Warning signs
Patient warning signs can include one or a combination of the symptoms listed below1-7:
A single kidney stone in children or recurring kidney stones in adults should cause suspicion of primary hyperoxaluria (PH).
- Family history of kidney or bladder stones
- A single pediatric kidney stone
- Recurring kidney stones in adults
- Chronic kidney disease (CKD) with unknown etiology
- Nephrocalcinosis
- Systemic oxalosis
- Failure to thrive, ESRD, severe retinal abnormalities or vision loss in infants
- End-stage renal disease (ESRD)
Family history of kidney or bladder stones
Many patients are asymptomatic for years, with 18% to 21% of people with primary hyperoxaluria being diagnosed by familial screening before they show any symptoms.4,5
A single pediatric kidney stone
Children should not develop bladder or kidney stones, and the presence of even a single kidney stone in an infant or child should immediately raise suspicion of a genetic condition like primary hyperoxaluria.2,10
Recurring kidney stones in adults
A single kidney stone in an adult is not uncommon, but recurring kidney stones can be indications of an underlying metabolic disorder or genetic disease. Recurrent UTIs, flank pain, and blood in the urine are often the first signs of kidney stones. Pediatric kidney stones can also present with vomiting and fever.2,10-12
Chronic kidney disease (CKD) with unknown etiology
Suspect primary hyperoxaluria when a patient presents with reduced renal function combined with nephrocalcinosis or a high occurrence of kidney stones.1,9,13
Nephrocalcinosis
Both pediatric and adult patients with early signs of nephrocalcinosis should be screened for primary hyperoxaluria.2,10
Systemic oxalosis
Renal failure can be the first clinical indication of primary hyperoxaluria in some patients, even in infancy. When patients are in renal failure, calcium oxalate can deposit in tissues throughout the body.9,14
Signs of systemic oxalosis include the following14,15:
- Stunted bone growth
- Recurrent low-trauma fractures
- Bone deformations with osteodystrophy
- Anemia
- Severe bone pain
- Skin nodules and ulcers
- Cardiomyopathy
- Cardiac conduction disturbances and heart block
- Retinopathy and visual impairment
Failure to thrive, ESRD, severe retinal abnormalities or vision loss in infants
Infantile onset occurs in 18% of patients with PH1. Infants with this severe form present with end-stage renal disease, failure to thrive, severe retinal abnormalities, and vision loss during their first year.3,6,7,16
End-stage renal disease (ESRD)
Many people are not diagnosed with PH until they are in ESRD (35% of all patients with PH1 and 11% of patients with PH2), although these patients often had earlier symptoms that went unrecognized, such as recurring kidney stones. 59% to 70% of people diagnosed with PH1 as adults are in ESRD at the time of diagnosis.3,5,17,18