Severe acute metabolic acidosis and Wernicke's encephalopathy following chemotherapy with 5-fluorouracil and cisplatin: case report and review of the literature

Wernicke's Encephalopathy in Acute and Chronic Kidney Disease: A Systematic Review

Thiamine (vitamin B1) deficiency is relatively common in patients with kidney disease. Wernicke's encephalopathy (WE) is caused by vitamin B1 deficiency. Our aim was to systematically review the signs and symptoms of WE in patients with kidney disease. We conducted a systematic literature review on WE in kidney disease and recorded clinical and radiographic characteristics, treatment and outcome. In total 323 manuscripts were reviewed, which yielded 46 cases diagnosed with acute and chronic kidney disease and WE published in 37 reports. Prodromal characteristics of WE were loss of appetite, vomiting, weight loss, abdominal pain, and diarrhea. Parenteral thiamine 500 mg 3 times per day often led to full recovery, while Korsakoff's syndrome was found in those receiving low doses. To prevent WE in kidney failure, we suggest administering high doses of parenteral thiamine in patients with kidney disease who present with severe malnutrition and (prodromal) signs of thiamine deficiency.

Wernicke's encephalopathy-induced hearing loss complicating sleeve gastrectomy

A 25-year-old woman brought to the hospital with symptoms of acute confusion, disorientation, diplopia, hearing loss and unsteady gait which started 4 days prior to her presentation with rapid worsening in its course until the day of admission. She had a surgical history of laparoscopic sleeve gastrectomy 2 months earlier which was complicated by persistent vomiting around one to three times per day. She lost 30 kg of her weight over 2 months and was not compliant to vitamin supplementation. CT of the brain was unremarkable. Brain MRI was done which showed high signal intensity lesions involving the bilateral thalamic regions symmetrically with restricted diffusion on fluid-attenuated inversion recovery imaging. Other radiological investigations, such as magnetic resonance venography and magnetic resonance angiography of the brain were unremarkable. An official audiogram confirmed the sensorineural hearing loss. A diagnosis of Wernicke's encephalopathy due to thiamin deficiency post-sleeve gastrectomy was made based on the constellation of her medical background, clinical presentation and further supported by the distinct MRI findings. Consequently, serum thiamin level was requested and intravenous thiamin 500 mg three times per day for six doses was started empirically, then thiamin 250 mg intravenously once daily given for 5 more days. Marked improvement in cognition, eye movements, strength and ambulation were noticed soon after therapy. She was maintained on a high caloric diet with calcium, magnesium oxide, vitamin D supplements and oral thiamin with successful recovery of the majority of her neurological function with normal cognition, strength, reflexes, ocular movements, but had minimal resolution of her hearing deficit. Serum thiamin level later was 36 nmol/L (67-200).

I can't hear you, you said I had what?: A case report and literature review

We report the case of a 46-year old African American woman who presented to the emergency department with one week of progressive bilateral deafness associated with worsening gait abnormalities, visual changes, and confusion. She was diagnosed with Wernicke encephalopathy (WE) attributed to alcohol abuse; her symptoms, including hearing loss, improved with thiamine replacement. WE, a condition due to thiamine deficiency, commonly affects those with alcohol use disorder or gastric bypass history. Though traditionally associated with a triad of encephalopathy, ophthalmoplegia, and ataxia, it can be more rarely associated with auditory deficits or other neurologic findings. Though hearing loss has previously been reported as a rare symptom of WE, it has not been described in WE due to alcohol abuse. We performed a review of the literature to determine if WE associated with hearing loss had been previously reported.

Resolved External Ophthalmoplegia and Hearing Loss in Wernicke's Encephalopathy With Thiamine Replacement

BACKGROUND

Wernicke encephalopathy (WE) is classically described by a clinical triad consisting of confusion, ataxia, and ophthalmoplegia, but recent reports emphasize a history of malnutrition along with 2 elements of the WE triad (Caine's criteria) to enhance diagnostic sensitivity. The ophthalmoplegia, vestibular, and auditory expeditious improvement with intravenous thiamine usually confirms the diagnosis; serum levels generally provide additional diagnostic certainty.

METHODS

Here, we discuss the case of a woman with a distant history of gastric sleeve, poor nutrition and protracted vomiting, who developed acute confusion, imbalance, near-total external ophthalmoplegia (EO), and hearing loss. The baseline thiamine level was 28 πmol/L (Normal: 70-180 πmol/L). We performed serial neurological, vestibular, and audiological examination to document over 5 days, the effect of intravenous (IV) thiamine, and again at 3 months with continued oral supplementation. We provide serial documentation with photographs and video recording of oculomotor abnormalities, audiometric testing, and a video of horizontal head impulse testing, and imaging findings.

RESULTS

Over the course of 5 days of IV thiamine supplementation, we demonstrate our patient's resolution of near complete EO. We assessed vestibular paresis with horizontal head impulse testing, after complete resolution of the EO. The initially positive bilateral h-HIT showed decreased gain and overt corrective saccades, it clinically resolved by day 5, but video h-HIT testing demonstrated persistent decreased horizontal vestibulo-ocular reflex (VOR) gain and covert horizontal saccades, which persisted at the 3-month examination. By contrast, the vertical VOR gain was normal without corrective saccades. Bedside audiometry completed during the acute phase demonstrated severely restricted auditory speech comprehension, which normalized 3 months later. Severe truncal ataxia improved as well.

CONCLUSIONS

This case is an example of how awareness of the variations in the clinical presentation of WE can be crucial in achieving an early diagnosis and obtaining better outcomes. A history of the poor nutritional status can be an important clue to aid in this early diagnosis.

Sensorineural Hearing Loss and Wernicke Encephalopathy: A Case Report and Literature Review

Sensorineural hearing loss (SNHL) is seldom associated with Wernicke encephalopathy (WE) or thiamine deficiency. While thiamine deficiency and repletion are often considered prior to dextrose infusions in patients with chronic alcohol abuse to prevent WE, they are often overlooked in non-alcoholic patients who are also at risk for malnutrition. In this paper we describe a case of a non-alcoholic 28-year-old female status post-sleeve gastrectomy who developed SNHL in the setting of thiamine deficiency and WE, with ongoing hearing impairment requiring hearing aids despite thiamine repletion.

Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement

OBJECTIVE

To review the current literature with respect to the physiology, pathophysiology, and measurement of lactate.

DATA SOURCES

Data were sourced from veterinary and human clinical trials, retrospective studies, experimental studies, and review articles. Articles were retrieved without date restrictions and were sourced primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Lactate is an important energy storage molecule, the production of which preserves cellular energy production and mitigates the acidosis from ATP hydrolysis. Although the most common cause of hyperlactatemia is inadequate tissue oxygen delivery, hyperlactatemia can, and does occur in the face of apparently adequate oxygen supply. At a cellular level, the pathogenesis of hyperlactatemia varies widely depending on the underlying cause. Microcirculatory dysfunction, mitochondrial dysfunction, and epinephrine-mediated stimulation of Na⁺ -K⁺ -ATPase pumps are likely important contributors to hyperlactatemia in critically ill patients. Ultimately, hyperlactatemia is a marker of altered cellular bioenergetics.

CONCLUSION

The etiology of hyperlactatemia is complex and multifactorial. Understanding the relevant pathophysiology is helpful when characterizing hyperlactatemia in clinical patients.

Wernicke’s Encephalopathy in a Patient Without Chronic Alcohol Abuse

Wernicke’s encephalopathy (WE) is traditionally seen in the emergency department in patients with chronic alcohol abuse. WE can result in significant morbidity and mortality if untreated, making early diagnosis and intervention paramount. We discuss a case of WE in a 63-year-old female with no history of chronic alcohol abuse, who presented with bilateral opthalmoplegia that resolved after intravenous thiamine administration. This case report highlights the varied clinical settings other than chronic alcohol abuse in which the diagnosis of WE should be considered.

[Two cases of Wernicke´s encephalopathy that developed during total parenteral nutrition in colon cancer patients treated with 5-fluorouracil-based chemotherapy]

Wernicke's encephalopathy (WE) caused by thiamine deficiency is an acute neurological disorder. Clinically, the classic triad of WE consists of ophthalmoplegia, ataxia, and mental status changes. Thiamine deficiency is known to occur commonly in chronic alcoholic patients. Sometimes, it can occur in patients after gastrointestinal surgery and in those with malabsorption. In addition, patients undergoing renal dialysis, suffering from hyperemesis gravidarum, receiving total parenteral nutrition (TPN), and being treated with chemotherapeutic agents are also prone to develop thiamine deficiency. Herein, we report two cases of WE that developed following simultaneous 5-fluorouracil (5-FU) chemotherapy and TPN in colon cancer patients which was successfully treated with thiamine administration.

Nonalcoholic Thiamine-Related Encephalopathy (Wernicke-Korsakoff Syndrome) Among Inpatients With Cancer: A Series of 18 Cases

BACKGROUND

Wernicke-Korsakoff Syndrome (WKS) is a neuropsychiatric syndrome caused by thiamine deficiency. Cancer predisposes to thiamine deficiency through various mechanisms. Although many case reports exist on nonalcoholic WKS in cancer, larger qualitative studies are lacking.

METHOD

Retrospective study of patients admitted to a cancer hospital and diagnosed with WKS during routine care on a psychiatric consultation service. Only patients with at least 1 additional supporting feature (magnetic resonance imaging findings, low serum thiamine concentrations, or response to treatment) were included. Data pertaining to demographics, risk factors, phenomenology, and outcomes were abstracted from medical records by chart review.

RESULTS

In all, 18 patients were included. All patients developed WKS during cancer treatment. Hematologic malignancy, gastrointestinal tract tumors, low oral intake, and weight loss were common risk factors. All patients presented with cognitive dysfunction, most commonly impaired alertness, attention, and short-term memory. All were diagnosed by operational criteria proposed by Caine et al., 1997 (where 2 of the following are required: nutritional deficiency, ocular signs, cerebellar signs, and either altered mental status or mild memory impairment). Few exhibited Wernicke's classic triad. Diagnostic and treatment delay were common. Only 3 patients recovered fully.

CONCLUSION

Nonalcoholic WKS can occur during cancer treatment and manifests clinically as delirium. Diagnosis should be made using operational criteria, not Wernicke's triad. Most patients were not underweight and had normal serum concentration of vitamin B12 and folate. A variety of mechanisms might predispose to thiamine deficiency and WKS in cancer. Given the high frequency of residual morbidity, studies should focus on decreasing diagnostic and treatment delay.

Bilateral Blindness Following Chemoradiation for Locally Advanced Oropharyngeal Carcinoma

Wernicke's encephalopathy is a life-threatening neurologic complication of thiamine deficiency. Though the presentation of symptoms can vary widely, the classical triad is founded on ophthalmoplegia, alteration of mental status, and gait disturbance. We describe a case of Wernicke's encephalopathy in an oncology patient shortly after concurrent 5-fluorouracil, carboplatin, and radiotherapy for locally advanced oropharyngeal cancer, presenting as complete bilateral blindness, ataxia, nystagmus, and confusion. Thiamine was given based on clinical suspicion and rapid improvement of clinical findings occurred. An MRI performed later supported the diagnosis of Wernicke's encephalopathy. A multifactorial etiology of thiamine deficiency from nutritional deficits and neurotoxic effects of chemotherapy are hypothesized.

Association between malignancy and non-alcoholic Wernicke's encephalopathy: a case report and literature review

Background

Wernicke's encephalopathy is a serious medical condition associated with high morbidity and mortality caused by deficiency of thiamine. This disease is classically associated with alcoholism, but is underappreciated in the nonalcoholic population. There is growing acknowledgement of the development of Wernicke's encephalopathy in patients with malignancies.

Methods

We conducted a literature review in PubMed for cases of Wernicke's encephalopathy occurring in patients with malignancy. We also present the case of a 47-year-old woman with recurrent laryngeal cancer and multiple hospital admissions for malnutrition. Neurological examination was notable for pendular nystagmus, severe gait ataxia, confusion, and poor memory consolidation. MRI of the brain was significant for T2-weighted fluid-attenuated inversion recovery hyperintensities in periaqueductal regions, medial thalami, and the tectal plate, typical for Wernicke's encephalopathy. She was treated with thiamine repletion, and had marked improvement in her mental status and some improvement in her vision problems and ataxia, although some nystagmus and significant short-term memory impairment persisted.

Results

The literature review yielded dozens of case reports of Wernicke's encephalopathy in patients with malignancy, dominated by cases of patients with malignancies of the gastrointestinal system, followed by those with hematologic malignancies.

Conclusions

Malignancy is an important risk factor for the development of Wernicke's encephalopathy. This diagnosis is underappreciated and difficult for the clinician to discern from multifactorial delirium. Clinicians should be aware to treat at-risk patients with thiamine immediately, especially if multiple risk factors are present.

Benfotiamine enhances antioxidant defenses and protects against cisplatin-induced DNA damage in nephrotoxic rats

The objective of the present study was to assess superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), paraoxonase (PON1), glutathione reductase (GR), and catalase (CAT) activities ratio and their relationship with DNA oxidative damage in rats treated with cisplatin (3 mg/kg bwt/day) in the presence and absence of benfotiamine (100 mg/kg/day) for 25 days. Cisplatin-induced renal damage was evidenced by renal dysfunction and elevated oxidative stress markers. SOD activity and levels of nitric oxide, protein carbonyl, malondialdehyde, and 8-hydroxy-2'-deoxyguanosine were significantly increased by cisplatin treatment. Moreover, the ratios of GPx/GR, SOD/GPx, SOD/CAT, and SOD/PON1 were significantly increased compared to control. In contrast, glutathione levels were significantly decreased by cisplatin treatment. Simultaneous treatment of rats with cisplatin and benfotiamine ameliorate these variables to values near to those of control rats. This study suggests that benfotiamine can prevent cisplatin-induced nephrotoxicity by inhibiting formation reactive species of oxygen and nitrogen.

Two cases of Wernicke's encephalopathy in young age patients receiving allogeneic hematopoietic stem cell transplantation

Wernicke's encephalopathy is an acute neurolopsychiatric syndrome caused by thiamine deficiency, and classically presents with the triad of opthalmopathy, ataxia and altered mentality. Both prolonged total parenteral nutrition and reduced oral intake can induce Wernicke's encephalopathy during hematopoietic stem cell transplantation (HSCT). Although early treatment is important for recovery from Wernicke's encephalopathy, the vague symptoms and characteristics hinder early diagnosis. Furthermore, Wernicke's encephalopathy is not infrequent and can develop at any age during HSCT. Herein, we present two young patients developing Wernicke's encephalopathy during HSCT.

Severe encephalopathy, lactic acidosis, vegetative instability and neuropathy with 5-Fluorouracil treatment - pyrimidine degradation defect or beriberi?

We present the case of a 19-year-old female with nasopharyngeal carcinoma, who received two courses of chemotherapy with 5-fluorouracil (5-FU) in combination with folic acid and cisplatin. Upon developing esophageal strictures in the course of her radiotherapy, she required total parenteral nutrition. In the course of therapy, the patient developed severe multisystem failure with encephalopathy, lactic acidosis, vegetative instability and neuropathy. The treatment with 5-FU can lead to severe toxicity due to enzyme deficiencies in the degradation of pyrimidines, but it can also lead to thiamine deficiency with the classic symptoms of beriberi. Beriberi is a rare disorder, usually attributed to malnutrition or alcoholism. 5-FU has been shown to induce thiamine depletion. Reduced food intake or total parenteral nutrition devoid of vitamin supplements may aggravate symptoms. We were unable to find a genetic cause for increased 5-FU toxicity in our patient, ruling out deficiencies of dihydropyrimidine dehydrogenase, dihydropyrimidinase or β-ureidopropionase and double-strand break repair deficits. We come to the conclusion that, even without any definable enzyme deficiency, treatment with 5-FU can lead to high toxicity due to thiamine deficiency if vitamin supplementation is not undertaken.

Fluorouracil Induces Myocardial Ischemia With Increases of Plasma Brain Natriuretic Peptide and Lactic Acid but Without Dysfunction of Left Ventricle

Purpose

Fluorouracil (FU) is a cornerstone of colorectal cancer treatment; however, it has clinical and subclinical influence on the heart. This study aimed to clarify the pathophysiology, risk factors, and long-term effects of FU cardiotoxicity.

Patients and Methods

The study prospectively accrued colorectal cancer patients (n = 106) completely resected and adjuvantly treated with FU and oxaliplatin according to the FOLFOX4 regimen (infusional FU, folinic acid, and oxaliplatin). Serial measurements were made of systolic and diastolic features of the left ventricle by radionuclide ventriculography, plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), lactic acid, and ECG before chemotherapy, immediately after a treatment infusion, and at follow-up 2 weeks after cessation of the intended 12 treatment courses and were further evaluated by multivariate regression analysis that included cardiovascular history and its risk factors.

Results

In the entire cohort, NT-proBNP significantly increased from baseline 14.5 ± 3.2 pmol/L (mean ± standard error) to 28.3 ± 5.3 pmol/L during FU therapy (P < .001). Nine patients (8.5%) with cardiotoxicity had significantly higher NT-proBNP of 55.3 ± 40.8 pmol/L compared with 25.4 ± 4.1 pmol/L in those without (P < .001). In multivariate analysis, the FU-induced rise of NT-proBNP was significantly higher in females (P < .001). Plasma lactic acid significantly increased from baseline (1.3 ± 0.1 mmol/L to 1.8 ± 0.1 mmol/L) during FU therapy (P < .001). Left ventricular ejection fraction at baseline of 0.66 ± 0.01 remained unchanged at 0.65 ± 0.01 during FU therapy and 0.66 ± 0.01 at follow-up (P = .4).

Conclusion

FU therapy generally induces myocardial neuroendocrine changes with increasing plasma NT-proBNP and lactic acid but without long-term dysfunction of the left ventricle. The usability of NT-proBNP as a predictive marker for FU cardiotoxicity remains to be clarified.

Cognitive functioning after radiotherapy or chemoradiotherapy for head-and-neck cancer

PURPOSE

To perform a comprehensive cognitive function (CF) assessment in patients who were relapse free after curative intent radiotherapy (RT) or chemoradiotherapy for squamous cell carcinoma of the head and neck.

METHODS AND MATERIALS

Patients underwent neuropsychological tests to assess their objective CF; completed questionnaires to assess subjective CF, quality of life, and affect; and underwent blood tests to assess hematologic, biochemical, endocrine, and cytokine status. Retrospectively, the dosimetry of incidental radiation to the brain was determined for all patients, and the dose intensity of cisplatin was determined in those who had undergone chemoradiotherapy.

RESULTS

A total of 10 patients were enrolled (5 treated with radiotherapy only and 5 with radiotherapy and cisplatin). The mean time from the end of treatment was 20 months (range, 9-41). All patients were able to complete the assessment protocol. Of the 10 patients, 9 had impaired objective CF, with memory the most severely affected. The severity of memory impairment correlated significantly with the radiation dose to the temporal lobes, and impaired dexterity correlated significantly with the radiation dose to the cerebellum, suggesting that these deficits might be treatment related. Patients receiving cisplatin appeared to have poorer objective CF than patients receiving only RT, although this difference did not achieve statistical significance, likely owing to the small sample size. Consistent with the published data, objective CF did not correlate with subjective CF or quality of life. No association was found between objective CF and patients' affect, hematologic, biochemical, endocrine, and cytokine status.

CONCLUSION

Neuropsychological testing is feasible in squamous cell carcinoma of the head-and-neck survivors. The findings were suggestive of treatment-related cognitive dysfunction. These results warrant additional investigation.

Wernicke's encephalopathy in advanced gastric cancer

PURPOSE

With their prolonged survival and malnutrition, cancer patients, and especially gastrointestinal (GI) tract cancer patients, can develop Wernicke's encephalopathy (WE). The aim of this study is to remind physicians of the importance of WE and prompt management in patients with GI tract cancer.

MATERIALS AND METHODS

This study is a retrospective review of 2 cases of WE in advanced gastric cancer (AGC) patients, and we review the literature for cases of GI tract cancer related to WE.

RESULTS

A 48-year-old female with AGC presented dizziness and diplopia for 5 days and a 20 kg weight loss. Neurologic exam showed nystagmus and gaze disturbance. Her symptoms improved after daily parenteral injection of thiamine 100 mg for 17 days. A 58-year-old female with AGC presented with sudden disorientation, confusion and 15 kg weight loss. Neurologic exam showed gaze limitation and mild ataxia. Despite daily parenteral injection of thiamine 100 mg for 4 days, she died 5 days after the onset of neurologic symptoms. Combining the cases noted in the literature review with our 2 cases, the 7 gastric cancer cases and 2 colorectal cancer cases related to WE showed similar clinical characteristics; 1) a history of long-period malnutrition and weight loss, 2) relatively typical neurologic signs and symptoms and 3) specific magnetic resonance image findings. Except for 2 patients who had irreversible neurologic symptoms, the other 7 patients were improved with prompt thiamine treatment.

CONCLUSION

It is important to consider WE in GI tract cancer patients with acute neurologic symptoms and who are in a state of malnutrition. Thiamine should be given as soon as possible when WE is suspected.

A case of Wernicke's encephalopathy following fluorouracil-based chemotherapy

The pyrimidine antimetabolite 5-fluorouracil (5-FU) is a chemotherapeutic agent used widely for various tumors. Common side effects of 5-FU are related to its effects on the bone marrow and gastrointestinal epithelium. Neurotoxicity caused by 5-FU is uncommon, although acute and delayed forms have been reported. Wernicke's encephalopathy is an acute, neuropsychiatric syndrome resulting from thiamine deficiency, and has significant morbidity and mortality. Central nervous system neurotoxicity such as Wernicke's encephalopathy following chemotherapy with 5-FU has been reported rarely, although it has been suggested that 5-FU can produce adverse neurological effects by causing thiamine deficiency. We report a patient with Wernicke's encephalopathy, reversible with thiamine therapy, associated with 5-FU-based chemotherapy.

Chemotherapy related encephalopathy in a patient with Stage IV cervical carcinoma treated with cisplatin and 5-fluorouracil: a case report

INTRODUCTION

Chemotherapy related encephalopathy is commonly reported with certain forms of chemotherapy but few reports note an association with low dose 5-Fluorouracil.

CASE PRESENTATION

A 57-year-old Caucasian lady received her first cycle of Cisplatin and 5-Fluorouracil for palliative treatment of cervical carcinoma, and presented several days later with signs of encephalopathy. Several causes were eliminated, and encephalopathy related to 5-Fluorouracil was thought to be the most likely cause. Magnetic Resonance Imaging of the head revealed changes related to the chemotherapy received. Symptoms resolved completely within three days of presentation.

CONCLUSION

Encephalopathy from low dose 5-Fluorouracil is not well documented in the literature. Fluid rehydration and supportive treatment is required. Signs and symptoms resolved completely with no residual effects on follow up.

Antioxidants and Other Micronutrients in Complementary Oncology

Many patients being treated for cancer use micronutrient supplements, with the intention to complement their cancer treatment or help them cope with the therapy- and disease-associated side effects. The majority are adding antioxidants without the knowledge of the treating physician. There are many concerns that antioxidants might decrease the effectiveness of chemotherapy, but increasing evidence suggests a benefit when antioxidants are added to conventional cytotoxic therapies. However, it is imperative that physicians explore the use of antioxidant and other micronutrient supplements with their cancer patients and educate them about potentially negative as well as potentially beneficial effects.

A case of manic episode during treatment with 5-fluorouracil, epirubicin and cyclophosphamide for breast cancer

A 41-year-old woman with breast cancer developed a manic episode while being treated with a 5-fluorouracil-epirubicin-cyclophosphamide combination (most likely caused by the first drug). Chemotherapy was discontinued, and antipsychotic treatment with haloperidol and olanzapine was instituted. She recovered after 10 days. Normal computerized tomography (CT) scans and neurological examinations were consistent with the absence of neurological symptoms on physical exam.

Deletion of SLC19A2, the high affinity thiamine transporter, causes selective inner hair cell loss and an auditory neuropathy phenotype

Mutations in the gene coding for the high-affinity thiamine transporter Slc19a2 underlie the clinical syndrome known as thiamine-responsive megaloblastic anemia (TRMA) characterized by anemia, diabetes, and sensorineural hearing loss. To create a mouse model of this disease, a mutant line was created with targeted disruption of the gene. Cochlear function is normal in these mutants when maintained on a high-thiamine diet. When challenged with a low-thiamine diet, Slc19a2-null mice showed 40-60 dB threshold elevations by auditory brainstem response (ABR), but only 10-20 dB elevation by otoacoustic emission (OAE) measures. Wild-type mice retain normal hearing on either diet. Cochlear histological analysis showed a pattern uncommon for sensorineural hearing loss: selective loss of inner hair cells after 1-2 weeks on low thiamine and significantly greater inner than outer hair cell loss after longer low-thiamine challenges. Such a pattern is consistent with the observed discrepancy between ABR and OAE threshold shifts. The possible role of thiamine transport in other reported cases of selective inner hair cell loss is considered.

Wernicke encephalopathy presented in the form of postoperative delirium in a patient with hepatocellular carcinoma and liver cirrhosis: A case report and review of the literature

Objective: Although Wernicke encephalopathy has been reported in the oncological literature, it has not previously been reported in postoperative cancer patients.

Methods: In this communication, we report a patient of hepatocellular carcinoma with liver cirrhosis who developed Wernicke encephalopathy in the form of postoperative delirium. Preoperatively, the patient had a very good appetite and had eaten all the food of an 1800 cal/day diet until 1 day before operation. The operation was done without any complications. The patient developed delirium 2 days after the lobectomy of the liver. The level of delirium remained unchanged until administration of thiamine starting on day 7 postoperatively, which resulted in palliation of delirium without brain damage. Laboratory data demonstrated that the serum thiamine level at day 6 postoperatively was below the lower limit of normal. As the mechanism of Wernicke encephalopathy, we thought that decreased ability to store thiamine due to liver cirrhosis led to depletion of thiamine faster than had been expected.

Results and significance of the research: In cancer patients, clinicians must always remain aware of the possibility of Wernicke encephalopathy, especially in patients with liver dysfunction, which decreases the ability to store thiamine in the liver. Early detection and intervention may alleviate the symptoms of delirium and prevent irreversible brain damage.