From Volume 39, Issue 9, November 2012 | Pages 654-655
This case report describes dental disease associated with mitochondrial disease (Leigh's disease) in a young adult. Normal preventive dentistry is difficult in these groups of patients and often leads to management required in secondary care. An awareness of the background pathology is needed when managing these groups of patients. Management of dental pathology in this particular patient often required input from other specialties to ensure a successful outcome.
Leigh's disease is a subacute, necrotizing, encephalomyopathy of the nervous system. Presentation is usually before the age of two, although can occur in juveniles and early adulthood.1
Usual presenting features of the condition are of motor impairment, ie dysphagia, dysphonia, regurgitation, motor retardation and hypotonia.
Leigh's disease is progressive and is often associated with acute relapses associated with infections. The progression involves progressive neurological disability associated with spasticity and movement disorders. Respiratory failure is common and metabolic acidosis is also a feature in some patients.
The underlying defect in many patients with Leigh's syndrome is a defect in mitochondrial function. These defects often involve the mitochondrial respiratory chain and can be due to mutations in either the mitochondrial or nuclear genome. The defect in our patient was a mitochondrial DNA mutation.1
Nutrition is important in patients with Leigh's disease in view of the primary defect of mitochondrial function. Periods of impaired nutrition can lead to episodes of encephalopathy but maintaining nutrition can be problematic owing to increasing difficulty with dysphagia and other motor abnormalities. Many patients have their nutrition maintained by PEG feeding, but this was not possible in our patient because of concerns about safety in maintaining the tube.
Currently, there is no evidence linking Leigh's disease to dento-alveolar pathologies or any periodontal disease. Characteristic features such as low frontal hairlines and prominent foreheads has been noted.2
Leigh's disease is a progressive disease with a stepwise clinical deterioration. Acute episodes of deterioration may be precipitated by infections, and consequently maintaining adequate dentition and prompt treatment of any dental abscess or pulpitis may benefit the background clinical condition.
To summarize what is already known about this condition:
A 50 kg, 21-year-old male with Leigh's disease caused by a mitochondrial DNA mutation presented to the department following referral from community dental services. The reason for referral was for management of multiple carious teeth arising from poor dental hygiene and frequent consumption of refined sugared drinks required for management of his condition. Dental hygiene was difficult because of dystonia (a neurological movement disorder in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures) and intervention of a percutaneous gastrostomy (PEG) feeding tube was not appropriate for this patient.
The patient was managed as part of the National Commissioning Group for Rare Mitochondrial Disorders of Children and Adults in Newcastle. Owing to his dystonia and cognitive difficulties, dental treatment could not be carried out under sedation or in the community.
Oral assessment revealed that he required multiple extractions under general anaesthetic (Figure 1).
The patient presented to hospital maxillofacial services as a referral from community dental services. A similar situation has been documented in the literature.3 Owing to the patient's myopathy and inability to undergo minor oral surgery in the community, maintaining good dental care had been challenging. This is a common feature amongst those children with congenitally acquired movement disorders.
Along with the difficulty of performing dental treatment in the community, the management of Leigh's disease requires frequent feeding, often with high sugar drinks.
Often, the lack of motor skills as the disease progresses means that the use of a drinking straw is not a viable option. Many patients, however, become more reliant on feeding through the PEG route and, as such, oral consumption may decrease.
Normal dental care, such as brushing and application of fluoride-enhanced mouthwash, is possible in the early stages, but disease progression may require others to brush for the patient and lack of co-ordination may require the use of fluoride-based dental gel rather than mouthwashes that may be aspirated.
Surgical techniques for the treatment of dento-alveolar disease in this group of patients do not need to be modified, with no special or disposable equipment required, and no particular bleeding disorders encountered. Brevity of surgery is worth attaining given that prolonged anaesthetic increases the risk of postoperative complications, such as lactic acidosis and failure to wean from ventilators.
Minor procedures may be achievable under light sedation but not with established disease and dystonia present.
As deteriorations in Leigh's disease may be precipitated by dental infections, it is recommended that these patients (and other patients with mitochondrial disorders) undergo regular dental checks, if necessary in a hospital setting where treatment may be more easily organized.
To summarize what this study adds to our knowledge of this condition:
To provide a safe general anaesthetic, patients are normally starved of food and then fluids to ensure minimal gastric contents at the time of induction, to avoid regurgitation.
In patients with Leigh's disease, this approach has to be modified to maintain a constant supply of easily metabolized calories to enable mitochondrial metabolism and human cell function.
The most straightforward approach that could be used for our case study was admission the previous night and normal oral intake until midnight. Subsequently, the patient was placed on a continuous intravenous infusion of 5% dextrose with frequent bedside blood glucose monitoring, nursing observations and the parents present, to help monitor the patient's vital functions.
The patient was allowed a small amount of clear sugary fluid orally three hours before the procedure to maintain an adequate calorie intake. Throughout his induction, procedure and recovery a continuous infusion of 5% glucose was maintained.
The main cause of anaesthetic-related morbidity and mortality is respiratory failure. The patients that are likely to suffer from difficulty from postoperative ventilatory weaning often display the neuromuscular signs of decreased respiratory drive, such as sighing, grunting and stridor.4 In these patients, the advanced stage of disease has to be balanced against the benefits of surgery.
With the majority of patients with Leigh's disease and other mitochondrial disease being diagnosed in infancy and the previously shortened life expectancy they encountered,5 the sequelae of neglected dentition rarely proved problematic.
However, better understanding of various metabolic diseases has led to earlier and more accurate diagnosis with the use of cytogenetics and improving management of patients. This increase in life expectancy has resulted in increased attendances for dental practitioners, whether in primary or secondary care.
This article aims to illustrate that, despite a more complex background medical history, intra-oral management remains reassuringly familiar, with preventive treatment effective. Good dentition also benefits the course of the background condition.
Given that treatment and follow-up of patients with mitochondrial disease occurs within a few specialist centres nationally, there may be a role for dental practitioners to develop an interest in treating these patients, in a similar manner to those with paediatric cardiac and cleft teams.
