Enteral Tube Feeding in Paediatric Mitochondrial Diseases

Impact of dietary ketosis on volatile anesthesia toxicity in a model of Leigh syndrome

BACKGROUND

Genetic mitochondrial diseases impact over 1 in 4000 individuals, most often presenting in infancy or early childhood. Seizures are major clinical sequelae in some mitochondrial diseases including Leigh syndrome, the most common pediatric presentation of mitochondrial disease. Dietary ketosis has been used to manage seizures in mitochondrial disease patients. Mitochondrial disease patients often require surgical interventions, leading to anesthetic exposures. Anesthetics have been shown to be toxic in the setting of mitochondrial disease, but the impact of a ketogenic diet on anesthetic toxicities in this setting has not been studied.

AIMS

Our aim in this study was to determine whether dietary ketosis impacts volatile anesthetic toxicities in the setting of genetic mitochondrial disease.

METHODS

The impact of dietary ketosis on toxicities of volatile anesthetic exposure in mitochondrial disease was studied by exposing young Ndufs4(-/-) mice fed ketogenic or control diet to isoflurane anesthesia. Blood metabolites were measured before and at the end of exposures, and survival and weight were monitored.

RESULTS

Compared to a regular diet, the ketogenic diet exacerbated hyperlactatemia resulting from isoflurane exposure (control vs. ketogenic diet in anesthesia mean difference 1.96 mM, Tukey's multiple comparison adjusted p = .0271) and was associated with a significant increase in mortality during and immediately after exposures (27% vs. 87.5% mortality in the control and ketogenic diet groups, respectively, during the exposure period, Fisher's exact test p = .0121). Our data indicate that dietary ketosis and volatile anesthesia interact negatively in the setting of mitochondrial disease.

CONCLUSIONS

Our findings suggest that extra caution should be taken in the anesthetic management of mitochondrial disease patients in dietary ketosis.

Nutrition rehabilitation-related complications in primary mitochondrial disorders

Primary mitochondrial disorders (PMDs) comprise a group of hundreds of individual genetic diseases affecting mitochondrial function, including oxidative phosphorylation and energy production. The estimated prevalence of these disorders ranges from 2.9 to 20 cases per 100,000. PMDs are commonly associated with malnutrition and growth failure. There is a paucity of literature regarding nutrition assessment and long-term data in the PMD population. We present three patients with various PMDs who presented complications related to malnutrition: (1) a 16-year-old male with Kearns-Sayre syndrome developed type 2 insulin-requiring diabetes mellitus after the initiation of high-calorie nutrition rehabilitation via gastrostomy tube (G-tube); (2) an 11-year-old female with myoclonic epilepsy associated with ragged red fibers developed diarrhea with metabolic decompensation and profound neurological and respiratory deterioration during nutrition rehabilitation after surgical G-tube placement; and (3) a 19-year-old male with a WARS2-associated PMD manifesting with developmental delay and severe parkinsonism presented complications related to poor wound healing after gastrojejunostomy tube placement. The last patient required prolonged hospitalization in the intensive care unit. Clinicians should be vigilant in monitoring these possible complications, as no standards of care exist for the initiation of enteral nutrition for this unique population.

Mitochondrial hepatopathy: Respiratory chain disorders- ‘breathing in and out of the liver’

Mitochondria, the powerhouse of a cell, are closely linked to the pathophysiology of various common as well as not so uncommon disorders of the liver and beyond. Evolution supports a prokaryotic descent, and, unsurprisingly, the organelle is worthy of being labeled an organism in itself. Since highly metabolically active organs require a continuous feed of energy, any dysfunction in the structure and function of mitochondria can have variable impact, with the worse end of the spectrum producing catastrophic consequences with a multisystem predisposition. Though categorized a hepatopathy, mitochondrial respiratory chain defects are not limited to the liver in time and space. The liver involvement is also variable in clinical presentation as well as in age of onset, from acute liver failure, cholestasis, or chronic liver disease. Other organs like eye, muscle, central and peripheral nervous system, gastrointestinal tract, hematological, endocrine, and renal systems are also variably involved. Diagnosis hinges on recognition of subtle clinical clues, screening metabolic investigations, evaluation of the extra-hepatic involvement, and role of genetics and tissue diagnosis. Treatment is aimed at both circumventing the acute metabolic crisis and long-term management including nutritional rehabilitation. This review lists and discusses the burden of mitochondrial respiratory chain defects, including various settings when to suspect, their evolution with time, including certain specific disorders, their tiered evaluation with diagnostic algorithms, management dilemmas, role of liver transplantation, and the future research tools.

Effective and safe diet therapies for Lennox-Gastaut syndrome with mitochondrial dysfunction

Background:

Lennox-Gastaut syndrome (LGS) is a typical intractable form of epilepsy that most often occurs between the second and sixth year of life. This study aimed to evaluate the clinical efficacy and safety of ketogenic diet therapies (DTs) for LGS with mitochondrial dysfunction.

Methods:

This was a retrospective study involving 20 LGS patients with mitochondrial dysfunction who received several DTs from 2004 to 2014 at a single tertiary care center. Seizure reduction rate, cognitive function, retention rate, electroencephalography (EEG) changes, and adverse effects were examined before and after DTs.

Results:

The retention rates at 1 and 2 years after initiation of DTs were 45% and 40%, respectively. After 1-year follow up, we observed seizure freedom in two patients, 75% seizure reduction in two patients, 50% reduction in three patients, and 25% reduction in one patient. After 2-year follow up, the outcomes were seizure freedom in two patients, 90% seizure reduction in one patient, 75% reduction in two patients, and 50% reduction in two patients. EEG findings improved in nine patients. Nine patients were treated with DTs for 1 year; all patients demonstrated improved cognitive status. Eight patients were treated with DTs for 2 years, of whom seven had improved cognitive status. Poor tolerability of DTs was due to poor oral intake and gastrointestinal problems.

Conclusions:

We demonstrate that, in LGS with mitochondrial dysfunction, improvement of seizures and cognitive function are not inferior to those in other patients treated with DTs. This study showed that DTs are efficacious and feasible for LGS patients with mitochondrial dysfunction and can significantly improve their prognosis.

Ophthalmoplegia in Mitochondrial Disease

PURPOSE

To evaluate the classification, diagnosis, and natural course of ophthalmoplegia associated with mitochondrial disease.

MATERIALS AND METHODS

Among 372 patients with mitochondrial disease who visited our hospital between January 2006 and January 2016, 21 patients with ophthalmoplegia were retrospectively identified. Inclusion criteria included onset before 20 years of age, pigmentary retinopathy, and cardiac involvement. The 16 patients who were finally included in the study were divided into three groups according to disease type: Kearns-Sayre syndrome (KSS), KSS-like, and chronic progressive external ophthalmoplegia (CPEO).

RESULTS

The prevalences of clinical findings were as follows: ptosis and retinopathy, both over 80%; myopathy, including extraocular muscles, 75%; lactic acidosis, 71%; and elevated levels of serum creatine kinase, 47%. Half of the patients had normal magnetic resonance imaging findings. A biochemical enzyme assay revealed mitochondrial respiratory chain complex I defect as the most common (50%). The prevalence of abnormal muscle findings in light or electron microscopic examinations was 50% each, while that of large-scale mitochondrial DNA (mtDNA) deletions in a gene study was 25%. We compared the KSS and KSS-like groups with the CPEO patient group, which showed pigmentary retinopathy (p<0.001), cardiac conduction disease (p=0.013), and large-scale mtDNA deletions (p=0.038). KSS and KSS-like groups also had gastrointestinal tract disorders such as abnormal gastrointestinal motility (p=0.013) unlike the CPEO group.

CONCLUSION

Patients with KSS had gastrointestinal symptoms, which may indicate another aspect of systemic involvement. The presence of large-scale mtDNA deletions was an objective diagnostic factor for KSS and a gene study may be helpful for evaluating patients with KSS.