Acute kidney injury associated with ingestion of star fruit: Acute oxalate nephropathy

Exploring the care experiences of hemodialysis nurses: from the cultural sensitivity approach

BACKGROUND

Culturally sensitive care has been identified as a best-practice approach for improving health outcomes. Hemodialysis patients require culturally sensitive care because it involves totally changing their previous life. The purpose of this study was to explore the subjective experiences of hemodialysis nurses in providing culturally sensitive care to hemodialysis patients.

METHODS

A qualitative study was carried out in the hemodialysis center of a teaching hospital in northern Taiwan. Purposive sampling and semi-structured interview guidelines were employed to interview 23 hemodialysis nurses. The interviews were recorded and transcribed verbatim, and the resulting data were analyzed and summarized using content analysis by constant comparative methods.

RESULTS

Hemodialysis nurses exhibited the characteristics for delivering culturally sensitive care, which comprised five aspects: finding the true meaning of the behavior of the participants, recognizing and honoring individual psychological states, culturally sensitive communication in line with patients' values, customizing care content through cultural transformation strategies, and empowerment rather than prohibition.

CONCLUSIONS

The findings of this study on the culturally sensitive care provided by hemodialysis nurses can be utilized by nursing educators and administrators as a reference to develop and enhance the nursing education related to culturally sensitive care for hemodialysis professionals.

Oxalate Nephropathy: A Case Report of Acute Kidney Injury Due to Juice Diet

Oxalate nephropathy occurs due to the deposition of calcium oxalate crystals in kidney tubules and/or the interstitium as a part of primary or secondary hyperoxaluria. Secondary oxalate nephropathy can occur even with moderately high doses of ascorbic acid intake under yet unidentified clinical circumstances. Vitamin C, although traditionally considered an antioxidant, leads to the formation of superoxide and subsequent generation of reactive oxidant species at pharmacologic concentrations. Ascorbic acid is partly converted to oxalic acid, which is responsible for deposition and renal tubular injury. We report a case of a diabetic patient with normal kidney function who was put on a juice diet for a week due to upper gastrointestinal bleeding. He developed acute kidney injury due to biopsy-proven oxalate nephropathy requiring dialysis. Though he was lost to follow-up after two weeks on dialysis, he was expected to have only a slow recovery or become dependent on dialysis given his age, comorbidities, and extent of tubular involvement. Hence, caution should be exercised before supplementing vitamin C either in its natural form or as a drug. Risk factors for secondary oxalate nephropathy due to excessive intake of oxalate or its precursor are likely to be age, diabetes, dehydration, and underlying chronic kidney disease. Most of the patients do not have a complete recovery of kidney function, and many become dependent on dialysis.

Antiepileptic therapy in a patient with star fruit intoxication: A case report

RATIONALE

It is rare for uremia patients to have epileptic seizures after eating star fruit, only a dozen cases are reported worldwide. Such patients usually have poor prognoses. Few patients had good prognoses, all of them were treated with expensive renal replacement therapy. At present, there is no report on the addition of drug therapy to these patients based on the initial renal replacement therapy.

PATIENT CONCERNS

A 67-year-old male patient with star fruit intoxication who had a history of diabetic nephropathy, hypertension, polycystic kidney, and chronic kidney disease in the uremic phase, and regular hemodialysis 3 times a week for 2 years. Initial clinical manifestations include hiccups, vomiting, speech disturbances, delayed reactions, and dizziness, which gradually progress to hearing and visual impairment, seizures, confusion, and coma.

DIAGNOSES

This patient was diagnosed with seizures caused by star fruit intoxication. The experience of eating star fruit and the electroencephalograms can prove our diagnosis.

INTERVENTIONS

We performed intensive renal replacement therapy according to the recommendations in the literature. However, his symptoms did not improve significantly until he received an extra dose of levetiracetam and resumed his previous dialysis schedule.

OUTCOMES

The patient was discharged after 21 days without neurologic sequelae. Five months after discharge, he was readmitted due to poor seizure control.

LESSONS

To improve the prognosis of these patients and to reduce their financial burden, the use of antiepileptic drugs should be emphasized.

Case report: Acute oxalate nephropathy due to traditional medicinal herbs

Acute oxalate nephropathy (AON), defined as the association between acute kidney injury (AKI) and the deposition of oxalate crystals in the renal parenchyma, is a rare complication of hyperoxaluria. We report a rare case of AON in an adult due to medicinal herbs intake leading to crystal-induced AKI. We recommend that a thorough medication history including the use of medicinal herbs, should be obtained for all patients with a rapid loss of kidney function, especially in the absence of known risk factors for AKI. The use of medicinal herbs with unknown oxalate contents would increase the risk of AON and should be avoided.

Oxalate nephropathy: a review

This review describes the clinical and pathological features of oxalate nephropathy (ON), defined as a syndrome of decreased renal function associated with deposition of calcium oxalate crystals in kidney tubules. We review the different causes of hyperoxaluria, including primary hyperoxaluria, enteric hyperoxaluria and ingestion-related hyperoxaluria. Recent case series of biopsy-proven ON are reviewed in detail, as well as the implications of these series. The possibility of antibiotic use predisposing to ON is discussed. Therapies for hyperoxaluria and ON are reviewed with an emphasis on newer treatments available and in development. Promising research avenues to explore in this area are discussed.

Acute Oxalate Nephropathy Caused by Excessive Vegetable Juicing and Concomitant Volume Depletion

Acute oxalate nephropathy (AON) induced by high dietary intake of oxalate-rich food is a rare cause of acute kidney injury and end-stage renal disease (ESRD). We describe a 68-year-old man with adequate baseline renal function who developed severe AON and ESRD. Six months earlier, he started a daily oxalate-rich fruit and vegetable juice diet high in spinach, with a calculated daily oxalate dietary intake of 1500 mg, about 10 times a typical diet. Renal biopsy showed extensive tubular oxalate deposits and acute tubular damage; the renal tissue was relatively free of chronic changes such as glomerulosclerosis, tubular atrophy, and interstitial fibrosis. A year later, he remains dialysis dependent.

Nephrotoxicity and neurotoxicity following star fruit (Averrhoa carambola) ingestion: a narrative review

In recent times, star fruit (Averrhoa carambola) nephrotoxicity and neurotoxicity have been increasingly reported, both in individuals with pre-existing renal disease and those with previously normal renal function. We summarise the clinical findings of star fruit toxicity in humans and outline the important pathogenetic insights provided by animal studies. Google Scholar, EMBASE, Scopus and PubMed were searched from 1995 through July 2020 for case reports/series on renal or neurological manifestations of star fruit toxicity in humans and mechanisms of star fruit toxicity in animal studies. Ten case series and 28 case reports in humans (total number of individuals=136) were included and 8 animal studies were analysed. Ninety-four (69.1%) patients had prior renal impairment. Renal histology showed acute oxalate nephropathy with tubulointerstitial nephritis or tubular necrosis. Neurotoxicity manifestations ranged from hiccups to status epilepticus. Oxalate and caramboxin are considered the main substances causing nephrotoxicity and neurotoxicity. Caramboxin inhibits GABA binding and activates the glutamatergic receptors. Haemodialysis improved outcomes in neurotoxicity. Nephrotoxicity and neurotoxicity need to be looked for with star fruit toxicity, both in individuals with abnormal or normal renal function. Once star fruit intoxication is identified, early renal replacement therapy should be considered. Further studies on the mechanisms of star fruit toxicity are needed.

Nutritional and medicinal properties of Star fruit (Averrhoa carambola): A review

Star fruit (Averrhoa carambola), a popular fruit in many parts of the world, is considered to have many beneficial nutritional and medicinal effects. However, harmful nephrotoxic and neurotoxic effects have also been described. In this review, we have discussed the reported beneficial effects of star fruit, explored the potential mechanisms for such beneficial effects, and outline factors that may affect the safe level of consumption. The beneficial effects include the following: antioxidant (mediated via L-ascorbic acid, epicatechin, and gallic acid), hypoglycemic (mediated via high fiber levels and 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione), hypotensive (mediated via apigenin), hypocholesterolemic (mediated via micronized fiber), anti-inflammatory, anti-infective, antitumor effects, and immune-boosting effects. The presence of chronic kidney disease, gastroenteropathies, chronic pancreatitis, dehydration, consumption on an empty stomach, and higher concentration of oxalate in fruit/juice consumed predisposes to toxicity. The level of ingestion at which the beneficial effects transition to nephrotoxicity and neurotoxicity is still to be accurately ascertained. Furthermore, the relationship between the amount of star fruit ingested and the severity of toxicity is not certain and warrants further study.

Acute Kidney Injury Following Star Fruit Ingestion: A Case Series

Star fruit (Averrhoa carambola) is a popular fruit in many tropical countries, including Sri Lanka. It is rich in oxalic acid, which is nephrotoxic in higher concentrations. The development of both acute (AKI) and chronic kidney injury after oxalate nephropathy is often underrecognized. Here we discuss the risk factors, clinical features, treatment, and outcomes of 4 patients who developed AKI after star fruit ingestion. Baseline clinical characteristics, the amount of star fruit ingested, clinical presentation, investigation, and outcome of the patients (ages 28, 50, 54, and 55 y; all male) were traced. More common symptoms of acute star fruit intoxication were nausea, vomiting, and abdominal and back pain, followed by low urine output and high serum creatinine over hours to days. Urinary analysis of all patients demonstrated oxalate crystals. Histopathologic examination of renal tissues of all 4 patients revealed acute tubular damage with calcium oxalate crystals, interstitial edema, and inflammatory cellular infiltration. The presence of calcium oxalate crystals was further confirmed with the brilliant birefringence seen under polarized light. Two patients needed intermittent hemodialysis over a week owing to oliguria and uremia. The other 2 patients did not require hemodialysis and had improvement of renal function with supportive treatment. All had high renal function on discharge but were back to normal within a month. This study highlights AKI as a serious complication of star fruit ingestion. The type and quantity of star fruit ingested and some patient factors may play a role in the pathogenesis of AKI. Public education about this serious uncommon complication is important.

Community-Acquired AKI in Asia: An Update

Community-acquired acute kidney injury (CA-AKI) is the dominant form of AKI encountered in developing countries in Asia. Economic disparities, variations in access to health care services, geographic conditions, environmental risk factors, and sociocultural circumstances shape the causes and outcomes of CA-AKI. Infections, drugs, plant and chemical toxins, envenomations, and obstetric complications are common causes of CA-AKI. Previously healthy young individuals who often work outdoors in fields or farms are exposed to a wide variety of work-related or environmental risk factors for CA-AKI. Improving disease definitions, better data, and evolving host-pathogen interactions have changed disease descriptions and presentations over the past 20 years. Among infections, although the incidence of malaria has decreased, the number of cases with dengue and scrub typhus have increased sharply. The recognition of AKI in relation to Plasmodium knowlesi, Plasmodium vivax, scrub typhus, and leptospirosis in areas not traditionally considered at risk, association of infections with the future development of chronic kidney disease, and the role of complement dysregulation in infection-associated AKI are important new findings. Snake-bite-related toxic envenomation continues to be an important cause of AKI in some counties and is a neglected public health problem. On the other hand, significant decreases in the incidence of AKI related to acute diarrheal illness or obstetric causes are signs of hope. Coordinated efforts between administrative stakeholders, society, and health care delivery services at all levels have the potential to propel research and improve outcomes in CA-AKI.

Mechanisms of star fruit (Averrhoa carambola) toxicity: A mini-review

The star fruit (Averrhoa carambola) is consumed in high amounts in Asia and Central/South America. It contains oxalic acid and caramboxin. In some individuals, its ingestion may lead to nephrotoxicity and neurotoxicity. The nephrotoxic effect is due to oxalate deposition in renal tubules resulting in acute tubular necrosis and interstitial nephritis. Although uraemic encephalopathy secondary to acute kidney injury may play a role, a shift to an excitatory state of the central nervous system (CNS) by caramboxin through activation of excitatory neuroreceptors and inhibition of GABA receptors leads to mental confusion, seizures and status epilepticus seen with star fruit intoxication. In this mini-review, we discuss the mechanisms of star fruit-related toxicity.

Circulating human microRNA biomarkers of oxalic acid-induced acute kidney injury

Oxalic acid-induced nephrotoxicity and acute kidney injury result from formation of calcium oxalate crystals. Oxalic acid-induced acute kidney injury is a significant problem in many parts of the world. Circulating biomarkers that can accurately and reproducibly detect acute kidney injury are highly desirable. We used a high sensitivity discovery platform to identify signature microRNAs to distinguish healthy individuals never exposed to oxalic acid (n = 4) from those who were exposed to oxalic acid but had no injury (NOAKI; n = 4), moderate injury (AKIN2; n = 4) or severe injury (AKIN3; n = 4). Longitudinal analyses identified 4-8 h post-ingestion as the best time to detect AKIN2/3. We validated a signature of 53 microRNAs identified in the discovery, in a second cohort of individuals exposed to oxalic acid (NOAKI = 11, AKIN2 = 8 and AKIN3 = 18) and healthy controls (n = 19). Thirteen microRNAs were significantly downregulated in acute kidney injury patients compared to NOAKI within 8-h post-ingestion. Five microRNAs (miR-20a, miR-92a, miR-93, miR-195, miR-451) had a highly significant correlation with normalized urinary albumin, serum creatinine at 24 h and creatinine clearance. Logistic regression of these microRNAs had AUC-ROC of 0.85 predicting AKIN2/3 and discriminated patients from healthy controls (AUC-ROC = 0.93). mRNA targets of these microRNAs identified oxidative stress pathways of nephrotoxicity in proximal tubule and glomeruli nephrotoxicity. In conclusion, the downregulation of multiple circulating microRNAs in patients correlated with the severity of oxalic acid-induced acute kidney injury. A set of microRNAs (miR-20a, miR-92a, miR-93, miR-195, miR-451) could be promising biomarkers for early detection of oxalic acid-induced acute kidney injury.

Acute Kidney Injury with Neurological Features: Beware of the Star Fruit and its Caramboxin

Star fruit (Averrhoa carambola) is a well-known product in tropical countries. There are few reports published in literature with acute kidney injury due to oxalate induced nephropathy. However, none of them have an important neurological feature. We present a case of a 51-year-old male with paresis and altered mental status. Screening for neurological diseases such as stroke, Guillain-Barre, meningitis and encephalitis were negative. In the evolution, he developed acute kidney failure and was submitted to 4 dialysis sessions. After talking to the family, we discovered he had ingested over 50 star fruits prior to the acute neurologic deficits. He recovered renal function so a renal biopsy was not required. Physicians should actively look for star fruit ingestion history in patients presenting with unexplained acute kidney injury with or without neurological features. Besides, taking star fruit in a large amount, accompanied by an empty stomach and dehydrated state, is a risk factor for neurotoxicity.

Secondary Oxalate Nephropathy: A Systematic Review

Introduction

Little is known of the clinical outcomes of secondary oxalate nephropathy. To inform clinical practice, we performed a systematic review of case reports and case series to examine the clinical characteristics and outcomes of patients with secondary oxalate nephropathy.

Methods

Electronic databases were searched for case reports and case series of individual cases or cohorts of patients with biopsy-proven oxalate nephropathy in native or transplanted kidneys from 1950 until January 2018.

Results

Fifty-seven case reports and 10 case series met the inclusion criteria, totaling 108 patients. The case series were meta-analyzed. Mean age was 56.4 years old, 59% were men, and 15% were kidney transplant recipients. Fat malabsorption (88%) was the most commonly attributed cause of oxalate nephropathy, followed by excessive dietary oxalate consumption (20%). The mean baseline serum creatinine was 1.3 mg/dl and peaked at 4.6 mg/dl. Proteinuria, hematuria, and urinary crystals was reported in 69%, 32%, and 26% of patients, respectively. Mean 24-hour urinary oxalate excretion was 85.4 mg/d. In addition to universal oxalate crystal deposition in tubules and/or interstitium, kidney biopsy findings included acute tubular injury (71%), tubular damage and atrophy (69%), and interstitial mononuclear cell infiltration (72%); 55% of patients required dialysis. None had complete recovery, 42% had partial recovery, and 58% remained dialysis-dependent. Thirty-three percent of patients died.

Conclusion

Secondary oxalate nephropathy is a rare but potentially devastating condition. Renal replacement therapy is required in >50% of patients, and most patients remain dialysis-dependent. Studies are needed for effective preventive and treatment strategies in high-risk patients with hyperoxaluria-enabling conditions.