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Biomedical subjects

D J Ewing

Publications and source records attributed to D J Ewing.

At least 109 records · Page 6Linked to original sources

Gastric emptying in diabetic autonomic neuropathy.

Gastric emptying was studied in 12 diabetic patients, six with and six without objective evidence of autonomic neuropathy and in 20 non-diabetic controls, using a double isotope scinti-scanning technique which differentiated between solid and liquid emptying. Three patients with autonomic neuropathy exhibited gastric stasis, although this was detected by conventional radiology in only one. Neither the patients with stasis nor those without exhibited abnormally rapid early gastric emptying. In patients without stasis, the normal differentiation between solid and liquid emptying was impaired, suggesting an abnormality of antral peristalsis not attributable to vagal denervation. Both intravenous and oral metoclopramide produced symptomatic improvement in two patients with gastric stasis and restored their gastric emptying to normal.

Adult↗

Peripheral and autonomic nerve function in newly diagnosed diabetes mellitus.

Peripheral and autonomic nerve function was assessed in 10 newly diagnosed male diabetics (six insulin-treated and four sulfonylurea-treated) with repeated observations over the subsequent six months. There was significant impairment of motor-conduction velocity in the common peroneal nerve at diagnosis in both treatment groups, with improvement following treatment in only the insulin-treated patients. In contrast, although the blood glucose level fell in both groups, the mean level was significantly lower in the sulfonylurea-treated patients at two months and at each subsequent visit. In the autonomic function tests significant abnormality was found in the electrocardiographic R-R-interval (beat-to-beat) variation in resting heart rate in two of the insulin-treated patients and all of the sulfonylurea-treated group, with improvement in only one of the latter. One patient in the sulfonylurea-treated group also showed an abnormal response to the Valsalva maneuver (expressed as the Valsalva ratio), and this remained abnormal throughout the period of study. All other patients had normal responses to the Valsalva maneuver and sustained handgrip test. None of the patients had postural hypotension. Abnormalities in autonomic nerve function in diabetics at diagnosis have not been previously reported.

Adolescent↗

Plasma renin activity in diabetic autonomic neuropathy.

Postural changes in plasma renin activity were studied in three groups of age and duration-matched male diabetics (potent, impotent and with postural hypotension) and in non-diabetic control subjects. Those diabetic subjects with postural hypotension due to automatic neuropathy had no increase in plasma renin activity to the erect posture whereas both the potent and impotent groups had similar plasma renin activity responses to the control subjects. There was a significant inverse correlation between the rise in plasma renin activity on standing and the postural drop in blood pressure (r = 0.476, P less than 0.01) but no correlation with other tests of autonomic reflex function such as the Valsalva manoeuvre and blood pressure response to sustained handgrip. The results suggested that the lesion responsible for the postural hypotension is in the efferent sympathetic pathway. However, neuropathy per se did not wholly explain the decreased postural plasma renin activity response. Diabetic nephropathy, with involvement of cells of juxtaglomerular apparatus, may also be implicated.

Adult↗

Peripheral and autonomic nerve function in diabetic ketoacidosis.

Peripheral and autonomic nerve function was assessed at intervals over a 3-month period in seven diabetics after ketoacidosis. There was marked improvement in motor conduction velocity and terminal latency of both ulnar and common peroneal nerves in all patients. Five had one or more abnormal autonomic function tests but there were no consistent changes during the same period. It is postulated that peripheral nerves may be more susceptible to acute metabolic damage than autonomic fibres.

Adolescent↗

Therapeutic experience with fludrocortisone in diabetic postural hypotension.

Fourteen patients with diabetic postural hypotension were treated with fludrocortisone for a mean 12 months (range 6-30 months). The mean daily dose of fludrocortisone was 0.2 mg (range 0.1 mg-0.4 mg). Standing systolic and diastolic blood pressures increased significantly (P less than 0.001) after treatment with fludrocortisone and the postural hypotension decreased significantly (P less than 0.001). Thirteen patients noted considerable symptomatic improvement. Fludrocortisone should be used cautiously in patients with congestive cardiac failure or the nephrotic syndrome.

Adult↗

Mortality in diabetic autonomic neuropathy.

Thirty-seven diabetics with symptoms and clinical features suggestive of autonomic neuropathy were followed up for 33 months. Of the twenty with abnormal Valsalva or handgrip tests initially, ten (50%) died. There were no other features at presentation that differentiated those who subsequently died from those who survived. The causes of death were renal failure (six patients), cerebrovascular accident (two patients), hypoglycaemic coma (one patient), and "sudden death" (one patient). Of the survivors whose autonomic-function tests were repeated 18 months to 2 years later, five had new or worsening symptoms of autonomic neuropathy with corresponding deterioration of their autonomic-function tests; while two, with initially normal tests, had improved symptomatically. It is concluded that in diabetics with the clinical features of autonomic neuropathy simple autonomic-function tests give a good guide to prognosis, and that abnormal tests are associated with a high mortality.

Adult↗

Interaction between cardiovascular responses to sustained handgrip and Valsalva manoeuvre.

Interactions between the cardiovascular responses to the Valsalva manoeuvre and sustained handgrip were analysed in 5 men with untreated mild hypertension and 4 young normal subjects. Though set at a higher level, there was a normal blood pressure response to the Valsalva manoeuvre during concurrent sustained handgrip in 4 of the 5 hypertensive subjects. At the end of the handgrip period in which the Valsalva manoeuvres were performed, the blood pressure was higher and the heart rate lower than in the control period of sustained handgrip. The fifth subject developed a 'square wave' Valsalva response, which returned to a normal response when sustained handgrip was discontinued. Analysis of RR interval changes in the normal subjects showed that both the tachycardia during, and the bradycardia after, the Valsalva strain period were significantly reduced during simultaneous sustained handgrip. These results show that the two reflexes interact, but only to a minor extent, and that the baroreflex response is modified by sustained handgrip, rather than overridden as had previously been suggested. In view of the effect on the blood pressure and heart rate, subjects should avoid performing a Valsalva manoeuvre during sustained handgrip testing.

Adult↗

Peripheral motor nerve function in diabetic autonomic neuropathy.

Motor conduction velocity was measured in the median, ulnar and common peroneal nerves of 32 diabetics with clinical features of autonomic neuropathy. The responses to the Valsalva manoeuvre and sustained handgrip, and the postural fall in blood pressure were used to assess the integrity of the autonomic nervous system. Abnormalities in the three autonomic function tests were significantly correlated with the forearm conduction velocity of the ulnar nerve, the conduction velocity and motor latency of the common peroneal nerve, and the H reflex. These results show that, in diabetics with autonomic neuropathy, abnormalities in the autonomic nervous system parallel changes in the peripheral nerves. Any diabetic with peripheral neuropathy should be examined for evidence of autonomic nervous system involvement.

Adult↗

A double-blind trial of patient-controlled nitrous-oxide/oxygen analgesia in myocardial infarction.

The analgesic effect of self-administered nitrous oxide 50%/oxygen 50% ('Entonox" analgesic apparatus) was compared with air given by the same method in a double-blind trial in 81 patients with myocardial infarction. Self-administered nitrous oxide/oxygen, which was associated with a low frequency of side-effects, proved significantly more effective than air in the early relief of severe cardiac pain, but not in the relief of moderate or slight pain or when administration was continued after ten minutes.

Adult↗

Weight carrying after myocardial infarction.

The blood-pressure responses to carrying a 15 kg. weight in a shoppong basket, and in a rucksack on the back, were compared in 13 ambulant male patients who were convalescing from an uncomplicated myocardial infarction. In 8 of the patients a sustained-handgrip test was also performed. Carrying the weight in the hand produced a distinct increase in blood-pressure, which did not occur when the weight was carried on the back. There was also a significant increase in blood-pressure during sustained handgrip. In view of the lack of symptoms with these circulatory changes, it is concluded that more specific advice about the possible dangers of sustained static exercise should be given to patients recovering from myocardial infarction.

Activities of Daily Living↗

RR interval variations in young male diabetics.

The beat-to-beat (RR interval) variation in resting heart rate was used to detect possible autonomic nerve damage in a group of 42 young asymptomatic male diabetics, employing a sensitive electrocardiographic computer technique. Compared with 25 age-matched controls, the diabetics showed both a significantly smaller mean RR interval (P less than 0.005) and less RR interval variation (P less than 0.001). Whereas only 4 of the diabetic subjects had shorter mean RR intervals, 22 (52%) of the diabetics had RR interval variations that were less than any of the normal subjects. This reduction in heart rate variation has not been previously reported in diabetics without clinical features of autonomic neuropathy and might provide a sensitive method of assessing early autonomic nerve involvement in diabetes.

Adult↗

Autonomic function in patients with chronic renal failure on intermittent haemodialysis.

The cardiovascular responses to the Valsalva manoeuvre and sustained handgrip were measured in 26 patients with chronic renal failure treated with intermittent haemodialysis. Twelve (50%) had an abnormal Valsalva response and ten (45%) had an abnormal handgrip response. There was a reduction in the beat-to-beat variation of heart rate at rest in those patients who had abnormal Valsalva manoeuvres, independent of age or the resting heart rate. It is concluded that autonomic nerve fibres may be damaged in patients with chronic renal failure on intermittent haemodialysis in the absence of symptoms of autonomic neuropathy. These studies suggest three simple ways of testing autonomic function in haemodialysis patients which could routinely be performed to detect patients at risk of developing an abnormal reaction to volume depletion during haemodialysis.

Adult↗

9-Alpha-fluorohydrocortisone in the treatment of postural hypotension in diabetic autonomic neuropathy.

A double-blind crossover study of fludrocortisone, 0,1 mg. twice daily, and placebo is reported in six diabetics with troublesome symptoms of postural hypotension due to autonomic neuropathy. During treatment with the active preparation there was an increase in the lying and tilted systolic blood pressure, a decrease in orthostatic tachycardia, and in increase in the total plasma volume and body weight, but with no change in plasma or urine osmolality; The symptoms of postural hypotension improved in four patients, while two patients with a low serum albumin developed ankle edema during treatment with fludrocortisone. It is concluded that fludrocortisone is effective in diabetics with symptomatic postural hypotesnion, but should be used with caution in patients with a low serum albumin.

Adult↗

Testicular pain sensation in diabetic autonomic neuropathy.

Testicular sensation was examined in 32 male diabetics with symptoms suggestive of autonomic neuropathy to evaluate its usefulness as a clinical sign in this condition. Vascular reflex responses to the Valsalva manoeuvre and sustained handgrip and blood pressure fall on standing were measured as objective tests of autonomic involvement. Absent or diminished testicular sensation correlated well both with the clinical features of autonomic neuropathy, except where impotence occurred alone, and with abnormal vascular reflexes. Most patients with impotence alone had normal testicular sensation and normal vascular reflexes. It is concluded that this sign is useful in diabetics with impotence, the presence of intact testicular sensation indicating that the impotence is unlikely to be due to autonomic neuropathy.

Achilles Tendon↗