Abstract
BackgroundStar fruit (Averrhoa carambola) is commonly consumed as a herbal remedy for various ailments in tropical countries. However, the dangers associated with consumption of star fruit are not commonly known. Although star fruit induced oxalate nephrotoxicity in those with existing renal impairment is well documented, reports on its effect on those with normal renal function are infrequent. We report two unique clinical presentation patterns of star fruit nephrotoxicity following consumption of the fruit as a remedy for diabetes mellitus—the first, in a patient with normal renal function and the second case which we believe is the first reported case of chronic kidney disease (CKD) due to prolonged and excessive consumption of star fruits.Case presentationThe first patient is a 56-year-old female diabetic patient who had normal renal function prior to developing acute kidney injury (AKI) after consuming large amount of star fruit juice at once. The second patient, a 60-year-old male, also diabetic presented with acute on chronic renal failure following ingestion of a significant number of star fruits in a short duration with a background history of regular star fruit consumption over the past 2–3 years. Both had histologically confirmed oxalate induced renal injury. The former had histological features of acute tubulo-interstitial disease whilst the latter had acute-on-chronic interstitial disease; neither had histological evidence of diabetic nephropathy. Both recovered over 2 weeks without the need for haemodialysis.ConclusionThese cases illustrate the importance of obtaining the patient’s detailed history with respect to ingestion of herbs, traditional medication and health foods such as star fruits especially in AKI or CKD of unknown cause.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1640-8) contains supplementary material, which is available to authorized users.
Highlights
Star fruit (Averrhoa carambola) is commonly consumed as a herbal remedy for various ailments in tropical countries
It could be postulated that the prolong consumption of star fruit had led to recurrent occult renal damage resulting in chronic interstitial nephritis and chronic kidney disease (CKD)
It is imperative that a history with respect to ingestion of foods such as star fruits is inquired especially in patients with acute kidney injury (AKI) or CKD of unknown cause
Summary
Star fruit (Averrhoa carambola), locally known as “Kamaranka”, is believed to have originated from Ceylon and Moluccas and is a popular fruit in tropical and subtropical countries [1]. She had no prior history of urinary tract stones or a family history of kidney disease On presentation her clinical examination was unremarkable with no neurological signs and a blood pressure of 138/80 mmHg. Investigations revealed a serum creatinine which had risen from her baseline value of 80 μmol/L and eGFR of 68.4 ml/ min/1.73 m2 from 1 month before to 290 μmol/L with urine full report showing trace amounts of protein and 20–25 pus cells/hpf. Apart from that there was no other history of drug consumption, vitamin C use, Fig. 1 Histology (haematoxylin and eosin stain) of the renal biopsy of case 1 showing acute oxalate induced tubulo-interstitial nephritis. The interstitium shows moderate numbers of lymphocytes herbal medication or substance abuse He had no family history of renal stone disease. After 2 weeks his serum creatinine returned to his baseline of 130 μmol/L and an eGFR of 51.91 ml/min/1.73 m2
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