MEDICAL MATTERS Dr Muiris HoustonThe continuing ill health of the Pope has focused attention on Parkinson's disease as well as raising questions about the ability of the head of the Catholic Church to continue in office. It has also stimulated an interesting debate about how we view disability in older people.
As the 84-year-old Pontiff spends a second period in Rome's Gemelli hospital, this time precipitated by the need for a tracheotomy to relieve acute respiratory problems brought on by influenza, I would like to examine some of the medical issues associated with his condition.
Parkinson's disease is a chronic neurological illness precipitated by the deficiency of a chemical messenger called dopamine. Nerve cells in a deep part of the brain, the basal ganglia, degenerate, with a particular loss of nerve cells in a part of the brain called the substantia nigra. These cells make dopamine; as the levels of the brain chemical decrease, the symptoms of Parkinson's disease begin.
It is essentially a disorder of movement, although other functions are also affected. It is helpful to imagine the substantia nigra as the brain's "gearbox" and to consider dopamine as the main lubricant for the gearbox. As this part of the brain seizes up, the three main symptoms of tremor, muscular rigidity and bradyknesia (a slowness in initiating movement with associated freezing) appear.
Other problems experienced by people with Parkinson's include difficulty with swallowing and speech, constipation and sleep disturbance. Both depression and dementia can also occur. About one in 100 people develop Parkinson's disease; it affects men and woman in equal numbers.
Television coverage of the Pope illustrates some of the symptoms and signs of the disease. He developed a shuffling gait and is now transported in a special chair or in his Popemobile. His face is mask-like and expressionless and his speech is slow and delivered in a flat, monotonous tone. Tremor, one of the key signs of Parkinson's, was first noted in the Pope's left hand in 1993. This especially affects the hands and arms and characteristically involves the rubbing together of the thumb and forefinger (doctors refer to this as a "pill-rolling" tremor).
We have not yet been told what medication "Il Papa" has been given for Parkinson's disease. The tried and tested treatment is to directly replace the depleted dopamine using a drug called levodopa. It is available in both regular and slow release formulations; research suggests both are equally effective. Other drugs include dopamine agonists, which work by "switching on" the brain's dopamine receptors and an agent called selgiline that has been found to improve symptoms and delay the need for levadopa.
One of the big dilemmas for doctors treating patients with the neurological condition is when to start levodopa treatment. After a period of years on the drug, people can develop what is called dysknesia, involving writhing and jerking movements, and the "on-off" syndrome, whereby the effects of levadopa literally stop and start. This can be very distressing for a number of patients; the incidence of these complications is 10 per cent per year of levadopa therapy.
A number of dopamine agonist drugs as well as other agents that block the enzyme responsible for breaking down dopamine in the brain have been shown to significantly reduce the "off" time for patients who have been taking levadopa for some time.
The Pope first exhibited signs of Parkinson's disease in 1993 when he was 73 years of age. As a result of developing the condition later in life, he is at some risk of dementia. But despite figures which show that 40 per cent of Parkinson's disease patients develop clinical depression, he exhibits a remarkable fighting spirit and a clear wish to take on the disease. Vatican sources have indicated he has chosen to publicly battle the condition as an inspiration to others with severe chronic illness. Last week a Polish journalist recalled being told by the Pope: "Never lose your trust, do not be defeated, do not be discouraged."
The reality of modern life is that many of us will face a similar struggle as the Pope when chronic illness becomes a daily companion. Writing in the current issue of Challenging Attitudes, the Age and Opportunity newsletter, Meadhbh Conway Piskorska says: "My inner self is ageless. In fact it is much better company now than it ever was... and I still want to change the world." It is a sentiment some commentators might reflect on before consigning the Pope to the dustbin of history.
Dr Muiris Houston is pleased to hear from readers at mhouston@irish-times.ie but regrets he cannot answer individual queries.