Fatal outcome after ingestion of star fruit (Averrhoa carambola) in uremic patients

Averrhoa carambola leaves prevent dyslipidemia and oxidative stress in a rat model of poloxamer-407-induced acute hyperlipidemia

Background: The star fruit [Averrhoa carambola L (Oxalidaceae)] is traditionally used in the treatment of many ailments in many countries. It possesses several pharmacological activities, including antioxidant and anti-inflammatory effects. However, it contains the neurotoxic caramboxin and its high content of oxalic acid limits its consumption by individuals with compromised kidney function. This study assessed the anti-hyperlipidemic and antioxidant activities of different fractions of the methanolic extract of A. carambola leaves (MEACL). Methods: The antioxidant activity was investigated using FRAP, and ABTS and DPPH radical-scavenging assays and the inhibitory activity toward pancreatic lipase (PL) and HMG-CoA reductase was assayed in vitro. Acute hyperlipidemia was induced by poloxamer-407 (P-407) in rats and different fractions of MEACL (n-hexane, chloroform, n-butanol, ethyl acetate (EA), water, and chloroform) were orally administered. Cholesterol and triglycerides were determined at 0, 12, 24, and 48 h and LDL-C, vLDL-C, HDL-C, lipid peroxidation (LPO) and antioxidants were assayed after 48 h. The expression of ABCA1, ABCG5, ABCG8, LDL-R, SREBP-1, and SREBP-2 and the activity of HMG-CoA reductase were assayed in the liver of P-407-administered rats treated with the EA fraction. Results: The in vitro data revealed potent radical-scavenging activities of MEACL fractions with the most potent effect showed by the EA fraction that also suppressed the activities of HMG-CoA reductase and PL. In P-407-induced hyperlipidemic rats, all fractions prevented dyslipidemia as shown by the decrease in total cholesterol, triglycerides, LDL-C, vLDL-C and atherogenic index. MEACL and its fractions prevented LPO and boosted GSH, superoxide dismutase, glutathione peroxidase, and catalase in P-407-administered rats. The EA fraction showed more effective anti-hyperlipidemic and antioxidant effects than other fractions and downregulated SREBP-2 while upregulated ABCA1 and LDL-R and ameliorated LPL and HMG-CoA reductase in hyperlipidemic rats. Conclusion: MEACL showed in vitro and in vivo antioxidant activity and the EA fraction significantly ameliorated dyslipidemia in a rat model of P-407-induced acute hyperlipidemia by modulating LPL, PL, HMG-CoA reductase, and cholesterolgenesis-related factors. Therefore, the leaves of A. carambola represent a safe alternative for the star fruit particularly in kidney disease patients, and the EA is the most effective anti-hyperlipidemic and antioxidant fraction.

Acute and sub-chronic toxicological evaluation of Averrhoa carambola leaves in Sprague Dawley rats

Averrhoa carambola is a species of tree native to tropical Southeast Asia. It possesses antioxidant and anti-hyperlipidemia effects and has traditionally been used to treat a variety of ailments. However, the presence of oxalic acid in its fruits might restrict its consumption by individuals suffering from kidney disease, and caramboxin can cause neurotoxicity. In this study, we evaluated the acute and sub-chronic toxicity of the methanolic extract of A. carambola leaves (MEAC) in male and female rats. In the acute study, female rats were given a single oral dose of 5000 mg/kg of MEAC and closely examined for distinct indications of toxic effects during the first 4 h, periodically for 48 h, and daily thereafter for 14 days. Rats of both sexes were employed in the sub-chronic investigation for the 28-day repeated dose oral toxicity study. Results of the acute study revealed the safety of MEAC up to a dose of 5000 mg/kg where the rats did not show changes or signs of toxicity. In the sub-chronic toxicity study, MEAC (250, 500, and 1000 mg/kg) administration did not affect the body weight, food, and water consumption, motor coordination, behavior, or mental alertness in the treated rats. In addition, no variations in hematological or biochemical markers were found in MEAC-treated rats. In conclusion, these findings pinpoint the safety of MEAC at doses up to 5000 mg/kg. The leaves of A. carambola could be safely consumed by people with kidney disease to treat other ailments.

Acute kidney injury associated with consumption of starfruit juice: A case report

BACKGROUND

This study aims to highlight the potential serious complications of acute kidney injury (AKI) resulting from the consumption of excessive amounts of starfruit, a common traditional remedy.

CASE SUMMARY

A 78-year-old male with a past medical history of hypertension, diabetes mellitus and hyperlipidemia without prior nephropathy presented to the emergency department (ED) with hiccups, nausea, vomiting and generalized weakness. In the preceding 1 wk, he had consumed 3 bottles of concentrated juice self-prepared from 1 kg of small sour starfruits. His serum creatinine was noted to be 1101 μmol/L from baseline normal prior to his ED visit. He was diagnosed with AKI secondary to excessive starfruit consumption.

CONCLUSION

Consumption of starfruit can cause acute renal failure, with a good outcome when promptly identified and treated.

Caffeinated drinks, fruit juices, and epilepsy: A systematic review

The aim of this systematic review was to provide the required information regarding different aspects of the relationship between epilepsy/antiseizure medications and non-alcoholic drinks. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement were followed. MEDLINE and Scopus from the inception until 7 August 2021 were systematically searched. These key words were used: "epilepsy" OR "seizure" OR "antiepileptic" OR "antiseizure" OR "anticonvulsant" AND "coffee" OR "tea" OR "soda" OR "juice" OR "drink" OR "cola" OR "diet" (35 key word combinations). The primary search yielded 21 458 publications (PubMed, n = 4778; Scopus, n = 16 680). Only 50 studies met all the inclusion criteria and were included in the current systematic review. In total, 17 articles investigated various non-alcoholic drinks in human studies, 11 studies were case reports/series, and 22 articles were animal/in vitro studies. None of the studies provided a class 1 of evidence. There is limited evidence suggesting that certain drinks (eg, caffeinated energy drinks) might trigger seizures. Patients with epilepsy should avoid excessive consumption of certain fruit juices (eg, grapefruit, lime, pomegranate, kinnow, and star fruit) and caffeinated drinks. However, daily coffee and tea intake can be part of a healthy balanced diet, and their consumption does not need to be stopped in patients with epilepsy. Coffee/tea consumption is not harmful if consumed at levels of 200 mg (caffeine) in one sitting (about 2½ cups of coffee) or 400 mg daily (about five cups of coffee).

Traditional Uses, Phytochemical Constituents and Pharmacological Properties of Averrhoa carambola L.: A Review

Averrhoa carambola L. (star fruit) is an edible fruit that is extensively cultivated in southern China, Southeast Asia, India, and northern South America. It has a sweet and juicy taste and is frequently used in fruit salads and fruit platters, as a garnish in cocktail drinks and beverages, or squeezed into juice and served as a beverage. Traditionally, it has been used for treating diabetes and diabetic nephropathy, arthralgia, vomiting, lithangiuria, coughing, hangovers, and chronic paroxysmal headache for thousands of years. Currently, approximately 132 compounds have been isolated from A. carambola. Among them, flavonoids, benzoquinone, and their glycosides have been considered as biologically active substances, which are responsible for various biological activities. Pharmacological studies have revealed that crude extracts or monomeric compounds from A. carambola exhibit multiple bioactivities, such as anti-oxidant, anti-hyperglycemic, anti-obesity, anti-hyperlipidemic, anti-tumor, anti-inflammatory, hepatoprotective, cardioprotective, anti-hypertensive, neuroprotective, and others. Thus, A. carambola is a valuable treatment in Chinese medicine with therapeutic potential for multiple diseases, especially diabetes and diabetes-related diseases. Even though it is a very promising candidate in the development of functional food and the pharmaceutical industry, reports on its bioactivities have only been conducted in vivo and in vitro and there is a gap in research regarding clinical settings and safety. This review therefore provides a comprehensive and systematic overview of current progress on botany, ethnopharmacology, phytochemistry, pharmacology, and toxicity of A. carambola, providing a valuable reference for further developments and applications of A. carambola in the pharmaceutical industry and functional food.

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.

Standardization of experimental model regarding star fruit intoxication in Wistar rats suffering with nephropathy

Purpose

To present a model to reproduce the clinical condition, in order to better understand the pathophysiology of neurological impairment related to intoxication.

Methods

Twenty-five Wistar rats were used and divided into five groups: Shaw group (WHI), water gavage group (WGV), star fruit gavage group (SGV), nephropathic group with water gavage (NPW), nephropathic group with star fruit gavage (NPS).Nephropathic groups were submitted to surgery, developing nephropathy. After surgery, they received preestablished gavage with star fruit juice or water. The electroencephalographic records were evaluated in the experimental nephropathic group that received gavage of star fruit juice.

Results

To assess the induction of neurotoxicity using electroencephalographic data, the NPS group demonstrated the presence of epileptic seizures associated with star fruit intoxication.

Conclusions

The experimental model herein presented was adequate to reproduce the clinical condition experienced by nephropathic patients who ingest star fruit juice, establishing, thus, an experimental model utterly important for the study of the neurological toxicity process.

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.

Acute nephrotoxicity and neurotoxicity associated with concentrated star fruit juice consumption

Star fruit toxicity has been hugely described in patients with chronic kidney disease, either on conservative or renal replacement therapy. This is a case report of a man, without prior kidney or neurological dysfunction, who appeared to develop nephrotoxicity and neurotoxicity less than 12 hours after drinking concentrated star fruit juice (approximately 20 units of the fruit). He received timely renal replacement therapy and renal function fully recovered after discharge.

Hiccups: You got to be kidney me!

Hiccups are usually benign processes that most people experience with spontaneous resolution. However, persistent hiccups with a duration greater than 48 h may prompt a thorough workup for structural, infectious, or inflammatory disorders. Moreover, toxic-metabolic states, including renal dysfunction and/or uremia, have also been identified as sources of hiccups. We present a 62-year-old male with persistent hiccups that developed acute, worsening renal function. Workup for a possible intrinsic renal disease process was negative. Ultimately, a kidney biopsy was performed, demonstrating acute tubular injury with oxalate crystals and interstitial fibrosis. Dialysis was initiated with resolution of the hiccups, and kidney function improved over an extended period of time.

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.

C-Fos expression in epileptogenic areas of nephropathic rats undergoing star fruit poisoning

Purpose

Studies have demonstrated that star fruit consumption by nephropathic patients triggers severe neurotoxic effects that can lead to convulsions or even death. Brain areas likely susceptible to star fruit poisoning have not been investigated. The objective of the present study was to map possible epileptogenic areas susceptible to star fruit intoxication in nephropathic rats.

Methods

The study analyzed 25 rats (5 groups). Rats in the experimental group underwent bilateral ureteral obstruction surgery and orogastric gavages with star fruit juice. An electroencephalogram was used to confirm convulsive seizures. Urea and creatinine levels were used to confirm the uremia model. Immunohistochemical analysis was used to map cells with c-Fos protein (c-Fos+ cells) to identify brain areas with increased neuronal activity. Control groups included non-nephropathic and nephropathic rats that did not receive star fruit.

Results

A statistically significant increase (p<0.01) in c-Fos+ cells was noted in nephropathic animals receiving star fruit juice compared to control groups, in brain areas commonly related to epileptogenic neural circuits including the hippocampus, amygdala, rhinal cortex, anterior cingulate area, piriform area, and medial dorsal thalamus.

Conclusion

These data corroborate the neurotoxic capacity of star fruit in nephropathic patients.

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.

Effect of an aqueous extract of Averrhoa carambola L. on endothelial function in rats with ventricular remodelling

Ventricular remodelling leads to cardiomyocyte hypertrophy, myocardial fibrosis, endothelial vasoactive substance changes and endothelial dysfunction. Our purpose was to research the effect of an aqueous extract of Averrhoa carambola L. (AEA) on endothelial function in rats with ventricular remodelling induced by isoprenaline. Rats were subjected to injection of isoprenaline and administration of various drugs. Vasoactive substances were measured, and the ventricular remodelling index was detected by the weighing method. Immunohistochemical analysis, pathological examination, Western blot and Masson's trichrome staining were performed. After AEA administration, the levels of transforming growth factor-β (TGF-β), angiotensin II (AngII), inducible NO synthase (iNOS), endothelin-converting enzyme (ECE), and endothelin 1 (ET-1); the ventricular remodelling index; and the collagen volume fraction were decreased, while the levels of total NO synthase (tNOS) and endothelial NO synthase (eNOS) were increased. The pathological examination results showed that apoptosis, fibrosis, necrosis and inflammatory infiltration of myocardial tissue were attenuated by AEA treatment. AEA might alleviate ventricular remodelling in rats by maintaining the balance of vasoactive substances and the function of the vascular endothelium.

Perspectives on the Medical, Quality of Life, and Economic Consequences of Hiccups

PURPOSE OF REVIEW

Singultus or hiccups (HU) is a common, usually temporary, event. Its potentially serious consequences are often overlooked. This review explores published evidence describing HU burden (clinical, economic, and quality of life [QoL] consequences) across patient populations.

RECENT FINDINGS

Literature review identified 81 articles (including 57 individual case reports). We extracted relevant information to better understand the burden of HU and to identify knowledge gaps for future study. HU are physiologic events that can complicate existing medical conditions and treatments regardless of duration. Relatively short episodes can have devastating consequences in patients who have pre-existing conditions. HU appear to impact physical and psychological health, diminish QoL, increase healthcare resource use, and increase costs. A better understanding of HU burden is needed.

Star fruit nephrotoxicity: a case series and literature review

Background

Star fruit is a popular medicinal fruit in the tropics. Its hypoglycaemic properties are considered useful in achieving glycaemic control in diabetes. Star fruit induced nephrotoxicity is a rare cause of acute kidney injury in individuals with both normal and reduced baseline renal function. We present three cases of acute kidney injury due to star fruit nephrotoxicity from Sri Lanka, and discuss the published literature on this topic.

Case presentation

Three Sri Lankan patients, all with a background of diabetes, presented to us with acute nausea and anorexia following recent consumption of star fruit. Two patients complained of diarrhoea and one patient complained of intractable hiccoughs. They all had elevated serum creatinine on admission. Two were known to have normal baseline serum creatinine levels. On renal biopsy two had evidence of oxalate crystal deposition. One did not show crystal deposition but had acute interstitial nephritis for which no alternate cause could be identified. Two were treated with short courses of prednisolone and two required acute haemodialysis. All recovered renal function, with both patients with known baselines approaching their premorbid serum creatinine levels.

Conclusion

Consumption of star fruit, especially on an empty stomach or in a state of dehydration may precipitate acute kidney injury. A history of star fruit ingestion must be actively looked for in patients presenting with unexplained acute kidney injury. The use of star fruit as a therapy for diabetes should be discouraged.

Kidney toxicity related to herbs and dietary supplements: Online table of case reports. Part 3 of 5 series

BACKGROUND

No tabular summary of potentially life-threatening, kidney-toxic dietary supplements (DS; includes herbs) based on PubMed case reports is currently available online and continually updated to forewarn United States consumers, clinicians, and companies manufacturing DS. The purpose of this review was to create an online research summary table of kidney toxicity case reports related to DS.

METHODS

Documented PubMed case reports (1966 to May 2016, and cross-referencing) of DS appearing to contribute to kidney toxicity were listed in "DS Toxic Tables." Keywords included "herb" or "dietary supplement" combined with "kidney" to generate an overview list, and possibly "toxicity" to narrow the selection. Case reports were excluded if they involved herb combinations (some exceptions), Chinese herb mixtures, teas of mixed herb contents, mushrooms, poisonous plants, self-harm, excessive doses (except vitamins/minerals), legal or illegal drugs, drug-herbal interactions, and confounders of drugs or diseases. Since commercial DS often include a combination of ingredients, they were treated separately; so were foods. A few foods with kidney-toxic effects were listed in a fourth table. The spectrum of herbal or DS-induced kidney injuries included kidney stones, nephritis, nephrotic syndrome, necrosis, acute kidney injury (AKI; previously known as acute renal failure [ARF]), chronic kidney disease, kidney transplant, and death.

RESULTS

Approximately 7 herbs (minus 4 no longer for sale) and 10 dietary supplements (minus 3 excluded due to excessive doses + germanium that is no longer sold) have been related to kidney injury case reports published in PubMed (+crosslisting) in the last 50 + years (1966 to May 2016). The implicated herbs include Chinese yew (Taxus celbica) extract, impila (Callilepis laureola), morning cypress (Cupressus funebris Endl), St. John's wort (Hypericum perforatum), thundergod vine (Tripterygium wilfordii hook F), tribulus (Tribulus terrestris) and wormwood (Artemisia herba-alba). No longer sold in the United States are chocolate vine or mu tong (Caulis aristolochiae), guang fang ji (Aristolochia fangchi), ma huang (Ephedra sinica), and Tenshin Tokishigyaku-ka-goshuyu-shokyo-to. The DS include bile (sheep), chlorella, chromium (Cr), CKLS, creatine, gallbladder (fish), glucosamine, hydrazine, N.O.-Xplode, Spanish fly, and excess intakes of vitamins A, C, and D. Germanium (Ge) is not available for sale. The top two DS with the largest number of reported publications, but not always case reports, in descending order, were the aristolochic acid-containing herbs guang fang ji (mistaken identity) and chocolate vine or mu tong. The remaining DS featured one to three publications over a 50+ year period. Numerous case reports were reported for kidney-toxic foods: djenkol bean, gallbladders (carp fish, pufferfish, & snake), and star fruit (only in chronic kidney disease patients), and uncooked yam powder or juice.

CONCLUSION

This online "DS Toxic Table" provides clinicians, consumers, and manufacturers with a list of herbs that could potentially contribute to kidney injuries.

Effects of Juice Processing on Oxalate Contents in Carambola Juice Products

Effects of processing methods including pressing, enzyme-assisted extraction, lactic acid fermentation by Lactobacillus acidophilus, and alcohol fermentation by Saccharomyces cerevisiae on total and soluble oxalate contents of carambola juices were studied. In comparison with pressing, the use of enzyme increased juice yields (15.89-17.29%), but resulted in higher total oxalate (1.60-1.73 times) and soluble oxalate contents (1.16-1.49 times). In addition, extension of enzyme incubation periods led to an increase in soluble oxalate contents in the products (p < 0.05). On the other hand, alcohol fermentation with Saccharomyces cerevisiae from 1 to 5 weeks reduced 37-58% of total oxalate and 39-59% of soluble oxalate contents. Prolonged fermentation also demonstrated better reduction of oxalate contents. Meanwhile, lactic acid fermentation using Lactobacillus acidophilus had no effects on total and soluble oxalate contents in carambola juices. These results suggested that carambola juice products should only be consumed moderately, and that alcohol fermentation could be a potential method to reduce oxalate contents in foods in order to prevent the risks of forming kidney stones.

Association of renal function and symptoms with mortality in star fruit (Averrhoa carambola) intoxication

BACKGROUND

Star fruit (SF) is a commonly available fruit produced and eaten in tropical and subtropical countries. Since 1993, various reports have described neurotoxicity after eating SF, but this clinical condition remains unfamiliar. We aimed to describe this clinical entity, the role of renal dysfunction in this disorder, treatment strategies, and prognosis of patients with SF intoxication.

METHODS

We conducted a search of PubMed and Google Scholar databases from 1993 to 2016. We included reports describing patients with a clear history of SF ingestion with acute symptoms. We described the demographic characteristics, reported SF intake, treatments used, and outcomes.

RESULTS

We reviewed totally 126 patients (male:female = 1.5:1) from 33 articles with mean age 54.4 ± 11 (range: 30-84). The most common symptom was hiccups (65%), whereas confusion and seizure were the most common symptoms associated with mortality (42% and 61%, respectively). Pre-intoxication renal function also affected mortality. While there was no mortality in patients with normal renal function (NRF), the mortality of patients among reported cases with chronic renal insufficiency and end-stage renal disease undergoing dialysis were 36% and 27%, respectively. With the inclusion of patients reported to have NRF, the overall mortality was 24%. Consistently, the number of SF consumed was substantially higher in the patients with NRF than those with renal functional impairment. The most common treatment strategy was hemodialysis (59%).

CONCLUSIONS

Patients with impaired renal function were at higher risks of SF intoxication. Severe neurologic symptoms mandate immediate medical intervention because of the association between their occurrence and high mortalities. Toxin removal through dialysis, rather than symptomatic relief, seems to be beneficial to patient survival. Early and continuous dialysis appears to alleviate severe symptoms and prevent symptom rebounds.

Nutritional, Medicinal and Toxicological Attributes of Star-Fruits (Averrhoa carambola L.): A Review

Plants are very complex organisms that produce medicinally important natural products. The Star-fruit producing plant (Averrhoa carambola L.) is a species of woody plant in the family Oxalidaceae native to the Philippines, Indonesia, Malaysia, Vietnam, India, Bangladesh and Sri Lanka; but, cultivated in many parts of the world. Star-fruits are popular tropical fruits and used commonly in Ayurvedic and Traditional Chinese Medicines (TCM) in India, China, and Brazil to relieve ailments such as chronic headache, fever, cough, gastro-enteritis, diarrhoea, ringworm infections, and skin inflammations. However, this fruit contains high amount of oxalate, which is hazardous for uremic patients, and caramboxin (CBX), which is neurotoxic. The aim of this review is to highlight the nutritional, medicinal and toxicological traits of the star-fruits.

N-acetylcysteine protects against star fruit-induced acute kidney injury

Background: Star fruit (SF) is a popular fruit, commonly cultivated in many tropical countries, that contains large amount of oxalate. Acute oxalate nephropathy and direct renal tubular damage through release of free radicals are the main mechanisms involved in SF-induced acute kidney injury (AKI). The aim of this study was to evaluate the protective effect of N-acetylcysteine (NAC) on SF-induced nephrotoxicity due to its potent antioxidant effect.

Materials and methods: Male Wistar rats received SF juice (4 mL/100 g body weight) by gavage after a 12 h fasting and water deprivation. Fasting and water deprivation continued for 6 h thereafter to warrant juice absorption. Thereafter, animals were allocated to three experimental groups: SF (n = 6): received tap water; SF + NAC (n = 6): received NAC (4.8 g/L) in drinking water for 48 h after gavage; and Sham (n = 6): no interventions. After 48 h, inulin clearance studies were performed to determine glomerular filtration rate. In a second series of experiment, rats were housed in metabolic cages for additional assessments.

Results: SF rats showed markedly reduced inulin clearance associated with hyperoxaluria, renal tubular damage, increased oxidative stress and inflammation. NAC treatment ameliorated all these alterations. Under polarized light microscopy, SF rats exhibited intense calcium oxalate birefringence crystals deposition, dilation of renal tubules and tubular epithelial degeneration, which were attenuate by NAC therapy.

Conclusions: Our data show that therapeutic NAC attenuates renal dysfunction in a model of acute oxalate nephropathy following SF ingestion by reducing oxidative stress, oxaluria, and inflammation. This might represent a novel indication of NAC for the treatment of SF-induced AKI.

Herbal Product Contamination and Toxicity

Herbal poisoning exposures reported to poison centers increased by 344% after passage of the Dietary Supplement Health and Education Act, with 24412 exposures reported in 2003. Increased toxicity is speculated to be related to lack of child-resistant packaging, new issues of contamination, proliferation of multiple ingredient products, excessive concentration of active ingredients, and discovery of new drug-herb interactions. This review addresses contamination issues such as heavy metals, pharmaceuticals, homeopathic remedies, microbes, insects, environmental chemicals, and mis-identification of one plant for another. Toxicity issues covered include carcinogenicity, delay in seeking medical treatment when using herbs to treat serious illness, toxic components, hypersensitivity reactions, hepatotoxins, nephrotoxins, epileptogenic compounds, cardiac toxins, gastrointestinal toxins, and hematologic toxins. Common drug-herb interactions are discussed. The pharmacist plays an important role in patient education and evaluation of potential toxicities related to herbal supplements.

Renin gene rs1464816 polymorphism contributes to chronic kidney disease progression in ADPKD

Background

Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic disorder and is a common genetic cause of chronic renal failure in children and adults. The enzyme renin plays a key role in the RAAS cascade and an important role in the development of hypertension and progression of renal disease in ADPKD. The present study is aimed to investigate the potential modifier effect of REN gene polymorphisms on the progression of chronic kidney disease (CKD) in ADPKD.

Methods

We analyzed 102 ADPKD patients and 106 healthy controls from the same geographic area. FRET-based KASPar single-nucleotide polymorphism (SNP) genotyping assays for REN gene tag-SNPs (rs2887284, rs2368564, rs1464816, rs7521667, rs10900555, rs6693954, rs6676670 and rs11571078) were performed. Cochran-Armitage trend test was used to assess the potential associations between these polymorphisms and CKD stages. Haplotype frequencies and LD measures were estimated by using the software Haploview. Mantel-Haenszel stratified analysis was used to explore confounding and interaction effects of these polymorphisms.

Results

Of the eight tag-SNPs genotyped, the rs10900555 polymorphism deviated from the Hardy-Weinberg equilibrium in controls. The presence of ADPKD in general was not significantly associated with the REN tag-SNPs included in this study. Linkage disequilibrium analysis yielded three haplotype blocks and the haplotypes of the respective blocks are not statistically different between ADPKD and controls. In multivariate analysis, the rs1464816 TG genotype showed a significant association with the advancement of CKD in ADPKD (OR = 4.80; 95 % CI = 1.30–17.82; p = 0.019).

Conclusions

The present study provides evidence that the rs1464816 polymorphism in REN is associated with CKD progression in ADPKD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-015-0217-0) contains supplementary material, which is available to authorized users.

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

Starfruit (Averrhoa carambola) and its juice are popular in the Indian subcontinent as an indigenous medicine. Oxalate concentration in this fruit and it's freshly prepared juice is very high. We present a report of patients presenting with acute kidney injury due to oxalate nephropathy admitted in a single center. All patients had history of ingesting star fruit. Patients became symptomatic after 10-12 h of eating and main symptoms were pain abdomen and decrease in urine output. Three patients needed hemodialysis. All improved with complete renal recovery. Taking star fruit in large amount on an empty stomach and in a dehydrated state is a risk factor for nephrotoxicity.

Nephropathy in dietary hyperoxaluria: A potentially preventable acute or chronic kidney disease

Hyperoxaluria can cause not only nephrolithiasis and nephrocalcinosis, but also renal parenchymal disease histologically characterized by deposition of calcium oxalate crystals throughout the renal parenchyma, profound tubular damage and interstitial inflammation and fibrosis. Hyperoxaluric nephropathy presents clinically as acute or chronic renal failure that may progress to end-stage renal disease (ESRD). This sequence of events, well recognized in the past in primary and enteric hyperoxalurias, has also been documented in a few cases of dietary hyperoxaluria. Estimates of oxalate intake in patients with chronic dietary hyperoxaluria who developed chronic kidney disease or ESRD were comparable to the reported average oxalate content of the diets of certain populations worldwide, thus raising the question whether dietary hyperoxaluria is a primary cause of ESRD in these regions. Studies addressing this question have the potential of improving population health and should be undertaken, alongside ongoing studies which are yielding fresh insights into the mechanisms of intestinal absorption and renal excretion of oxalate, and into the mechanisms of development of oxalate-induced renal parenchymal disease. Novel preventive and therapeutic strategies for treating all types of hyperoxaluria are expected to develop from these studies.

Sustained low-efficiency daily diafiltration with hemoperfusion as a therapy for severe star fruit intoxication: a report of two cases

Over the past decade, star fruit (Averrhoa carambola) intoxication decreased in the Taiwanese society due to improved public education on chronic kidney disease (CKD). Various complications including hiccups, altered levels of consciousness, coma, and seizures have been reported in individuals with renal failure who ingested fresh star fruit or star fruit juice. A high mortality rate (from 33 to 80%) was observed in patients with altered levels of consciousness, despite prompt dialysis and supportive care. According to previous case reports, the proposed treatment of choice for severe star fruit intoxication may be continuous renal replacement therapy with or without hemoperfusion. We report two cases of star fruit intoxication with stage V CKD (one case is predialysis) presenting with coma and generalized tonic-clonic seizures. The two patients were treated with sustained low-efficiency daily diafiltration (SLEDD-f) and charcoal hemoperfusion. Status epilepticus was controlled fairly quickly after treatment with SLEDD-f and hemoperfusion. However, the outcomes in this report are still poor (both remained comatose; one of two patients died). Currently, there are no data for the use of SLEDD-f with hemoperfusion for severe star fruit intoxication. SLEDD-f with charcoal hemoperfusion may play a role in managing refractory status epilepticus in patients with severe star fruit poisoning.

Hypotensive effect of aqueous extract of Averrhoa carambola L. (Oxalidaceae) in rats: an in vivo and in vitro approach

AIM OF THE STUDY

Averrhoa carambola L. (Oxalidaceae) leaves are used in Brazilian traditional medicine to treat hypertension. This study was conducted to evaluate the hypotensive effect of the aqueous extract of Averrhoa carambola (AEAc) and its underlying mechanisms in the isolated rat aorta.

MATERIALS AND METHODS

The effect of AEAc on the mean arterial pressure (MAP) was determined in vivo in anesthetized rats. In vitro, thoracic aortic rings were isolated and suspended in organ baths, and the effects of AEAc were studied by means of isometric tension recording experiments. In HPLC analysis, the fingerprint chromatogram of AEAc was established.

RESULTS

In normotensive rats, AEAc (12.5-50.0 mg/kg, i.v.) induced dose-dependent hypotension. In vitro, AEAc caused a depression in the E(max) response to phenylephrine without a change in sensibility. Also, in a depolarized Ca(2+)-free medium, AEAc inhibited CaCl(2)-induced contractions and caused a concentration-dependent rightward shift of the response curves, indicating that AEAc inhibited the contractile mechanisms involving extracellular Ca(2+) influx.

CONCLUSIONS

These results demonstrate the hypotensive effects of AEAc, and these effects may, in part, be due to the inhibition of Ca(2+), which supports previous claims of its traditional use.

The uncommon causes of status epilepticus: a systematic review

This paper reports the first systematic review of uncommon causes of status epilepticus reported in the literature between 1990 and 2008. Uncommon causes are defined as those not listed in the main epidemiological studies of status epilepticus. 181 causes were identified. These were easily categorised into 5 specific aetiological categories: immunological disorders, mitochondrial disorders, infectious diseases, genetic disorders and drugs/toxins. A sixth category of 'other causes' has also been included. Knowledge of these causes is important for clinical management and treatment, and also for a better understanding of the pathophysiology of status epilepticus.

Severe encephalopathy after ingestion of star fruit juice in a patient with chronic renal failure admitted to the intensive care unit

Star fruit (Averrhoa carambola) is a popular tropical fruit that is usually consumed as fresh fruit or fruit juice. Consumption of star fruit by patients with chronic renal failure can lead to neurologic symptoms. The present report describes the clinical course, management, and outcome of a patient with chronic renal failure admitted to an intensive care unit after ingestion of star fruit juice 2 days before hospital admission. A case of nausea, vomiting, intractable hiccups, and severe encephalopathy along with mental confusion, disorientation, agitation, and seizures in a 53-year-old woman is presented. The patient's ventilatory pattern worsened, with development of dyspnea and tachypnea, which resulted in her transfer to an intensive care unit. Although hemodialysis was performed and the septic shock was adequately treated, the patient died on the fifth day after hospital admission. The susceptibility of patients with chronic renal failure to star fruit and the severity of intoxication are poorly known by intensivists. This case demonstrates that star fruit consumption should be considered as a cause of rapid deterioration in the renal function of patients with underlying chronic renal failure, potentially resulting in a fatal outcome.

[Star fruit (Averrhoa carambola) toxic encephalopathy]

Ingestion of star fruit (Averrhoa carambola) can induce severe intoxication in subjects with chronic renal failure. Oxalate plays a key role in the neurotoxicity of star fruit. We report the cases of two patients with unknown chronic renal insufficiency who developed severe encephalopathy after ingestion of star fruit. The two patients developed intractable hiccups, vomiting, impaired consciousness and status epilepticus. Diffusion-weighted MR imaging showed cortical and thalamic hyperintense lesions related to epileptic status. They improved after being submitted to continuous hemofiltration which constitutes the most effective treatment during the acute phase.

The role of oxalate in star fruit neurotoxicity of five-sixths nephrectomized rats

To investigate the role of oxalate in star fruit neurotoxicity, rats were given star fruit or oxalate after a sham operation or modified five-sixths nephrectomy; namely, star fruit (SC) or oxalate (OxC) for sham-operated rats and star fruit (SNx), calcium gluconate treated star fruit juice (SCaNx), or oxalate (OxNx) for nephrectomized rats. After feedings, none of the rats in SC, OxC, and SCaNx groups developed movement disorders or died, while all rats in SNx group and OxNx group presented movement disorders and two rats in SNx group and four rats in OxNx group died within minute to hour after development of myoclonic jerk and/or tonic-clonic convulsion. The plasma oxalate levels rose significantly only in the SNx group and OxNx group that also presented clusters of generalized spike-waves in the electroencephalographic recordings. In conclusion, oxalate may play a key role in star fruit neurotoxicity in nephrectomized rats and probably in uremic patients.

Hemoperfusion as an Effective Alternative Therapy for Star Fruit Intoxication: A Report of 2 Cases

This report describes 2 cases of star fruit intoxication successfully treated with charcoal hemoperfusion (CHP). Common clinical characteristics of the reported cases included persistent hiccup, consciousness disturbance, coma, need for ventilator support, and admission to an intensive care unit. The optimum treatment for star fruit intoxication has been controversial, with modality, dose, and appropriate timing of extracorporeal therapy debated. Analysis of the 2 reported cases shows several advantages of CHP, including increased extraction efficiency, rapid recovery of consciousness, decreased time of intensive care unit admission, and good clinical tolerance. CHP may provide an alternative treatment modality in cases with life-threatening star fruit intoxication with poor response to intensified hemodialysis.

Electrophysiological effects of the aqueous extract of Averrhoa carambola L. leaves on the guinea pig heart

This work aims to describe some electrophysiological changes promoted by the aqueous extract (AEx) from Averrhoa carambola leaves in guinea pig heart. The experiments were carried out on isolated heart or on right atrium-ventricle preparations. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd degrees); increased the QT interval from 229+/-23 to 264+/-19 ms; increased the QRS complex duration from 27+/-3.1 to 59+/-11 ms, and depressed the cardiac rate from 136+/-17 to 89+/-14b pm. Furthermore, it decreased the conduction velocity of atrial impulse (17+/-3%); reduced the intraventricular pressure (86+/-6%), and increased the conduction time between the right atrium and the His bundle (27+/-6.5%). The conduction time from the His bundle to the right ventricle was not altered. Atropine sulfate did not change either the electrocardiographic parameters or the intraventricular pressure effects promoted by the A. carambola AEx. Based on these results, the popular use of such extracts should be avoided because it can promote electrical and mechanical changes in the normal heart.

Management of Star Fruit—Induced Neurotoxicity and Seizures in a Patient with Chronic Renal Failure

An 84-year-old Asian woman with hypertension and chronic renal failure was evaluated for incoherent speech, followed by intermittent interruptions of consciousness, and then status epilepticus after ingesting one star fruit (Averrhoa carambola) each day for 3 days. Conventional first-line anticonvulsants and hemodialysis were administered without significant control of the patient's seizures. Treatment was started with propofol, an intravenous agent that induces anesthesia with rapid onset and elimination from the central nervous system; this resulted in complete control of the seizures. Propofol may be an effective alternative when dialysis and conventional first-line anticonvulsants are unsuccessful in treating the symptoms of neurotoxicity.

Status epilepticus induced by star fruit intoxication in patients with chronic renal disease

Star fruit has been reported as containing neurotoxins that often cause severe neurological complications in patients with chronic renal disease. We report two patients with chronic renal failure at a pre-dialyzed stage who developed refractory status epilepticus after ingestion of star fruit. In addition, we review 51 cases in the literature. Among 53 patients, 16 patients presented with epileptic seizures (30%). The mortality rate was as high as 75% in patients with seizures. On the other hand, in patients without seizures, the mortality rate was only 0.03%. There is a poor correlation with the degree of underlying renal function and mortality due to intoxication. We propose that epileptic seizure is significantly associated with poor prognosis, and that status epilepticus is an unpredictable and potentially fatal complication in star fruit intoxication. We advise consultant neurologists that star fruit intoxication must be considered when patients with chronic renal disease present with seizures or other unexplained neurological or psychiatric symptoms. Since no effective treatment has been established, star fruit consumption should be avoided in patients with chronic renal disease, especially in the elderly.

A novel type of encephalopathy associated with mushroom Sugihiratake ingestion in patients with chronic kidney diseases

BACKGROUND

The etiology of encephalopathy in uremic patients is multiple. We recently encountered a novel type of encephalopathy which occurred exclusively in patients with chronic kidney diseases after ingestion of a mushroom called Sugihiratake. While the exact etiology of this encephalopathy remained mysterious, we aimed to describe its clinical features.

METHODS

A total of 32 patients with chronic kidney diseases who had presented with encephalopathy following ingestion of Sugihiratake were enrolled from seven prefectures in Japan., with 24 of the 32 patients undergoing regular hemodialysis. The patient's clinical data were from surveillance by The Japanese Society of Nephrology.

RESULTS

There was a significant association between Sugihiratake ingestion and the occurrence of encephalopathy in 524 hemodialysis patients questioned for a recent ingestion of this mushroom (P= 0.0006). The latent asymptomatic period before the onset of symptoms varied from 1 to 31 days (mean 9.1 +/- 7.3) days. The patient's symptoms consisted of disturbed consciousness in 30 patients (93.8%), convulsions in 25 (78.1%), myoclonus in 15 (46.9%), dysarthria in ten (31.3%), ataxia in eight (25.0%), paresis or paralysis in seven (21.9%), and skin parasthesia in two patients (6.3%). Nine (27.2%) patients died, mostly due to respiratory failure. The other patients were either discharged or still in hospitals with various degrees of clinical improvement.

CONCLUSION

Patients with chronic kidney diseases are at risk of having serious encephalopathy following Sugihiratake ingestion and must refrain from eating it. Physicians, in those parts of the world, where this mushroom harvesting is common, should be aware of this complication.

Negative inotropic and chronotropic effects on the guinea pig atrium of extracts obtained from Averrhoa carambola L. leaves

It has been reported that star fruit can lead to a fatal outcome in uremic patients. The intoxication syndrome consists of hiccups, mental confusion, dizziness, and vomiting. On the other hand, folk medicine uses teas and infusions of carambola leaves to treat headache, vomiting, cough, insomnia, and diabetes. This motivated us to determine if Averrhoa carambola can act on the contractility and automaticity of the guinea pig heart. We measured the atrial isometric force in stimulated left atria and determined the chronotropic changes in spontaneously beating right atria. The carambola leaf extracts (1.5 mg/ml) abolished the contractile force in a concentration-dependent manner. Among the crude, methanolic, ethanolic, aqueous, and acetic extracts, the aqueous one was the most potent (EC50 = 520 +/- 94 microg/ml; flavonoids and tannins are the main constituents; Na+ and K+ contents in 1.0 mg/ml of aqueous extract were 0.12 +/- 0.016 and 1.19 +/- 0.15 mM, respectively). The aqueous extract abolished the positive Bowditch staircase phenomenon and reduced the inotropic response to CaCl2 (0.17-8.22 mM), events that are dependent on the cellular Ca2+ inward current. The adrenergic, muscarinic or opioid membrane receptors do not seem to participate in the mechanism of action of the cardioactive substance(s). In spontaneously beating atria, the aqueous extract promoted a negative chronotropic effect that was antagonized by 0.1 microM isoproterenol bitartrate. With this agonist, the EC50 of the aqueous extract increased from 133 +/- 58 to 650 +/- 100 microg/ml. These data regarding the effect of A. carambola on guinea pig atrial contractility and automaticity indicate an L-type Ca2+ channel blockade.

Non-convulsive status epilepticus and consciousness disturbance after star fruit (Averrhoa carambola) ingestion in a dialysis patient

Star fruit ingestion may induce severe neurological complications in chronic renal failure patients. We present a case on maintenance dialysis therapy who developed a consciousness disturbance without convulsion after eating star fruit. The symptoms became aggravated after haemodialysis. The brain computed tomography scan showed no abnormal findings, but the electroencephalogram found active focal sharp waves in the left central regions and diffusion-weighted magnetic resonance imaging also showed hyperintense lesions in the left central regions that were compatible with non-convulsive status epilepticus. His condition improved dramatically after anticonvulsant therapy and regular haemodialysis. The patient was discharged 20 days later without neurological sequela.

Star fruit intoxication in uraemic patients: case series and review of the literature

Star fruit, belonging to the Oxalidaceae family, species Averrhoa carambola, is a popular fruit among Orientals. There have been reports of hiccup, confusion, and occasional fatal outcomes in uraemic patients after ingestion of star fruit. An excitatory neurotoxin from star fruit has been implicated although the exact nature of this toxic substance has not been identified. A group of seven patients is described from the dialysis centres at Queen Mary and Tung Wah Hospitals who developed symptoms including hiccup, confusion, vomiting, impaired consciousness, muscle twitching and hyperkalaemia shortly after ingestion of star fruit. Symptoms of most patients resolved after intensified dialysis or spontaneously, and no mortality was observed. The close temporal relationship of ingestion of star fruit and onset of symptoms strongly suggests the existence of a causal relationship between the two. It is recommended that uraemic patients should totally abstain from star fruit due to these rare but potentially fatal complications. The clinical manifestations of other reported series and current evidence for the possible candidate(s) of the neurotoxin are discussed.