This Syrian boy, the second child of consanguineous parents, presented with kidney stones in his country of origin at the age of 5½ years. In the following years he developed end stage kidney disease. He started hemodialysis treatment at the age of 11 years. In 2012 he underwent a kidney transplant, which failed soon after surgery. Hemodialysis was resumed. The following year he lost his ability to walk. In 2015 the patient moved to the Netherlands. Upon arrival, he was found to be underdialysed, underfed and to suffer from severe bone disease. An abdominal X-ray was performed.
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Question 1: What is the diagnosis?Correct
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A. Zwagemaker & M.J.S. Oosterveld
Genitourinary tuberculosis is commonly seen in developing countries and may lead to urinary tract infections and nephritides. The diagnosis is established by detection of tubercle bacilli in urine and heterogeneous imaging findings. These include signs of chronic pyelonephritis, papillary necrosis and scarring of renal tissue.1 A plain abdominal radiograph may demonstrate localized calcifications, but usually not generalized involvement as seen on the X-ray of our patient.
Our patient suffered from nephrocalcinosis. The most striking finding on his abdominal X-ray is nephrocalcinosis, which is characterized by generalized calcium deposition in the kidney. Calcification occurs when urinary excretion of calcium phosphate or oxalate is increased. Causes include primary hyperparathyroidism, sarcoidosis and a range of inherited conditions.2 In our patient a homozygous mutation in the AGXT-gen was detected, confirming a diagnosis of primary hyperoxaluria type 1. This is a rare autosomal recessive defect of hepatic oxalate metabolism leading to nephrocalcinosis and recurrent kidney stones.3 As a result of advanced renal disease, our patient suffered from renal osteodystrophy and (uremic) polyneuropathy. His clinical condition was deemed too poor for liver transplantation and the patient passed away at the age of 18 years.
Kidney stones are related to, but not the same as, nephrocalcinosis. Whereas nephrocalcinosis reflects calcification of renal tissue, nephrolithiasis is stone formation within the renal collecting system. Therefore, abdominal X-ray would depict stones within the collecting system and no generalized calcification.
In contrast to nephrolithiasis, urolithiasis refers to stones within the urinary tract. Typically, stones are formed in the kidney and lead to symptoms when they pass the ureter. Clinical manifestations include renal colic pain and gross hematuria. Both nephrolithiasis and urolithiasis are much more common compared to nephrocalcinosis.
- Pais VM, Dionne-Odom J. UpToDate: Renal disease in tuberculosis. Last updated May 02, 2017.
- Kobrin SM. UpToDate: Nephrocalcinosis. Last updated April 17, 2017.Strauss SB, Waltuch T, Bivin W et al.
- Primary hyperoxaluria: spectrum of clinical and imaging findings. Pediatr Radiol, 2017; 47(1): 96-103.