What is Huntington's disease (HD)
Huntington's disease (HD) is a hereditary neurodegenerative disorder. Each child of an affected parent has a 50% chance of developing the disease. While patients may start showing the onset of symptoms in young (Juvenile HD) or old age, most patients present in their forties and fifties. Since 1993 a genetic test has become available for HD. There are a number of ethical issues attached to predictive and prenatal testing.
A clinical trial has been described in relation to HD. This primarily consists of psychiatric, motor and cognitive disorders. Patients may suffer from nutritional problems that can lead to weight loss and may lead to tube feeding. Given the nature of the illness, long term support and cares issues will always need to be viewed as important elements of a multidisciplinary integrated treatment plan. Management of HD patients should address a number of pharmacological and non pharmacological aspects. Environmental adaptation and educating families and care staff are far from an unnecessary luxury.
While the disease will inevitably progress over time, there are a number of effective treatment strategies that clinical teams can help with.
Consequences of Huntington's disease
The motor aspect of the condition usually manifests itself with both involuntary movements and slowness in voluntary ones. It is not uncommon for patients to also suffer from swallowing problems with potentially serious consequences. Cognitively, patients present with mental inflexibility, problems with multitasking and implicit memory amongst other difficulties. Personality changes and irritability are among the most troublesome features to patients and families.
Emotional Implications of Huntington's disease
Studies have suggested that emotional, cognitive and behavioural problems are more disabling than the motor disorder and their effective treatment can determine the viability of community treatment. Personality changes and mental problems add to the care giving burden. Depression is common and potentially treatable although it can be masked by the HD clinical features. Other mental problems such as psychotic disorders, apathy, irritability and anxiety can also add to the disability. Suicide risk should be monitored and regularly assessed.
Cognitive impact of Huntington's disease
Cognitive impairment is primarily related to pathological changes that take place in the deep parts of the brain (subcortical) and its connectivity with the frontal lobes. This can predate the onset of motor symptoms. Patients may develop problems with planning and organizing their daily lives and struggle with minor deviation from predictable routines. Many patients present with poor motivation and task initiation. Further, they may "get stuck" with minor details.
The impaired memory and mental manipulation of personal space can increase the risk to patients. They can also become less aware of their own behaviour and less appreciative of others' view points. Problems with divided attention together with failing abilities lead to considerable frustrations. Patients' difficulties in controlling impulsivity and expressing themselves effectively would make the situation worse.
However, despite slow thought processing and expressive language difficulties, patients may continue to be able to express themselves even in advanced stages.
Treatment of patients with Huntington's disease
While HD is an incurable condition it has many treatable features. There is hardly an alternative to a multidisciplinary approach should an effective treatment be aimed for. HD is a familial and multifaceted disorder that would require a holistic management plan taking into account clinical, environmental and social factors. Patients can have different presentations even within the same family. Further, a successful treatment can lead to unfavourable effects as the disease progresses. Issues such as swallowing problems and vulnerability to side effects will need special attention. Similarly, end of life and mental capacity issues can lead to ethical and medico legal problems.