15.8 Huntington's Disease
15.8.1 Introduction
(i) Huntington's disease is an inherited condition, occurring in 1 per 20,000 people (ie. about 3,000 in the United Kingdom). Children of an affected individual have a 50% chance of also developing the disease. Its onset is usually in middle life, between the ages of 30 and 50, although it can present as progressive dystonia (rigidity) in the teens. It is a progressive disease leading inevitably to severe disability and death. Death occurs on average 14 years after the onset.
(ii) The condition is due to a slowly progressive destruction of the cells of the brain, and is characterised by the gradual onset of uncontrollable movements (chorea) of either an abrupt jerking, or slow writhing nature; together with progressive loss of mental function. The initial symptoms are frequently of a change of personality and behaviour, but chorea may be the first sign. As the disease progresses dementia [See Chapter 21] becomes more obvious and the chorea more severe. The person has increasing difficulty with walking, with use of the hands and with speech. Gait is impaired by uncontrollable lurching and staggering. Attempts to pick up a pen or cup of tea set off wild, uncontrolled lunges. At this stage insight is lost, as is awareness of dangers, and behavioural problems increase. In the final stages many people develop increasing muscle rigidity and loss of movement. This leaves the person totally helpless and bed-ridden.
15.8.2 Care Needs and Mobility Considerations
(i) These will depend on the stage of the disease reached and the particular features shown by the affected individual. In the very early stages of Huntington's disease when the chorea is mild and insight is retained there may be few problems with day-to-day activities or with walking. As the chorea worsens, walking becomes more and more difficult as do many everyday activities such as dressing, eating, drinking and managing at the toilet. If dementia is a significant feature then there will be a serious risk of danger and a need for supervision.
(ii) Disability is relentlessly progressive, and in the final stages when the person is emaciated and bed-ridden a considerable amount of attention will be needed both by day and by night.
15.8.3 Further Evidence
In most instances the care and mobility needs should be clear. Factual reports may help in those early cases where, either the diagnosis is not clear, or where there may be a significant suicide risk. In these early stages when insight is retained, with an awareness of what may be in store, depression is not uncommon and suicide is a risk. In the first instance a hospital factual report should be obtained, but if the person has not attended hospital, the GP may well be able to confirm the presence of the disease in previous generations of the family.