Medical Matters Dr Muiris HoustonMost people are familiar with the acronym SIDS, for sudden infant death syndrome. Otherwise known as cot death, it has been the subject of a public-health campaign whose success has reduced the incidence of SIDS significantly.
Equally traumatic for patients and families is the sudden death of an older child or young adult. Like SIDS, this occurs out of the blue, a previously healthy young person dying in their sleep or collapsing and dying suddenly during normal activity. Now some doctors are calling for these deaths to be recorded in the same way as cot deaths.
"Following the official classification of cot deaths as sudden infant death syndrome, deaths fell by 70 per cent over 10 years," says Dr Tim Bowker, associate medical director of the British Heart Foundation. He argues that not until it is accepted practice to identify and label all unexplained deaths in young people will it be possible to identify a cause and find ways of preventing their occurrence. The name he proposes is sudden adult death syndrome, or SADS.
Although not all sudden deaths in young, otherwise healthy adults have a cardiac cause, many do. The term sudden cardiac death is used to describe these cases. The number of adolescents and young adults dying each year in the US from sudden cardiac arrest rose by 10 per cent between 1989 and 1996, and the increase was much higher among young women than men. Thirty-four per cent had a heart-rhythm problem or a condition called cardiomyopathy.
Hypertrophic cardiomyopathy (HCM) affects one in 500 people, although only a small proportion are at risk of sudden death. The term HCM describes a thickening (hypertrophy) of the heart muscle (myocardium). Primarily affecting the left ventricle, the heart's main pumping chamber, it also disrupts the dividing wall down the middle of the heart. This wall carries the transmission system that both triggers and spreads the normal beat through the heart. So as the heart muscle thickens, its efficiency and ability to maintain a smooth heart rate are impaired.
HCM is usually inherited; when it is identified it is important that all close relatives are screened. Unfortunately, it may come to light only following the sudden death of a young family member and after a full post-mortem. In life, many of those with the condition are symptomless; others have episodes of fainting, palpitations, chest pain or breathlessness, although each of these symptoms can be a marker for many other conditions.Treatment includes lifestyle advice, beta blocking drugs and, in some cases, the use of a pacemaker to induce a regular heartbeat.
The other principal cardiac cause for sudden death in young people is a rhythm disturbance in the heart. As this is essentially an electrical malfunction, it cannot be tested for at post-mortem. Some families have to face the additional stress of being told that no cause of death could be found. But doctors believe most of these are due to a sudden catastrophic malfunctioning of the heart's electrical pacemaker. Recent interest has focused on a condition called long QT syndrome. Fans of ER and other medical soaps have become familiar with the characteristic blips on a heart monitor (see illustration). Each represents the progression of an electrical impulse through the heart. Measuring the interval between the spikes and troughs can reveal abnormalities. Long QT syndrome refers to a prolonged interval between the Q and T waves, which can suddenly produce a potentially fatal fast rhythm of the heart, leading to sudden collapse and death.
Long-term treatment is aimed at shortening the QT interval; beta-blocking drugs are very effective and are recommended in people under 40 at diagnosis, even if they are symptomless.
The sudden death of an older child or adolescent is every bit as devastating as a cot death. It is probably time we looked at collecting information on these deaths in the Republic, as well as providing a package of care, including screening, for families who have lost loved ones in this way.
You can e-mail Dr Muiris Houston at mhouston@irish-times.ie. He regrets he cannot answer individual queries