Prolonged misdiagnosis of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome: A case report.

RATIONALE: Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a subset of rare mitochondrial diseases characterized by diverse clinical manifestations, which often complicates its diagnosis. PATIENT CONCERNS: This report chronicles the experiences of a 14-year-old female patient who underwent multiple misdiagnoses before the eventual identification of MELAS syndrome. Her journey began with symptoms that included growth retardation, hypertrophic cardiomyopathy, and epilepsy. DIAGNOSIS: The definitive diagnosis of MELAS syndrome was established through genetic confirmation, revealing a mutation in the MT-TL1 gene (m.3242A > G). INTERVENTIONS: Upon diagnosis, the patient received targeted symptomatic treatment, which led to pronounced improvements in her symptoms. OUTCOMES: The patient's condition stabilized with the administered treatments, and she exhibited significant symptom relief, emphasizing the importance of accurate diagnosis and timely intervention. LESSONS: This case underscores the imperative for heightened clinical vigilance and thorough differential diagnosis in the face of complex clinical presentations, such as those seen in MELAS syndrome, to ensure timely and appropriate interventions.

Identification of genotype-biochemical phenotype correlations associated with fructose 1,6-bisphosphatase deficiency.

Fructose-1,6-bisphosphatase (FBPase) deficiency, caused by an FBP1 mutation, is an autosomal recessive disorder characterized by hypoglycemic lactic acidosis. Due to the rarity of FBPase deficiency, the mechanism by which the mutations cause enzyme activity loss still remains unclear. Here we identify compound heterozygous missense mutations of FBP1, c.491G>A (p.G164D) and c.581T>C (p.F194S), in an adult patient with hypoglycemic lactic acidosis. The G164D and F194S FBP1 mutants exhibit decreased FBP1 protein expression and a loss of FBPase enzyme activity. The biochemical phenotypes of all previously reported FBP1 missense mutations in addition to G164D and F194S are classified into three functional categories. Type 1 mutations are located at pivotal residues in enzyme activity motifs and have no effects on protein expression. Type 2 mutations structurally cluster around the substrate binding pocket and are associated with decreased protein expression due to protein misfolding. Type 3 mutations are likely nonpathogenic. These findings demonstrate a key role of protein misfolding in mediating the pathogenesis of FBPase deficiency, particularly for Type 2 mutations. This study provides important insights that certain patients with Type 2 mutations may respond to chaperone molecules.

Thiamine deficiency: a commonly unrecognised but easily treatable condition.

Thiamine is present in many foods and is well recognised as an essential nutrient critical for energy metabolism. While thiamine deficiency is commonly recognised in alcoholism, it can present in many other settings where it is often not considered and goes unrecognised. One challenging aspect to diagnosis is that it may have varied metabolic, neurological and cardiac presentations. Here we present an overview of the disorder, focusing on the multiple causes and clinical presentations. Interestingly, thiamine deficiency is likely increasing in frequency, especially among wildlife, where it is linked with changing environments and climate change. Thiamine deficiency should be considered whenever neurological or cardiological disease of unknown aetiology presents, especially in any patient presenting with lactic acidosis.

Diffuse posterior leukoencephalopathy in MELAS without stroke-like episodes: A case report.

RATIONALE: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is the most common subtype of mitochondrial encephalopathy. In the past, it was believed that most hereditary white matter lesions were lysosome storage disorders or peroxisome diseases. However, in recent years, white matter lesions have been increasingly regarded as a common feature of patients with mitochondrial diseases. In addition to stroke-like lesions, about half of the patients with MELAS reported white matter lesions in the brain. PATIENT CONCERNS: Herein, we provide a case of A 48-year-old female who presented with episodic loss of consciousness with twitching of extremities. Previous medical history revealed 10 years of history of epilepsy, 10 years of history of diabetes, a history of hearing loss, and unknown etiology. Ancillary findings included brain magnetic fluid-attenuated inversion recovery showed symmetrical lesions in the bilateral parietal lobe with high signal intensity at the edge, and high signal intensity in the bilateral occipital lobe, paraventricular white matter, corona radiata, and the center of semiovale. DIAGNOSES: Mitochondrial deoxyribonucleic acid gene sequencing returned A3243G point mutation and it supports the diagnosis of intracranial hypertension. INTERVENTIONS: Considered the diagnosis of symptomatic epilepsy, the patient was treated with mechanical ventilation, midazolam, and levetiracetam, and the limb twitching symptoms were controlled. The patient was comatose, chronically bedridden, with gastrointestinal dysfunction, and was treated prophylactically with antibiotics against infection, parenteral nutrition, and other supportive measures. B vitamins, vitamin C, vitamin E, coenzyme Q10, and idebenone were given, and mechanical ventilation and midazolam were stopped after 8 days. He was discharged from the hospital on 30 days and continued symptomatic treatment with B-vitamins, vitamin C, vitamin E, coenzyme Q10, and idebenone, and antiepileptic treatment with levetiracetam, with outpatient follow-up. OUTCOMES: No further seizures were recorded and the patient recovered well. LESSONS: MELAS syndrome without stroke-like episodes of diffuse posterior cerebral white matter lesions is rare in clinical practice, and the possibility of MELAS syndrome should be considered in symmetric posterior cerebral white matter lesions.

Renal Complications after Percutaneous Coronary Interventions on Concurrent Metformin Therapy: A Systematic Review with Meta-Analysis.

Objective: Metformin, commonly prescribed in diabetic patients, can cause lactic acidosis. Although generally rare, this side effect remains a source of concern in procedures requiring contrast media, due to the risk of contrast-induced nephropathy. Temporarily withdrawing metformin during the peri-procedural period is often practiced, but clinical decisions are difficult in emergency situations, such as acute coronary syndromes. In this systematic review with meta-analysis, we aimed to further investigate the safety of percutaneous coronary interventions in patients on concurrent metformin therapy.Design, Setting and Participants: We analyzed studies in patients undergoing (elective or emergency) percutaneous coronary interventions with or without concurrent metformin administration, reporting on the incidence of metformin-associated lactic acidosis and peri-procedural renal function.Methods: PubMed, ClinicalTrials.gov, Cochrane Library, and Scopus were systematically searched without language restrictions throughout August 2022. Randomized clinical trials and observational studies were assessed with the Revised Cochrane Collaboration Risk of Bias tool and the Newcastle-Ottawa quality scale, respectively. Data synthesis addressed the mean drop in estimated glomerular filtration rate (eGFR) and the incidence of contrast-induced nephropathy, in addition to lactic acidosis.Results: Nine studies were included, totaling 2235 patients (1076 continuing metformin during the peri-procedural period), mostly with eGFR above 30 mL/min/1.73m2 No cases of lactic acidosis were reported. The mean post-procedural drop in eGFR was 6.81mL/min/1.73m2 (95% confidence interval [CI]: 3.41 to 10.21) in the presence of metformin and 5.34 mL/min/1.73m2 (95% CI: 2.98 to 7.70) in its absence. The incidence of contrast-induced nephropathy was not affected by concurrent metformin, as shown by a (between-groups) standardized mean difference of 0.0007 (95% CI: -0.1007 to 0.1022).Conclusion: Concurrent metformin during percutaneous coronary interventions in patients with relatively preserved renal function is safe, without added risk of lactic acidosis or contrast-induced nephropathy. Thus, emergency revascularization in the context of acute coronary syndromes should not be deferred. More data from clinical trials in patients with severe renal disease are needed.

The Possible Role of COVID-19 in the Triggering of Underlying Mitochondrial Dysfunction in MELAS Syndrome, A Brief Report of three cases.

BACKGROUND: During corona virus pandemic, various neurological complications of COVID-19 have been reported. Recent studies demonstrated different pathophysiology for neurological manifestations of COVID-19 such as mitochondrial dysfunction and damage to cerebral vasculature. In addition, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a mitochondrial disorder with a variety of neurological symptoms. In this study, we aim to assess a potential predisposition in mitochondrial dysfunction of COVID-19, leading to MELAS presentation. METHODS: We studied three previously healthy patients with the first presentation of acute stroke-like symptoms, following COVID-19 infection. We analyzed the patients' clinical data and brain magnetic resonance imaging (MRI) lesions that presented to the neurological center of a university-affiliated hospital in Tehran, Iran, from September 2020 to August 2021. RESULTS: All cases are characterized by a temporoparietal abnormality in imaging studies and electroencephalogram (EEG). Based on electrodiagnostic tests, three patients were diagnosed with myopathy. In two brothers with relatively the same symptoms, one performed muscle biopsy finding myopathic process, and genetic testing confirmed a 3243A>G point mutation in a heteroplasmic state in one of our patients. CONCLUSION: Although MELAS is not a prevalent condition, the recent increase in the number of these patients in our center might indicate the potential role of COVID-19 in triggering the silent pre- existing mitochondrial dysfunction in these patients.

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes diagnosed after metformin-triggered stroke-like episodes.

A 40-year-old man with sensorineural hearing loss and diabetes mellitus was hospitalized with acute-onset impaired consciousness and clumsiness in his left hand. He had been taking metformin for 4 months. A neurological examination revealed confusion and weakness in the left upper limb. Increased lactate levels were detected in the serum and cerebrospinal fluid. Magnetic resonance imaging revealed lesions in the right parietal and bilateral temporal lobes with a lactate peak in magnetic resonance spectroscopy. Finally, we made a genetic diagnosis of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes based on the detection of m.3243A>G. It is well-known that metformin should not be administered in patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes because metformin inhibits mitochondrial function and triggers stroke-like episodes. However, our patient was diagnosed with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes after metformin administration. Thus, we encourage physicians to exercise caution in the prescription of metformin in patients with short stature, sensorineural hearing loss, or young-onset diabetes mellitus because these patients may have undiagnosed mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes.

Encephalopathy in short bowel syndrome: a diagnostic challenge.

A 15-year-old boy was admitted to the hospital due to ataxia, drowsiness and bradypsychia. He was known to have a short bowel syndrome Initial venous blood gases revealed a metabolic acidosis with a high anion gap of 24 mmol/L and normal L-lactate. He improved with fasting and fluids and was discharged with oral metronidazole. 2 weeks later he was admitted again with similar symptoms. A specific study of D-Lactic acidosis was carried out, confirming the diagnosis. D-lactic acidosis is an uncommon complication of short bowel syndrome. It occurs as a consequence of the metabolism of unabsorbed carbohydrates. The symptoms are mainly neurological. Limiting the dietary carbohydrates is useful to avoid recurrences. Poorly absorbable antibiotics are used but with varying results. Surgery may be an option if medical treatment fails. Probiotics might be useful to avoid symthoms recurrence.

Reversible cerebral artery constriction accompanied with stroke-like episode in MELAS: A case series.

OBJECTIVE: The pathophysiology of stroke-like episode (SLE) in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) was uncertain, though mitochondrial metabolic crisis of cortical neurons and mitochondrial proliferation in small vessels of brain have been considered. However, the involvement of major cerebral vessels was debated. We aimed to investigate whether major cerebral vessels participate in SLE. METHODS: We retrospectively collected the clinical and neuroimaging data of MELAS patients diagnosed in our center. Through follow-up, the cases harboring reversible cerebral artery constriction on brain magnetic resonance angiography (MRA) examination were included in this study. RESULTS: There were 20 patients with intact brain MRA data at acute and non-acute phases. Only 3 cases with m.3243A > G mutation were enrolled. They suffered once or twice SLEs manifesting headache, blurred vision, seizures or mental and behavior disorder. New lesions were present in temporo-parietal and/or temporo-occipital regions. Segmental stenosis at middle cerebral artery and/or posterior cerebral artery, proximal portions in particular, was ipsilateral to the lesions at acute phase in all the 3 patients, which was resolved during the subacute or chronic stages. Moreover, the SLEs lesions were located within the stenotic arteries territory. In addition, dilation at distal portions of the stenotic arteries was observed at acute phase as well in 2 patients. CONCLUSION: Reversible constriction of cerebral arteries may contribute to SLE of MELAS. MELAS should be a differential diagnosis when stenosis of major cerebral vessels is present at acute phase of SLE.

Resistant Lactic Acidemia Due to Accidental Cheese Starter Culture Ingestion.

Lactic acid is the end-product of anaerobic glycolysis. It is generally believed that elevated blood lactate levels are associated with poor patient outcomes. Literature reports that lactic acidosis can be related to supplementary food intake in the pediatric age group however, in adult patients, it is not common to see lactic acidosis due to oral ingestion unless the patient has a history of short bowel syndrome or jejunoileal bypass surgery. With the current case presentation, we report an accidental cheese starter culture intake that resulted in resistant lactic acidosis with no signs of critical illnesses.

Association Between the Acidemia, Lactic Acidosis, and Shock Severity With Outcomes in Patients With Cardiogenic Shock.

Background Lactic acidosis is associated with mortality in patients with cardiogenic shock (CS). Elevated lactate levels and systemic acidemia (low blood pH) have both been proposed as drivers of death. We, therefore, analyzed the association of both high lactate concentrations and low blood pH with 30-day mortality in patients with CS. Methods and Results This was a 2-center historical cohort study of unselected patients with CS with available data for admission lactate level or blood pH. CS severity was graded using the Society for Cardiovascular Angiography and Intervention (SCAI) shock classification. All-cause survival at 30 days was analyzed using Kaplan-Meier curves and Cox proportional-hazards analysis. There were 1814 patients with CS (mean age, 67.3 years; 68.5% men); 51.8% had myocardial infarction and 53.0% had cardiac arrest. The distribution of SCAI shock stages was B, 10.8%; C, 30.7%; D, 38.1%; and E, 18.7%. In both cohorts, higher lactate or lower pH predicted a higher risk of adjusted 30-day mortality. Patients with a lactate ≥5 mmol/L or pH <7.2 were at increased risk of adjusted 30-day mortality; patients with both lactate ≥5 mmol/L and pH <7.2 had the highest risk of adjusted 30-day mortality. Patients in SCAI shock stages C, D, and E had higher 30-day mortality in each SCAI shock stage if they had lactate ≥5 mmol/L or pH <7.2, particularly if they met both criteria. Conclusions Higher lactate and lower pH predict mortality in patients with cardiogenic shock beyond standard measures of shock severity. Severe lactic acidosis may serve as a risk modifier for the SCAI shock classification. Definitions of refractory or hemometabolic shock should include high lactate levels and low blood pH.

Wernicke Encephalopathy Mimicking MELAS.

OBJECTIVES: a stroke-like lesion, the morphological equivalent of a stroke-like episode and the hallmark of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, have not been reported as manifestations of thiamine deficiency. CASE REPORT: a 62-year-old man with a history of chronic alcoholism was admitted after a series of epileptic seizures. Upon waking up from the coma, he presented with disorientation, confusion, confabulation, psychomotor agitation, aggressiveness, right hemianopsia, aphasia, and right hemineglect over weeks. Electroencephalography showed a questionable focal status epilepticus over the left hemisphere, responsive to lorazepam and oxcarbazepine. Follow-up electroencephalographies no longer recorded epileptiform discharges. Cerebral magnetic resonance imaging (MRI) revealed T2-/diffusion weighted imaging (DWI) hyperintensity in the left occipito-temporal region that was not congruent to a vascular territory which persisted for at least nine weeks. Since a lactate-peak could be seen in this lesion by magnetic resonance-spectroscopy, this was interpreted as a stroke-like lesion. Since thiamine was reduced, the stroke-like lesion was attributed to thiamine deficiency after the exclusion of differential diseases, including MELAS and status epilepticus. The patient's behavioural and cognitive dysfunctions largely resolved upon vitamin-B1 substitution. CONCLUSIONS: the case suggests that thiamine deficiency presumably causes mitochondrial dysfunction with cerebrospinal fluid lactic acidosis and a stroke-like lesion mimicking MELAS syndrome. It should be further studied whether nutritional deficits, such as thiamine deficiency, could give rise to secondary stroke-like lesions.

Thalamic aphasia associated with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes: A case report.

BACKGROUND: Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) with aphasia is a rare disorder, with the associated aphasia reported as either Wernicke's or Broca's. Herein, we report a patient with MELAS complicated by thalamic aphasia. CASE: A 15-year-old right-handed girl presented with headache, nausea, right homonymous hemianopsia, and aphasia. She could repeat words said by others, but had word-finding difficulty, paraphasia, and dysgraphia. Brain MRI revealed abnormal signals from the left occipital lobe to the temporal lobe and left thalamus, but Wernicke's area and Broca's area were not involved. Additionally, she had short stature, lactic acidosis, bilateral sensorineural hearing loss, and a maternal family history of diabetes and mild deafness. Based on clinical findings and the presence of a mitochondrial A3243G mutation, she was diagnosed with MELAS. With treatment, the brain MRI lesions disappeared and her symptoms improved. Her aphasia was classified as amnesic aphasia because she could repeat words, despite having word-finding difficulty, paraphasia, and dysgraphia. Based on MRI findings of a left thalamic lesion, we diagnosed her with thalamic aphasia. CONCLUSION: Thalamic aphasia may be caused by MELAS. Assessment of whether repetition is preserved is important for classifying aphasia.

Mitochondrial stroke-like episodes: The search for new therapies.

A mitochondrial stroke-like event is an evolving subacute neurological syndrome linked to seizure activity and focal metabolic brain derangement in a genetically determined mitochondrial disorder. The acronym "MELAS" (mitochondrial encephalopathy associated with lactic acidosis and stroke-like lesions) identifies subjects with molecular, biochemical and/or histological evidence of mitochondrial disorder who experience stroke-like lesions. MELAS is a rare inherited mitochondrial disease linked to severe multiorgan involvement and stress-induced episodes of metabolic decompensation and lactic acidosis. Unfortunately, there are no etiopathogenetic therapies for stroke-like episodes to date, and the treatment is mainly based on anti-epileptic drugs and supportive therapies. This perspective opinion article discusses the current care standards for MELAS patients and revises current and innovative emerging therapies for mitochondrial stroke-like episodes.

Transient Postictal Hyperglycemia as a Diagnostic Clue of Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes.

PURPOSE: To propose that transient postictal hyperglycemia as a diagnostic clue of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). CASE REPORT: We reported two non-diabetic patients presenting with generalized seizure and transient postictal hyperglycemia. At the acute stage, both patients had hyperglycemia with serum glucose levels more than 400 mg/dl, normal glycated hemoglobin (HbA1C) levels, normal ketone body levels, and absence of infection signs. Within three days of the seizure event, both patients were euglycemic and did not require any diabetes treatment. Brain MRI examination revealed gyriform restricted diffusion at bilateral superior temporal gyrus in one patient, and diffuse cerebral and cerebellar atrophy without restricted diffusion lesions in another patient. Polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis confirmed that both patients harbored the m.3243A more than G mutation. CONCLUSION: Seizure-induced stress hyperglycemia is uncommon in normal individuals, but such kind of energy crisis may be pronounced in patients with mitochondrial dysfunction. Early diagnosis of mitochondrial diseases-related epilepsy and hyperglycemia is crucial since certain antiepileptic drugs (ex. Valproic acid) and antihyperglycemic agents (ex. Metformin) are contraindicated in patients with mitochondrial diseases. Our findings support that transient postictal hyperglycemia may be a red flag to consider the diagnosis of MELAS.

Type B lactic acidosis associated with diffuse large B-cell lymphoma and the Warburg effect.

Type B lactic acidosis is a rare complication of non-tissue perfusion abnormalities caused by solid tumors or hematologic malignancies. Herein, we present the case of a 42-year-old man with type B lactic acidosis and hypoglycemia who was found to have a diffuse large B-cell lymphoma. The cause of lactic acidosis and/or hypoglycemia is thought to be the Warburg effect, which is when the metabolic rate of a rapidly growing malignant tumor is very high and dominated by glycolysis. Systemic damage from type B lactic acidosis can occur when the increased rate of glycolysis exceeds the normal muscle and liver lactic acid clearance rate. The Warburg effect is a rare but serious condition that needs to be recognized, not only in diffuse large B-cell lymphoma, but also in other malignancies. The prognosis of lactic acidosis in patients with malignant tumors is very poor. Currently, effective chemotherapy seems to be the only hope for survival.

[Postoperative cognitive dysfunction in elderly patients after aorta-coronary bypass under conditions of artificial blood circulation.]

In patients undergoing open myocardial revascularization under cardiopulmonary bypass (CB), one of the complications is cognitive dysfunction. The aim of the work is to study the effect of intraoperative lactic acidosis, anemia and the duration of myocardial anoxia on the change in cognitive status with the help of FAB after coronary artery bypass grafting (CABG) with CB. The negative impact of lactic acidosis on cognitive status in patients after CABG has been proven. The relationship between the decrease in hemoglobin concentration during surgery and the negative dynamics of cognitive changes in the postoperative period (R=0,41; p=0,021) was determined. A negative effect of prolonged myocardial anoxia during surgery on the dynamics of cognitive functions of patients was revealed. Thus, the above indicators may be markers of the formation of postoperative cognitive dysfunction in patients undergoing CABG with CB.