPOSE: Oxalosis is an unusual pathological condition with calcium oxalate deposits in soft tissue and bone, recognized as osteosclerosis on radiography. Osteosclerotic bone changes in patients treated with hemodialysis are in most cases due to secondary hyperparathyroidism, but several other diagnoses have to be considered. MATERIAL, METHODS AND RESULTS: We describe the case of a young woman with advanced renal failure treated with hemodialysis since her youth. She had skeletal pain and radiological examination showed: osteosclerosis with sclerotic vertebral bodies; irregular sclerosis and unsharp periostal outline in the tubular bones of the extremities; and acrolysis and calcifications of vascular and soft tissue in the hands. Histological examination showed changes typical of oxalosis. A liver biopsy excluded primary oxalosis type I, and she probably had a secondary oxalosis due to renal failure. This condition (as opposed to primary oxalosis) can be treated with renal transplantation. CONCLUSION: Oxalosis is a rare condition but it should be considered in patients with radiological skeletal changes and chronic renal failure and should not be misinterpreted as renal osteodystrophy. The classification of oxalosis as primary or secondary is important for further treatment.

Primary hyperoxaluria type I: renal ultrasound before and after treatment.

Three patients with primary hyperoxaluria type I received therapy consisting of vitamin B6, magnesium oxide, and high oral fluid intake. Sonographic follow-up showed a variable response to treatment, ranging from normalization of renal tissue to no change at all. However, there is evidence of a correlation between laboratory findings and ultrasound findings during treatment.

Secondary oxalosis of bone in a dialysis patient.

Secondary oxalosis of bone is a complication of chronic renal failure. Its frequency and the mechanism of the deposition is unknown. We report the case of chronic renal failure patient on hemodialysis with deposition of oxalate in bone. Possible mechanisms and the significance of the depositions is also discussed.

Systemic oxalosis: pathognomonic renal and specific extrarenal findings on US and CT.

Hyperoxaluria is characterized by nephrocalcinosis and nephrolithiasis on radiological examination and may also result in diffuse deposition of calcium oxalate crystals in multiple extrarenal organs (oxalosis). In two cases, the renal findings of primary hyperoxaluria were diagnosed by ultrasound and computed tomography scans. In addition to renal involvement, both patients had liver involvement, and one patient had cardiac involvement.

Rapid reversal of bone scan abnormalities in a patient with type 1 primary hyperoxaluria and oxalosis.

Serial bone scanning was performed on a 23-year-old man with type 1 primary hyperoxaluria, renal failure, oxalosis, and cardiac failure. The initial bone scan (6/22/90) demonstrated diffuse increased uptake in the axial and peripheral skeleton, heart, and the soft tissues of the lower extremities. A combined liver and kidney transplant was successfully performed with subsequent resolution of the oxalosis, renal failure, and cardiac failure. A follow-up bone scan (9/24/90) demonstrated resolution of abnormal heart and soft tissue uptake, as well as decreased uptake in the long bones. This case demonstrates that bone scanning may be a useful tool in the management of patients with oxalosis. The scintigraphic findings closely paralleled the clinical response to treatment of the disease and suggested decreased total body stores of calcium oxalate.

Late presentation and development of nephrocalcinosis in primary hyperoxaluria.

A case of primary hyperoxaluria type 1 with complete deficiency of alanine:glyoxalate aminotransferase that first manifested at the age of 59 with irreversible acute on chronic renal failure is reported. Nephrocalcinosis, initially absent, developed rapidly after renal failure evolved. The possible role of hypovolaemia and contrast nephrotoxicity in precipitating the clinical onset is discussed. Primary hyperoxaluria should be considered in patients of any age presenting with unexplained renal failure, and appropriate systemic pathology of oxalosis.

[Radiological characteristics of primary hyperoxaluria with oxalosis]. / Caratteristiche radiologiche della iperossaluria primitiva con ossalosi.

Oxalosis is a rare disorder, in which there are widely and evenly spread deposits of oxalate crystals in the kidneys with progressive renal failure. An inborn error of metabolism is the cause of oxalosis. The incidence of this disease in boys and girls is practically equal. Most patients do not survive their 20th year. In our case there were changes in the skeleton and extensive deposits of oxalates in the kidneys.