Physiological changes due to age. Implications for cardiovascular drug therapy.

Cardiovascular disease is the single largest cause of death in the elderly. Many of the published studies concerning the physiology and pharmacology of the aging cardiovascular system are seriously flawed. Problems include failure to measure the drug bioavailability and the selection of subjects with overt or subclinical disease. With exercise, the rise in heart rate is inversely proportional to age and maximum heart rate is reduced. Baroreceptor reflex activity appears to decline with age. Cardiac output is maintained in the elderly, with a slower heart rate and a greater stroke volume than in the young. Plasma noradrenaline (norepinephrine) levels increase in the elderly but there is no change in the sensitivity of the vasoconstrictor alpha 1-adrenoceptor. There is evidence for a decline in the activity of the vasodilator beta 2-adrenoceptor with age. It is difficult to make general rules about the effect of aging on the disposition and elimination of drugs. Each drug must be tested separately.

Review of 18 years' experience of a diagnostic geriatric neurology referral service.

From 1971 to 1989, 1446 cases were referred from Glasgow and the West of Scotland to the University Department of Geriatric Medicine for neurological diagnosis. In that time, the number increased from one per week to more than two per week, and the proportion from outside Glasgow from 2% to 24%. Eighty-seven per cent had CT scans and 8% electrophysiological studies. One third of patients stayed three days or less, and one third over a week. Cerebrovascular disease was diagnosed in 637 cases (44%), subdural haematoma or hygroma in 59 (4%), and intracranial tumour in 228 (16%), of which 26 (11%) were benign. In 104 cases (7%) no definite diagnosis was made. Management was changed in 402 of the 1446 cases (28%). In the 635 (44%) in whom a referring diagnosis was documented, this was not confirmed in 63%; diagnosis and/or management was changed in 80%. The proportions of referring diagnoses of subdural haematoma and intracranial tumour that were confirmed rose with time. The value of the service lay in the speed and ease of access to it, and the opportunities for teaching and learning it provided. The problems it posed were those of the transfer of ill patients, the distances sometimes necessary, and the need for high standards of communication.

Motor neuron disease: a disease of old age.

There is little information dealing specifically with motor neuron disease (MND) in the elderly. Given current epidemiological trends, geriatricians will be increasingly called upon to diagnose and manage this condition. We report four patients who presented within a six month period to a geriatric medical unit, and place this experience in the perspective of 229 patients from a population-based study of adult-onset MND in Scotland in 1989 and 1990. In 1990 Scotland had a crude annual incidence of MND of 2.25/100,000; the figure for those over 65 is four times greater. MND is more common in men, but the sex ratio was nearly equal over the age of 65. The risk of presenting with bulbar palsy was greater in women, and even higher in elderly women. This, together with increasing age, is the most important negative prognostic factor in MND. Problems with the diagnosis and management of MND in the elderly are highlighted.

Undergraduate teaching in geriatric medicine in Glasgow.

The undergraduate course in geriatric medicine at the University of Glasgow comprises 40 h in the first clinical year. Half of this time is devoted to formal lectures and the remaining 20 h to bedside clinical teaching, correlated as far as possible with the lecture course. Visits to the day hospital and local authority homes are included and a class examination is held.

Intracranial tumours in the elderly: diagnosis and treatment.

A series of 111 intracranial tumours in elderly patients, investigated by modern methods, is reviewed. The clinical picture of progressive neurological deficit, and/or intellectual impairment, did not differ greatly from that of younger patients, but the manifestations of raised intracranial pressure (headache and papilloedema) were much less common in the elderly. Intermittency of symptoms appeared to be a relatively common phenomenon with meningiomas, occurring in four of 12 symptomatic cases. Operative treatment, for removal of meningiomas or relief of obstructive hydrocephalus, produced improvement in almost all cases, with a low morbidity and mortality. High-dose steroid therapy produced substantial, if temporary, benefit in 51% of hemisphere tumours.

The response of the apparent receptive speech disorder of Parkinson's disease to speech therapy.

Eleven patients with Parkinson's disease were tested for prosodic abnormality, on three tests of speech production (of angry, questioning, and neutral statement forms), and four tests of appreciation of the prosodic features of speech and facial expression. The tests were repeated after a control period of two weeks without speech therapy and were not substantially different. After two weeks of intensive domiciliary prosodic therapy, the prosodic abnormality score was improved, as were three of the four tests of recognition of the prosodic features of speech and facial expression, and two of the three tests of production (of angry and questioning forms). The apparent receptive disorder of speech in Parkinson's disease can thus respond to therapy. Possible mechanisms of improvement are briefly discussed.

Speech therapy for Parkinson's disease.

Twenty-six patients with the speech disorder of Parkinson's disease received daily speech therapy (prosodic exercises) at home for 2 to 3 weeks. There were significant improvements in speech as assessed by scores for prosodic abnormality and intelligibility' and these were maintained in part for up to 3 months. The degree of improvement was clinically and psychologically important, and relatives commented on the social benefits. The use of a visual reinforcement device produced limited benefit over and above that from prosodic exercises alone, except to patients with severe speech disorder.

Accuracy of the impedance cardiogram in the measurement of cardiac output in the elderly.

The cardiac output has been determined by radionuclide angiocardiography and by impedance cardiography in 93 elderly patients. The agreement between the two methods was excellent in patients in sinus rhythm, without regurgitant valvular lesions, and without severe airways obstruction or right bundle branch block. In atrial fibrillation the lack of correlation may be due to differences in heart rate during the two measurements, in regurgitant valvular lesions to the fact that impedance cardiography measures stroke output, whether forward or backward, in airways obstruction to high values for the basal thoracic impedance, and in right bundle branch block perhaps to the abnormal impedance wave-form often present.

Collaboration between geriatricians and general surgeons.

The operation over ten years of a simple and practical method of collaboration between general surgeons and geriatricians is described. This was designed, by means of a weekly ward round by geriatricians and consultant surgeons on general surgical wards (120 beds), to give geriatric medical advice and, when appropriate, to arrange transfer for geriatric assessment, medical treatment and rehabilitation, long-term care, or terminal care. Some 240 such transfers are described, comprising approximately 2% of all patients over the age of 65 admitted to the surgical units. The commonest single surgical diagnosis was of malignant disease. A total of 43% had had no operation and 18% had no medical diagnosis. 64% of those transferred for assessment etc. went home, half of them within two weeks, but nearly a third of them after more than four weeks. The system was effective, and benefited both surgeons and geriatricians, at no cost to the former and little to the latter in terms of time or increase in work load.

Steady-state kinetics of digoxin in the elderly.

Renal clearance of digoxin and creatinine was determined simultaneously on 30 occasions in 28 elderly in-patients on maintenance digoxin therapy. The mean ratio of digoxin to creatinine clearance was 1.04 (+/- S.E.M. 0.08). Multiple 24-hour urinary excretions of digoxin were measured in 10 patients on digoxin on a dose of 0.25 mg/day, four on 0.125 mg/day, and six on 0.0625 mg/day. Mean urinary excretion was 42% of dose per day. Calculated "net biliary clearance" averaged 18 ml/min. Knowledge of the magnitude of renal and net biliary clearance, together with assumed values for fractional absorption allows a relationship between serum digoxin levels and creatinine clearance to be calculated for each dose level. There was reasonable agreement between observed and expected serum digoxin levels in 41 elderly patients in whom creatinine clearance was measured, and in 106 in whom glomerular filtration rate was estimated from serum urea and creatinine concentrations. Quantitation of the kinetics of digoxin in the elderly can make maintenance therapy more rational and therefore safer and more effectove.