Severe hemolysis and methemoglobinemia following fava beans ingestion in glucose-6-phosphatase dehydrogenase deficiency: case report and literature review

Naphthalene Ball Ingestion Leading to Intravascular Hemolysis and Acute Kidney Injury

Naphthalene is an aromatic hydrocarbon found in mothballs, deodorizers, or insecticides. Naphthalene poisoning is not commonly seen in the pediatric age group due to its pungent odor and taste, water insolubility, and poor absorption from the gastrointestinal tract (GIT). This case report describes a five-year-old boy who experienced accidental naphthalene mothball ingestion resulting in intravascular hemolysis and acute kidney injury (AKI). Naphthalene exposure can cause severe complications, especially in children. The clinical presentation included fever, abdominal pain, vomiting, decreased urine output, and hematuria. The laboratory findings revealed hemolytic anemia, elevated serum creatinine, and proteinuria. The child received supportive treatment including intravenous fluids, packed red blood cell transfusions, and hemodialysis for AKI. Early diagnosis and intervention are crucial for a favorable outcome. This case highlights the importance of considering naphthalene poisoning in the differential diagnosis of children with hemolysis and AKI.

Acute Kidney Injury Following Naphthalene (Mothball) Poisoning

Naphthalene is a widely available moth repellant in the Asian subcontinent. Toxicity can occur either accidentally or intentionally as a suicide attempt. An overdose can lead to a variety of clinical symptoms, including intravascular hemolysis, and can sometimes lead to life-threatening clinical situations. A young male was admitted to our center with an alleged history of ingesting an unknown quantity of naphthalene balls (mothballs). He developed methemoglobinemia, intra-vascular hemolysis, anuria, and acute kidney injury (AKI), followed by cardiorespiratory arrest. He was treated successfully with intravenous methylene blue and dialysis. Naphthalene toxicity can lead to methemoglobinemia and intravascular hemolysis. This can result in AKI caused by pigment nephropathy.

Methemoglobinemia and Delayed Encephalopathy After 5-Bromo-2-Nitropyridine Poisoning: A Rare Case Report

5-bromo-2-nitropyridine, an intermediate in the synthesis of pharmaceutical and pesticide products, is toxic to the human body. However, 5-bromo-2-nitropyridine poisoning has not been previously reported. Here, we report the case of a 40-year-old man who suffered skin and respiratory tract exposure to leaked 5-Bromo-2-nitropyridine at work. After exposure, the patient rapidly developed dizziness, fatigue, nausea, vomiting, chest distress, diffuse cyanosis, and coma. Methemoglobinemia, hemolytic anemia, rhabdomyolysis, and acute renal failure were observed after admission. He improved markedly after treatment, but delayed encephalopathy was confirmed 82 days after the exposure. This case highlights that 5-bromo-2-nitropyridine can be absorbed through the skin and respiratory tract, resulting in methemoglobinemia and delayed encephalopathy.

Favism: A Case Report

Favism is an acute hemolytic syndrome that occurs in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency following the ingestion of fava beans. Diagnosis can be challenging because the severity of hemolytic anemia varies among this patient population. Furthermore, the severity of hemolytic episodes can vary in the same patient. The diagnosis of G6PD deficiency and patient education pertaining to safe and unsafe medications and foods are crucial to prevent the reoccurrence of hemolytic episodes. Here, we report the case of a man admitted to our hospital with an acute hemolytic episode. At the time of admission, we were unaware that he had ingested fava beans and only discovered that he had G6PD deficiency while performing complementary studies during the hemolytic crisis to determine its etiology.

Cyanosis Due to Methemoglobinemia as the Presenting Sign of Glucose-6-Phosphate Dehydrogenase Deficiency in a Child: Diagnostic and Clinical Implications

A previously healthy 3-year-old boy presented with pallor, jaundice, cyanosis, and a 24-hour history of vomiting and anorexia following fava bean ingestion. Clinical examination and laboratory findings were consistent with severe nonimmune hemolytic anemia with methemoglobinemia. Given the patient's history, a previously unrecognized glucose-6-phosphate dehydrogenase deficiency was suspected and diagnosed. The aim of this article is to delineate the possible coexistence of methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency in children presented with acute hemolysis and discuss its management while reviewing the existing literature.

Favism-induced methemoglobinemia in a G6PD deficient male with a subsequent hemolytic cascade, a therapeutic challenge: Case report and review of literature

The co-occurrence of acute hemolysis and methemoglobinemia secondary to favism in G6PD deficient individuals is rare. Identifying it promptly is of high clinical significance as treating methemoglobinemia (with methylene blue) can worsen hemolysis.

Therapeutic Intervention of COVID-19 by Natural Products: A Population-Specific Survey Directed Approach

To date very few promising leads from natural products (NP) secondary metabolites with antiviral and immunomodulatory properties have been identified for promising/potential intervention for COVID-19. Using in-silico docking studies and genome based various molecular targets, and their in vitro anti-SARS CoV-2 activities against whole cell and/or selected protein targets, we select a few compounds of interest, which can be used as potential leads to counteract effects of uncontrolled innate immune responses, in particular those related to the cytokine storm. A critical factor for prevention and treatment of SARS-CoV-2 infection relates to factors independent of viral infection or host response. They include population-related variables such as concurrent comorbidities and genetic factors critically relevant to COVID-19 health disparities. We discuss population risk factors related to SARS-CoV-2. In addition, we focus on virulence related to glucose-6-phosphate dehydrogenase deficiency (G6PDd), the most common human enzymopathy. Review of data on the response of individuals and communities with high prevalence of G6PDd to NP, prompts us to propose the rationale for a population-specific management approach to rationalize design of therapeutic interventions of SARS-CoV-2 infection, based on use of NP. This strategy may lead to personalized approaches and improve disease-related outcomes.

Methemoglobinemia and hemolytic anemia after COVID-19 infection without identifiable eliciting drug: A case-report

We report a second case of methemoglobinemia and non-autoimmune hemolytic anemia after contracting the SARS-CoV-2 infection in the absence of an identifiable eliciting drug. A 35-year old male without previous known comorbidities was admitted after he was diagnosed with the COVID-19 infection and had large pulmonary involvement. Seven days later, he desaturated but was without any signs of respiratory distress. A check of arterial blood gas revealed normal partial pressure of oxygen and follow-up tests confirmed a methemoglobinemia diagnosis. Over the next few days, hemolysis was established after decreased levels of hemoglobin and increased levels of indirect bilirubin and lactate dehydrogenase. A hemolytic anemia investigation panel came back normal, including G6PD. A second G6PD test was ordered at the 5-month follow-up appointment and revealed decreased levels. Clinicians should thus be aware of possible false negative tests when testing for G6PD during hemolytic crisis. In addition, whether the COVID-19 infection alone would be responsible for this chain of events remains a challenging question.

Hemolytic Dynamics of Weekly Primaquine Antirelapse Therapy Among Cambodians With Acute Plasmodium vivax Malaria With or Without Glucose-6-Phosphate Dehydrogenase Deficiency

Background

Hemoglobin (Hb) data are limited in Southeast Asian glucose-6-phosphate dehydrogenase (G6PD) deficient (G6PD⁻) patients treated weekly with the World Health Organization–recommended primaquine regimen (ie, 0.75 mg/kg/week for 8 weeks [PQ _0.75]).

Methods

We treated Cambodians who had acute Plasmodium vivax infection with PQ_0.75 and a 3-day course of dihydroartemisinin/piperaquine and determined the Hb level, reticulocyte count, G6PD genotype, and Hb type.

Results

Seventy-five patients (male sex, 63) aged 5–63 years (median, 24 years) were enrolled. Eighteen were G6PD deficient (including 17 with G6PD Viangchan) and 57 were not G6PD deficient; 26 had HbE (of whom 25 were heterozygous), and 6 had α-/β-thalassemia. Mean Hb concentrations at baseline (ie, day 0) were similar between G6PD deficient and G6PD normal patients (12.9 g/dL [range, 9‒16.3 g/dL] and 13.26 g/dL [range, 9.6‒16 g/dL], respectively; P = .46). G6PD deficiency (P = <.001), higher Hb concentration at baseline (P = <.001), higher parasitemia level at baseline (P = .02), and thalassemia (P = .027) influenced the initial decrease in Hb level, calculated as the nadir level minus the baseline level (range, −5.8–0 g/dL; mean, −1.88 g/dL). By day 14, the mean difference from the day 7 level (calculated as the day 14 level minus the day 7 level) was 0.03 g/dL (range, −0.25‒0.32 g/dL). Reticulocyte counts decreased from days 1 to 3, peaking on day 7 (in the G6PD normal group) and day 14 (in the G6PD deficient group); reticulocytemia at baseline (P = .001), G6PD deficiency (P = <.001), and female sex (P = .034) correlated with higher counts. One symptomatic, G6PD-deficient, anemic male patient was transfused on day 4.

Conclusions

The first PQ_0.75 exposure was associated with the greatest decrease in Hb level and 1 blood transfusion, followed by clinically insignificant decreases in Hb levels. PQ_0.75 requires monitoring during the week after treatment. Safer antirelapse regimens are needed in Southeast Asia.

Clinical Trials Registration

ACTRN12613000003774.

Tafenoquine: A Step toward Malaria Elimination

There is a pressing need for compounds with broad-spectrum activity against malaria parasites at various life cycle stages to achieve malaria elimination. However, this goal cannot be accomplished without targeting the tenacious dormant liver-stage hypnozoite that causes multiple relapses after the first episode of illness. In the search for the magic bullet to radically cure Plasmodium vivax malaria, tafenoquine outperformed other candidate drugs and was approved by the U.S. Food and Drug Administration in 2018. Tafenoquine is an 8-aminoquinoline that inhibits multiple life stages of various Plasmodium species. Additionally, its much longer half-life allows for single-dose treatment, which will improve the compliance rate. Despite its approval and the long-time use of other 8-aminoquinolines, the mechanisms behind tafenoquine's activity and adverse effects are still largely unknown. In this Perspective, we discuss the plausible underlying mechanisms of tafenoquine's antiparasitic activity and highlight its role as a cellular stressor. We also discuss potential drug combinations and the development of next-generation 8-aminoquinolines to further improve the therapeutic index of tafenoquine for malaria treatment and prevention.

Severe acute kidney injury owing to rhabdomyolysis and intravascular haemolysis in an 11-year-old child with G6PD deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency leading to acute intravascular haemolysis and acute kidney injury (AKI) is a known clinical presentation. However, there is a paucity of information regarding the occurrence of rhabdomyolysis and myoglobinuria in G6PD-deficient individuals, especially children. An 11-year-old south Indian Tamil girl presented with severe anaemia and anuric AKI following a short febrile illness. Investigations demonstrated evidence of intravascular haemolysis and rhabdomyolysis, and on histopathology myoglobin deposits (casts) were detected in the renal tubules. She was successfully managed with repeated sessions of haemodialysis and blood transfusions. Follow-up estimation of G6PD levels after 3 months confirmed severe G6PD deficiency (0.003 nkat/g haemoglobin). Although there are anecdotal reports of myoglobinuria in G6PD-deficient individuals, the occurrence of severe anuric AKI in this clinical setting has not been reported. It can be speculated that myoglobinuria (in addition to haemoglobinuria) can contribute towards jeopardising renal function in G6PD deficiency-related acute haemolytic crisis.

Acyanotic Hypoxia in a Febrile Child

Glucose-6-phosphate dehydrogenase deficiency affects approximately 400 million people worldwide and is an X-linked disorder most commonly found in individuals of African, Asian, Mediterranean, and Middle Eastern descent. It can present with acute hemolysis in response to certain drugs, infections, or fava beans, and affected individuals may not be aware that they have glucose-6-phosphate dehydrogenase deficiency. This case illustrates the importance of those working in the acute and urgent care sector having an awareness of the condition and the value of a full set of vital signs in an unwell child.

Genotypic and phenotypic characterization of G6PD deficiency in Bengali adults with severe and uncomplicated malaria

BACKGROUND

Control of malaria increasingly involves administration of 8-aminoquinolines, with accompanying risk of haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Few data on the prevalence and genotypic basis of G6PD deficiency are available from Bangladesh, where malaria remains a major problem in the South (Chittagong Division). The aim of this study was to determine the prevalence of G6PD deficiency, and associated G6PD genotypes, in adults with falciparum malaria in southern Bangladesh.

METHODS

G6PD status was assessed via a combination of fluorescent spot testing (FST) and genotyping in 141 Bengali patients admitted with falciparum malaria to two centres in Chittagong Division from 2012 to 2014. In addition, an analysis of genomic data from 1000 Genomes Project was carried out among five healthy Indian subcontinent populations.

RESULTS

One male patient with uncomplicated malaria was found to have G6PD deficiency on FST and a genotype associated with deficiency (hemizygous Orissa variant). In addition, there were two female patients heterozygous for deficiency variants (Orissa and Kerala-Kalyan). These three patients had a relatively long duration of symptoms prior to admission compared to G6PD normal cases, possibly suggesting an interaction with parasite multiplication rate. In addition, one of 27 healthy local controls was deficient on FST and hemizygous for the Mahidol variant of G6PD deficiency. Examination of 1000 Genomes Project sequencing data across the Indian subcontinent showed that 19/723 chromosomes (2.63%) carried a variant associated with deficiency. In the Bengali from Bangladesh 1000 Genomes population, three of 130 chromosomes (2.31%) carried deficient alleles; this included single chromosomes carrying the Kerala-Kalyan and Orissa variants.

CONCLUSIONS

In line with other recent work, G6PD deficiency is uncommon in Bengalis in Bangladesh. Further studies of particular ethnic groups are needed to evaluate the potential risk of wide deployment of primaquine in malaria control efforts in Bangladesh.

Heterogeneity of G6PD deficiency prevalence in Mozambique: a school-based cross-sectional survey in three different regions

Background

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked hereditary enzymatic abnormality that affects more than 400 million people worldwide. Most deficient individuals do not manifest any symptoms; however, several precipitant agents—such as fava intake, infections, or several drugs—may trigger acute haemolytic anaemia. Countries should be informed of the prevalence of this enzymatic anomaly within their borders, in order to make safe and appropriate national decisions regarding the use of potentially unsafe drugs for G6PD deficient individuals.

Methods

A school-based cross-sectional survey was conducted in three districts in Mozambique, namely Manhiça, located in the south; Mocuba in the centre; and Pemba in the northern tip of the country. G6PD deficiency was evaluated using the CareStart™ diagnostic test, and enzyme activity levels were measured through fluorescence spectrophotometry in deficient individuals. Chi squared and ANOVA tests were used to assess prevalence and mean enzyme activity differences, and logistic regression was used to identify risk factors associated to the deficiency.

Results

G6PD deficiency prevalence estimates were lowest in the northern city of Pemba (8.3%) and among Emakhuwas and Shimakondes, and higher in the centre and southern regions of the country (16.8 and 14.6%, respectively), particularly among Elomwes and Xichanganas. G6PD deficiency was significantly more prevalent among male students than females (OR = 1.4, 95% CI 1.0–1.8, p = 0.02), although enzyme activity levels were not different among deficient individuals from either gender group. Finally, median deficiency levels were found to be more severe among the deficient students from the north (0.7 U/gHg [0.2–0.7] p < 0.001) and south (0.7 U/gHg [0.5–2.5]), compared to those from the centre (1.4 U/gHg [0.6–2.1]).

Conclusion

These findings suggest that Mozambique, as a historically high malaria-endemic country has considerable levels of G6PD deficiency, that vary significantly across the country. This should be considered when planning national strategies for the use of licensed drugs that may be associated to haemolysis among G6PD individuals, or prior to the performance of future trials using primaquine and other 8-aminoquinolines derivatives.

Registration Number CISM local ethics committee (CIBS-25/013, 4th of December 2013), and the National Ethics Committee of Mozambique (IRB00002657, 28th of February 2014).

Central Nervous System Symptoms Due to Transient Methemoglobinemia in a Child With G6PD Deficiency

The authors herein report a 5-year-old child who presented with massive hemolysis, irritability, and cyanosis. The final diagnosis was glucose-6-phosphate dehydrogenase deficiency with associated central nervous system symptoms probably because of concomitantly acquired methemoglobinemia following oxidant drug exposure. The associated acute-onset anemia would have contributed to the development of cerebral anoxia-related seizures and encephalopathy.

Detection of Occult Acute Kidney Injury in Glucose-6-Phosphate Dehydrogenase Deficiency Anemia

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency anemia is associated with intravascular hemolysis. The freely filtered hemoglobin can damage the kidney. We aimed to assess any subclinical renal injury in G6PD children.

METHODS

Sixty children were included. Thirty G6PD deficiency anemia children were enrolled during the acute hemolytic crisis and after the hemolytic episode had elapsed. Another thirty healthy children were included as controls. Serum cystatin C, creatinine levels, and urinary albumin/creatinine (A/C) ratio were measured, and the glomerular filtration rate (GFR) was calculated.

RESULTS

Significantly higher urinary A/C ratio (p=0.001,0.002 respectively) and lower GFR (p=0.001 for both) were found during hemolysis and after the hemolytic episode compared to the controls. Also, significant higher serum cystatin C (p=0.001), creatinine (p=0.05) and A/C (p= 0.001) ratio and insignificant lower GFR (p=0.3) during acute hemolytic crisis compared to the same children after the hemolytic episode subsided.

CONCLUSIONS

G6PD deficiency anemia is associated with a variable degree of acute renal injury during acute hemolytic episodes which may persist after elapsing of the hemolytic crises.

A Pale Baby With Blue Blood

A previously healthy 9-month-old boy presented to the emergency department with sudden onset of pallor and reduced activity. A detailed history and initial blood tests revealed the diagnosis of oxidant stress-induced hemolysis caused by glucose-6-phosphate dehydrogenase deficiency. However, the child also had a second diagnosis that was revealed with additional testing. This case is described to illustrate the dual diagnosis and management guidelines for both potentially serious conditions.

Overexpression of G6PD and HSP90 Beta in Mice with Benzene Exposure Revealed by Serum Peptidome Analysis

The small peptides representation of the original proteins are a valuable source of information that can be used as biomarkers involved in toxicity mechanism for chemical exposure. The aim of this study is to investigate serum peptide biomarkers of benzene exposure. C57BL/6 mice were enrolled into control group and benzene groups of 150 and 300 mg/kg/d Serum peptides were identified by mass spectrometry using an assisted laser desorption ionization/time of flight mass spectrometry (MS). Differential peptide spectra were obtained by tandem mass spectrometry and analyzed by searching the International Protein Index using the Sequest program. Forty-one peptide peaks were found in the range of 1000-10,000 Da molecular weight. Among them, seven peaks showed significantly different expression between exposure groups and control group. Two peptide peaks (1231.2 and 1241.8), which showed a two-fold increase in expression, were sequenced and confirmed as glucose 6-phosphate dehydrogenase (G6PD) and heat shock protein 90 Beta (HSP90 Beta), respectively. Furthermore, the expression of the two proteins in liver cells showed the same trend as in serum. In conclusion, G6PD and HSP90 beta might be the candidate serum biomarkers of benzene exposure. It also provided possible clues for the molecular mechanism of benzene-induced oxidative stress.

From prejudice to evidence: the case of rhizoma coptidis in singapore

Rhizoma Coptidis (RC), commonly known as huanglian, is a herb frequently used in Traditional Chinese Medicine (TCM) prescriptions. Known to have "clearing damp-heat, quenching fire and counteracting poison" properties, it was widely used in the Chinese community in Singapore. Berberine, an alkaloid isolated from RC, is known to have a wide array of therapeutic effects including antimicrobial, antineoplastic, and hepatoprotective effects. In 1978, RC was implicated in causing neonatal jaundice (NNJ) and kernicterus in neonates suffering from glucose-6-phosphate dehydrogenase (G6PD) deficiency, leading to the banning of RC and berberine in Singapore. More than three decades later, accumulating evidence-based studies pointing to the safety of RC for general public and better understanding of G6PD deficiency, the Health Sciences Authority (HSA) in Singapore reviewed and lifted the prohibition on RC and berberine, turning a brand new chapter in the history of TCM in Singapore. This paper aims to review the safety of RC and berberine, using the prohibition of use and subsequent lifting of ban on RC and berberine in Singapore as an illustration to highlight the importance of evidence-based studies in Traditional Chinese Medicine (TCM).

Glucose-6-phosphate dehydrogenase--beyond the realm of red cell biology

Glucose-6-phosphate dehydrogenase (G6PD) is critical to the maintenance of NADPH pool and redox homeostasis. Conventionally, G6PD deficiency has been associated with hemolytic disorders. Most biochemical variants were identified and characterized at molecular level. Recently, a number of studies have shone light on the roles of G6PD in aspects of physiology other than erythrocytic pathophysiology. G6PD deficiency alters the redox homeostasis, and affects dysfunctional cell growth and signaling, anomalous embryonic development, and altered susceptibility to infection. The present article gives a brief review of basic science and clinical findings about G6PD, and covers the latest development in the field. Moreover, how G6PD status alters the susceptibility of the affected individuals to certain degenerative diseases is also discussed.

A case of sodium chlorite toxicity managed with concurrent renal replacement therapy and red cell exchange

INTRODUCTION

Sodium chlorite is a powerful oxidizing agent with multiple commercial applications. We report the presentation and management of a single case of human toxicity of sodium chlorite.

CASE REPORT

A 65-year-old man presented to hospital after accidentally ingesting a small amount of a sodium chlorite solution. His principal manifestations were mild methemoglobinemia, severe oxidative hemolysis, disseminated intravascular coagulation, and anuric acute kidney injury. He was managed with intermittent hemodialysis, followed by continuous venovenous hemofiltration for management of acute kidney injury and in an effort to remove free plasma chlorite. Concurrently, he underwent two red cell exchanges, as well as a plasma exchange, to reduce the burden of red cells affected by chlorite. These interventions resulted in the cessation of hemolysis with stabilization of serum hemoglobin and platelets. The patient survived and subsequently recovered normal renal function.

DISCUSSION

This is only the second case of sodium chlorite intoxication reported in the medical literature and the first to report the use of renal replacement therapy in combination with red cell exchange in its management.

Methemoglobinemia induced by rasburicase in a pediatric patient: A case report and literature review

Rasburicase is a recombinant urate oxidase enzyme indicated for tumor lysis syndrome (TLS), a potential life-threatening oncologic emergency that occurs most commonly during chemotherapy for hematological malignancies. As a result of the defects in the physiological antioxidant pathway, erythrocytes of patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency are not protected against the oxidating stress exerted by hydrogen peroxide generated with the administration of rasburicase. Therefore, rasburicase is contraindicated in patients with known G6PD deficiency and the manufacturer recommends screening all patients with high risk for G6PD deficiency before initiating rasburicase therapy. However, it is logistically difficult in clinical settings because of the high risk of morbidity and mortality associated with TLS if treatment is delayed and the long turnaround time of the G6PD deficiency screening. Therefore, administering rasburicase to patients developing TLS before confirming a patient’s G6PD status is practically inevitable. Methemoglobinemia, and/or hemolysis, may result from the oxidative stress. Descriptions of the clinical course should it happen are limited in the literature. There are eight reported cases of rasburicase-related methemoglobinemia, with or without hemolytic anemia, in the literature of which five are pediatric patients. Six reports (including three pediatric patients) had detailed descriptions of the event and management. The recent reports of methemoglobinemia observed in patients with probable G6PD activity further complicated the picture. We are reporting a 16-year-old patient diagnosed with Burkitt’s lymphoma who developed methemoglobinemia after receiving one dose of rasburicase. He was managed by transfusion and oxygen support. The patient recovered well and the observed methemoglobinemia was reversible.

Case files of the medical toxicology fellowship at Banner Good Samaritan Medical Center in Phoenix, AZ: methemoglobinemia following dapsone exposure

Acquired methemoglobinemia is a common, potentially fatal syndrome that can occur as a result of exposure to numerous xenobiotics. A case report of a 14-month-old female who developed methemoglobinemia following a dapsone ingestion. The child was treated with numerous boluses of methylene blue and ultimately required a continuous infusion of methylene blue. The common causes of methemoglobinemia, as well as the underlying pathophysiology, diagnosis, and treatment strategies are discussed.

Tubulointerstitial damage as the major pathological lesion in endemic chronic kidney disease among farmers in North Central Province of Sri Lanka

Chronic kidney disease of uncertain etiology (CKDu) in North Central Province of Sri Lanka has become a key public health concern in the agricultural sector due to the dramatic rise in its prevalence and mortality among young farmers. Although cadmium has been suspected as a causative pathogen, there have been controversies. To date, the pathological characteristics of the disease have not been reported. Histopathological observations of 64 renal biopsies obtained at Anuradhapura General Hospital from October 2008 to July 2009 were scored according to Banff 97 Working Classification of Renal Allograft pathology. The correlations between the histological observations and clinical parameters were statistically analyzed. Interstitial fibrosis and tubular atrophy with or without nonspecific interstitial mononuclear cell infiltration was the dominant histopathological observation. Glomerular sclerosis, glomerular collapse, and features of vascular pathology such as fibrous intimal thickening and arteriolar hyalinosis were also common. Although hypertension was identified as one of the common clinical features among the cases, it did not influence the histopathological lesions in all the cases. This study concludes that tubulointerstitial damage is the major pathological lesion in CKDu. Exposure(s) to an environmental pathogen(s) should be systematically investigated to elucidate such tubulointerstitial damage in CKDu.

Unsuspected glucose-6-phosphate dehydrogenase deficiency presenting as symptomatic methemoglobinemia with severe hemolysis after fava bean ingestion in a 6-year-old boy

We report the occurrence of symptomatic methemoglobinemia in a previously healthy boy, who presented with severe acute hemolysis after fava bean ingestion. The methemoglobinemia revealed a previously unrecognized glucose-6-phosphate dehydrogenase (G6PD) deficiency. We discuss the pathophysiology of severe methemoglobinemia when associated with acute hemolysis, favism, and the common African G6PD A-variant [G6PD, VAL68MET, ASN126ASP]. In conclusion, screening for G6PD deficiency must be considered in symptomatic methemoglobinemia, especially in young boys, when associated with intravascular hemolysis.

Dapsone-induced methemoglobinemia: a dose-related occurrence?

BACKGROUND

Dapsone, used for Pneumocystis jiroveci (PCP) prophylaxis, is associated with increased risk of methemoglobinemia. Absence of cytochrome b5 reductase enzyme activity causes congenital methemoglobinemia, but its role in dapsone-associated methemoglobinemia is unknown. The authors sought to elucidate drug-related risk factors for dapsone-associated methemoglobinemia in pediatric oncology patients, including contribution of cytochrome b5 reductase enzyme activity.

METHODS

Among 167 pediatric patients treated for hematologic malignancies or aplastic anemia who received dapsone for PCP prophylaxis, demographic and dapsone treatment data were retrospectively collected. Drug-related risk factors were evaluated by Cox proportional hazards, and in a cross-sectional subgroup of 40 patients, cytochrome b5 reductase enzyme activity was assessed.

RESULTS

Methemoglobinemia (median methemoglobin level = 9.0% [3.5-22.4]) was documented in 32 (19.8%) patients. There was a 73% risk reduction in methemoglobinemia with dosing ≥20% below the target dose of 2 mg/kg/d (hazard ratio [HR], 0.27; 95% confidence interval [CI], 0.09-0.78; P = .016), whereas methemoglobinemia risk was increased with dosing ≥20% above the target dose (HR, 6.25; 95% CI, 2.45-15.93; P < .001). Sex, body mass index, and age were not associated with increased risk. Cytochrome b5 reductase enzyme activity did not differ by methemoglobinemia status (median 8.6 IU/g hemoglobin [Hb]; [5.5-12.1] vs 9.1 IU/g Hb; [6.7-12.7]). No patient developed PCP on dapsone.

CONCLUSIONS

Methemoglobinemia occurred in almost 20% of pediatric oncology patients receiving dapsone for PCP prophylaxis. Higher dapsone dosing is associated with increased risk. A cross-sectionally acquired cytochrome b5 reductase enzyme activity level was not associated with methemoglobinemia risk. Studies are needed to define biologic correlates of methemoglobinemia and evaluate lower dapsone doses for PCP prophylaxis.

An unusual syncope cause in the ED: favism

Favism is an acute hemolytic syndrome occurring in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals after the consumption of fava beans. The highest incidence is in boys aged 2-6 years. We report a 56-year-old man presented to the emergency department (ED) with recurrent syncope attacks due to favism. In our knowledge, this is the first report of favism-caused syncope in an adult patient without a G6PD deficiency diagnosis in the past and diagnosed in ED.